Чинганджинская флора Охотско-Чукотского вулканогенного пояса Текст научной статьи по специальности «Биологические науки»

Палеоботаника, 2019, Т. 10, С. 13-179 Palaeobotany, 2019, Vol. 10, P. 13-179

THE CHINGANDZHA FLORA OF THE OKHOTSK-CHUKOTKA VOLCANIC BELT

L. B. Golovneva

Komarov Botanical Institute RAS, St. Petersburg, [email protected]

ЧИНГАНДЖИНСКАЯ ФЛОРА ОХОТСКОЧУКОТСКОГО ВУЛКАНОГЕННОГО ПОЯСА

Л. Б. Головнева

Ботанический институт им. В. Л. Комарова РАН, Санкт-Петербург, [email protected]

Резюме. Чинганджинская флора происходит из вулканогенно-осадочных отложений чинганджинской свиты (Охотско-Чукотский вулканогенный пояс, Северо-Восток России). Основные местонахождения находятся на территории Омсукчанского района Магаданской области: на р. Тап (бассейн среднего течения р. Вилига), на р. Кананыга, около устья ручья Ронд и в среднем течении р. Чинганджа (бассейн р. Туманы).

Чинганджинская флора включает 23 рода и 33 вида. Описано два новых вида (Taxodium vili-gense Golovn. и Cupressinocladus shelikhovii Golovn.) и создано две новые номенклатурные комбинации (Arctopteris ochotica (Samyl.) Golovn. и Dalembia kryshtofovichii (Samyl.) Golovn.). Чинганджинская флора состоит из печеночников, хвощей, папоротников, семенных папоротников, гинкговых, хвойных и цветковых. В ней преобладают роды Arctopteris, Os-munda, Coniopteris, Cladophlebis, Ginkgo, Sagenoptepis, Sequoia, Taxodium, Metasequoia, Cupressinocladus, Pro-tophyllocladus, Pseudoprotophyllum, Trochodendroides, Dalembia, Menispermites, Araliaephyllum, Quereuxia. От других флор Охотско-Чукотского вулканогенного пояса (ОЧВП) чинганджинская флора отличается доминированием цветковых растений и отсутствием реликтовых элементов, таких как Podozamites, Phoe-nicopsis, цикадофиты.

По систематическому составу и палеоэкологическим особенностям чинганджинская флора близка коньякским флорам Северо-Востока России: кайва-ямской и тыльпэгыргынайской, которые в позднем мелу были распространены на приморских низменностях, располагавшихся к востоку от горной гряды ОЧВП. Поэтому возраст чинганджинской флоры определяется как коньякский. Она отнесена к кай-ваямскому этапу эволюции флоры Анадырской провинции Сибирско-Канадской палеофлористической области. Чинганджинская флора развивалась одновременно с аликской флорой из междуречья Вилига-Туманы и другими коньякскими флорами ОЧВП: ча-унской флорой Центральной Чукотки, хольчанской флорой Магаданской области и ульинской флорой из Ульинской впадины.

Ключевые слова: палеофлоры, поздний мел, Северо-Восток России.

Abstract. The Chingandzha flora comes from the volcanic-sedimentary deposits of the Chingandzha Formation (the Okhotsk-Chukotka volcanic belt, NorthEast of Russia). The main localities of the Chingan-dzha flora are situated in the Omsukchan district of the Magadan Region: on the Tap River (basin of the middle course of the Viliga River), on the Kananyga River, near the mouth of the Rond Creek, and in the middle reaches of the Chingandzha River (basin of the Tumany River).

The Chingandzha flora includes 23 genera and 33 species. Two new species (Taxodium viligense Golovn. and Cupressinocladus shelikhovii Golovn.) are described, and two new combinations (Arctopteris ochotica (Samyl.) Golovn. and Dalembia kryshtofovichii (Samyl.) Golovn.) are created. The Chingandzha flora consists of liverworts, horsetails, ferns, seed ferns, ginkgoaleans, conifers, and angiosperms. The main genera are Arctopteris, Osmunda, Coniopteris, Cladophlebis, Ginkgo, Sagenoptepis, Sequoia, Taxodium, Metasequoia, Cupressinocladus, Protophyllocladus, Pseudoprotophyllum, Trocho-dendroides, Dalembia, Menispermites, Araliaephyllum, Quereuxia. The Chingandzha flora is distinct from other floras of the Okhotsk-Chukotka volcanic belt (OCVB) in predominance of flowering plants and in absence of the Early Cretaceous relicts such as Podozamites, Phoen-icopsis and cycadophytes.

According to its systematic composition and pa-laeoecological features, the Chingandzha flora is similar to the Coniacian Kaivayam and Tylpegyrgynay floras of the North-East of Russia, which were distributed at coastal lowlands east of the mountain ridges of the OCVB. Therefore, the age of the Chingandzha flora is determined as the Coniacian. This flora is assigned to the Kaivayam phase of the flora evolution and to the Anadyr Province of the Siberian-Canadian floristic realm. The Chingandzha flora is correlated with the Coniacian Aleeky flora from the Viliga-Tumany interfluve area and with other Coniacian floras of the OCVB: the Chaun flora of the Central Chukotka, the Kholchan flora of the Magadan Region and the Ul'ya flora of the Ul'ya Depression.

Keywords: paleofloras, Late Cretaceous, North-East of Russia.

https://doi.org/10.31111/palaeobotany/2019.10.13 Received 6.11.2019; accepted for publication 5.12.2019.

INTRODUCTION

The Okhotsk-Chukotka volcanic belt (OCVB) was formed in the Cretaceous period in a result of intensive volcanic activity related to continental margin subduction. It extends for more than 3200 km along the Sea of Okhotsk and the Bering Sea coasts from the Uda River in the Khabarovsk Region to the Chu-kotka Peninsula (Belyi, 1977). It is composed mainly of nonmarine volcanic rocks (basalts, andesites, rhyo-lites, and ignimbrites) and pyroclastic interlayers, containing numerous localities of fossil plants, reflecting mountain vegetation.

In the territory of the OCVB, rich deposits of tin, coal, and polymetallic ores were discovered. Since there is no marine sediments in the belt, age determination and spatial relationships of volcanic rocks were based many years on paleobotanical data (Samylina, 1974, 1976, 1988; Belyi, 1977; Lebedev, 1987; Philip-pova, Abramova, 1993). Therefore, during geological research, numerous collections of fossil plants were gathered. As a result, the Ola, Chaun, Amka, Chingandzha, Arman, Leurvaam and Ust'-Emuneret floras were revealed, as well as a number of less representative floristic assemblages.

However, the Cretaceous floras of the OCVB significantly differ from the contemporaneous floras of adjacent coastal lowlands, dated by relation to marine deposits. The OCVB floras developed in montane environments and are marked by high endemism, predominance of ferns and conifers, a minor share of an-giosperms, and considerable numbers of the Early Cretaceous relicts in all plant groups (Philippova, Abramova, 1993; Shczepetov, Golovneva, 2010; Herman, 2013; Golovneva, 2018).

The Chingandzha flora is one of the most important for stratigraphy of the OCVB, because it has a significant resemblance to the lowland floras, located along the eastern margin of the volcanic belt. It comes from the Upper Cretaceous volcanic-sedimentary deposits of the Chingandzha Formation, distributed in the territory of the Northern coast of the Sea of Okhotsk (Fig. 1), in the Viliga-Tumany interfluve area (the Omsukchan district of the Magadan Region). The plant fossils were first discovered by geologist D. S. Kharkevich in 1943 on the Chingandzha River. A little later, in 1945, similar plant fossils were found by A. M. Demin on the Kananyga River, and also by S. I. Filatov in 1959 on the Tap River. The first information about the systematic composition and age of the Chingandzha flora was published by V. A. Samylina (1976). She used for it the name "Tap flora" after the Tap River. Samylina dated the Tap flora as the Turoni-an based on the similarity of its systematic composition with the Turonian-Coniacian floras of the Penzhina Bay. She considered the Tap flora as the youngest in comparison with other OCVB floras (Samylina, 1976). However, geological data indicated that the plant-bearing deposits are located at the base of the volcanic section, lying on the marine Jurassic sediments.

Another problem is related to the systematic composition of the Chingandzha flora. Other floras of the belt are characterized by an abundance of relict elements, an extremely insignificant share of flowering plants, while in the Chingandzha flora there are no relict elements, and angiosperms predominate. Similar in systematic composition floras were not found anywhere else in the OCVB territory. In particular, the Chingandzha flora is significantly different from the Arman and Zarya floras, which come from the similar stratigraphic level.

The contradictions between the age and the stratigraphic position of the Chingandzha flora forced to undertake additional investigations, which were carried out by the geologists of the North-East Interdisciplinary Scientific Research Institute (Magadan) V. F. Belyi, S. V. Shczepetov and V. V. Akinin in 19821985. All fossiliferous sections of this region were studied in detail and their stratigraphic relationships with underlying and overlying deposits were clarified. In addition, numerous localities of plant fossils were discovered in overlying volcanic deposits (Shczepetov, 1988, 1991a , 1995). The name "Chingandzha flora" was proposed by Shczepetov (1988) for fossil plants of the Chingandzha Formation from the several sites on the rivers Tap, Kananyga and Chingandzha. The collections, gathered during these stratigraphic investigations, were partly studied by Samylina, who provided general information about the flora composition and described several new species (Samylina, 1984a, b, 1989). Unfortunately, a significant part of taxa remained undescribed and not illustrated.

The importance of the Chingandzha flora for understanding the history of the OCVB led us to undertake new paleofloristic, stratigraphic, and paleoecological studies. The plane trees of the Chingandzha flora (Shczepetov, Golovneva, 2009) were re-studied and some other taxa were revised (Golovneva et al., 2011; Yudova, Golovneva, 2014, 2015; Yudova et al., 2016). For comparative purposes, the Aleeky flora from overlying volcanic rocks and also the Arman and Zarya floras from the base of the OCVB section were described (Shczepetov, Golovneva, 2010, 2014; Herman et al., 2016).

The main purpose of this paper is to reassess the taxonomic composition of the Chingandzha flora and to clarify its age. The second aim is to define relationships between the Late Cretaceous floras of this

Fig 1. A - distribution area of the Chingandzha flora (2) at the territory of the Okhotsk-Chukotka volcanic belt (1). B - localities of the Chingandzha flora (3) in the Viliga-Tumany interfluve.

region and to evaluate their contribution to an understanding of the Late Cretaceous phytogeography and florogenesis.

The present study was carried out within the framework of the Federal institutional research program of the Komarov Botanical Institute RAS. The fieldwork of 2010 was supported by the Russian Foundation for Basic Research (project no. 11-04-10125-k). We are sincerely grateful to S. V. Shczepetov and P. I. Alek-seev for their assistance in the fieldworks and useful discussions and to all other people, who helped us during preparation of manuscript.

CHAPTER1 STRATIGRAPHY

The Okhotsk-Chukotka volcanic belt is a linear object extended from southeast to northwest for more than 3200 km. Its geological structure varies in different parts. According to V. F. Belyi (1977), the belt is subdivided into the main part and the East Chukotka and the West Okhotsk flank zones. The main part is divided into the Central Chukotka, Anadyr, Penzhina and Okhotsk sectors (Fig. 1.1). The distribution area of the Chingandzha flora belongs to the Okhotsk sector of the OCVB. In this region the deposits of the Okhotsk-Chukotka volcanogenic belt overlie the Early Cretaceous volcano-sedimentary rock or highly dislocated Jurassic and Triassic deposits of the Verkhoyansk complex.

In the north, in the interfluve of the Balygychan and Sugoi rivers (tributaries of the Kolyma River), the Balygychan-Sugoi Trough is located, filled with the Lower Cretaceous deposits (Fig. 1.2). It is submeridio-nally oriented strip of about 250 km in length. The thickness of the nonmarine terrigenous coal-bearing or volcanogenic sediments varies from 400 m in the northern part of the trough to 4500 m in the southern part.

The basal part of the section is represented by volcanogenic rocks of the Askol'd Formation and Ary-lakh Unit and by terrigenous rocks of the Uliki Formation. These strata are overlain by the terrigenous coal-bearing Galimyi and Aigur formations and by the Toptan Formation, which does not contain coal (Table 1). All these stratigraphic units contain the plant fossils.

Table 1

Stratigraphy of the Cretaceous deposits in the Omsukchan area (after Shczepetov, Golovneva, 2014, with changes)

„ , , „ . _ , Upper reaches of the Tap, Kananyga and Stage Balygychan-Sugoi Trough , , . Kananyga River Chingandzha rivers

Campanian Santonian Dzhagyn Unit Geramryn Unit Shorokh Fm

Coniacian Kakhovka Fm Kananyga Fm Kananyga Fm Yum Fm Yum Fm Gydra Fm Rond Fm Chingandzha Fm

Turonian upper Zarya Fm Parnyi Fm

lower

Cenomanian

Albian upper

middle Toptan Fm lower Aigur Fm Galimyi Fm

Aptian Askol'd Fm Arylakh Unit Uliki Fm

The age of plant assemblages from the Askol'd and Uliki formations and also from the Arylakh Unit was determined as the Aptian (Samylina, 1976, 1988; Shczepetov, 1988). These assemblages were attributed to

Fig. 1.1. The territory of the Okhotsk-Chukotka volcanic belt (1) and boundaries between sectors (2).

the Silyap stage of the flora development (Samylina, 1974, 1976, 1988). The taphofloras from the Galimyi and Aigur formations Samylina dated as early Albian and attributed to the Buor-Kemyus stage. Plant assemblage from the Toptan Formation was considered by Samylina (1976, 1988) as the independent Toptan stage and dated as middle Albian.

The analysis of the plant fossils distribution in the deposits of the Aigur and Toptan formations showed that the main part of the species, that were included by Samylina (1976) in the Toptan flora, comes actually from the Aigur Formation (Golovneva et al., 2017). Plant assemblages of the Aigur and Toptan formations are very similar in systematic composition. Increasing of the angiosperms diversity and reduction of typical Cretaceous taxa (cycadophytes and ginkgoaleans) were not observed on the boundary between these strata. Thus, there is no evidence of existence of the independent Toptan stage in the evolution of the mid-Cretaceous flora of the North-East of Russia. Floristic assemblages from the Galimyi, Aigur and Toptan formations were proposed to combine into a single Sugoi flora, which should be attributed to the early-middle Albian Buor-Kemyus stage of floral development (Golovneva et al., 2017).

The Toptan Formation is unconformably overlain by the Zarya Formation. These volcano-sedimentary deposits are considered as the result of the Okhotsk-Chukotka volcanic belt activity. The Zarya Formation is exposed in the upper reaches of the Nevsky, Zarya, and Left Omchikchan streams. Samylina (1976, 1988) correlated the Zarya flora with the Arman flora from the Arman Formation of the Magadan Region, which she dated as late Albian. Later, the Zarya Formation was determined as being the Turonian-Coniacian in age on the basis of its stratigraphic relation to the Chingandzha Formation (Golovneva et al., 2011; Shczepetov, Golovneva, 2014).

The Kakhovka Formation conformably overlies the Zarya Formation. Its composition is dominated by two-pyroxene andesites lavas. Higher in the section, the Kakhovka Formation is overlain also without apparent unconformity by the Shorokh Formation, composed of ignimbrites, felsic lavas and tuffs (Shczepetov, 1995). These rocks yield sparse Upper Cretaceous plant fossils. The section is crowned by the Dzhagyn Unit, composed of olivine basalts.

In the south, in the Viliga-Tumany interfluve, the Lower Cretaceous terrigenous deposits are absent, and the rocks of the Okhotsk-Chukotka volcanic belt lies immediately on the marine Jurassic and Triassic deposits.

Fig. 1.2. Localities of the Cretaceous floras in the Omsukchan area: 1 - Aleeky flora; 2 - Chingandzha flora; 3 - Parnyi floristic assemblage; 4 - Zarya floristic assemblage; 5 - the Early Cretaceous floras of the Balygychan-Sugoi Trough.

The volcanic succession of the OCVB is divided into the Chingandzha, Rond, Yum, Kananyga formations and the Geramryn Unit in this area (Table 1). The Chingandzha Formation is exposed in several small isolated areas in the basins of the Kananyga, Viliga and Tumany rivers (Fig. 1.2).

The Chingandzha Formation consists of conglomerates, sandstones, gravelites, tuff sandstones, tuff silt-stones, siltstones and tuffs of medium composition. Initially, these plant-bearing deposits were described by A. D. Silinsky under the name of the Chinandzha Unit. After additional stratigraphic and petrographic studies, the Chinandzha Unit was transferred to the Chingandzha Formation (Shczepetov, 1988) and its name was slightly changed in accordance with the original name of the Chingandzha River. The stratotype of the Chingandzha Formation is located in the middle reaches of the Kananyga River, on the watershed of the Kananyga River and the Gorbatyi Creek. It includes lower and upper parts of the Chingandzha Formation. A detailed description of the section is given in Shczepetov (1988, 1995).

1. Small and large pebble tuff conglomerates with thin intercalations of volcanomict sandstones,

dark gray and black siltstones.....................................................................................................................35-40 m

2. Greenish gray and dark gray siltstones............................................................................................................. 40 m

3. Variegated small pebble conglomerates and volcanomictic gravelites ..................................................... 25 m

4. Greenish gray medium-grained volcanomictic sandstones with interlayers of variegated

small pebble tuff conglomerates, dark gray tuffs and andesite clastic lavas ............................................ 50 m

5. Dark gray andesite clastic lavas ........................................................................................................................20 m

6. Gray fine-grained volcanomictic sandstones with interlayers of gravelites....................................45-50 m

7. Dark gray and greenish gray medium-grained volcanomictic sandstones.......................................25-30 m

8. Variegated tuff conglomerates and gravelites with thin interlayers of gray volcanomictic sandstones...............................................................................................................................................................25 m

9. Gray coarse-grained volcanomictic sandstones......................................................................................45-50 m

10. Gray siltstones and black mudstones, yielding plant fossils...................................................................7-10 m

11. Dark gray andesites and andesite clastic lavas..............................................................................................20 m

12. Gray medium- and coarse-grained volcanomictic sandstones with interlayers of dark gray siltstones, yielding plant fossils .......................................................................................................................... 40 m

13. Variegated small pebble tuff conglomerates with intercalations of greenish gray andesite tuffs

and dark gray siltstones .................................................................................................................................35-40 m

Total thickness of the section is 440 m.

The upper part of the Chingandzha Formation is exposed on the left bank of the Kanayga River. This section is described in the next chapter (description of the Kananyga plant fossils locality).

The Chingandzha Formation is overlain conformably by the Rond Formation, which is composed of tuffs and lavas of medium and medium-felsic composition. The upper boundary of the Chingandzha Formation is defined by disappearance of sedimentary and volcano-sedimentary rocks from the section (Shczepe-tov, 1988, 1995). The total thickness of the formation is 500-600 m.

In the stratotype section of the Chingandzha Formation, the remains of fossil plants are fragmentary and rare. The preliminary list of species, made by A. F. Efimova, was published in Shczepetov (1988). The better localities were found on the Tap River, on the Kananyga River, near the mouth of the Rond Creek, and in the middle reaches of the Chingandzha River (Fig. 1.2).

The Rond Formation is overlain by the Yum Formation (rhyolite lavas and tuffs), the Kananyga Formation (basalts, andesites and their tuffs) and Geramryn Unit (felsic ignimbrites). The deposits of the Yum and Kananyga formations yield plant fossils, which were united in the Aleeky flora (Shczepetov, Golovneva, 2010). Its age is estimated as the Coniacian.

In the upper reaches of the Kananyga River the succession of the volcanogenic sediments of the OCVB is somewhat different. The section begins with the Parnyi Formation, which consists of volca-nomictic and polymictic conglomerates, gravelites, sandstones, siltstones and tuffs of medium and moderate acid composition. The total thickness of the Parnyi Formation is 700 m. Plant fossils from this formation are united in the Parnyi floristic assemblage, which is dated as the Turonian-Coniacian (Shczepetov, Golovneva, 2014).

The Parnyi Formation is overlain by the Gydra Formation, which is composed of tuffs and lavas of medium and medim-felsic composition with interlayers of volcano-sedimentary rocks. Its thickness is 400600 m. This formation yields plant fossils of the Aleeky flora (Shczepetov, Golovneva, 2010). Above in the section, there are the Yum and Kananyga formations, as well as in the middle reaches of the Kananyga River.

CHAPTER 2 LOCALITIES

The main localities of the Chingandzha flora are situated on the Tap River (basin of the middle course of the Viliga River), on the Kananyga River, near the mouth of the Rond Creek, and in the middle reaches of the Chingandzha River (basin of the Tumany River).

Among them, the locality on the Kananyga River is the most productive (Fig. 1; Fig. 2.1). This is a cliff over 300 m long on the left bank of the river, slightly upstream than the mouth of the Rond Creek and opposite the stratotype section of the Chingandzha Formation. In this outcrop the upper part of the Chin-gandzha Formation is exposed and overlapped conformably by the volcanic rocks of the Rond Formation. A detailed description of this locality is given in Shczepetov (1988).

to o

NNW-

-> SSE

WWN-

■>EES

300 m

Kananyga River

t? 5? V ,1 I / \ E

P P f 2 6 4 |/ 15 b X X X x

Fig. 2.1. Outcrop of the Chingandzha Formation in the riverine cliffs of the Kananyga River (after Golovneva et al., 2011): 1 - modern vegetation; 2 - scree; 3 - intercalation of sandstones, tuff sandstones, tuffs and siltstones; 4 - layers of sandstones and conglomerates; 5 - faults; 6 - plant fossils sites; 7 - andesite intrusion.

Fig. 2.2. Outcrop of the Chingandzha Formation in the riverine cliffs of the Chingandzha River (after Golovneva et al., 2011): 1 - modern vegetation; 2 - scree; 3 - modern allivium; 4 - intercalation of sandstones, tuffs and conglomerates; 5 - frequent interbedding of tuffs, tuff sandstones and siltstones; 6 - plant fossils sites.

1. Dark gray fine-grained sandstones...................................................................................................................0,7 m

2. Grey tuffs of medium composition.......................................................................................................................1 m

3. Black silstones and mudstones with abundant plant debris..........................................................................2 m

4. Scree....................................................................................................................................................................1,5-2 m

5. Gray andesite psammite tuffs.......................................................................................................................2-2,5 m

6. Light gray andesite tuffs with interlayers of dark gray tuff sandstones and siltstones.....................5-6 m

7. Scree ............................................................................................................................................................................. 5 m

8. Thin intercalation of gray fine-grained tuff sandstones and siltstones.................................................3-5 m

9. Light gray fine- and medium-grained tuff sandstones.................................................................................1,5 m

10. Gray siltstones with interlayers dark gray and black mudstones..........................................................3-4 m

Andesite intrusion............................................................................................................................................................2 m

11. Black bedded siltstones.......................................................................................................................................1,5 m

12. Gray medium-grained volcanic sandstones with interlayers of dark gray siltstones...........................1,5 m

Total thickness of fossiliferous layers in this locality is 35-40 m. Plants fossils were collected in approximately 30 different sites (Fig. 2.1). Usually they are scattered and quite rare, but there are also interlayers overflowing with leaf impressions (leaf mats).

The locality of the Chingandzha River is situated 10 km south from the locality on the Kananyga River (Fig. 1). This is a long cliff on the left bank of the river, in which the upper part of the Chingandzha Formation is exposed (Fig. 2.2). The section was divided into two units (Shczepetov, 1991a).

2 km

V V V v V

x X x x x

1 2

3

4

5

6

7

8

Fig. 2.3. Schematic geological structure of the left bank of the Tap River (after Golovneva et al., 2011): 1 - Quaternary deposits; 2 - Yum Formation; 3 - Rond Formation; 4 - Chingandzha Formation; 5 -Jurassic deposits; 6 - intrusions; 7 - faults; 8 - plant fossils sites.

1. Frequent interbedding of gray and greenish gray fine- and medium-grained tuffs and tuff sandstones (thickness of layers 0,4-1,5 m) with dark gray and black siltstones and mudstones (thickness of layers from several mm to 10-15 cm)...............................................................................10-15 m

2. Interbedding of: a) gray and greenish gray coarse- and medium-grained volcanic sandstones;

b) gray and yellowish gray medium-grained tuff sandstones; c) gray tuffs of medium composition; d) variegated small pebble volcanic conglomerates. Thickness of layers increases up the section

from 0,5-1,5 m to 2 m....................................................................................................................................20-25 m

Total thickness of the section is 30-35 m. The Chingandzha Formation is conformably overlain by the volcanic rocks of the Rond Formation. The Chingandzha floristic assemblage is very similar in composition to the Kananyga floristic assemblage, but it is less diverse.

The locality of fossil plants on the Tap River was discovered by S. I. Filatov in 1959. Next gatherings were held in 1965 by Filatov together with V. A. Samylina. In 1982-84 this area was additionally studied by V. F. Belyi, S. V. Shczepetov and V. V. Akinin. The locality is situated on the left bank of the Tap River, about 10 km from its confluence with the Viliga River and 1 km above the mouth of the Pinya Creek (Fig. 2.3).

The section of the Chingandzha Formation begins with tuff conglomerates with interlayers of tuff sandstones (thickness 50-70 m) comprising abundant plant fossils (Fig. 2.4). The fossiliferous beds are overlapped by the horizon of andesite and dacite lavas of about 100 m in thickness. Volcano-sedimentary deposits, that overlap the lava horizon, are exposed on the watershed of the Niaz and Mercuri creeks. They are represented by volcanomictic conglomerates, sandstones and tuffs with a total thickness of about 45 m. In the middle part of this bed, the fossil plants were also found in the lens of tuff siltstones and mudstones

Ph fe

(Shczepetov, 1991a). Above there are lavas of medium composition with a thickness of about 60-70 m, which are overlain by rhyolite ignimbrites with a visible thickness of 120-140 m.

Initially, the plant-bearing deposits on the Tap River were attributed to the Tavatum Formation (Samylina, 1976). After fieldworks of Belyi, they were attributed to the Rond Formation (Shczepetov, 1988, 1991a). However, the plant-bearing layers from the Tap River practically do not differ from the volcano-sedimentary deposits of the Chingandzha Formation. Therefore, we believe that these deposits belong to the Chingandzha Formation. We attribute to the Rond Formation only lavas lying above the second volcano-sedimentary unit. It should be noted that the lower and upper lava horizons are almost identical in structure and composition, and the lower one exceeds the upper one in thickness. Thus, the boundary between the Chingandzha and Rond formations is somewhat supposi-tive in this section. In other sections of the Omsukchan area, the differences between the Rond (predominantly volcanic) and the Chingandzha (volcano-sedimentary) formations are more pronounced, although lava horizons up to 20 m thick are also present in the stratotype section of the Chingandzha Formation.

In addition to these three main localities, the remains of plants in the Chingandzha Formation were reported from the stratotype of the formation, as well as from the Ulchan Creek, which flows into the Sea of Okhotsk north of the Tumany River, and from the Elge River basin (Shczepetov, 1991a, 1995). But we have no collections from these sites.

CHAPTER 3 MATERIAL AND METHODS

The present paper is based on collections of plant fossils gathered during several field seasons in the period from 1965 to 2010. Materials collected by geologist D. S. Kharkevich in 1943 on the Chingandzha River and by A. M. Demin in 1945 on the Kananyga River during the first geological survey of the territory, were lost. All other collections are kept in the Komarov Botanical Institute of the Russian Academy of Sciences in St. Petersburg (prefix BIN).

First studied collections come from the locality on the Tap River. Paleobotanical material collected in 1959 by geologist S. I. Filatov (North-East Territorial Department) is included in collection BIN 524. Second collection from this locality (BIN 519) was gathered in 1965 by S. I. Filatov together with V. A. Samylina, paleobotanist of the Komarov Botanical Institute (Table 2).

Fieldworks of 1982-1985 were organized by V. F. Belyi, geologist from of the North-East Interdisciplinary Scientific Research Institute (Magadan), who was interested in the origin and age of the OCVB. S. V. Shczepe-

tov and V. V. Akinin participated in these works. In the result, the representative collections were gathered from two other localities on the Kananyga and Chingandzha rivers. In summer 2010, a field team from the Botanical Museum of the Komarov Botanical Institute led by L. B. Golovneva (accompanied by P. I. Alekseev and S. V. Shczepetov)collected additional materials from the same two localities.

Table 2

Collections of plant fossils from the Chingandzha Formation

Collection Locality Collectors Year

BIN 519 Tap River Filatov S. I., Samylina V. A. 1965

BIN 524 Tap River Filatov S. I. 1959

BIN 538 Kananyga River Belyi V. F, Akinin V. V., Shczepetov S. V. 1982

BIN 547 Chingandzha River Shczepetov S. V. 1984

BIN 1565 Kananyga and Chingandzha rivers Golovneva L. B., Shczepetov S. V., Alekseev P. I. 2010

The data about repositories of plant fossils, mentioned in the text, are summarized in the Table 3.

Table 3

Abbreviation Institute City

BIN Komarov Botanical Institute RAS St. Petersburg

NEISRI North-East Interdisciplinary Scientific Research Institute Magadan

TFI Territorial Fund of Geological Information on the Far East Federal Region Magadan

TSNIGR Museum F. N. Chernyshev Central scientific research geological survey museum St. Petersburg

On the Tap and Chingandzha rivers the plant remains are preserved as brown or black leaf impressions in fine-grained sandstones. On the Kananyga River leaves looks like silvery white impressions in dark gray siltstones. They yield no structurally preserved material.

We used Manual of Leaf Architecture (Ellis et al. 2009) for terminology of leaf morphology. The specimens were studied using an Carl Zeiss Jena SM-XX binocular microscope and photographed using a Nikon D5300 digital camera with macro-lens objective and a Nikon Coolpix P7700, sometimes underwater in order to increase contrast of leaf venation.

CHAPTER 4

COMPOSITION OF THE CHINGANDZHA FLORA

V. A. Samylina (1989) identified about 60 species in the composition of the Chingandzha flora. Our systematic revision allowed to reduce significantly this list. Now the Chingandzha flora includes 33 species. The table 4 shows the distribution of species by main localities (the Kananyga, Tap and Chingandzha rivers). It can be seen that the Kananyga, Tap and Chingandzha floristic assemblages are characterized by a large number of common species. The Kananyga floristic assemblage is the most diverse (31 species). The Chingandzha and Tap assemblages are less diverse (13 and 12 species, respectively), however, almost all of their species are present in the Kananyga assemblage. Only two species of the Tap assemblage are absent in the Kananyga one: Anemia ochotica and Trochodendroides sp. All species of the Chingandzha assemblage are present in the Kananyga one. The similarity of the systematic composition in different localities allowed to combine these assemblages into a single Chingandzha flora.

Table 4

The systematic composition of the Chingandzha flora and distribution of species in localities

Species Kananyga Chingandzha Tap

Marchantiophyta

Jungermannites sp.

Hepaticites sp. 1

Hepaticites sp. 2

Hepaticites sp. 3

Hepaticites sp. 4

Equisetophyta

Equisetum sp.

Polypodiophyta

Asplenium dicksonianum Heer

Arctopteris ochotica (Samyl.) Golovn.

Arctopteris ilirnensis Golovn.

Coniopteris opposita Samyl.

C. tschuktschorum (Krysht.) Samyl.

Cladophlebis inaequipinnulata Samyl.

Lobifolia gleichenioides Golovn. et Grabovskiy

Osmunda tapensis Samyl.

Pinophyta Caytoniales

Sagenopteris variabilis (Velen.) Velen.

Ginkgoopsida

Ginkgo ex gr. adiantoides (Ung.) Heer

G. ex gr. sibirica Heer

Pinopsida

Sequoia ochotica Yudova et Golovn.

Metasequoia sp.

Taxodium viligense Golovn.

Cupressinocladus shelikhovii Golovn.

Protophyllocladus subintegrifolius (Lesq.) Berry

Magnoliophyta

Trochodendroides tumanensis Yudova

Trochodendroides deminii Yudova et Golovn.

Trochodendroides pekulneensis Philipp.

Trochodendroides sp.

Pseudoprotophyllum cordatum Samyl.

Araliaephyllum devjatilovae Philipp.

Araliaephyllum speciosum Philipp.

Dalembia kryshtofovichii (Samyl.) Golovn.

Menispermites sibiricus (Heer) Golovn.

Ievlevia dorofeevii Samyl.

Quereuxia angulata (Newb.) Krysht. ex Baik.

Total: 31 13 12

The Chingandzha flora consists of liverworts, horsetails, ferns, seed ferns, ginkgoaleans, conifers, and angiosperms. The latter (11 species) make up about a third of the total number of species. Ferns (8 species), liverworts (5 species) and conifers (5 species) are present in smaller quantities. The remaining groups are represented by 1-2 species.

Liverworts are represented by two genera: Hepaticites and Jungermannites. The fist genus includes 4 species of flat, dichotomously branching thalli without of reproductive structures. The second genus is represented by dorso-ventrally flattened thalli with two rows of overlapping leaves, resembling thalli of modern Jungermannia. Samylina (1989) attributed these remains to the genus Selaginellites (putative lyco-psid affinity).

Horsetails are represented by underground rhizomes with tubers, which assigned to the genus Equisetum.

Ferns are represented by families Osmundaceae (Osmunda), Dicksoniaceae (Coniopteris), Aspleniaceae (Asplenium), Pteridaceae (Arctopteris) and by genera of an uncertain systematic position (Cladophlebis). Pinnae of Coniopteris opposita and Cladophlebis inaequipinnulata occur most often in localities. The species Asplenium dicksonianum and Coniopteris tschuktschorum were widespread in the Late Cretaceous floras of Northern Asia. Two species (Coniopteris opposita and Arctopteris ochotica) are endemic to the Chingan-dzha flora. The remaining species (Osmunda tapensis, Cladophlebis inaequipinnulata and Arctopteris ilirn-ensis) are characteristic also for late Turonian Arman flora. Besides that, Cladophlebis inaequipinnulata and Arctopteris ilirnensis occur in common with the Coniacian Aleeky flora (Shczepetov, Golovneva, 2010). The species Arctopteris ilirnensis was reported in addition from the Coniacian Chaun flora of Central Chukotka (Golovneva, 2018).

The gymnosperms of the Chingandzha flora are rather diverse and include seed ferns, ginkgoaleans and conifers. Seed ferns are represented by the order Caytoniales, which includes the cosmopolitan species Sagenopteris variabilis.

Ginkgoaleans are represented by the genus Ginkgo with two form species: G. ex gr. adiantoides with bilobate or entire leaves, and G. ex gr. sibirica with deeply dissected leaves. The last species is the most common among ginkgoaleans.

Conifers of the Chingandzha flora consists of families Cupressaceae and Podocarpaceae. The family Cu-pressaceae is the most diverse and includes four genera: Sequoia, Metasequoia, Taxodium and Cupressinocla-dus. These genera were widely distributed in the Late Cretaceous floras of the OCVB. The lack of cuticles and insufficient preservation of cones hamper accurate species determinations. Shoots of Sequoia ochotica are the most frequent ly occuring fossils in localities. Remains of Metasequoia sp. and Taxodium viligense are also numerous. Shoots of Cupressinocladus shelikhovii occur sparsely and are usually fragmented. The family Podocarpaceae is represented by Protophyllocladus subintegrifolius.

Angiosperms are rather diverse in comparison with the other OCVB floras. Representatives of the families Platanaceae and Cercidiphyllaceae predominate. The genus Trochodendroides from the family Cer-cidiphyllaceae is represented by four species: T. tumanensis, T. deminii, T. pekulneensis and Trochodendroides sp. Platanaceous leaves are characterized by significant variability. Previously, three genera were determined in the Chingandzha flora: Pseudoprotophyllum, Paraprotophyllum, and Platanus (Samylina, 1989). A recent revision revealed the presence of only one species - Pseudoprotophyllum cordatum. This species, unlike others, often forms leaf mats.

The systematic affinity of the other angiosperms remains unclear. All form genera of the Chingandzha flora: Dalembia, Menispermites, Quereuxia and Araliaephyllum, - are characteristic for many Late Cretaceous floras of the North-East of Russia. The one exception is levlevia dorofeevii. The fruits of this species have been found yet only in the lower-middle Albian Toptan Formation of the Omsukchan district. The species Dalembia kryshtofovichii is endemic for the Chingandzha flora.

CHAPTER 5 TAPHONOMY AND PALEOECOLOGY

The volcanic-sedimentary Chingandzha Formation is represented mainly by alluvial cyclically alternating deposits. The lower part of the section is dominated by conglomerates and sandstones. In the upper part, they are gradually replaced by tuffaceous siltstones and mudstones.

The locality on the Tap River is dominated by conglomerates and sandstones with thin layers of tuff siltstones and mudstones, including plant fossils. The abundance of coarse rocks may indicate the proximity of the burial site to the upland area.

On the Chingandzha River, the plant-bearing part of the section is represented by a frequent alternation of thin (10-15 cm) layers of bedded coaly siltstones or mudstones with fine-grained volcanic sandstones (30-40 cm). Such deposits are characteristic for floodplains of large rivers with variable flow activity. Coaly siltstones contain a significant amount of decomposed plant detritus, among which only occasionally detect-

able plant remains can be found. This indicates burial under calm conditions with a slow supply of terrigenous material. The sandstones contain scattered remains of well-preserved leaves. These are usually whole leaves of Trochodendroides and fragments of platanoid leaves. The bedding of sandstones is not pronounced, but rolled leaves were not observed. These features indicate rapid sedimentation with low flow rates. Most of the finds of plant fossils are confined to the transitional layers from siltstones to sandstones, where the burial conditions were the best. Shoots of Sequoia and leaves of Ginkgo predominate on the bedding planes.

On the Kananyga River, the plant-bearing part of the section is represented mostly by fine-grained sediments. Sandstones are rare. In the section there are interbedded tuffaceous mudstones and siltstones, as well as tuffs and tuffites. Within the outcrop, most layers are traced without significant changes in thickness. Probably, these deposits were accumulated on the lacustrine-paludal lowland. The high rate of sedimentation was provided by the constant supply of thin tuffaceous material.

The abundance of plant fossils is much higher here than on the Chingandzha River. They are mainly occur in light gray, low carbonaceous bedded tuffites. Most often, the bedding planes are covered with shoots of Sequoia. Usually they are mixed with leaves of ferns, ginkgos and angiosperms. Platanoid leaves form sometimes almost monodominant leaf mats in which numerous leaves overlap each other. Sometimes there are remnants of primitive soils penetrated by thin roots. A large amount of wood remains was found in sandy and siltstone layers, from small fragments to trunks about 10-20 cm in diameter. Usually the wood is saved as flat impressions or mineralized flat compressions. Some layers of coaly siltstones 10-30 cm thick are overflowing with small leaves of the aquatic plant Quereuxia. Rarer finds of Junger-mannites sp. and Hepaticites spp. are also associated with the same deposits. These layers were probably deposited in small lakes.

Despite some different burial conditions, all localities of the Chingandzha flora contain approximately the same set of species. This fact indicates that the most common plants of the lacustrine-alluvial lowland are represented in the floristic assemblages. Almost all localities are allochthonous, with the exception of the Quereuxia layers, which are probably parautochthonous burials.

Reconstruction of the main types of plant communities is based on the facies association and the assumed ecology of fossil plants (based on the ecology of their closest modern relatives). Riparian vegetation along rivers and channels was formed by platanoids. Leafy mats with a predominance of slightly damaged leaves of Pseudoproophyllum cordatum indicate a limited transport. The floodplains of the river valleys were probably occupied by forests dominated by various species of the genus Trochodendroides. Groves, consisting of Metasequoia or Ginkgo, could also occupy similar habitats. Plants from the genera Araliaephyllum, Dalembia, Menispermites most likely formed undergrowth in the lowland forests. Less flooded and better drained parts of river valleys and lower slopes were occupied by Sequoia forests. Forests of Taxodium inhabited lowland wetlands. Ferns in the localities of the Chingandzha flora are not numerous, and their remains are fragmentary. Probably they did not form independent open communities, and grew under the canopy of forests or along the banks of lakes and rivers. Aquatic vegetation is represented by the genus Quereuxia. Floating rosettes of this plant could be found on the surface of small still lakes. Horsetails and liverworts settled on fresh sandy and silty sediments.

CHAPTER 6

COMPARISON OF THE CHINGANDZHA FLORA WITH OTHER FLORAS OF THE OKHOTSK-CHUKOTKA VOLCANIC BELT

The systematic composition of the Chingandzha flora significantly differs from that of other floras of the Okhotsk-Chukotka volcanic belt. Between these floras, the Aleeky and Zarya floras are the closest to the Chingandzha flora by their geographic position and stratigraphic level (Fig. 1.2).

The Zarya flora comes from the volcano-sedimentary deposits of the Zarya and Parnyi formations, which occupy the same stratigraphic level as the Chingandzha Formation, at the basal part of the OCVB section. The Aleeky flora comes from the volcanic and volcano-sedimentary deposits of the Gydra, Yum and Kananyga formations, which overlap the Parnyi and the Rond formations.

The Zarya flora

The Zarya flora consists of two floristic assemblages: the Zarya floristic assemblage from the Zarya Formation and the Parnyi floristic assemblage from the Parnyi Formation (Shczepetov, 1991a; Shczepetov,

Golovneva, 2014). All collections of plant fossils are kept in the Komarov Botanical institute, St. Peters-

The outcrops of the Zarya Formation are located in the southern part of the Balygychan-Sugoi Trough, in the upper reaches of the Omsukchan River, approximately 30 km southwest of the settlement Omsukchan. The Zarya Formation is 1100-1450 m thick and is composed of polymictic conglomerates and tuff conglomerates, sandstones, andesite lavas and tuffs, siltstones and mudstones. This formation overlaps unconformably the coal-bearing deposits of the Galimyi and Aigur formations and is overlain without apparent unconformity by volcanics of the Kakhovka Formation. The main plant fossils localities are situated on the Zarya and Zanozistyi creeks, left tributaries of the Omsukchan River, which flows into the Sugoi River (Fig. 6.1). Additional sites were found in the Shirokii Creek basin.

The Parnyi Formation is exposed in a limited area in the upper reaches of the Teukich Creek, one of the largest tributaries of the Kananyga River, approximately 120 km south of the settlement Omsukchan (Fig. 1.2). This formation is 700 m thick and composed of alternating volcanic and polymictic sandstones, gravelites, and conglomerates with intercalations and lenses of moderately felsic lavas and their tuffs.

The Parnyi Formation overlaps with the angular unconformity the Jurassic marine terrigenous rocks and is overlain by amphibole tuffs, moderately felsic lavas, and rare volcanogenic - sedimentary rocks attributed to the Gydra Formation (Table 1). The plant fossils were sampled from outcrops in the upper reaches of the Gydra Creek, a right tributary of the Right Elan Creek (Fig. 6.2). Second site is located slightly more than 1 km to the west on the western slope of the watershed facing toward the Kananyga River.

During the preliminary analysis, Samylina and Shczepetov identified approximately 50 species in the floral assemblages from the Parnyi and Zarya formations (Shczepetov, 1988). Later the systematic composition of the Zarya flora was revised (Shczepetov, Golovneva, 2014). This revision was resulted in the significant reduction of taxonomic list up to approximately 25 species. After monographic descriptions of the Arman and Chaun floras (Herman et al., 2016; Golovneva, 2018), the interpretation of some taxa was also changed (Table 5).

Fig. 6.1. Schematic geological map of the sampling area of the Zarya floristic assemblage (after Shczepetov, Golovneva, 2014): 1 - recent channel alluvium; 2 - Quaternary sediments and areas covered by vegetation; 3 - Shorokh Formation; 4 - Kakhovka Formation; 5 - Zarya Formation; 6 - deposits of the Balygychan-Sugoi Trough; 7 - intrusions; 8 - faults; 9 - sites of the Zarya flora assemblage and their numbers.

Table 5

The systematic composition of the Zarya flora

Species Zarya floristic assemblage Parnyi floristic assemblage

Equisetophyta

Equisetum sp.

Polypodiophyta

Birisia alata (Pryn.) Samyl.

Tchaunia filatovii Samyl.

Cladophlebis oppositipinnata Samyl.

Arctopteris sp.

Hausmannia sp.

Pinophyta

Cycadopsida

Nilssonia pilifera Samyl.

Ginkgoopsida

Ginkgo ex gr. adiantoides (Ung.) Heer

Sphenobaiera sp.

Czekanowskiopsida

Phoenicopsis sp.

Pinopsida

Podozamites sp.

Taxodium amguemense (Efimova) Golovn.

Pityophyllum sp.

Sequoia ochotica Yudova et Golovn.

Araucarites ochotensis Golovn. et Shczep.

Magnoliophyta

Platanus cf. louravetlanica Herman et Shczep.

Trochodendroides sp.

Menispermites orientalis Golovn.

Menispermites virginiensis Fontaine

Menispermites sp.

?Terechovia sp.

Cissites bidentatus (Philipp.) Herman

C. cordatus Philipp.

Scheffleraephyllum venustum (Philipp.) Philipp.

Dalembia pergamentii Herman et E. Lebed.

Araliaephyllum sp.

Viburniphyllum sp.

Dicotylophyllum sp. 1

Dicotylophyllum sp. 2

The Zarya and the Parnyi floristic assemblages are close to each other by their systematic compositions and are considered together as the single Zarya flora. This flora is not diverse and includes 29 species (Fig. 6.3). But all collections yield a large number of angiosperm leaves fragments that cannot be determined.

The Zarya flora consists of horsetails, ferns, cycadophytes, ginkgoaleans, czekanowskialeans, conifers and angiosperms. Among these groups, angiosperms are most diverse (13 species). Ferns and conifers are second in diversity (five species of each group), while other plant groups are represented by one or two species.

Horsetails include the single genus Equisetum, represented by creeping underground stems of unclear species affinity.

Ferns are represented by the families Dicksoninaceae (Birisia, Tchaunia), Pteridaceae (Arctopteris), Dipteridaceae (Hausmannia) and by taxa of an uncertain systematic position (Cladophlebis).

Two species (Cladophlebis oppositipinnata and Tchaunia filatovii) are endemic taxa of the Zarya flora. The genera Birisia, Arctopteris and Hausmannia were widespread in the Cretaceous floras of the North-East

Fig. 6.2. Schematic geological map of the sampling area of the Pamyi floristic assemblage (after Shcze-petov, Golovneva, 2014): 1 - recent channel alluvium; 2 - Kananyga Formation; 3 - Yum Formation; 4 - Rond Formation; 5 - Parnyi Formation; 6 - Triassic and Jurassic marine deposits; 7 - intrusions; 8 - faults; 9 - sites of the Parnyi floristis assemblage and their numbers; 10 -localities of the Aleeky flora.

of Russia. In coastal lowlands, they were mostly characteristic in the Early Cretaceous floras, while in the OCVB area they occur in the Late Cretaceous floras and are considered as relict taxa (Grabovskiy, Golovneva, 2018). Most likely, the fragmentary Hausmannia remains belong to the species H. bipartita Samyl. et Shczep., which was widespread in the Late Cretaceous floras of the OCVB (Golovneva, Grabovskiy, 2019).

Leaves of Nilssoniapilifera occur rarely, but they are found in the deposits of both formations. This species is also found in the Arman Formation as well as in the older formations of the Omsukchan Series.

Ginkgoales are represented by two genera: Ginkgo and Sphenobaiera. The impressions of Ginkgo ex gr. adiantoides are relatively frequent in localities. This species was widespread in the Late Cretaceous floras of Eurasia. Sphenobaiera leaves are poorly preserved. This taxon is the Early Cretaceous relict in the Zarya flora similar to Phoenicopsis (Czekanowskiales) and Podozamites (ancient conifers) genera. The leaves of Phoenicopsis and Podozamites are rare.

The absence of phytoleims prevents identification of Ginkgoales, Czekanowskiales, and conifers remains at the species level. Therefore, most of them are determined at the generic level or attributed to form species.

The conifers are represented by Pinaceae, Taxodiaceae and Podozamitaceae. The large flat shoots of Taxodium amguemense with a distichous leaf arrangement predominate in localities. Shoots and cones of Sequoia ochotica are also common.

The Pinaceae remains are represented by impressions of linear leaves up to 5 cm long, which are attributed to the form genus Pityophyllum.

The form genus Araucarites includes shoots with spirally arranged hamate leaves with rhomboidal section. Shoots of A. ochotensis were found also in the Volchya flora from the left side of the Anadyr River, where they were previously described as Sequoia reichenbachii (Geintiz) Heer (Philippova, Abramova, 1993). On the basis of co-occurring floral and faunal remains, the Volch'ya flora is dated as the late Turonian (Philippova, Abramova, 1993).

The angiosperm remains are relatively abundant, but most of them are represented by fragments. This makes them difficult to identify. In total, 10 genera are determined: Platanus, Menispermites, Terechovia, Cis-sites, Scheffleraephyllum, Dalembia, Viburniphyllum, Trochodendroides, Araliaephyllum, Dicotylophyllum. Only

Fig. 6.3. Angiosperms of the Zarya flora (after Shczepetov, Golovneva, 2014): a-c - Menispermites orientalis Golovn., spec. BIN 518/10, 518/14, 518/9, respectively; d-f - Cissites bidentatus (Philipp.) Herman, spec. BIN 548/5, 525/28, 548/4, respectively; g - Platanus cf. louravetlanica Herman et Shczep., spec. BIN 550/23b; h - Trochodendroides sp., spec. BIN 548/12a; i - Terechovia sp., spec. BIN 525/29; j-o - Dalembia pergamentii Herman et E. Lebed., spec. BIN 548/11, 548/10, 548/7, 548/9, 548/9a, 548/9b, respectively; p - Scheffleraephyllum venustum (Philipp.) Philipp., spec. BIN 548/8. Scale bar is 1 cm.

two of these genera may be attributed to recent families: Trochodendroides (Cercidiphyllaceae) and Plata-nus (Platanaceae). Leaves of Trochodendroides are identifiable only at the generic level (Fig. 6.3h). Leaves of Platanus are most similar to those of the species Platanus louravetlanica from the Grebenka flora (Fig. 6.3g).

Other genera are considered as dicotyledonous plants of unknown taxonomic affinity. Leaves of Dalembia pergamentii are most common. They are characterized by highly variable shape of leaf blade and margin (Fig. 6.3 j-o). Remains of Menispermites are also relatively abundant. This genus is represented by three species. Leaves of M. virginiensis are characterized by a peltate base. The species M. orientalis was found also in the late Albian-early Turonian Grebenka flora and in the Coniacian Tylpegyrgynay flora (Golovneva et al., 2015).

The genus Cissites includes two species: C. bidentatus and C. cordatus (Fig. 6.3 d-f). They are still known only from the Arman flora. The same distribution is characteristic of Scheffleraephyllum venustum (Fig. 6.3p). Of significant interest is a leaf fragment similar in the large marginal teeth to leaves of the genus Terechovia (Fig. 6.3i), which is characteristic of the Turonian-Coniacian floras in the Anadyr-Koryak region, including the Arman flora (Herman et al., 2016).

Samylina (1976), who described several new species from the Zarya flora, considered the Zarya flora to be coeval with the Arman flora from the Arman, Nel'kandzha, and Khasyn rivers (Ola, Ten'ka, and Khasyn districts of the Magadan Region). Despite its high taxonomic diversity, the age of the Arman flora was debatable for a long time. At first the Arman flora (together with the Zarya flora) was dated as the late Albian (Samylina, 1976, 1988). According to the latest paleofloral and isotopic data, the age of the Arman flora is estimated to range from the Turonian to Coniacian (Akinin, Miller, 2011; Herman et al., 2016). We consider the late Turonian age of the Arman and Zarya floras as the most probable (Golovneva, 2018).

The peculiar feature of the Zarya flora is the combination of the Early Cretaceous relicts (Hausman-nia, Birisia, Sphenobaiera, Phoenicopsis, Nilssonia, Podozamites) and typical Late Cretaceous taxa (Taxodium, Sequoia, Menispermites, Dalembia, Trochodendroides, Cissites, Terechovia, Platanaceae). Among all the OCVB floras, the Zarya flora is the most similar to the Arman flora. These floras have similar proportions between the main plant groups, and close taxonomic composition at species and genera levels. Only these two floras include endemic species of the genus Cissites: C. bidentatus, C. cordatus.

The Chingandzha flora differs from the Zarya flora in the significant amount of flowering plants and in the absence of the Early Cretaceous relicts, foremost cycadophytes and czekanowskialeans. There are no common species in these two floras, with the exception of Sequoia ochotica and Ginkgo ex gr. adiantoides. The common genera are few: Equisetum, Arctopteris, Cladophlebis, Ginkgo, Sequoia, Taxodium, Trochoden-droides, Dalembia, Menispermites. All these taxa are characterized by wide distribution in the mid Cretaceous floristic assemblages.

The Aleeky flora

The Aleeky flora consists of floristic assemblages from the Gydra, Yum and Kananyga formations of the Viliga-Tumany interfluve (Shczepetov, Golovneva, 2010). The plants fossils from these formations were collected by V. F. Belyi in 1982 (coll. BIN 1553, 1556) and S. V. Shczepetov in 1983-1985 (coll. BIN 546, 810-812, 1557). Collections are stored at the Komarov Botanical Institute, St. Petersburg. Localities and their numbers are shown in Fig. 6.4 and Table 6.

Table 6

Collections of the Aleeky flora

Collection Formation Locality Collectors

BIN 546 Gydra Teukich Creek, Kananyga River basin, site 132 Shczepetov S. V., 1983-1985

BIN 810 Gydra Merenga River, Viliga River basin, site 400 Shczepetov S. V., 1983-1985

BIN 811 Yum Aleeky River, Viliga River basin, site 412 Shczepetov S. V., 1983-1985

BIN 812 Kananyga Merenga River, Viliga River basin, site 410, 433; Zlobny Creek, Viliga River basin, site 450 Shczepetov S. V., 1983-1985

BIN 1553 Kananyga Elan Creek, , Kananyga River basin Belyi V. F., 1982

BIN 1556 Kananyga Elan Creek, , Kananyga River basin Belyi V. F., 1982

BIN 1557 Kananyga Kholodny Creek, Kalalaga River basin Shczepetov S. V., 1983-1985

Fig. 6.4. Schematic geological map of the Viliga-Tumany interfluve (after Shczepetov, Golovneva, 2010): 1 - Quaternary deposits; 2 - the OCVB volcanic deposits; 3 - Triassic and Jurassic marine deposits; 4 - intrusions; 5 - localities of the Aleeky flora and collection numbers; 6 - localities of the Chingandzha flora; 7 - localities of the Parnyi flora.

The Aleeky flora includes more than 30 species (Shczepetov, Golovneva, 2010), among which ferns and gymnosperms (mostly conifers) predominate (pl. XLIV-LII). Flowering plants are rather diverse, but their remains are less frequent than the remains of gymnosperms.

Ferns are the most diverse in the Aleeky flora and include 10 species. They are represented by the families Dipteridaceae (Hausmannia), Aspleniaceae (Asplenium), Dicksoniaceae (Coniopteris, Birisia, Tchaunia) and by ferns of unknown taxonomic affinity (Cladophlebis, Lobifolia). The genera Arctopteris and Pteris are thought to belong to the family Pteridaceae.

The species Cladophlebis grandis (Pl. XLVIII, fig. 3) and Tchaunia lobifolia (Pl. XLVIII, fig. 2) so far have been known only from the Chaun flora. Their discovery in the Okhotsk sector of the OCVB shows that some species of the Chaun flora were distributed outside the territory of Central Chukotka and could penetrate quite far to the south. T. lobifolia was recently discovered also in the Ul'ya flora in the southern part of the OCVB (Akinin et al., 2019).

The fern Cladophlebis inaequipinnulata (Pl. XLIV, fig. 4, 5) was first described from the Tap River, in the Chingandzha flora (Samylina, 1984a). Later collections showed a wide distribution of this species in the deposits of the Gydra, Yum, Kananyga and Arman formations (Shczepetov, Golovneva, 2010; Herman et al., 2016). In morphology, it is very close to C. tschukschorum Philipp. from the Chaun flora.

Fern Hausmannia bipartita (Pl. XLV, fig. 1-5), except the Aleeky flora, is known from the Grebenka, Arman, Amka, Tylpegyrgynay and Valizhgen floras, which are dated from the early Albian to the Santonian (Golovneva, Grabovskiy, 2019). Probably, fragmentary remains from the Zarya and Parnyi formations belong to the same species. The genus Lobifolia is represented by a new species L. alikensis. This genus, as well as Hausmannia, is characteristic of the Jurassic and Early Cretaceous (Lebedev, Rasskazova, 1968) and is relict in the Aleeky flora. The Late Cretaceous occurrences of this genus are also known from the Arman, Chingandzha and Arkagala formations (Samylina, 1988; Herman et al., 2016).

The species Asplenium dicksonianum, Coniopteris tschuktschorum and Arctopteris ilirnensis are characteristic elements of the Late Cretaceous flora and were widespread in the North-East of Russia. Pinnae of Pteris sp. have insufficient preservation. In morphology, they are similar to the leaves from the Tylpegyr-gynay flora, which are described as Gleichenia crenata Krysht. (Philippova, Abramova, 1993).

The gymnosperms of the Aleeky flora are highly diverse and include seed ferns, cycadophytes, cze-kanowskialeans, ginkgoaleans and conifers. Seed ferns are represented by the order Caytoniales and by cosmopolitan species Sagenopteris variabilis.

Remains of cycadophytes are rare and represented by fragmentary leaves of Heilungia sp. (Pl. XLIX, fig. 8). This plant is of particular interest. Earlier this genus was unknown from unequivocally Upper Cretaceous deposits and, therefore, was supposed to disappear at the Early/Late Cretaceous boundary, similarly to the majority of other Mesophytic genera of cycadophytes and ginkgophytes. Finds of recent years have extended considerably the stratigraphic range of Heilungia (Shczepetov, Golovneva, 2010). In the northern Sea of Okhotsk region, remains of Heilungia were found in deposits of the Kananyga Formation (pl. XLIX, fig. 8). Four species of this genus were described from the Coniacian Chaun flora (Golovneva, 2018). The youngest occurrence of Heilungia comes from the Maastrichtian-Danian Temlyan flora, Chukotka (Golovneva, Grabovskiy, 2015). Although cycadophytes gradually faded away in the Late Cretaceous, the diversity of the genus Heilungia increased, especially in the northern part of the OCVB.

Ginkgoaleans of the Aleeky flora are represented by two genera: Ginkgo and Sphenobaiera. All remains are assigned to form species because of the absence of phytoleims.

The genus Ginkgo includes two species: G. ex gr. adiantoides with bilobate or entire leaves, and G. ex gr. sibirica with deeply dissected leaves. Leaves of Sphenobaiera are characterized by large sizes, up to 10-13 cm in length, and are usually dissected into four lobes, each of which reaches about 1 cm in width. Similar leaves were found in the Late Cretaceous Karamken and Chaun floras of the OCVB (Golovneva, Shczepetov, 2011; Golovneva, 2018).

Czekanowskialeans are represented by the form species Phoenicopsis ex. gr. angustifolia (Pl. XLVIII, fig. 7). Remains of this species are numerous in many localities of the Late Cretaceous floras of the OCVB up to Maastrichtian-Danian (Golovneva, Grabovskiy, 2015). Together with Sphenobaiera and Heilungia, the genus Phoenicopsis is a typical Early Cretaceous relict in the Late Cretaceous Aleeky flora.

Conifers of the Aleeky flora are represented by Cupressaceae, Pinaceae and by genera of uncertain taxonomic affinity. The family Cupressaceae includes Sequoia ochotica (Pl. XLVIII, fig. 6, pl. XLIX, fig. 5, 6), Metasequoia sp. (Pl. XLIV, fig. 3) and Taxodium amguemense (Pl. XLIX, fig. 3). All these species were widely distributed in the Late Cretaceous floras of the OCVB. Shoots of Sequoia ochotica are the most

Table l

The systematic composition of the Aleeky flora

Species Gydra Formation Yum Formation Kananyga Formation

546 810 811 812 1553, 1556 1557

EQUISETOPHYTA

Equisetum sp.

POLYPODIOPHYTA

Asplenium dicksonianum Heer

Hausmannia bipartita Samyl. et Shczep.

Arctopteris ilirnensis Golovn.

Coniopteris tschuktschorum (Krysht.) Samyl.

Cladophlebis inaequipinnulata Samyl.

Cladophlebis grandis Samyl.

Lobifolia alikensis Golovn. et Shczep.

Tchaunia lobifolia Philipp.

Pteris sp.

Birisia alata (Pryn.) Samyl.

CYCADOPSIDA

Heilungia sp.

CAYTONIALES

Sagenopteris variabilis (Velen.) Velen.

CZEKANOWSKIOPSIDA

Phoenicopsis ex gr. angustifolia Heer

GINKGOOPSIDA

Ginkgo ex gr. adiantoides (Ung.) Heer

G. ex gr. sibirica Heer

Sphenobaiera sp.

PINOPSIDA

Sequoia ochotica Yudova et Golovn.

Metasequoia sp.

Taxodium amguemense (Efimova) Golovn.

Pityophyllum sp.

Picea sp.

Pityolepis sp.

Araucarites subacutensis Philipp.

Elatocladus sp. 1

Elatocladus sp. 2

Sciadopitys (?) sp.,

MAGNOLIOPHYTA

Trochodendroides tumanensis Yudova

T. deminii Yudova et Golovn.

Trochodendroides sp.

Dalembia kryshtofovichii (Samyl.) Golovn.

Nelumbites extenuinervis Upchurch, Crane et Drinnan

Menispermites sp.

Dicotylophyllum sp.

Pseudoprotophyllum (?) sp.

Platanaceae gen et sp. indet.

frequent in localities. The family Pinaceae is represented by cones, dispersed scales and leaves, identified as Picea sp., Pityophyllum sp. and Pityolepsis sp. (Pl. L, fig. 1, 2).

Find of Araucarites subacutensis shoots is very important (Pl. XLIX, fig. 4). This species is a characteristic element of the Chaun flora, and besides Central Chukotka, it has been found only in the Auney Unit of the Eropol River basin (Philippova, Abramova, 1993; Golovneva, Shczepetov, 2013).

The morphological diversity of angiosperms is quite high, but due to poor preservation, not all leaves can be determined. The presence of the genera Trochodendroides and Dalembia is reliably established. The genus Trochodendroides includes two species: T. tumanensis and T. deminii, both common with the Tylp-egyrgynay and Chingandzha floras. The species Dalembia kryshtofovichii (Pl. L, fig. 5) is known only for the Aleeky and Chingandzha floras.

Fragments of large leaves of Platanaceae family are quite often. They cannot be determined even at the generic level. The presence of the genera Paraprotophyllum and Pseudoprotophyllum is most likely. Leaves of Menispermites sp. are similar in morphology to M. sibirica, but their exact species determination is impossible due to poor preservation of the material.

Peltate leaves of Nelumbites extenuinervis (Pl. LI, fig. 1-5, 6a) were described from the Albian deposits of North America (Upchurch et al., 1994). In the Aleeky flora, this species is an ancient relict.

In contrast to the Chingandzha flora, the Aleeky flora is a typical flora of the Okhotsk-Chukotka volcanic belt. It includes few flowering plants, which are represented by rare fragments, and a large proportion of relict elements among ferns (Hausmannia, Lobifolia), cycadophytes (Heilungia), czekanowskialeans (Phoenicopsis) and ginkgoaleans (Sphenobaiera, Ginkgo ex gr. sibirica). The Aleeky flora, as well as other flora of the belt, is characterized by a great variety of pine family. These conifers are absent in the Chingandzha flora.

The Chingandzha and the Aleeky floras have many common taxa, which were widespread in the Late Cretaceous of the North-East of Russia: Coniopteris tschuktschorum, Asplenium dicksonianum, Arctopteris ilirnensis, Sagenopteris variabilis, Ginkgo ex gr. adiantoides, G. ex gr. sibirica, Sequoia ochotica, Metasequoia sp., Trochodendroides tumanensis, Menispermites sp. Species Cladophlebis inaequipinnulata and Dalembia kryshtofovichii are known only for these two floras.

Among the OCVB floras, the Aleeky flora is most similar to the Coniacian Chaun flora of the Central Chukotka. Characteristic elements of these two floras are Coniopteris, Asplenium, Arctopteris, Cladophlebis, Ginkgo, Sphenobaiera, Heilungia, Phoenicopsis, Picea, Sequoia, Metasequoia, Menispermites, Dalembia and Trochodendroides. Besides that, the Aleeky flora contains some species, which were previously believed to be endemics of the Chaun flora: Tchaunia lobifolia, Cladophlebis grandis and Araucarites subacutensis. On this basis, the age of the Aleeky flora is estimated to be the Coniacian (Shczepetov, Golovneva, 2010).

CHAPTER 7

COMPARISON OF THE CHINGANDZHA FLORA WITH OTHER FLORAS OF THE NORTH-EAST OF RUSSIA

In species composition, the Chingandzha flora is close to the floras from the coal-bearing deposits of the coastal lowlands of the Anadyr Province (Fig. 7.1): the Penzhina (late Turonian), Kaivayam (Coniacian) and Omgon floras of northwestern Kamchatka and the Tylpegyrgynay (Coniacian) flora of the Pekulney Ridge (Budantsev, 1983; Samylina, 1989; Herman, Lebedev, 1991; Philippova, 2010). The age of most of these floras has been reliably determined by their relationship with the marine sediments containing the inoceramid molluscs.

All these Turonian-Coniacian floras are characterized by a similar taxonomic composition at the generic and species level, by predominance of flowering plants, a high diversity of representatives of the family Platanaceae and the genus Trochodendroides, a significant variety of conifers and a moderate participation of ferns. Many species from these floras had wide geographical distribution.

Among Turonian-Coniacian floras of the Anadyr Province, the Chingandzha flora has the greatest similarity with the Tylpegyrgynay flora from the northern Pekulney Ridge. This flora comprises two flo-ristic assemblages: one from the Tylpegyrgynay Formation on the western slopes of the Pekulney Ridge and the other from the Poperechnenskaya Formation on its eastern slopes. This flora is described in most detail in the monograph by Philippova (2010). Some taxa were revised later (Yudova, Golovneva, 2014, 2015; Golovneva et al., 2017; Golovneva, Grabovskiy, 2019). The Coniacian age of this flora is based on biostratigraphic correlation of the plant-bearing beds with underlying and overlying marine units (Philippova, 2010).

Fig. 7.1. Localities of the Chingandzha flora and similar in composition Turonian-Coniacian floras of the Anadyr Province (after Golovneva et al., 2011): 1 - the OCVB volcanogenic deposits; 2 - localities of the Chingandzha flora; 3 - localities of the Turonian-Coniacian floras of the Anadyr Province: 1 -Omgon Cape, Omgon flora; 2 -Ubienka River, Volchinsk flora; 3, 4 - western (3) and eastern (4) slopes of the Pekulney Ridge, Tylpegyrgynay flora; 5-7 - Valyzhgen Cape (5), Konglomeratovy Cape (6) and Yelistratov Peninsula (7), Penzhina and Kaivayam floras.

The Tylpegyrgynay flora is dominated by angiosperms (about 50%) followed by conifers and ferns. Other groups of plants are less diverse. Liverworts, lycopods and horsetails are rare and represented by Thallites tchucotica Philipp., Selaginella sp., and Equisetites sp. respectively.

Ferns include families Osmundaceae (Osmunda), Dipteridaceae (Hausmannia) Dicksoniaceae (Coni-opteris, Onychiopsis, Birisia), Aspleniaceae (Asplenium), Pteridaceae (Arctopteris), and by genera of an uncertain systematic position (Cladophlebis, Ochotopteris, Gleichenites). The species Asplenium dicksonianum, Coniopteris tschuktschorum and Arctopteris ilirnensis are in common with the Chingandzha flora.

The Early Cretaceous relicts are more diverse in the Tylpegyrgynay flora than in the Chingandzha one. They are represented by ferns (Hausmannia), cycadophytes (Nilssonia, Ctenis) and czekanowskialeans (Phoenicopsis). Such a large number of relicts are possibly related with a large number of localities and their territorial proximity to the OCVB (Fig. 7.1). But their remains are rather rare and fragmented. Ginkgoales are represented by only Ginkgo ex gr. adiantoides.

Conifers of the Tylpegyrgynay flora are very diverse and represented by families Cupressaceae, Pina-ceae and by genera of an uncertain systematic position (Elatocladus). The family Cupressaceae is the most diverse and includes five genera: Sequoia, Metasequoia, Taxodium, Taiwania and Cupressinocladus. Shoots of Metasequoia and Taxodium are the most frequent fossils in localities. The family Pinaceae is represented by genera Pityophyllum, Pityocladus, Pinus, Pityostrobus, Cedrus. Such a high diversity of Pinaceae is more typical for the mountain flora of the OCVB than for the floras of the coastal lowlands.

Angiosperm leaves are the most abundant and have the greatest taxonomic diversity. The large-leaved platanoids (Arthollia, Pseudoprotophyllum and Paraprotophyllum) form the dominant group. The smaller-leaved Trochodendroides is also well represented. The other less frequently found genera include Menisper-mites, Araliaephyllum, Viburniphyllum, Celastrophyllum, Leguminosites and Terechovia.

Leaves, described as Pseudoprotophyllum boreale Holl., are practically indistinguishable from leaves of P. cordatum from the Chingandzha flora. The genus Trochodendroides is represented in the Tylpegyrgynay and Chingandzha floras by common species: Trochodendroides tumanensis, T. deminii and T. pekulneensis. Among other genera, the common species is Araliaephyllum speciosum.

The other Turonian-Coniacian floras of the Anadyr Province (the Penzhina, the Kaivayam and the Omgon floras) have also many common genera with the Chingandzha flora: Equisetum, Asplenium, Coniop-teris, Cladophlebis, Osmunda, Arctopteris, Sagenopteris, Ginkgo, Sequoia, Metasequoia, Taxodium, Cupressi-nocladus, Protophyllocladus, Dalembia, Trochodendroides, Menispermites, Pseudoprotophyllum, Araliaephyllum, Quereuxia. But the similarity at the species level of these floras with the Chingandzha flora is lower than the similarity of the Chingandzha and Tylpegyrgynay floras. The significant similarity indicates their similar age and similar conditions of growth and burial of species.

CHAPTER 8 AGE OF THE CHINGANDZHA FLORA AND ITS PLACE IN THE EVOLUTIONARY PALEOFLORISTIC SUCCESSIONS

OF THE NORTH-EAST OF RUSSIA

Due to the large number of common taxa with well-dated coastal floras of the Anadyr Province, the age of the Chingandzha flora from the beginning of its study was determined rather accurately, in contrast to the other floras of the OCVB. Samylina (1989) dated the Chingandzha flora as the late Turonian-Coniacian based on the similarity of its systematic composition with the floras of northwestern Kamchatka and included it in the Valizhgen stratoflora. However Samylina considered the Chingandzha flora as the youngest in comparison with the other OCVB floras, which was in conflict with its stratigraphic position.

In the result of further studies, the ages of paleofloras from volcanic deposits of the Viliga-Tumany in-terfluve were changed. According to the latest paleofloristic data, the age of the Zarya flora is estimated to range from the Turonian to Coniacian (Shczepetov, Golovneva, 2014). We consider the late Turonian age of the Zarya flora as the most probable (Golovneva, 2018). The age of the Aleeky flora is estimated as the Coniacian (Shczepetov, Golovneva, 2010). The Chingandzha flora was dated as the Turonian-Coniacian and considered to be coeval with the Zarya flora, based on its stratigraphic position in the base of the volcanic succession of the OCVB (Golovneva et al., 2011).

Now more detailed study of the taxonomic composition of the Chingandzha flora and the revision of the Tylpegyrgynay flora allow to precise the age of the first one.

Similar ratio of plant groups and a large number of common species with the Tylpegyrgynay flora suggests the Coniacian age for the Chingandzha flora. Comparison with the Zarya and Aleeky floras (Chapter 6) showed that the Chingandzha flora has a greater number of common taxa with the Coniacian Aleeky flora, then with the late Turonian Zarya flora. These common taxa include Coniopteris tschuktschorum, Asplenium dicksonianum, Arctopteris ilirnensis, Sagenopteris variabilis, Ginkgo ex gr. adiantoides, G. ex gr. sibirica, Sequoia ochotica, Metasequoia sp., Trochodendroides tumanensis, Menispermites sp. Species Cladophlebis inaequipinnulata and Dalembia kryshtofovichii are known only for these two floras.

Two taxa of the Chingandzha flora are of great biostratigraphic importance. These are Metasequoia and Quereuxia. These genera appeared in the floras of northeastern Asia and northwestern America only starting from the Coniacian (Golovneva, 2013). Both genera were recorded in the Coniacian Kaivayam flora of Northwestern Kamchatka (Herman, 2011). In the older Turonian Penzhina flora, these taxa are absent. The Coniacian Tylpegyrgynay flora contains only Metasequoia (Philippova, 2010).

On Sakhalin, the most ancient occurrence of Quereuxia is known from the Coniacian Ainus flora, which comes from the lower part of the Arkovo Formation (Krassilov, 1979), and in Alaska, this genus is known from the Coniacian flora of the Tuluvak stage (Herman, 2011). In the OCVB, these taxa appeared in the Chaun and Ul'ya floras, the Coniacian age of which is confirmed by isotope data (Kelley et al., 1999; Aki-nin et al., 2019). Metasequoia and Quereuxia were not been found in the Zarya and the Arman floras of the Magadan Region and in the Turonian flora of the Kaolak stage in Alaska. Based on all these data, the age of the Chingandzha flora can be determined as the Coniacian.

Thus, the Chingandzha flora existed simultaneously not with the Zarya flora, as was previously thought, but with the Aleeky flora. It can be correlated also with the other Coniacian floras of the Okhotsk-Chu-kotka volcanic belt: the Chaun flora of the Central Chukotka, the Kholchan flora of the Magadan Region and the Ul'ya flora of the Ul'ya Depression.

This flora reflects vegetation, typical of the coastal lowlands of Northern Asia, and differs from all floras of the OCVB in the significant participation of flowering plants and in the absence of the Early Cretaceous relicts.

Why was this coastal flora found on the territory of the OCVB? It seems to us more likely that the Chingandzha flora was developed in a large river valley, which crossed mountain ranges of the OCVB and had a connection with the coastal lowlands from the east side of the belt. The main localities of the Chingandzha flora are situated along the axis of the Balygychan-Sugoy Trough, which is located almost perpendicular to the axis of the Okhotsk-Chukotka volcanic belt (Fig. 7.1). Possibly, this river valley was associated with the Balygychan-Sugoy Trough. The plant fossils of the Aleeky flora could have accumulated in small intermountain depressions adjacent to this river valley.

Since the Chingandzha flora differs considerably from the other floras of the Mountain Okhotsk-Chukotka Province and has a large number of common taxa with the floras of the Anadyr Province, we refer it to the Anadyr Province. The floras of the Mountain Okhotsk-Chukotka Province were formed on the volcanic highlands. They are characterized by high endemism, a predominance of ferns and conifers, an insignificant participation of angiosperms and a large number of the Early Cretaceous relicts (Golov-neva, 2014a, 2018).

The Anadyr Province includes the floras distributed in the coastal lowlands east of the Okhotsk-Chu-kotka volcanic belt. The descriptions of these floras are given in monographs and papers by A. B. Herman, L. B. Golovneva, G. G. Philippova and M. G. Moiseeva (Herman, Lebedev, 1991; Herman, 1999, 2011; Golovneva, 1994; Philippova, Abramova, 1993; Philippova, 2010; Moiseeva, 2012). The phytostratigraphic scheme of the Anadyr-Koryak region is based on phases of floral evolution. According to Herman (1993, 2013) and Golovneva (1994, 1998), paleofloral succession of this region from the late Albian to the Maas-trichtian includes seven phases of flora evolution: Early Ginter, Grebenka, Penzhina, Kaivayam, Barykov, Gornorechenian, and Rarytkin. The alternation of marine and continental facies in the Cretaceous sections of this region is favorable for dating the plant-bearing rocks.

We assign the Chingandzha flora to the Kaivayam floral phase (Table 8) together with the Kaivayam flora of Northwestern Kamchatka and the Tylpegyrgynay flora of the Pekulney Ridge. The Kaivayam flora is characterized by a higher species diversity than the Penzhina flora. An increase in the number of species of angiosperms with entire-margined leaves, along with an increase in the species diversity, indicate a warming of the climate in the Coniacian (Golovneva, Herman, 1998).

Table 8

Correlation of floristic assemblages of the Anadyr Province and the Okhotsk subprovince of the Mountain Okhotsk-Chukotka Province

Age Mountain Okhotsk-Chukotka Province Anadyr Province

Phases of floral evolution (Golovneva, 2014b, 2018) Floristic assemblages of the Okhotsk subprovince Floristic assemblages Phases of floral evolution (Herman, 2011)

Campanian early Ola Ola Mygdykit Barykov Valizhgen Barykov

Santonian late

early

Coniacian late Chaun Kholchan Aleeky Kaivayam Tylpegyrgynay Chingandzha Kaivayam

early

Turanian late Arman Arman Zarya Penzhina Penzhina

In the Viliga-Tumany interfluve, the Chingandzha flora coexisted with the floras of the Okhotsk subprovince of the Mountain Okhotsk-Chukotka Province (Table 8).

The Okhotsk subprovince occupied the territory from the headwaters of the Omolon River in the northeast to the Okhota River in the southwest, roughly corresponding to the boundaries of the Okhotsk sector of the OCVB.

The main localities of plant fossils in this subprovince are situated in two areas: in the basins of the Viliga, Kananyga and Tumany rivers in the Omsukchan district of the Magadan Region and in the basins of the Arman, Yana, Ola and Maltan rivers in the vicinity of Magadan. From the first area, the Zarya and Aleeky floras are known, from the second area - the Arman, Kholchan and Ola floras.

The Arman regional flora is the most ancient and dated as the late Turonian. It is represented by the Arman flora from numerous localities in the basins of the Arman and Nelkandya rivers (Herman et al., 2016) and by the Zarya flora from the basins of the Sugoi and Kananyga rivers. The Coniacian Kholchan and Aleeky floras are somewhat younger. The Ola flora (Santonian-early Campanian) is the youngest in the Okhotsk subprovince. It combines plant remains from the Ola, Pervomaiskaya and Mygdykit formations (Herman, 2011). Plant fossils of the Ola flora were described mostly by Samylina and Philippova (Belyi, Samylina, 1987; Samylina, 1988; Philippova, Abramova, 1993)

The most characteristic species of the Ola flora are Sequoiadendron microphyllum Samyl., Cryptomeria cretacea Samyl., Cunninghamia orientalis (Philipp.) Samyl., Taiwania cretacea Samyl., Elatocladus communis Philipp., Sequoiaparvifolia Samyl., Trochodendroides samyliniae P. Alekseev, Trochodendroides montana P. Alekseev u Lokyma onkilonica (Krysht.) Samyl. In addition, Quereuxia angulata leaves are very common, as well as various remains of the family Pinaceae, represented by several modern (Abies, Picea, Cedrus, Larix, Pinus) and formal genera (Pityocladus, Pityophyllum, Pityospermum, Pityostrobus). The relict elements are represented by the genera Hausmannia, Taeniopteris, Phoenicopsis, Sphenobaiera. However, their remains are very rare compared to the other OCVB floras.

The Arman flora is dominated by angiosperms, represented mainly by endemic species. In the Conia-cian floras of the OCVB, the diversity of flowering plants and the amount of their remains in burials sharply decrease. This process was previously related with a strong cooling caused by increased volcanic activity (Samylina, 1974; Lebedev, 1976, 1979, 1987). However, such a cooling is not recorded by any paleoclimatic studies. On the contrary, climate warming was observed in many regions of Northern Asia in the Coniacian and also in the Santonian-early Campanian (Spicer, Herman, 2010). We associate a reduction of angio-sperm in the Coniacian and Santonian-Campanian floras of the OCVB with an increase in the height of the volcanic highlands. In the upper mountain zones, temperatures were consistently lower than in the lower ones. Mountain conditions were probably also unfavorable for ferns, the diversity and number of which in the Ola flora is much lower than in the Arman flora.

The most significant changes are observed in the composition of conifers. The genera of Cupressaceae, which were also common in the coastal lowlands (Sequoia, Taxodium, Cupressinocladus) are dominated in the Arman flora. In Ola time, many new endemic conifers appeared, which were characteristic only for the volcanic uplands in this subprovince.

Due to abundance of angiosperms and ferns, the prevalence of widespread taxa, the participation of such valley plants as platanoids, Sequoia and Taxodium, the Arman flora is similar to the late Turonian and Coniacian floras of the coastal lowlands from the territory of the Anadyr Province. To the other floras of the Mountain Okhotsk-Chukotka Province, the Arman flora is similar in abundance of the Early Cretaceous relicts and in high endemism at the species and generic levels. Most likely, the Arman flora reflects low-mountain vegetation or vegetation of intermontane depressions.

In the Kholchan and Aleeky floras, angiosperms are already few, but endemic conifers have not yet appeared. The main role was played by the Early Cretaceous relicts (Ginkgo, Sphenobaiera, Phoenicopsis, Podozamites) and valley Cupressaceae (Sequoia, Metasequoia, Taxodium) inherited from the Arman flora. Plant communities, consisting of gynkgophytes, chekanowskialeans, cycadophytes and some conifers, existed in the mountains from the Early Cretaceous and, unlike angiosperms, were preadapted to the conditions of gradually rising volcanic uplands.

The Chingandzha flora did not participate in these florogenetic processes. Despite this, the Chingan-dzha flora is an important age benchmark for reconstructing the OCVB history, since its age is easily determined by its correlation with the other coastal floras of the Anadyr-Koryak region.

CHAPTER 9

SYSTEMATIC DESCRIPTION OF FOSSIL PLANTS

Below, we list the fossil plants of the Chingandzha flora in the systematic order. Their numbers correspond to the numbers of their descriptions in this chapter.

Division MARCHANTIOPHYTA

Order JUNGERMANNIALES

Genus JUNGERMANNITES Goepp., 1845

1. Jungermannites sp. MARCHANTIOPHYTA incertae sedis

Genus HEPATICITES Walton, 1925

2. Hepaticites sp. 1

3. Hepaticites sp. 2

4. Hepaticites sp. 3

5. Hepaticites sp. 4 Division EQUISETOPHYTA

Class EQUISETOPSIDA

Genus EQUISETUM L., 1753

6. Equisetum sp. Division POLYPODIOPHYTA

Class POLYPODIOPSIDA

Family OSMUNDACEAE

Genus OSMUNDA L., 1753

7. Osmunda tapensis Samyl. Family DICKSONIACEAE

Genus CONIOPTERIS Brongn., 1849

8. Coniopteris tschuktschorum (Krysht.) Samyl.

9. C. opposita Samyl. Family ASPLENIACEAE

Genus ASPLENIUM L., 1753

10. Asplenium dicksonianum Heer Family PTERIDACEAE

Genus ARCTOPTERIS Samyl., 1964

11. Arctopteris ilirnensis Golovn.

12. Arctopteris ochotica (Samyl.) Golovn., comb. nov. POLYPODIOPSIDA incertae sedis

Genus CLADOPHLEBIS Brongn., 1849

13. Cladophlebis inaequipinnulata Samyl. Genus LOBIFOLIA Rasskazova et E. Lebed., 1968

14. Lobifolia gleichenioides Golovn. et Grabovskiy

Division PINOPHYTA

Class PTERIDOSPERMAE Order CAYTONIALES

Genus SAGENOPTERIS Presl, 1938

15. Sagenopteris variabilis (Velen.) Velen. Class GINKGOOPSIDA

Family GINKGOACEAE

Genus GINKGO L., 1771

16. Ginkgo ex gr. adiantoides (Ung.) Heer

17. Ginkgo ex gr. sibirica Heer Class PINOPSIDA

Family CUPRESSACEAE

Genus SEQUOIA Endl., 1847

18. Sequoia ochotica Yudova et Golovn.

Genus METASEQUOIA Miki, 1941

19. Metasequoia sp.

Genus TAXODIUM Richard, 1810

20. Taxodium viligense Golovn., sp. nov. Genus CUPRESSINOCLADUS Seward, 1919

21. Cupressinocladus shelikhovii Golovn., sp. nov. Family PODOCARPACEAE

Genus PROTOPHYLLOCLADUS Berry, 1903

22. Protophyllocladus subintegrifolius (Lesq.) Berry Division MAGNOLIOPHYTA

Class MAGNOLIOPSIDA

Family PLATANACEAE

Genus PSEUDOPROTOPHYLLUM Holl., 1930

23. Pseudoprotophyllum cordatum Samyl. Family CERCIDIPHYLLACEAE

Genus TROCHODENDROIDES Berry, 1922

24. Trochodendroides tumanensis Yudova

25. Trochodendroides deminii Yudova et Golovn.

26. Trochodendroidespekulneensis Philipp.

27. Trochodendroides sp. MAGNOLIOPSIDA incertae sedis

Genus ARALIAEPHYLLUM Fontaine, 1889

28. Araliaephyllum devjatilovae Philipp.

29. Araliaephyllum speciosum Philipp. Genus DALEMBIA E. Lebed. et Herman, 1989

30. Dalembia kryshtofovichii (Samyl.) Golovn., comb. nov. Genus IEVLEVIA Samyl., 1976

31. levlevia dorofeevii Samyl. Genus MENISPERMITES Lesq., 1874

32. Menispermites sibiricus (Heer) Golovn. Genus QUEREUXIA Krysht. ex Baik., 1963

33. Quereuxia angulata (Newb.) Krysht. ex Baik.

Division MARCHANTIOPHYTA The lack of reproductive structures and insufficient preservation of fossil liverwort thalli hamper their accurate taxonomic determinations. They are usually accommodated within several morphogenera. According to C. Oostendorp (1987), the genus Hepaticites Walton is used for fossils that show clear affinities with the Marchantiophyta, but cannot be classified further, the genus Thallites Walton is used for thalloid fossils of indeterminate affinity, generaJungermannites Goepp. and Marchantites Brongn. are used for fossils that can be classified to the ordinal level. However, the boundaries of these genera are not clearly defined and their application is somewhat arbitrary.

Order JUNGERMANNIALES Genus JUNGERMANNITES Goepp., 1845 1. Jungermannites sp.

Pl. I, fig. 1-6, pl. III, fig. 3, pl. XL, fig. 4b, pl. XLIII, fig. 2b

Description. Thalli are prostrate, foliose, flattened, dorso-ventral, branching at an angle 70-90°, with two rows of scarcely overlapping leaves. Underleaves are lacking. Leaves are ovate or elliptical, with acute apices and sessile, obliquely inserted bases, 0,8-1,5 mm long, 0,4-1 mm wide. Leaves at lateral branches are significantly smaller than at main axis.

Comparison and remarks. Among living liverworts, these thalli most resemble those ofJungermannia, but they cannot be compared with any extant species.

Material. Collection BIN 538, spec. 22, 28, 200, 201-211; collection BIN 1565, spec. 191.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian.

MARCHANTIOPHYTA incertae sedis Genus HEPATICITES Walton, 1925

2. Hepaticites sp. 1

Pl. II, fig. 1

Description. Plants are thalloid, prostrate, forming flat rosettes up to 80 mm in diameter. The thallus is ribbon-like, 2,5-3 mm wide, with smooth or slightly undulate margin, evenly dichotomously branching 3-4 times at an angle 25-30°. The midrib is prominent, with irregular, oblique, alternating protrusions that may represent remains of ventral scales.

Comparison and remarks. Ventral scales and prominent midrib indicate affinities with the Marchantiales, but air pores or gemmae cups were not observed. Thus, assignment to Hepaticites is favored.

Thallites arctica Philipp. from the Krivorechenskaya Formation (Grebenka River, upper Albian-lower Turonian) is also characterized by rather large thalli up to 6-10 cm in diameter (Philippova, 1975; Philip-pova, Abramova, 1993). It differs from Hepaticites sp. 1 in narrower branches, 1-1,5 mm in width, which very often dichotomize.

T. tchucotica Philipp. from the Tylpegyrgynay Formation (Pekulney Ridge, Coniacian) and Chaun Group (Central Chukotka, Coniacian) has rosettes 3-6 cm in diameter and branches up to 3 mm in width (Philippova, Abramova, 1993). Its thalli are distinguished by extensions at the branch apices.

Material. Collection BIN 538, spec. 94a, 217a; collection BIN 1565, spec. 222.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian.

3. Hepaticites sp. 2

Pl. II, fig. 2, 4

Thallites sp., Golovneva et al., 2011, pl. I, fig. 3.

Description. Thalli are flat, rarely and unevenly branching. Branches are linear, 2,5-7 mm wide, with entire margin and prominent midrib that is about 1 mm wide with smooth edges. The branching angle varies from 25° to 70°.

Comparison and remarks. Thin lamina without ventral scales resembles thalli of some Metzgeriales. This liverwort is similar with Thallites sp. from the Arman Formation, Coniacian (Herman et al., 2016), which also has dichotomously forked thin thallus, 6-7 mm wide, with entire margin and pronounced median rib.

Material. Collection BIN 1565, spec. 221, 224-227, 229.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian.

4. Hepaticites sp. 3

Pl. II, fig. 3, pl. III, fig. 1, 2

Description. Thalli are flat, linear, 2-3 mm wide, prostrate, composed of midrib and a lamina, which is dissected by deep incisions into leaf-like lobes. They are rarely dichotomously branched at an angle 25-30°. Sometimes additional narrower branches diverge at an angle 70-90°. Midrib is prominent, about 0,3 mm in diameter. Lamina is very thin. Lobes are elliptic or ribbon-like, with decurrent base, convex outer side and rounded apex, 2-4 mm long and 1-1,5 mm wide.

Comparison and remarks. We could not find similar thalli among fossil liverworts. Among living plants these fossils may be more closely compared with the Jungermanniales than with any other group of the Marchantiophyta.

Material. Collection BIN 1565, spec. 223, 230, 377.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian.

5. Hepaticites sp. 4

Pl. III, fig. 4

Description. Plant is very small, rosette-like, with very thin thallus about 0,5 mm wide, dichotomously branched at an angle 20-30°. Midrib is not visible.

Comparison and remarks. Hepaticites sp. 4 is distinguished from Hepaticites sp. 1 and Hepaticites sp. 2 in smaller size, lack of midrib and in more acute angle branching.

Material. Collection BIN 538, spec. 241.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian.

Division EQUISETOPHYTA

Class EQUISETOPSIDA Genus EQUISETUM L., 1753

6. Equisetum sp. Pl. III, fig. 5, pl. XLVIII, fig. 5

Description. Horsetails are represented by underground rhizomes with tubers. The internodes are 2-4 cm long and about 2 mm wide, with longitudinal ribs. The tubers are ellipsoid, 10-13 mm long and about 5 mm wide.

Material. Collection BIN 547, spec. 117; collection BIN 1565, spec. 155.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga and Chingan-dzha rivers, Chingandzha Formation, Coniacian.

Division POLYPODIOPHYTA Class POLYPODIOPSIDA Family OSMUNDACEAE Genus OSMUNDA L., 1753 7. Osmunda tapensis Samyl.

Pl. IV, fig. 6

Osmunda tapensis Samylina, 1984a, p. 238, pl. I, fig. 2, 3, text-fig. 1. - Herman et al., 2016, p. 670, pl. I,

fig. 5, 10, 11, text-fig. 6.

Holotype. Spec. BIN 519/1, North-East of Russia, northern coast of the Sea of Okhotsk, Tap River, Chingandzha Formation, Coniacian; Samylina, 1984a, pl. I, fig. 2. - Pl. IV, fig. 6.

Description. Fronds are bipinnate. The pinnae are linear, 2,5-4,5 cm wide, gradually tapering toward the apices. The collections from the Chingandzha Formation yield fragments of pinnae up to 7 cm in length. The rachises of pinnae are thin, 1-1,5 mm wide, with longitudinal striations. The pinnules are alternate or opposite, tongue-shaped, with obtuse or rounded apices and sessile or petiolate bases, up to 22 mm long and 7 mm wide, densely arranged on the rachis and extend at an angle of 70-90°. The margins of the pinnules are parallel to each other for a considerable part of the length, finely dentate or entire. The pinnules usually are contracted on both sides in the base. In the lower part of the pinnae, their bases become truncate and have short petioles, which facilitated their easy separation from the rachis. Such pinnules are often found in dispersed condition. The venation is pinnate. The middle vein is straight, possessing 9-13 pairs of lateral veins, which usually dichotomize once. In some pinnules, the basal veins dichotomize twice.

Comparison and remarks. This species resembles Osmunda denticulata Samyl. from the Lower Cretaceous of the North-East of Russia (Samylina, 1976) in shape and size of pinnules, but lateral veins of O. den-ticulata usually dichotomize twice.

Material. Collection BIN 519, spec. 1-5.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Tap, Chingandzha and Kananyga rivers, Chingandzha Formation, Coniacian; Arman River, Arman Formation, upper Turonian.

Family DICKSONIACEAE Genus CONIOPTERIS Brongn., 1849 8. Coniopteris tschuktschorum (Krysht.) Samyl.

Pl. V, fig. 1-5, pl. XLIV, fig. 1, 2, 6

Dennstaedtia tschuktschorum Kryshtofovich, 1958, p. 23, pl. 1, fig. 1-5, text-fig. 2-5. - Efimova, 1966, p. 173, pl. 1, fig. 3, 4, pl. 2, fig. 1a, 2a, pl. 3, fig. 1, 2, 6. - Budantsev, 1983, pl. 3, fig. 5. - Philippova, 2010, p. 70, pl. 1, fig. 1-10, pl. 2, fig. 5. Coniopteris tschuktschorum (Krysht.) Samylina, 1976, p. 10. - Samylina, 1988, p. 33, pl. 1, fig. 6, 7. - Go-lovneva, 1994, p. 63, pl. 20, fig. 11-14, pl. 21, fig. 1, 2. - Shczepetov, Golovneva, 2010, p. 54, pl. 1, fig. 1, 2, 5. - Golovneva, 2018, p. 113, pl. 2, fig. 1-5, pl. 3, fig. 1-7, pl. 51, fig. 1a, 3a, pl. 53, fig. 5, 6. Coniopteris aff. bicrenata Samyl., in Shczepetov, 1991b, pl. 3, fig. 1-4, pl. 4, pl. 5, fig. 1-4, pl. 6, pl. 7, fig.

1-2, pl. 8, pl. 9, fig. 1-3, pl. 10, fig. 1-3, pl. 11, fig. 1-4. - Philippova, 2011, pl. 5, fig. 1, 2. Coniopteris sp., Philippova, Abramova, 1993, pl. 43, fig. 1, pl. 47, fig. 2-4.

Holotype. Spec. TSNIGR Museum 5649/5, North-East of Russia, northern coast of the Sea of Okhotsk, Pekulney Ridge, Pekulneyveem River, Upper Cretaceous; Kryshtofovich, 1958, pl. 1, fig. 1.

Description. Fronds are bipinnate, triangular, elongated. The pinnae are alternate or opposite, linear, gradually tapering toward the apices, 4-9 cm long and 1-2 cm wide near the base, diverging from rachis at an angle of 40-60° at a distance of 0,5-1,5 cm from each other, densely spaced, sometimes overlapping. The bases of the pinnae are asymmetrical, acroscopic pinnules are longer than the basiscopic ones and diverging from the axis at a more open angle. This asymmetry is gradually decreases to the pinna apex.

There are 14-20 pinnules on each side of the pinna. They are 5-10 mm long, the largest up to 1,5 cm long, alternate, ovate-lanceolate or rhomboidal, with obtuse or acute apex and cuneate decurrent conracted base, sessile in the upper part of the pinna and petiolate in the lower part of the pinna, asymmetric, dissected into two lobes on the basiscopic side and three lobes on the acroscopic side. The lobes on the acroscopic side are larger and extend at a more open angle than on the basiscopic side. The largest pinnules have up to 3-4 lobes on each side. In small pinnules near the apex of the pinna, the lobes gradually transform into the teeth. A single vein enters the pinnule, where unevenly dichotomously branches. Each lobe is innervated by 1-3 veins, which end near the margin, usually forming small teeth.

Fertile pinnules have a slightly reduced blade. Sori are located in the upper parts of the lobes at the ends of the veins, transversely oval, about 1 mm long and 1,5 mm wide.

Comparison and remarks. Coniopteris tschuktschorum was originally referred to the genus Dennstaedtia (Kryshtofovich, 1958). Samylina (1976) transferred this species to the genus Coniopteris based on the characteristic structure of vegetative and reproductive pinnae.

The sterile and fertile pinnae of C. tschuktschorum are morphologically indistinguishable from the pinnae of C. blomstrandii (Heer) Kvacek et Manum from the Paleogene flora of Spitsbergen (Kvacek, Ma-num, 1993) and pinnae of Dennstaedtia americana Knowlton from the Paleocene-Eocene floras of Northern America and Eurasia (Knowlton, 1910; Brown, 1962; Wolf, 1966; Budantsev, 1983, 1997, 2006) and pinnae of D. nipponica Oishi et Huzioka from the Oligocene flora of Japan (Oishi, Huzioka, 1941).

A study of spores of Coniopteris blomstrandii from Spitsbergen proved that this species could not be assigned to the genus Dennstaedtia, which are characterized by ornamental surface, while spores of Coniopteris blomstrandii have smooth exine (Kvacek, Manum, 1993).

Material. Collection BIN 519, spec. 6-10, 23, 24; collection BIN 524, spec. 3, 4; collection BIN 1565, spec. 575.

Stratigraphic horizon and occurrence. Upper Cretaceous of the North-East of Russia.

9. Coniopteris opposita Samyl.

Pl. VI, fig. 1-5, pl. VII, fig. 1-5

Coniopteris opposita Samylina, 1984b, p. 184, pl. 1, fig. 4-10, pl. 2, fig. 3-7. - Golovneva et al., 2011, pl. I, fig. 4.

Holotype. Spec. BIN 538/174, North-East of Russia, northern coast of the Sea of Okhotsk, Kananyga River, Chingandzha Formation, Coniacian; Samylina, 1984b, pl. 1, fig. 4. - Pl. VI, fig. 2.

Description. Fronds are bipinnate, small and delicate. The pinnae are alternate or subopposite, linear, gradually tapering to the apices, 1,5-2 cm long and about 0,5 cm wide near the base, diverging from rachis at an angle of 60-90°, widely spaced. The pinnuleas are opposite, sessile, ovate-lanceolate or rhomboidal, with obtuse apex and decurrent conracted base, small, 1,5-3 mm long, finely crenulate to lobed and dissected. Venation is pinnate; veins are short and simple. Basal pinnules are significantly larger, especially from acroscopic side.

Fertile pinnae are slightly reduced. Sori are rounded, 0,5 mm in diameter, located at the ends of the veins, usually in sinuses of pinnule lobes, rarely in the lobe apex.

Comparison and remarks. Coniopteris opposita differs from other species of the genus Coniopteris by small sizes, opposite arrangement of pinnules and weak reduction of fertile pinnae.

Material. Collection BIN 538, spec. 53, 171, 172, 174, 177, 179, 180, 181, 222; collection BIN 1565, spec. 174, 189, 190, 194, 195, 207, 213, 218, 220, 486, 488, 503, 504, 506, 520, 521a, 571, 572.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian.

Family ASPLENIACEAE Genus ASPLENIUM L., 1753

10. Asplenium dicksonianum Heer

Pl. X, fig. 5, 6

Asplenium dicksonianum Heer, 1874, p. 31, pl. 1, fig. 1-5. - Kryshtofovich, Baikovskaya, 1960, p. 11, pl. 1, fig. 1-6, pl. 2, fig. 1-4. - Samylina, 1964, p. 63, pl. 11, fig. 1-2. - Samylina, 1976, p. 34, pl. 14, fig. 3-5, pl. 17, fig. 6. - Lebedev, 1974, p. 40, pl. 6, fig. 4. - Herman, Lebedev, 1991, p. 163, pl. 19, fig. 2, pl. 21, fig. 6, pl. 13, fig. 3. - Philippova, Abramova, 1993, p. 60, pl. 1, fig. 1, 2, pl. 14, fig. 1, pl. 16, fig. 5, pl. 69, fig. 6, pl. 70, fig. 2, pl. 71, fig. 3. - Herman et al., 2016, p. 676, pl. V, fig. 1, 3, 12, 15. Description. Fronds are bipinnate. The preserved fragments are small, up to 6 cm in length. The rachis is straight, thin, usually winged. The pinnae are linear, tapering apically, alternate, from 1,0 up to 1,5 cm wide, extending from the rachis at angle 30°-40°. The pinnules are narrow, lanceolate, from 3 to 15 mm long and from 1 to 4 mm wide, inclined to the axis of the pinna at an angle 25-30°, slightly asymmetric, with an acute apices and cuneate decurrent base. Depending on the size, the margins of the pinnules are entire, slightly incised near the apices, dentate or have 3-7 partitions. The partitions are elongate-lanceolate, with an entire margin, with obtuse or shortly acute apex. The pinnule venation is pinnate, alternating.

Comparison and remarks. This species is widespread in the Cretaceous deposits of the Northern Hemisphere. Its assignment to the genus Asplenium L. was always doubtful. However, the lack of reproductive structures hampers its more accurate taxonomic determination.

Krassilov (1976) transferred Asplenium dicksonianum to the genus Anemia. However, the fertile fronds, which he described from the Upper Cretaceous of Sakhalin, were not found in the immediate connection with sterile leaves, and affiliation of these remains with the extant genus Anemia has not been proved owing to the poor preservation of sporangia and spores. Finally, when proposing this combination, Krassilov did not give the reference to the basionym. Therefore, this combination is invalid.

Material. Collection BIN 538, spec. 261; collection BIN 547, spec. 35-38, 52; collection BIN 1565, spec. 202, 208.

Stratigraphic horizon and occurrence. Cretaceous of Northern Asia.

Family PTERIDACEAE Genus ARCTOPTERIS Samyl., 1964

11. Arctopteris ilirnensis Golovn.

Pl. VIII, fig. 1-4, pl. XLVII, fig. 1, pl. XLVIII, fig. 1

Arctopteris ilirnensis Golovneva, 2018, p. 119, pl. 9, fig. 1-7, pl. 10, fig. 1-2.

A. aff. tschumicanensis E. Lebed., in Shczepetov, 1991b, pl. 12, fig. 4-6, pl. 13, fig. 1, 2, pl. 14, fig. 1, 2, pl. 15, pl. 16.

Arctopteris sp., Herman et al., 2016, p. 678, pl. V, fig. 13, 14.

Holotype. Spec. NEISRI PF3/29, North-East of Russia, Central Chukotka, Palyavaam River basin, the Voron'ya Formation, Coniacian; Golovneva, 2018, pl. 9, fig. 2.

Description. The preserved bipinnate leaf fragments are up to 8 cm in length. The rachis is thin, striated. The pinnae are subopposite, arising from the rachis at an angle 50-60°, linear-lanceolate, tapering in apical direction, up to 2,5 cm wide. The pinnules are alternate or subopposite, arising from the rachis at an angle 40-50°, linear-lanceolate, with acute, sometimes attenuate apex and dentate margin, 1-3 cm long and up to 1 cm wide, gradually reduced in sizes toward pinna apex and fused there in the bases. The pinnule base is sessile, decurrent or slightly contracted from basiscopic side and slightly contracted or straight from acroscopic side. Basal pinnule from basiscopic side of pinnae is decurrent to the frond rachis. There are also additional triangular pinnules on the frond rachis between pinnae. Pinna and pinnules usually fused in the bases near the frond apex. Venation is pinnate, lateral veins are simple or forked 1-2 times. The lateral basal veins from basiscopic side are arising from the rachis of pinna.

Comparison and remarks. The genus Arctopteris is widespread in the Cretaceous of Northern Asia, mainly in the Lower Cretaceous deposits. The type species A. kolymensis Samyl. comes from the lower-middle Albian deposits of the Buor-Kemyus Formation of the Kolyma River basin (Samylina, 1964). A. ilirnensis is distinguished from A. kolymensis to a lesser degree of branching of the pinnule lateral basal veins. They are simple or fork only once in A. ilirnensis, and branch two or three times in A. kolymensis. In addition, the pinnules of A. kolymensis are narrower and longer in shape, almost linear.

A. ilirnensis more resembles to A. rarinervis Samyl., also described from the Buor-Kemius Formation. These species are similar in shape of pinnules and branching pattern. However, A. ilirnensis has well-developed teeth along the margin, while in A. rarinervis the margin is entire. A. lenaensis Vassilevsk. from the Ap-tian deposits of the Ogoner-Yuryakh Formation of the Lena River basin also has entire pinnules, which are oval-rhombic in shape (Vassilevskaya, 1967). A. rarytkinensis Vassilevsk. from the Maastrichtian-Danian deposits of the Rarytkin Formation, the Koryak Upland (Vassilevskaya, 1977) is distinguished from A. ili-rnensis by the entire margin and by wide triangular, tongue-shaped pinnules.

Fronds fragments, described from the Arman Formation (Magadan Region) as Arctopteris sp. (Herman et al., 2016), is very similar with leaves of A. ilirnensis and we attribute these fossils to this species.

Material. Collection BIN 1565, spec. 197, 199-201, 206, 216.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian; Gydra Formation, Coniacian; Central Chukotka, Chaun Group, Coniacian; Arman River, Arman Formation, upper Turonian.

12. Arctopteris ochotica (Samyl.) Golovn., comb. nov.

Pl. IX, fig. 1, 4

Anemia ochotica Samylina, Late Cretaceous flora of the Tap River (Northern coast of the Sea of Okhotsk), 1984a, p. 239, pl. II, fig. 1.

Holotype. Spec. BIN 524/1, North-East of Russia, northern coast of the Sea of Okhotsk, Tap River, Chingandzha Formation, Coniacian; Samylina, 1984a, pl. II, fig. 1. - Pl. IX, fig. 1, 4.

Description. Fronds are bipinnate. The pinnae are alternate, arising from the rachis at an angle 40-50°, linear, tapering in apical direction, up to 6 cm long and 6-15 mm wide, densely spaced. There are 15 pairs of pinnae at preserved leaf fragments. The pinnules are cladophleboid, with entire margin, 5-9 mm long and 2-3,5 mm wide, extending from the rachis at an angle 50-80°. In the upper part of pinnae, the pinnules are narrower, with acute triangular apices, a slightly contracted basiscopic margin and decurrent acroscopic margin. In the lower part of pinnae, the pinnules are smaller and wider, with rounded apices. Basal pinnule from basiscopic side of pinnae is decurrent to the frond rachis. In the upper 7-8 pinnae, pinnules merge in their bases. The margin of these fused linear pinnae become gradually lobate, dentate, undulate or entire near leaf apex. The pinnule venation is pinnate, with 5-7 pairs of veins. Lateral veins are simple or dichotomize one time.

Comparison and remarks. Samylina (1984a) assigned this species to the genus Anemia. Its sterile pinnae are very diverse in shape and venation. However, cladophleboid pinnules with pinnate venation were not reported for this genus. Among Cretaceous ferns, such features as the fusion of pinnules on upper pinnae and decurrence of basal pinnule from basiscopic side of pinnae to the frond rachis are characteristic to the genus Arctopteris. Therefore, we transferred Anemia ochotica to the genus Arctopteris. From other species of this genus Arctopteris ochotica differs by lacking of additional pinnules on the rachis between pinnae and by shape

of pinnules. The pinnules of Arctopteris are usually longer, linear or linear-lanceolate, with numerous lateral veins, while the pinnules of A. ochotica are cladophleboid, triangular or oblong, with 5-7 pairs of lateral veins.

Material. Collection BIN 524, spec. 1.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Tap River, Chingandzha Formation, Coniacian.

POLYPODIOPSIDA incertae sedis Genus CLADOPHLEBIS Brongn., 1849 13. Cladophlebis inaequipinnulata Samyl.

Pl. III, fig. 6, pl. IV, fig. 1-5, pl. IX, fig. 2, 3, pl. X, fig. 1-3, 7, pl. XLIV, fig. 4, 5

Cladoplebis inaequipinnulata Samylina, 1984a, p. 240, pl. II, fig. 2-4. - Herman et al., 2016, p. 678, pl. VI,

fig. 5-11.

Holotype. Spec. BIN 519/12, North-East of Russia, northern coast of the Sea of Okhotsk, Tap River, Chingandzha Formation, Coniacian; Samylina, 1984a, pl. II, fig. 3. - Pl. X, fig. 1.

Description. The leaves are bipinnate. The rachis is thin, straight, 1 mm wide. The pinnae are opposite, linear or linear-lanceolate, from 4 to 8 cm long and from 0,9 to 2,2 cm wide, tapering apically and basally, extending from the rachis at an angle of 60°-80°.

The pinnules are tongue-shaped or triangular, sometimes slightly falcate, with acute or rounded apices and entire margin, from 5 to 15 mm long and from 3 up to 8 mm wide, extending from the rachis at an angle of 70°-80°. Basal pinnules are narrowed and smaller than in middle part of the pinna (sometimes twice), tongue-shaped with rounded apices and extend at a nearly right angle. The venation of pinnules is pinnate. The middle vein at the base is curved, decurrent along the rachis, and enters the pinnule near its basiscopic margin, in the middle part of the pinnule frequently slightly undulating. The lateral veins (7-8 pairs) dichotomize only once.

Comparison and remarks. This species is similar to Cladoplebis tschuktschorum Philipp. from the Chaun flora of Central Chukotka (Philippova, 1972; Golovneva, 2018) in pinnules extending at a nearly right angle, and their shape. However, the Chaun species differs in larger size of pinnules and in a larger number of lateral basal veins in the pinnules (up to 8-9 pairs), and also in lacking of small narrow basal pinnules.

The species C. septentrionalis Holl. was widespread in the younger deposits of the OCVB from the Ola and Mygdykit formations (Samylina, 1988). The leaves of this fern differ in narrower falcate pinnules with acute apices.

Material. Collection BIN 519, spec. 12-19; collection BIN 524, spec. 5, 6; collection BIN 1565, spec. 211, 212, 514-518, 545-550, 574.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Tap and Kananyga rivers, Chingandzha Formation, Coniacian; Gidra, Yum and Kananyga formations, Coniacian; Arman River, Arman Formation, upper Turonian.

Genus LOBIFOLIA Rasskazova et E. Lebed., 1968 14. Lobifolia gleichenioides Golovn. et Grabovskiy Pl. XI, fig. 1

Lobifolia gleichenioides Golovn. et Grabovskiy in Herman et al., 2016, p. 682, pl. VII, fig. 1, 2.

Holotype. Spec. BIN 528/35, Northeastern Russia, Arman River, Arman Formation, upper Turonian; Herman et al., 2016, pl. VII, figs. 1, 2.

Description. The leaves are bipinnate. The rachis is thick, 1,5-2 mm wide. The pinnae are alternate, linear, 5-7 mm wide, arising from the rachis at an angle of 80-90°. The pinnae are arranged at some distance from one another. The pinnules are alternate, tongue-shaped, with rounded apex and entire margin, 2-4 mm long and 1-2 mm wide, arising from the rachis at an angle of 60-80°. In the upper part of the pinnae, the pinnules are narrower and slightly falcate, sometimes with acute apex. In the lower part of the pinnae, the pinnules are wider, with a rounded apex and slightly contracted base. The basiscopic and acro-scopic basal pinnules are usually larger than the others, obovate, with a contracted base. The venation of pinnules is pinnate. The middle vein is straight, and the lateral veins are simple, in 5-7 pairs, extending from the middle vein at acute angle.

Comparison and remarks. The leaves of L. gleichenioides are distinguished from the leaves of type species L. novopokrovskii (Prynada) Rasskazova et E. Lebed. from the Lower Cretaceous deposits of the Urgal and Chemchuk formations of the Bureya River basin (Lebedev, Rasskazova, 1968) in the shape and size of pinnules, and also in the shape of the basal pinnule. The pinnules of L. novopokrovskii are triangular-ovate, 4-8 mm long, and in L. gleichenioides they are tongue-shaped, 3-5 mm long. The basiscopic basal pinnules are usually subdivided into two lobes in L. novopokrovskii, and the basal pinnules in L. gleichenioides are obovate and larger, then others.

The leaves of L. tschagdamensis (Vachr.) Vachr., also from the Urgal Formation (Lebedev, Rasskazova, 1968), have similar shape of basal pinnules, but they are distinguished by larger sizes (up to 7-9 mm long and 4-5 mm wide).

The species L. parvifolia Golovn. et Grabovskiy from the upper Turonian Arman Formation differs from L. gleichenioides by triangular-ovate pinnules with attenuate or acute apices and 3-5 pairs of lateral basal veins, which fork once, rarely twice. The basal pinnules of L. parvifolia are subdivided into two lobes, as in L. novopokrovskii.

Material. Collection BIN 1565, spec. 500.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian; Arman River, Arman Formation, upper Turonian.

Division PINOPHYTA Class PTERIDOSPERMAE Order CAYTONIALES Genus SAGENOPTERIS Presl, 1938

15. Sagenopteris variabilis (Velen.) Velen.

Pl. VIII, fig. 5, pl. XLVIII, fig. 4

Thinnfeldia variabilis Velenovsky, 1885, p. 6, pl. 2, fig. 1-5.

Sagenopteris variabilis (Velen.) Velen., in Velenovsky, 1889, p. 40. - Shczepetov et al., 1992, pl. 26, fig. 1, 5, 6. - Philippova, Abramova, 1993, p. 70, pl. 16, fig. 6, pl. 18, fig. 2-7. - Herman et al., 2016, p. 686, pl. VII, fig. 4-6.

Description. There are only isolated leaflets in the Chingandzha collections. They are obovate, with a short petiole, rounded or acute apex and gradually tapering cuneate base, 2-3 cm long and 1-1,4 cm wide. The margin is entire. The midvein is thin and traced approximately up to a half of the leaflet length. The lateral veins extend from the middle vein at acute angle and are connected by anastomoses, forming elongated meshes.

Comparison and remarks. The leaves of Sagenopteris are commonly found in the Lower Cretaceous and the lower part of the Upper Cretaceous of the Northern Hemisphere. Usually, they are assigned to S. variabilis (Kryshtofovich, Baikovskaya, 1960; Philippova, Abramova, 1993), described for the first time from the Cenomanian deposits of the Czech Republic (Velenovsky, 1889). The leaflets of this species are characterized by a relatively variable shape and size. Material. Collection BIN 1565, spec. 585, 586.

Stratigraphic horizon and occurrence. Jurassic-Cretaceous of the Northern Hemisphere.

Class GINKGOOPSIDA Family GINKGOACEAE Genus GINKGO L., 1771

16. Ginkgo ex gr. adiantoides (Ung.) Heer Pl. XI, fig. 2-9, pl. XII, fig. 1-4, pl. XLVIII, fig. 9

Ginkgo ex gr. adiantoides (Ung.) Heer in Lebedev, 1974, p. 62, pl. 16, fig. 1-6, pl. 17, fig. 1. - Samylina, 1976, p. 54, pl. 20, fig. 1, 2, pl. 26, fig. 7-9. - Samylina, 1984a, pl. III, fig. 7. -Samylina, 1989, pl. I, fig. 1, 2.- Philippova, Abramova, 1993, p. 79, pl. 1, fig. 6, pl. 21, fig. 9, 10, pl. 22, fig. 4-6, pl. 62, fig. 10, pl. 70, fig. 8, 9. - Golovneva, 1994, p. 65, pl. 1, fig. 1, 2, 12, 13, pl. 11, fig. 2, pl. 20, fig. 8. - Moiseeva, Sokolova, 2011, pl. 1, fig. 10, 13. - Herman et al., 2016, p. 688, pl. IX, fig. 1, 3, 5, 12. - Golovneva, 2016, p. 81, pl. 3, fig. 2, pl. 4, fig. 1. - Golovneva, 2018, p. 135, pl. 27, fig. 9, pl. 50, fig. 10.

Description. Leaf blades are broadly fan-shaped, with long petiole, 2-9 cm long and 2,5-10 cm wide. The base is broadly cuneate with basal angle 70°-300°. The upper margin is rounded or undulating, often with several shallow incisions. The middle incision is the deepest (up to 1/2 of the length of the leaf blade) and subdivides the blade into two parts. The venation is dichotomous with veins radiating out into the leaf blade. Vein density is 12-24 per 1 cm.

Comparison and remarks. Ginkgo ex gr. adiantoides is conventionally used as a formal name for entire-margined leaves of Ginkgo without preserved cuticle. Such remains, resembling leaves of the modern G. biloba L., are often found in the Cretaceous deposits of Northern Asia since the Albian. The entire-margined leaves of Ginkgo with the preserved cuticle were recorded from the upper Albian-lower Turonian Krivorechenskaya Formation, in the Turonian-Coniacian Valizhgen Formation and in the Santonian-lower Campanian Arkagala Formation. All these fossils were assigned to the widespread species G. pilifera Samyl. (Samylina, 1967, 1988). It is possible, that the remains from the Chingandzha Formation may belong to this species.

Material. Collection BIN 519, spec. 22; collection BIN 538, spec. 63; collection BIN 547, spec. 3, 4, 15-33, 65, 79b, 100, 162; collection BIN 1565, spec. 140-142, 144-148, 152, 158, 357a, 524, 558, 587, 588. Stratigraphic horizon and occurrence. Upper Cretaceous and Paleogene of the Northern Hemisphere.

17. Ginkgo ex gr. sibirica Heer Pl. XII, fig. 5-10, pl. XLVIII, fig. 8, pl. XLIX, fig. 1, 2, 9

Ginkgo ex gr. sibirica Heer, in Samylina, 1976, p. 56, pl. 27, fig. 4, 5. - Samylina, 1988, p. 40, pl. 3, fig. 2, 3a, 4-6. - Shczepetov, Golovneva, 2010, p. 59, pl. 5, fig. 9, pl. 10, fig. 1, 4, 8, 9. - Golovneva et al., 2011, pl. II, fig. 1, 6. - Shczepetov, Herman, 2013, pl. 3, fig. 5.- Herman et al., 2016, p. 690, pl. IX, fig. 2, 4, 6-8, 10, 11, 13. - Golovneva, 2016, p. 82, pl. 1, fig. 2, pl. 3, fig. 1, 3-5, pl. 4, fig. 2-4. - Golovneva, 2018, p. 135, pl. 27, fig. 1-4, pl. 50, fig. 1-9, pl. 52, fig. 6b. G. ex gr. concinna Heer, in Shczepetov, 1991b, pl. 55, fig. 1.

G. ex gr. huttoniiauct. non (Sternb.) Heer, in Philippova, Abramova, 1993, p. 80, pl. 22, fig. 1, 2, pl. 63, fig. 2. G. ex gr. lepida Heer, in Samylina, 1989, pl. I, fig. 3. - Shczepetov, 1991b, pl. 57, fig. 1-3, 4b. - Philippova, Abramova, 1993, p. 81, pl. 22, fig. 3.

Description. The leaves are fan-shaped, 3,5-6 cm long and 3,5-7 cm wide, with long petiole, rounded upper part and broadly cuneate or truncate base. The leaf blade is deeply incised into 6-10 lobes. They are usually narrowly lanceolate, 4-8 mm wide, with rounded apices. The incisions are deep, almost reaching the petiole. The venation is dichotomous.

Comparison and remarks. The remains of Ginkgo with a dissected leaf blade are common in the Jurassic and Lower Cretaceous deposits of Northern Asia. Leaves without cuticle are assigned to several formal species with indistinct boundaries: Ginkgo ex gr. sibirica, G. ex gr. huttonii, G. ex gr. lepida (Samylina, 1976; Philippova, Abramova, 1993).

The Late Cretaceous dissected leaves with the preserved cuticle were found only in the Arkagala Formation. In the structure of the epidermis, they are similar to G. pilifera Samyl. (Samylina, 1988) and are clearly distinct from G. sibirica from its type locality (Ust'-Baley, Cheremkhovaya Formation, Middle Jurassic).

Material. Collection BIN 538, spec. 158, 160; collection BIN 547, spec. 6, 39-51; collection BIN 1565, spec. 502, 522.

Stratigraphic horizon and occurrence. Jurassic-Cretaceous of the Northern Hemisphere.

Class PINOPSIDA Family CUPRESSACEAE Genus SEQUOIA Endl., 1847 18. Sequoia ochotica Yudova et Golovn. Pl. XIII, fig. 1-4, pl. XIV, fig. 1-6, pl. XV, fig. 1-5, pl. XVI, fig. 1-9, pl. XVII, fig. 1-5, pl. XXIV, fig. 1, 2, pl. XLIV, fig. 7, 9, pl. XLVIII, fig. 6, pl. XLIX, fig. 5, 6, pl. L, fig. 3, 6, 7

Sequoia ochotica Yudova et Golovn., in Yudova, Golovneva, 2015, p. 82, pl. I, fig. 1-4, pl. II, fig. 1-6, pl. III, fig. 1-5, pl. IV, fig. 1-3, pl. V, fig. 1-5, pl. VI, fig. 1-8. - Herman et al., 2016, p. 696, pl. XVI, fig. 1-8. -Golovneva, 2018, p. 146, pl. 35, fig. 1, 2, 4-7, pl. 57, fig. 3.

S. cf. minuta auct. non Sveshn., in Samylina, 1976, pl. XLIII, fig. 16-18.

S. minuta auct. non Sveshn., in Samylina, 1989, pl. I, fig. 5, pl. II, fig. 3.

S. tenuifolia auct. non (Schmalh.) Sveshn.; in Samylina, 1989, pl. I, fig. 7, pl. II, fig. 13.

S. obovata auct. non Knowlton, in Philippova, Abramova, 1993, pl. 2, fig. 5. - Philippova, 2011, pl. 2, fig. 8.

Sequoia sp., Golovneva et al., 2011, pl. III, fig. 1-3.

Sequoia sp. 1, Shczepetov, Golovneva, 2010, p. 60, pl. I, fig. 6, 8, pl. V, fig. 2, 5, 6, pl. VII, fig. 3, pl. X, fig. 7,

pl. XII, fig. 2, 4, 7, 8, pl. XIII, fig. 7. Cephalotaxopsis heterophylla auct. non Holl., in Philippova, Abramova, 1993, pl. 2, fig. 1, 2. Taxites heterophyllus auct. non (Holl.) Samyl. in Samylina, 1984a, pl. III, fig. 6. - Samylina, 1989, pl. II, fig. 2.

T. ex gr. intermedius auct. non (Holl.) Samyl. in Samylina, 1989, pl. I, fig. 6.

Holotype. Spec. BIN 1565/451, North-East of Russia, northern coast of the Sea of Okhotsk, Kananyga River, Chingandzha Formation, Coniacian; Yudova, Golovneva, 2015, pl. I, fig. 2. - Pl. XIII, fig. 2.

Diagnosis (Yudova, Golovneva, 2015). Axial shoots with helically arranged flat linear or scale-shaped leaves, varying in size from 2 to 5 mm; ultimate branchlets with linear or linear-lanceolate leaves, arranging distichously, 4-14 mm in length and 1-1,5 mm in width; apex of the linear leaves broadly triangular with blunt or rounded point; branches often with small scales in the base.

Description. The branching shoots are with a helical or distichous leaf arrangement. The ultimate flattened shoots with distichous leaves reach 1-10 cm in length and 3-28 mm in width. At the base of the branches, there are 4-6 short small scales. The leaves are linear or linear-lanceolate, with one vein, slightly widened in the middle part, 2-16 mm long and 1-1,5 mm wide, extend from the axis at an angle of 30-80°. The leaves are tapering toward the apex, which has a triangular, obtuse, or rounded shape with a mucro. The leaf bases are decurrent to the shoot, leaving prominent oblique lines. Axial shoots possess helically arranged scalelike, small subulate or falcate leaves 1-5 mm long and approximately 1 mm wide, extending from the axis at acute angle. Sometimes the ultimate shoots bear spirally arranged flattened leaves extending from the shoot at an angle of 20-40°. The buds and microstrobiles are ovoid, approximately 2 mm in diameter and 3-4 mm in length, and occur on the ends of short branchlets with narrow curved leaves up to 3 mm long. Cones are broadly ellipsoid or oblong, 12-15 mm in diameter, with a spiral arrangement of peltate scales.

Comparison and remarks. The genus Sequoia is often recorded in Siberia and in the North-East of Russia since the Late Cretaceous. Formal taxa S. concinna Heer, S. reichenbachii (Gein.) Heer, S. fastigiata (Sternb.) Heer, S. obovata Knowlton, S. ambigua Heer are widely used previously for description of such fossils (Samylina, 1976; Philippova, Abramova, 1993). In addition, five species have been described based on leaf epidermal characters. The species S. minuta Sveshn. comes from the Cenomanian-Coniacian deposits of the Timmerdyakh Formation in the Vilyuy River basin (Sveshnikova, 1967). The species S. tenuifolia (Schmalh.) Sveshn. et Budants. is described from the Turonian-Coniacian deposits of New Siberia Island (Sveshnikova, Budantsev, 1969). Two species were described by Samylina (1988) based on material from the Santonian-lower Campanian Arkagala Formation of the Kolyma River basin: S. parvifolia Samyl. and S. antiqua Samyl. The species S. lebedevii N. Nosova et Golovn. comes from the Cenomanian-Turonian deposits of the Simonovo Formation of Western Siberia (Golovneva, Nosova, 2012).

The shoots of Sequoia ochotica have significant morphological similarity with shoots of modern S. sempervirens (D. Don) Endl., from which they differ in smaller sizes. Leaves of S. sempervirens reach 25 mm in length, most often the length of leaves varies between 12 and 20 mm. In S. ochotica, the leaves usually reach 7-8 mm, less often 10-12 mm.

Two Cretaceous species S. tenuifolia and S. minuta also have shoots with smaller leaves than modern Sequoia. They are almost indistinguishable from S. ochotica in morphological features. However, the diagnostic characters of these species are based on the epidermal structure. Hence, these names should not be used for shoots lacking a cuticle. Species S. parvifolia and S. antiqua are characterized by even smaller sizes, rather wide, closely spaced leaves and frequent branching (Samylina, 1988). The species S. lebedevii is distinguished by rounded leaf apices and by rather large falcate leaves on axial shoots.

The shoots of S. ochotica differ from those of S. armanensis Golovn. from the upper Turonian Arman Formation (Herman et al., 2016) in the narrower, mainly linear leaves with acute apices and widely spaced leaf arrangement. The leaves on the axial shoots are also smaller and mostly scale-like. In S. armanensis the ultimate branchlets have closely spaced wider linear-lanceolate distichous leaves with rounded apices. Leaves on the axial shoots are larger, usually falcate.

Material. Collection BIN 519, spec. 28-41, 73b; collection BIN 538, spec. 11, 52, 67, 101b, 152; collection BIN 547, spec. 1, 57-61, 66, 69-71, 73, 74, 79a, 81, 84, 101-112; collection BIN 1565, spec. 45-54, 61, 62, 66-70, 72, 74-76, 84a, 89, 90, 93, 99, 112-121, 130-133, 160-167, 369, 370, 408, 417, 419, 421, 430, 432, 437, 443, 447, 450, 451, 455, 456, 457, 458, 460, 463, 466-472, 474, 478, 481, 526-531.

Stratigraphie horizon and occurrence. Northern coast of the Sea of Okhotsk, Tap, Kananyga and Chingandzha rivers, Chingandzha Formation, Coniacian; Gydra and Kananyga formations, Coniacian; Parnyi Formation, upper Turonian; Arman River, Arman Formation, upper Turonian; Central Chukotka, Chaun Group, Coniacian.

Genus METASEQUOIA Miki, 1941 19. Metasequoia sp.

Pl. XVIII, fig. 1-8, pl. XIX, fig. 2, 3, pl. XLIV, fig. 3

Metasequoia sp., Shczepetov, 1991b, pl. 93, fig. 1-4. - Shczepetov, Golovneva, 2010, p. 61, pl. I, fig. 3, pl. 9, fig. 4. - Golovneva, 2018, p. 147, pl. 35, fig. 8, 10, 12, 13, pl. 50, fig. 4, pl. 54, fig. 2, 3, pl. 62, fig. 4. - Akinin et al., 2019, pl. 6, fig. 5. M. ex gr. occidentalis auct. non (Newb.) Chaney, in Samylina, 1989, pl. III, fig. 3.

M. cuneata auct. non (Newb.) Chaney, in Philippova, Abramova, 1993, pl. 55, fig. 3. - Philippova, 2011, pl. 5, fig. 8.

Description. Ultimate branchlets are 1,5-7 cm long and 5-32 mm wide, flattened, with two rows of opposite leaves. The leaves are linear-lanceolate or linear, with a single midvein, rounded base and rounded or bluntly pointed apex, 3-25 mm long and 1-2,5 mm wide, extend from the shoot at an angle of 40-60°. The leaf bases are decurrent to the shoot, leaving prominent oblique lines. The leaf length can reach 30 mm on large axial shoots, where the opposite leaf arrangement can sometimes be transformed to alternate. Some leafy shoots are compound, consisting of two orders of branching (pl. XVIII, fig. 1-3, pl. XIX, fig. 2, 3).

Comparison and remarks. The genus Metasequoia was widespread in the Late Cretaceous flora of Northern Asia from the Coniacian. It is known in the Chingandzha, Chaun, Aleeky, and Ola floras of the OCVB, as well as in the Tylpegyrgynay and Kakanaut floras of the Anadyr Province (Samylina, 1988; Philippova, Abramova, 1993; Golovneva, 1994; Shczepetov, 1995; Philippova, 2010).

Two species were described from Northern Asia based on epidermal characters: M. asiatica Samyl. from the Arkagala Formation (Samylina, 1988) and M. paradoxa Sveshn. from the Timmerdakh Formation of Eastern Siberia (Sveshnikova, 1967).

Shoots from different localities are very similar in morphology. The distinction of species is inpossible without well-preserved leaf epidermis and reproductive structures. Therefore, shoots from the Chingand-zha Formation are identified only as Metasequoia sp.

Material. Collection BIN 519, spec. 25; collection BIN 547, spec. 2, 33, 67, 89-96, 113-115; collection BIN 1565, spec. 58, 60a, 71, 73, 77, 94-97, 103, 105, 424, 454, 457, 465a, 532, 565, 567.

Stratigraphic horizon and occurrence. Upper Cretaceous and Paleogene of the Northern Hemisphere.

Genus TAXODIUM Richard, 1810 20. Taxodium viligense Golovn., sp. nov.

Pl. XIX, fig. 1, 4, pl. XX, fig. 1-5, pl. XXI, fig. 1-4, pl. XXII, fig. 1-5

Etymology - from the Viliga River.

Holotype. Spec. BIN 1565/466a, leafy shoot, North-East of Russia, northern coast of the Sea of Okhotsk, Kananyga River, Chingandzha Formation, Coniacian. - Pl. XXI, fig. 1.

Paratypes. Spec. BIN 538/138, shoot with pollen cones, pl. XXII, fig. 2; spec. BIN 1565/470, branch with short and long shoots, pl. XX, fig. 4, 5.

Diagnosis. Long perennial shoots with helically arranged short shoots and rare short flat appressed lanceolate leaves; short shoots 2-3 mm long and about 1,5 mm in diameter, diverging from the shoot at an angle 40-50° and bearing several alternate, closely spaced leaf scars; ultimate annual shoots located on short shoots in terminal position with helical or distichous leaf arrangement; leaves narrow and widely spaced, flattened, linear, with acute apices, twisted in their basal parts, 12-25 mm long, 1-1,5 mm wide; leaf bases narrowing into short petiole, decurrent to the shoot axis.

Description. Long perennial shoots are up to 4 mm in diameter with irregularly alternate short shoots and rare short flat appressed leaves. Short shoots are 2-3 mm long and about 1,5 mm in diameter, diverging from the shoot at angle 40-50° and bearing several alternate, closely spaced leaf scars. Leaves on the long perennial shoots are widely spaced, flat, sessile, lanceolate, 3-4 mm long, about 1 mm wide, with acute apex and wide de-current base, diverging from the shoot at an angle 20-30°. Ultimate annual shoots are located on short shoots in terminal position. They are 6-11 cm long and 1,3-2,5 cm wide, sometimes branching, with helical or distichous leaf arrangement. The axes of ultimate shoots are 1-1,5 mm in diameter, with longitudinal striation.

Leaves are thin and widely spaced. Leaf blades are dorsiventrally flattened, linear or lanceolate, straight, with acute apices, twisted in their basal parts, 12-25 mm long, 1-1,5 mm wide. Angles between shoot axes and leaf axis vary between 20° and 50° (sometimes up to 80°). Leaf bases are narrowing into short petiole and decurrent to the shoot axis. Decurrent lines of the shoot axis are parallel. There are several scale-like leaves in the base of annual shoots (pl. XX, fig. 4, 5, pl. XXI, fig. 4). They are oval, flat, 1-2 mm long and about 1 mm wide. The longest leaves are near the middle of the shoot or below. The leaf length is gradually decreasing towards the apex. Leaves of the annual shoots are helically arranged and helically or distichously spreading. Large annual shoots often have additional axillary branchlets (pl. XIX, fig. 4, pl. XX, fig. 2, 3, pl. XXI, fig. 3, pl. XXII, fig. 1, 4, 5). Usually they are small, 0,5-3 cm long, with shorter, closely spaced leaves.

Pollen cones are arranged helically in short leafless terminal racemes (pl. XXII, fig. 2). They are attached solitarily, in lateral and terminal positions, closely spaced, ovoid-oblong in shape, 1,5-2 mm long and 1-1,5 in diameter. Number and size of microsporophylls are unclear.

Comparison and remarks. Shoots of Taxodium viligense differ from shoots of other Late Cretaceous species of Taxodium in very narrow and widely spaced leaves. The species T. amguemense (Efimova) Golovn., widely distributed in the Upper Cretaceous deposits of the OCVB (Golovneva, Shczepetov, 2011; Herman et al., 2016; Golovneva, 2018), is distinct in significantly larger sizes of shoots and in wider leaves. The annual branchlets of T. amguemense are flat, with distichous leaf arrangement, 6-14 cm long and 2-9 cm wide. The leaves are 1-6 cm long and 1,5-3 mm wide.

Shoots of T. cf. olrikii (Heer) Brown were described from the Turonian-Coniacian Kholokhovchan flora. They come from tuffaceous-terrigenous deposits of the Vetvinskaya Member (the Chalbugchan Group) in the Penzhina and Oklan rivers interfluve, the North-East of Russia (Herman, Sokolova, 2016). The terminal shoots of this species vary in length from 1 to 7 cm, with linear-lanceolate leaves, 0,3-1,1 cm long and up to 1,3 mm wide. They are significantly smaller then shoots of T. viligense. Foliage of the Kholokhovchan Taxodium is associated with panicle of spherical pollen cones 1,5-2mm in diameter.

Leaves of T. pseudotinajorum Sveshn. from the Turonian-Coniacian Timmerdyakh Formation of the Vilyuy River (Sveshnikova, 1967) are also wider than those of T. viligense. Its leaves reached 15-23 mm in length and 2,5-3 mm in width. The affinity of T. pseudotinajorum to the genus Taxodium is confirmed by its epidermal features (Sveshnikova, 1967). Leaves of T. sibiricum (I. Lebed.) Golovn. from the Cenomanian-Turonian Simonovo Formation of Western Siberia reached 5-18 mm in length and 1,5-2 mm in width (Golovneva, Nosova, 2012).

Reproductive organs of Taxodium were described from the Cenomanian and Maastrichtian of Europe (Knobloch, Mai, 1986) and from the Maastrichtian of North America (Aulenback, LePage, 1998).

Material. Collection BIN 538, spec. 64, 70, 77, 82, 84, 88, 215, 216, 217b, 222b; collection BIN 1565, spec. 57, 63, 65, 77, 80-84, 86, 98, 104, 107, 122-128, 134, 138, 367, 422a, b, c, 429, 466, 470, 473, 475-477, 479, 480, 482, 512b.

Stratigraphie horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian.

Genus CUPRESSINOCLADUS Seward, 1919 21. Cupressinocladus shelikhovii Golovn., sp. nov.

Pl. XXIII, fig. 1-7

Libocedrus catenulata (Bell) Krysht., in Samylina, 1989, pl. I, fig. 4. Thuja cretaceae (Heer) Newb., in Samylina, 1989, pl. II, fig. 8, 9. Cupressinocladus sp., Golovneva et al., 2011, pl. II, fig. 2-4.

Etymology - after Russian explorer Grigory Shelikhov.

Holotype. Spec. BIN 1565/183, North-East of Russia, northern coast of the Sea of Okhotsk, Kananyga River, Chingandzha Formation, Coniacian. - Pl. XXIII, fig. 7.

Diagnosis. Branching shoots opposite; leaves persistent, decussate, scaly, dimorphic; branches and branchlets arising in axils of lateral leaves almost in each node, obliquely spreading, closely spaced; facial and lateral leaves approximately equal in length or marginal leaves slightly shorter; facial leaves flat, appressed, widely-rhombic, weakly keeled, with acute apices; marginal leaves folded along the midline, slightly falcate, with acute and very short free portion.

Description. Foliage sprays are flat, oblong in outline, with opposite branching and decussate arrangement of leaves. In collection there are several fragments 3-5 cm in length with three orders of branching. The branches and branchlets are borne in the axils of lateral leaves at an angle of 40-50° almost in each node, closely spaced.

Ultimate branches are 2-7 mm long and 1-2 mm wide and penultimate branches are 13-30 mm long and 4-14 mm wide. Leaves of the ultimate and penultimate branches are similar in shape and size, but sometimes leaves of the ultimate order are two times smaller than the leaves of the penultimate order.

Leaves are scale-like, decussate, imbricate, adpressed, dimorphic: facial and marginal. The facial leaves are flat, widely-rhombic, weakly keeled, with acute apices, 1-2,5 mm long and 1-2,5 mm wide. The marginal leaves are as long as facial leaves or slightly shorter; their bases embrace the facial leaves on the sides, partially covering them in the lower part. The marginal leaves are folded along the midline, boat-like, slightly falcate, 1-2,5 mm in length, 0,5-1 mm in width. The apices of the marginal leaves are acute, with very short free portion.

Leaves on the first order axes are longer, 3-5 mm in length. The marginal leaves are more strongly bent and have longer falcate free upper portions.

Comparison and remarks. Opposite branching is characteristic for several taxa of the Cretaceous and Paleocene Cupressaceae. Based on the morphology of plagiotropic shoots, type of branching and leaf outline, the description of new species fits well to the diagnosis of the genus Mesocyparis, occurring in the Maastrichtian and Paleocene deposits of the Northern Hemisphere (McIver, Basinger, 1987; Golovneva, 1988; Kodrul et al., 2006). But facial and marginal leaves in the shoots of Mesocyparis with opposite branching (M. borealis McIver et Basinger, M. beringiana (Golovn.) McIver et Aulenback) are more elongated and branches and branchlets are more widely spaced. Ultimate and penultimate branches in Cupressinocladus shelikhovii are longer, then in Mesocyparis. The number of nodes on ultimate branches is 2-9 in C. shelikho-vii, and 1-6 in Mesocyparis. The number of nodes on penultimate branches reaches 18 in C. shelikhovii, and 9-10 in Mesocyparis. Such long shoots are characteristic for species from tribe Libocedreae, but their marginal leaves are developed considerably better, then facial leaves (Golovneva, 1988). More detailed comparison of these fossils is hampered by lacking of seed cones in C. shelikhovii.

The shoots of new species closely resemble the shoots described as Libocedrus arctica Sveshn. et Bu-dants. from the New Siberia Island and the Arman Formation of the Magadan Region (Sveshnikova, Bu-dantsev, 1969; Herman et al., 2016). However in the shoots of C. shelikhovii the marginal leaves are approximately equal to the marginal leaves and have short free apices extending parallel to the axis of the shoot, and in shoots of Libocedrus arctica, the marginal leaves are considerably longer than the facial leaves and have long free apices declining from the shoot axis.

Samylina (1984b, 1989) considered the shoots of C. shelikhovii from the Chingandzha Formation as belonging to Libocedrus catenulata or Thuja cretaceae. The shoots of Libocedrus catenulata (now Ditaxocladus catenulatus (W. A. Bell) S. X. Guo, Kvacek, Manchester et Z. K. Zhou) differ from the shoots of Cupressinocladus shelikhovii by cladode-like foliage with fused leaves (Guo et al., 2012). The species Libocedrus catenu-lata was also reported from several other Upper Cretaceous localities of the Northern Asia (Sveshnikova, 1967; Lebedev, 1987; Samylina, 1988), but all this material shoud be restudied.

The species Thuja cretaceae was initially described from the Upper Cretaceous deposits of Greenland as Libocedrus cretaceae Heer (1882, pl. XXIX, fig. 1, 2) based on vegetative shoots with opposite branching. These shoots are rather similar with the Chingandzha material in leaf morphology, but detailed comparison is not possible since Libocedrus cretaceae is represented only by small fragments.

Material. Collection BIN 538, spec. 137, 193-197, 227; collection BIN 547, spec. 10; collection BIN 1565, spec. 171-178, 181-183.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga and Chingan-dzha rivers, Chingandzha Formation, Coniacian.

Family PODOCARPACEAE Genus PROTOPHYLLOCLADUS Berry, 1903 22. Protophyllocladus subintegrifolius (Lesq.) Berry Pl. XXV, fig. 1-5

Description. The material comprises several small detached phylloclades. They are simple, oblong-lanceolate or oblong-obovate in outline, often asymmetric, 2-7 cm long, 0,3-1 cm wide, with cuneate de-current base. The apex is acute or rounded. The margin is entire or dentate, with rare acute teeth about

1-1,5 mm long. The midvein is straight and thin. The lateral veins diverge from midvein at acute angle, and bifurcate 2-3 times.

Comparison and remarks. The genus Protophyllocladus was established for the phylloclades from the Cenomanian deposits of the Dakota Formation, USA (Berry, 1903). Originally, Berry included three species in this genus: P. subintegrifolius (Lesq.) Berry, P. lanceolatus (Knowlton) Berry, and P. polymorphus (Lesq.) Berry. Later, Berry described P. lobatus Berry with pinnatilobate phylloclades from the Upper Cretaceous Magothy Formation, Maryland, USA (Berry, 1911) and Black Creek Formation, South Carolina, USA (Berry, 1914). Two additional species were described by Hollick (1930) from the Upper Cretaceous Kaltag Formation, Alaska: P. obesus Holl. and P. simplex Holl.

There are no clear morphological boundaries between these species, since the structure of phylloclades of Protophyllocladus is characterized by significant variability. Kryshtofovich united all species of Protophyllocladus, except P. lobatus, under the name of P. polymorphus (Kryshtofovich, 1937; Kryshtofovich, Baikovskaya, 1960). Later Tanai (1979) showed that the name P. subintegrifolius has a priority over P. polymorphus.

Four species of Protophyllocladus were described on the base of epidermal characters (Nosova, Golov-neva, 2014). Epidermal features of Protophyllocladus are similar to those of the modern genus Phyllocladus Richard, suggesting the podocarpaceous affinity of Protophyllocladus. Unfortunately, the epidermal structure of the Chingandzha specimens is unknown.

The phylloclades from the Chingandzha Formation are morphologically similar to those of type species P. subintegrifolius from Kansas (Berry, 1903) and many other localities. Unlike other findings, the Chingan-dzha specimens show well preserved lateral veins, which are actually rather widely spaced and bifurcate

2-3 times.

Material. Collection BIN 519, spec. 54-61; collection BIN 538, spec. 214. Stratigraphic horizon and occurrence. Cretaceous of the Northern Hemisphere.

Division MAGNOLIOPHYTA Class MAGNOLIOPSIDA

Family PLATANACEAE Genus PSEUDOPROTOPHYLLUM Holl., 1930 23. Pseudoprotophyllum cordatum Samyl. Pl. XXIV, fig. 3-6, pl. XXV, fig. 6-9, pl. XXVI, fig. 1-5, pl. XXVII, fig. 1-3; pl. XXVIII, fig. 1-4, pl. XXIX, fig. 1-3, pl. XXX, fig. 1-7, pl. XXXIV, fig. 1, text-fig. 9.1, 9.2.

Pseudoprotophyllum cordatum Samylina, 1984b, p. 185, pl. 1, fig. 1-3, pl. 2, text-fig. 1, 2. - Shczepetov, Golovneva, 2009, p. 1333, pl. 30, fig. 1-5, pl. 31, fig. 1-4. - Golovneva et al., 2011, pl. IV, fig. 1-7, text-fig. 5a-i.

Paraprotophyllum cordatum (Samyl.) Samyl., in Herman, Lebedev, 1991, p. 84. - Samylina, 1988, p. 105,

non rite publ. - Samylina, 1989, pl. III, fig. 1, pl. IV, fig. 1, pl. V, fig. 1. Viburniphyllum ochoticum Samylina, 1989, p. 70, pl. IV, fig. 2. Platanus primaeva auct. non Vachr., in Samylina, 1989, pl. I, fig. 8. Credneria sp., Samylina, 1989, pl. II, fig. 2.

Pseudoprotophyllum boreale auct. non (Daws.) Bell, in Samylina, 1984a, pl. I, fig. 1. - Samylina, 1989, pl. VI, fig. 1.

Holotype. Spec. BIN 538/136, North-East of Russia, northern coast of the Sea of Okhotsk, Kananyga River, Chingandzha Formation, Coniacian; Samylina, 1984b, pl. 1, fig. 1, pl. 2, fig. 1. - Pl. XXIV, fig. 5.

Diagnosis (after Shczepetov, Golovneva, 2009). Leaves rounded-ovate or broadly elliptic; apex acute or acuminate; base varying in shape, usually deeply cordate, more rarely peltate, truncate, rounded or cune-

Fig. 9.1. Morphological diversity of Pseudoprotophyllum cordatum Samyl.: a - spec. BIN 519/45; b -spec. BIN 519/48a; c - spec. BIN 519/44; d - spec. BIN 519/47; e - spec. BIN 538/136, holotype; f - spec. BIN 547/9; g - spec. BIN 547/164; h - spec. BIN 538/135; i - spec. BIN 547/13; j - spec. BIN 547/8a. Scale bar 1 cm.

ate; leaf margin toothed, teeth with pointed apex and concave sinuses; venation craspedodromous, pinnate-palmate or more rarely pinnate; basal veins diverging suprabasally, with 5-7 basiscopic branches, mostly forked or branched; basal and suprabasal veins weakly arching, subopposite, 6-8 pairs; subbasal veins simple or branched, radiating laterally and downwards, looping or terminating in teeth; tertiary venation weakly arching, scalariform.

Description. Leaves are simple, entire, usually rounded-ovate or, more rarely, broadly elliptical. The length varies from 6 cm to approximately 18 cm, and the width varies from 4 to 18 cm. Most of leaves are 10-14 cm long and 10-13 cm wide. The apex is acute or acuminate. The base is most often deeply cordate, less often peltate, truncate, rounded or cuneate. Only 5% of leaves are peltate. The leaf margin is dentate. The teeth are triangular, 1-4 mm high, usually glandular, with an acute apex and low concave sinuses. Only one leaf has small lateral lobes (pl. XXIX, fig. 3).

The venation is craspedodromous, pinnate-palmate or pinnate. There are 6-8 pairs of secondary veins (basal and suprabasal), which are subopposite, straight or slightly arching, diverging from the midvein at an angle of about 45-80°. The basal veins are the thickest and the longest and reach about 2/3 of the lamina length in leaves with pinnate-palmate venation. In leaves with pinnate venation, basal veins are thinner and reach about 1/3 of the leaf lamina. Pinnate venation occurs in both small and large leaves. Basal veins diverge from the midvein 0,2-1,0 cm above the margin of the leaf lamina and bear 5-7 basiscopic branches. Suprabasal lateral veins bear 1-4 basiscopic branches in the distal part. One-three pairs of thin curved sub-basal veins diverge from the midvein below the basal veins. The longest subbasal veins (usually upper pair) can branch near the leaf margin. The subbasal veins are looping or terminate in teeth. The tertiary venation is well developed, scalariform or branchy-scalariform, represented by curved and branching anastomoses. The venation of the fourth order is orthogonal-reticulate.

Comparison and remarks. The type species of Pseudoprotophyllum is P. boreale Holl. from the Upper Cretaceous of Alaska and northern Canada (Hollick, 1930). Leaves of P. cordatum differ from leaves of P. boreale by prevailing rounded-ovate shape with deeply cordate base and by lacking of lobes (Shczepetov, Golovneva, 2009). P. boreale is characterized by leaves with peltate, truncate and rounded base. A cordate base was not reported for this species.

Several more species of Pseudoprotophyllum are known from the Late Cretaceous of Northern Asia (Golovneva, 2009). These are P. giganteum Budants. et Sveshn. from the Turonian-Coniacian of New Siberia Island (Sveshnikova, Budantsev, 1969), P. evenkiense I. Lebed. and P. lebedevii Budants. from the Cenomanian-Turonian of Western Siberia (Lebedev, 1954, 1962; Budantsev, 1975; Golovneva, Nosova, 2012), and P. hatangaense Abramova from the Turonian-Coniacian of the Khatanga Depression (Abra-mova, 1983; Golovneva, 2012).

Leaves of P. cordatum are most resembling leaves of P. hatangaense in broadly ovate lamina shape with predominance of cordate base. P. hatangaense differs from P. cordatum by the leaf shape, which is usually broadly ovate with obtuse or rounded apex. In addition, P. hatangaense is characterized by more intensive branching of secondary and tertiary veins near margin. Other species of Pseudoprotophyllum are characterized by peltate, truncate or rounded bases. Besides that, leaves of P. evenkiense and P. lebedevii usually have small lateral lobes. P. giganteum mostly has large peltate non-lobate leaves.

Due to highly variable leaf shape, many specimens of P. cordatum from the Chingandzha flora were previously assigned to other genera: Paraprotophyllum, Credneria, Viburniphyllum and Platanus.

Specimens with cordate or truncate bases were referred to Paraprotophyllum (Samylina, 1989, pl. III, fig. 1, pl. IV, fig. 1, pl. V, fig. 1). However, this genus is characterized by 8-12 pairs of secondary veins (Herman, 1984; Golovneva, 2010), while Pseudoprotophyllum cordatum has 6-8 pairs.

Samylina (1989, pl. I, fig. 8) figured a lower part of P. cordatum leaf with a truncate base under the name Platanus primaeva Vachr. But morphology of the leaf base, margin, and venation of this specimen completely fits to that of other specimens of Pseudoprotophyllum cordatum.

Two specimens with rounded-cuneate bases (pl. XXVI, fig. 3, 5), which were earlier reported as Viburniphyllum ochoticum (Samylina, 1989, pl. IV, fig. 2) and Credneria sp. (Samylina, 1989, pl. II, fig. 2), differ in the greatest degree from the typical leaves of Pseudoprotophyllum cordatum with deeply cordate bases. The genus Credneria was established for leaves from the Senonian deposits of Germany (Zenker, 1833). They are obovate, with small lobes and thick and long basal veins. In contrast, the specimen described by Samylina as Credneria sp., has palmate-pinnate venation and, therefore, cannot be assigned to the genus Credneria. The form-genus Viburniphyllum includes various leaves of unclear systematic position, which have pinnate venation and dentate margin (Krassilov, 1976; Herman, Lebedev, 1991). Although specimen BIN 547/8a is

Fig. 9.2. Morphological diversity of Pseudoprotophyllum cordatum Samyl.: a - spec. BIN 1565/256a, b; b - spec. BIN 1565/258; c - spec. BIN 1565/305; d - spec. BIN 1565/284; e - spec. BIN 1565/364; f - spec. BIN 1565/409; g - spec. BIN 1565/318; h - spec. BIN 1565/262; i - spec. BIN 1565/312; j -spec. BIN 1565/257; k - spec. BIN 1565/410; l - spec. BIN 1565/291; m - spec. BIN 1565/387. Scale bar 1 cm.

assignable to this genus by formal characters, its distinct subbasal veins and dentate margin relate it with the Platanaceae. We assign both specimens to Pseudoprotophyllum cordatum based on such characters as the identical morphology of the leaf margin, subbasal veins, and venation of the third and fourth orders. They differ from other P. cordatum leaves by narrower base and by acute angle between the main vein and basal veins. However, both characters are very variable in P. cordatum. Many leaves with a truncate base also have narrow undeveloped pomes, resembling those in leaves described as Viburniphyllum ochoticum and Credneria sp.

The cordate base relates P. cordatum with species of the genus Arthollia, also occurring in the Turonian-Coniacian of Northern Asia (Herman, Golovneva, 1988). However, peltate leaves are not characteristic for the latter genus.

Material. Collection BIN 519, spec. 43-50; collection BIN 538, spec. 15, 133-136, 221, 224; collection BIN 547, spec. 5, 8a, 9, 13, 14, 136, 164; collection BIN 1565, spec. 256-258, 261, 262, 265, 267, 269, 272, 277, 280, 284-286, 286, 291, 292, 305, 310, 312, 314, 317, 318, 320, 364, 380, 387, 389-392, 394, 395, 409, 410, 4986 539, 544, 563, 591.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga, Tap and Chingandzha rivers, Chingandzha Formation, Coniacian.

Family CERCIDIPHYLLACEAE Genus TROCHODENDROIDES Berry, 1922 24. Trochodendroides tumanensis Yudova Pl. XXXI, fig. 1-13, pl. XXXIII, fig. 6-8, pl. LII, fig. 1, 3, 7

Trochodendroides tumanensis Yudova, in Yudova, Golovneva, 2014, p. 63, pl. I, fig. 1-9.

Zizyphus smilacifolia auct. non Budants., in Samylina, 1989, pl. 4, fig. 4. - Philippova, Abramova, 1993,

p. 160, pl. 77, fig. 2, 3. - Philippova, 2010, p. 117, pl. 26, fig. 2, 3. Zizyphus aff. hyperborea auct. non Heer, in Samylina, 1989, pl. II, fig. 11. Trochodendroides sp. 2, Golovneva et al., 2011, pl. V, fig. 2, 3.

Holotype. Spec. BIN 1565/27, North-East of Russia, northern coast of the Sea of Okhotsk, Kananyga River basin, Chingandzha Formation, Coniacian; Yudova, Golovneva, 2014, pl. I, fig. 3. - Pl. XXXI, fig. 3.

Diagnosis. Leaves narrowly ovate or elliptical, with rounded or widely cuneate base and tapering attenuate or acute apex; margin dentate; teeth small, about 1 mm in length, triangular, frequent, adpressed, evenly developed, with acute or obtuse apex.

Description. The leaves are narrowly ovate or elliptical, varying in size from 4 cm up to 12 cm in length and from 1,8 cm up to 5 cm in width, with rounded or widely cuneate base and tapering attenuate or acute apex. The petiole is rather thick and shorter, than leaf lamina (pl. XXXIV, fig. 2, 3). The margin is dentate. The teeth are small, about 1 mm in length, triangular, frequent, adpressed, evenly developed, with acute or obtuse apex. The sinuses between the teeth are acute.

The venation is palmate, brochidodromous, 3-5-nervous. The central vein is straight, terminates at the top of the leaf, having 1-3 pairs of short secondary branches in the upper part. The inner basal veins are arcuately curved and rise to the top of the leaf, where they are joined with the branches extending from the central vein. The arena between the inner basal veins is narrowly elliptical. Inner basal veins bear 9-10 basi-scopic curved branches, which connected each other to form a row (in large leaves 2-3 rows) of diminishing loops along the margin. The outer basal veins are connected with branches of inner basal veins in the lower third of the leaf and bear 5-6 basiscopic branches, which also form loops.

The tertiary venation is scalariform-reticulate. The central and inner basal veins are connected by curved percurrent branching anastomoses (pl. XXXI, fig. 5, 6). The thin short veins go from the outer sides of the loops into teeth apices.

Comparison and remarks. Leaves of the genus Trochodendroides with elongated blades are sometimes assigned to other genera, such as Zizyphus or Macclintockia (Golovneva, Alekseev, 2010). In particular, Samylina (1989) described two leaves of Trochodendroides tumanensis from the Chingandzha Formation under the names Zizyphus aff. hyperborea and Z. smilacifolia. The species Z. smilacifolia previously was described from the upper part of the Timmerdakh Formation of the Lena-Vilyuy Depression (Budantsev, 1968) and then was transferred to the genus Trochodendroides (Golovneva, Alekseev, 2010). However, since the name T. smilacifolia (Newb.) Krysht. already existed (Kryshtofovich, 1958), this species was renamed as T. budantsevii Golovn. This species is distinguished from T. tumanensis by a

long, narrow apex, a more elongated leaf blade and by dentation. The teeth of T. budantsevii are larger and uneven in size, an alternation of large and small teeth is observed (Golovneva, Alekseev, 2010). The leaves of T. beketovii Golovn., from the same locality as T. budantsevii, are characterized by a more elongated narrowly lanceolate shape and by smaller adpressed teeth with a blunt apex (Golovneva, Alekseev, 2010).

The species T. tumanensis is very similar to Zizyphus anadyrensis Philipp. from the Tylpegyrgynay Formation of the Pekulney Ridge (Philippova, Abramova, 1993; Philippova, 2010) in ovate or elliptical leaves with rounded or widely cuneate base. Now this species is considered as conspecific with T. pekulneensis Philipp. from the Poperechnenskaya Formation of the Pekulney Ridge (Golovneva et al., 2017). The leaves of T. pekulneensis differ in acute attenuate apex and in small, often compound, with additional denticle on basal side, teeth.

The leaves of Trochodendroides tumanensis are similar to several other species of this genus having an elongated leaf blade.

The leaves of T. ananjevii Golovn. from the Simonovo Formation of the Chulym-Yenisei region (Golov-neva, Alekseev, 2010) differ from leaves of T. tumanensis in a widely elliptical or obovate leaf blade with a short-pointed apex and rounded teeth.

The species T. sachalinensis (Krysht.) Krysht. from the Coniacian deposits of Sakhalin (Kryshtofovich, 1937; Kryshtofovich, Baikovskaya, 1960) differs from T. tumanensis in a wider leaf blade and larger triangular or helm-like teeth with acute apex.

The leaves of T. ochotica (Vachr. et Herman) Golovn. et Gnilovskaya from the Campanian-Maastrich-tian deposits of the North-East of Russia are characterized by elliptical or elliptical-ovate, rarely obovate leaves with widely cuneate or rounded base and gradually tapering, acute or obtuse apex, that is similar with T. tumanensis. But teeth of this species are very small, rather frequent, and triangular, with acute or obtuse apex, adpressed, with long basal side and short apical side. Teeth of T. tumanensis are wider and rounded.

The species T. tumanensis was indicated for the Arman flora of the Okhotsk-Chukotka volcanic belt (Herman et al., 2016, pl. XXV, fig. 14-17). We believe that features of these specimens correspond to the diagnosis of T. magadanica Golovn. The last species differs from T. tumanensis by small, frequent, rounded-triangular teeth with obtuse apices and acute sinuses. The teeth of T. tumanensis are more rare and wider.

Material. Collection BIN 538, spec. 5, 58, 74, 89, 90, 97, 108, 110, 147, 149, 150; collection BIN 547, spec. 7, 118-120, 122, 123, 125; collection BIN 1565, spec. 2, 3, 5, 7, 14, 16-18, 21, 27, 39, 54b, 231, 240, 241, 242, 244, 245, 249, 253, 319, 402, 403, 496, 497, 510, 511, 542.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga and Chingan-dzha rivers, Chingandzha Formation, Coniacian; Gydra and Yum formations, Coniacian; Pekulney Ridge, Tylpegyrgynay Formation, Coniacian.

25. Trochodendroides deminii Yudova et Golovn.

Pl. XXXII, fig. 1-9, pl. XXXIII, fig. 4, pl. LII, fig. 2

Trochodendroides deminii Yudova et Golovneva, 2014, p. 64, pl. II, fig. 1-9. - Golovneva et al., 2017,

p. 129, pl. II, fig. 1-9, pl. III, fig. 1-13, text-fig. 3f. T. ex gr. arctica auct. non (Heer) Berry, in Shczepetov et al., 1992, pl. 40, fig. 3-5. - Spicer et al., 2002,

Fig. 12 B.

T. arctica auct. non (Heer) Berry, in Philippova, 2010, p. 105, pl. 14, fig. 1-6, 8, 9, pl. 17, fig. 7. T. richardsonii auct. non (Heer) Krysht., in Herman, Lebedev, 1991, p. 116, pl. XIII, fig. 2. T. sachalinensis auct. non (Krysht.) Krysht., in Herman, Lebedev, 1991, p. 118, pl. XIII, fig. 3, 4. Zizyphus varietas auct. non Holl., in Samylina, 1989, pl. II, fig. 5. Trochodendroides sp. 1, Golovneva et al., 2011, pl. V, fig. 1.

Holotype. Spec. BIN 1565/233, North-East of Russia, northern coast of the Sea of Okhotsk, Kananyga River, Chingandzha Formation, Coniacian; Yudova, Golovneva, 2014, pl. II, fig. 4. - Pl. XXXII, fig. 6.

Diagnosis (emended in Golovneva et al., 2017). Leaves varying in shape from orbicular-ovate, ovate, and elliptical-ovate to widely elliptical, elliptical or rhomboid, with rounded, widely cuneate, truncate or cordate base and rounded or acute apex; margin crenate-dentate; teeth rather large, rounded-triangular, 2-3 mm in length, slightly adpressed, with rounded apex.

Description. The leaves are ovate, orbicular-ovate, oval-ovate, widely elliptical, sometimes transversely oval, elliptical and rhomboid-oval, with a rounded, truncated, widely cuneate, less often cordate base and a rounded or acute apex, 3,5-9 cm long and 3-7 cm wide. Ovate or widely elliptical shape with rounded or slightly cordate base and acute apex prevail. The petiole is thin, its full length is not known. The leaf margin is crenate-dentate. Teeth are rather large, 2-3 mm in length, rounded-triangular, slightly adpressed, with a wide base and rounded or blunt apex.

The venation is palmate, brochidodromous, 3-5-nervous. The central vein is straight, terminates at the top of the leaf, having 2-3 pairs of secondary branches in the upper part. The inner basal veins usually depart from the central vein slightly higher than the outer basal veins. They are arcuately curved and rise to the top of the leaf, where they are connected with the lower branches extending from the central vein. The arena between the inner basal veins is wedge-shaped or elliptical. The inner basal veins bear 4-5 basiscopic branches forming a series of loops along the margin. The outer basal veins are thinner and shorter, than inner ones, curved, connected to the lower branches of the inner basal veins in the lower part of the leaf, and bear 4-6 short basiscopic branches, which also form series of loops along the margin. Well-defined thin veins extend from the outer side of the loops to the teeth. The central and inner basal veins are connected by percurrent, curved and branching anastomoses. The tertiary venation inside the loops is reticulate.

Comparison and remarks. This species was described on the material from the Chingandzha Formation (Yudova, Golovneva, 2014). The study of the genus Trochodendroides from other localities revealed the wide occurrence of T. deminii in the Upper Cretaceous of the North-East of Russia (Golovneva et al., 2017).

Previously leaves of T. deminii from the Anadyr River basin and the Pekulney Ridge were described under the name T. arctica (Heer) Berry (Shczepetov et al., 1992; Spicer et al., 2002; Philippova, 2010). However, the type material of T. arctica from the Paleocene deposits of Greenland now belongs to the genus Zizyphoides (Crane et al., 1991). Leaves of this genus have a wavy, scalloped or irregularly dentate margin. The leaves of T. deminii are characterized by crenate margin with triangular-rounded teeth, which corresponds to the diagnosis of the genus Trochodendroides.

The elliptical leaves of T. deminii from the Coniacian deposits of the Valizhgen Formation from the Cape Konglomeratovy were assigned to T. sachalinensis (Krysht.) Krysht., and the rounded-ovate leaves from the lower Campanian deposits of the upper subformation of the Bystrinskaya Formation of the Cape Valizhgen to T. richardsonii (Heer) Krysht. (Herman, Lebedev, 1991). The species T. sachalinensis is similar to T. deminii in the shape of the leaf blade, but differs by fine-toothed margin with acute, elongated, triangular teeth. The leaves of T. deminii from the Valizhgen Formation have large, rounded, rather low teeth with a wide base. The species T. richardsonii comes from the Paleocene deposits of Greenland. In the North-East of Russia it was found in the Maastrichtian-Danian deposits of the Rarytkin Formation (Golovneva, 1994). This species also has orbicular-ovate or widely elliptical leaves and similar large teeth. However, it differs by well-developed inner basal veins and their branches, which often are craspedodromous. This feature is not characteristic for T. deminii.

The species T. deminii differs from T. tumanensis in wider leaf blades and in other teeth shape. In T. tu-manensis the teeth are small, triangular, adpressed, and in T. deminii the teeth are larger, with a rounded apex.

The leaves of T. notabilis Herman from the Turonian-Coniacian of Northwestern Kamchatka (Herman, Lebedev, 1991) differ in the bicrenate teeth.

The species T. intermedia Budants. from the upper part of the Timmerdakh Formation of the Lena-Vily-uy Depression (Budantsev, 1968) is similar to T. deminii in shape of the base and apex, but differs in a wider form of the leaf blade with smaller teeth, which are often notched at the apex. The species T. zizyphoides Budants. from the same formation (Budantsev, 1968) is characterized by varying leaf shapes, among which there are orbicular-ovate and elliptical-ovate. Unlike T. deminii, this species has a narrowed apex with a long acute tip and alternating teeth of different sizes.

The leaves of T. bidentata Vassilevsk. et Golovn. from the Rarytkin Formation of the Koryak Upland (Golovneva, 1991) are distinguished by a pointed elongated apex and by large teeth with additional small denticle on the basal side.

Material. Collection BIN 547, spec. 11, 138-140; collection BIN 1565, spec. 1, 22, 37, 38, 40, 44, 233, 234, 508.

Stratigraphic horizon and occurrence. Anadyr River basin, Grebenka River, Krivorechenskaya Formation, upper Albian-lower Turonian; northern coast of the Sea of Okhotsk, Kananyga, Tap and Chingan-

dzha rivers, Chingandzha Formation, Coniacian; Gydra Formation, Coniacian; Ul'ya River basin, Amka Formation, Coniacian; Pekulney Ridge, Poperechnenskaya and Tylpegyrgynay formations, Coniacian; Cape Konglomeratovy, Valyzhgen Formation, Coniacian; Cape Valyzhgen, upper part of the Bystrinskaya Formation, lower Campanian; Kakanaut River, Kakanaut Formation, Maastrichtian.

26. Trochodendroides pekulneensis Philipp.

Pl. XXXIII, fig. 1, 2

Trochodendroides pekulneensis Philippova, 1991, p. 88, pl. X, fig. 1-3. - Philippova, Abramova, 1993, p. 130, pl. 76, fig. 4, pl. 77, fig. 6, pl. 114, fig. 1. - Philippova, 2010, p. 106, pl. 15, fig. 1-5, text-fig. 21. -Golovneva et al., 2017, p. 134, pl. VIII, fig. 1-5, pl. IX, fig. 1, 2, 4, 5, 7, 8. Zizyphus anadyrensis Philipp., in Philippova, Abramova, 1993, p. 162, pl. 71, fig. 8, pl. 85, fig. 6-8, pl. 86,

fig. 8, 9, pl. 114, fig. 3, 4. - Philippova, 2010, p. 118, pl. 26, fig. 8, 9, text-fig. 24. Trochodendroides sp. Yudova, Golovneva, 2014, p. 65, pl. III, fig. 1, 2.

Holotype: Spec. TFI 1017/465, North-East of Russia, Pekulney Ridge, Poperechnenskaya Formation, Coniacian; Philippova, 2010, pl. XV, fig. 2.

Diagnosis (emended in Golovneva et al., 2017). Leaves ovate, widely ovate, elliptical and widely elliptical, with cordate or widely cuneate, often asymmetric base and acute attenuate apex; margin dentate; teeth small, compound, 1-3 mm in length, helm-shaped, rounded or triangular, with obtuse apices and with additional denticle on basal side; denticle is smaller then main tooth.

Description. The leaves are ovate, widely ovate, elliptical and widely elliptical, 4-13 cm long and 1,88 cm wide. The apex is acute, attenuate or triangular. The base is slightly cordate or widely cuneate, often asymmetric. The petiole is not preserved. The margin is double-dentate. The teeth are small, compound, 1-3 mm in length, helm-shaped, rounded or triangular, with obtuse apices and with additional denticle on basal side. This denticle is smaller then main tooth. The sinuses between the teeth are acute.

The venation is palmate, brochidodromous, 3-5-nervous. The central vein is straight, terminates at the top of the leaf. The inner basal veins usually depart from the central vein at the same level as outer basal veins and rise upward, where they are connected with the short branches extending from the central vein. The arena between the inner basal veins is elliptical. The inner basal veins bear 6-7 basiscopic curved branches, which join and form two rows of loops. The outer basal veins are thinner and shorter, than inner ones, curved, connected to the lower branches of the inner basal veins in the lower part of the leaf, and bear several short basiscopic curved branches, which also form series of loops along the margin. Well-defined thin veins extend from the outer side of the loops to the teeth. The central and inner basal veins are connected by percurrent branching anastomoses. The tertiary venation inside the loops is reticulate.

Comparison and remarks. Philippova (2010) established two similar species with elongated leaf blades and compound teeth in the Tylpegyrgynay flora: Trochodendroides pekulneensis and Zizyphus anadyrensis. They differ in leaf shape. The leaves of T. pekulneensis are ovate or widely ovate, with an expanded, slightly cordate or rounded, often asymmetric base. The leaves of Z. anadyrensis are usually elliptical with widely cuneate base. However, between these two types there are transitional shapes. In addition, these species have very similar compound double teeth with an additional denticle on the basal side. This character is rather unusual for the genus Trochodendroides. We believe that the leaves described under the names T. pekulneensis and Z. anadyrensis belong to the same species, for which the name T. pe-kulneensis is priority.

Among other species of the genus Trochodendroides, double dentation has been described in T. zizyphoi-des Budants. and T. budantsevii Golovn. The species T. zizyphoides from the Turonian-Coniacian deposits of the Lena-Vilyuy Depression (Golovneva, Alekseev, 2010) is characterized by a variable leaf shape from elliptical and ovate to orbicular and obovate, while in T. pekulneensis it is mostly elliptical or ovate. In T. zizyphoides teeth are narrow, oval-triangular with rounded apices and teeth of different sizes alternate, while in T. pekulneensis teeth are wider, helm-shaped, rounded or triangular, with acute or obtuse apices and additional small denticle on the basal side. The species T. budantsevii comes from the same deposits as T. zizyphoides (Golovneva, Alekseev, 2010). This species, unlike T. pekulneensis, usually has a narrower leaf blade with an attenuate apex and alternating in size, obliquely directed triangular teeth. Material. Collection BIN 1565, spec. 10.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian; Pekulney Ridge, Poperechnenskaya and Tylpegyrgynay formations, Conia-cian.

27. Trochodendroides sp.

Pl. XXXIII, fig. 3, 5

Description. The leaves are simple, weakly asymmetric, ovate in outline, with broadly cuneate or rounded base and acute attenuate apex, 10-12 cm long and 6 cm wide. The margin is dentate. The teeth are large, 5-7 mm long, oblong-triangular, with a wide base and rounded or blunt apex. The petiole is not preserved. The venation is palmate, brochidodromous, 3-5-nervous. The central vein is straight, terminates at the top of the leaf, having 3-4 pairs of secondary branches in the upper part. The inner basal veins usually depart from the central vein slightly higher than the outer basal veins. The arena between the inner basal veins is wedge-shaped. The inner basal veins bear 4-5 basiscopic branches. The outer basal veins are thinner and shorter, rising no higher than half the leaf lamina. The inner and outer basal veins and their branches form several series of loops along the margin. Well-defined thin veins extend from the outer side of the loops to the teeth. The tertiary venation is prominent.The tertiary veins are percurrent within the arena and are reticulate inside the loops.

Comparison and remarks. These leaves are very similar with leaves of T. notabilis from the Turonian-Coniacian of Northwestern Kamchatka (Herman, Lebedev, 1991) in venation and large teeth, but last species differs in the bicrenate teeth.

Material. Collection BIN 519, spec. 80, 81.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Tap River, Chingandzha Formation, Coniacian.

MAGNOLIOPSIDA incertae sedis Genus ARALIAEPHYLLUM Fontaine, 1889 28. Araliaephyllum devjatilovae Philipp.

Pl. XXXIV, fig. 5, 6, pl. XXXV, fig. 1-4

Araliaephyllum devjatilovae Philippova, 1989, p. 85, pl. 10, fig. 1, 2, text-fig. 2. - Philippova, Abramova,

1993, p. 152, pl. 36, fig. 1, 2. Lindera jarmolenkoi auct. non Imch., in Samylina, 1989, pl. II, fig. 1.

Holotype. Spec. TFI 622/20, North-East of Russia, Anadyr River basin, Bystraya River, Krivorechen-skaya Formation, upper Albian-lower Turonian; Philippova, 1989, pl. 10, fig. 1.

Diagnosis emended. Leaves 3-7-lobed, rounded, ovate, or transversely widely elliptical in outline, with rounded or cordate base; margin entire; lobes short, their length is equal to 1/3-1/4 of leaf length, they wide-triangular or helmet-shaped; sinuses wide (up to 90°), triangular; upper lateral basal veins diverging from the midvein at an angle about 45° and lower lateral basal veins diverging from the midvein at an angle about 90°.

Description. The leaves are simple, 3-7-lobed, rounded, ovate, or transversely widely elliptical in outline, with rounded or cordate base, 6-10 cm long, 4-10 cm wide. The margin is entire. Lobes are rather short, their length is equal to 1/3-1/4 of leaf length. They are wide-triangular or helmet-shaped, with convex sides and rounded or acute apices. The central lobe is the biggest. Lateral lobes are shorter. Sinuses are wide, triangular (up to 90°) with obtuse apices. The primary venation is palmate, the secondary venation is brochidodromous. The midvein and upper lateral basal veins are straight and rather thick. Upper lateral basal veins diverge from the midvein at an angle about 45° and terminate in the upper lateral lobe apices. Lower lateral basal veins are straight or curved, diverging from the midvein at an angle about 90° and ending in the lower lateral lobe apices or joining with secondary veins branching from upper basal veins. The lowest lobes are innervated by strong straight veins, which branched from lower basal veins near petiole. Midvein and basal veins bear several curved acroscopic and basiscopic branches, which form loops near the margin. Tertiary venation is thin, usually irregular. In middle part of large leaves tertiary veins are irregularly percurrent, with curved and branching anastomoses. Higher-order venation is not well preserved.

Comparison and remarks. Leaves of A. devjatilovae from the Krivorechenskaya Formation of the Anadyr River basin sometimes have additional lobe-like teeth on upper or lower side of main lobes (Philip-pova, Abramova, 1993).

Leaves of A. montanum Philipp. from the upper Turonian Arman Formation (Philippova, Abramova, 1993; Herman et al., 2016) are similar with those of A. devjatilovae in small triangular lateral lobes and wide sinuses, but differ in number of lobes (9) and in cuneate base.

Material. Collection BIN 1565, spec. 301, 371, 372, 382, 385a, 493, 495b,c.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chingandzha Formation, Coniacian; Anadyr River basin, Krivorechenskaya Formation, upper Albian-lower Turonian.

29. Araliaephyllum speciosum Philipp.

Pl. XXXIV, fig. 4, pl. XXXVI, fig. 1-3

Araliaephyllum speciosum Philippova, 1991, p. 90, pl. IX, fig. 6. - Philippova, Abramova, 1993, p. 153, pl. 75, fig. 7. - Philippova, 2010, p. 99, pl. 21, fig. 3, text-fig. 20.

Holotype. Spec. TFI 1069/25, North-East of Russia, Pekulney Ridge, Uval'naya River, Poperechnenskaya Formation, Coniacian; Philippova, 1991, pl. IX, fig. 6.

Diagnosis emended. Leaves 3-5-lobed, rounded or widely ovate in outline, with cordate base; margin is entire; lobes are widely elliptic or ovate, slightly narrowing basally, with rounded or obtuse apices; lateral lobes gradually decrease in size towards the leaf base; lobe length is equal to 1/3-1/2 of blade length; sinuses between lobes are narrow with rounded apices; basal veins are usually strong, straight or sometimes slightly curved; lateral basal veins diverge from the midvein at an angle of 35-45° and end in the upper lobe apices; the lowest basiscopic branches of lateral basal veins are stronger, straight and innervate lower pair of lateral lobes.

Description. Leaves are simple, 3-5-lobed, rounded or widely ovate in outline, with cordate base, 4-7 cm long, 4-6 cm wide. Margin is entire. Lobes are widely elliptic or ovate, slightly narrowing basally, with rounded or obtuse apices. The central lobe is the longest and the widest. Lateral lobes gradually decrease in size towards the leaf base. The lobe length is equal to 1/3-1/2 of blade length. Sinuses between lobes are narrow with rounded apices. The primary venation is palmate, the secondary venation is brochido-dromous. Basal veins are usually strong, straight or sometimes slightly curved. Lateral basal veins diverge from the midvein at an angle of 35-45° and end in the upper lobe apices. They bear 4-5 curved acroscopic and basiscopic branches, which form loops near the margin. The lowest basiscopic branches are stronger, straight and innervate lower pair of lateral lobes. There are thin marginal veins along leaf base. Tertiary venation is very thin, usually irregular. Higher-order venation is not well preserved.

Comparison and remarks. These specimens are the most similar to the leaves of Araliaephyllum are-narium (Philipp.) Philipp. from the Krivorechenskaya Formation of the Anadyr River (Philippova, Abra-mova, 1993) in number and arrangement of the lobes, however the lobes of A. arenarium are narrower and longer. In addition, the base of A. arenarium is cuneate, and the base of A. speciosum is cordate. Leaves of A. devjatilovae Philipp. differ in shorter triangular lobes with wide sinuses between them.

Material. Collection BIN 538, spec. 63, 93; collection BIN 1565, spec. 378, 385b, 495a, 514. Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian; Pekulney Ridge, Uval'naya River, Poperechnenskaya Formation, Conia-cian.

Genus DALEMBIA E. Lebed. et Herman, 1989 30. Dalembia kryshtofovichii (Samyl.) Golovn., comb. nov.

Pl. XXXVII, fig. 1-7, pl. XXXVIII, fig. 1-6, pl. XXXIX, fig. 1-6, pl. XL, fig. 1-3, 5, pl. XLI, fig. 6, pl. XLII, fig. 6, 7, pl. L, fig. 5

Celastrophyllum kryshtofovichii Samylina, Late Cretaceous flora of the Tap River (Northern coast of the

Sea of Okhotsk), 1984a, p. 241, pl. III, fig. 1-4, text-fig. 2. - Samylina, 1989, pl. II, fig. 4. Dalembia argentea Yudova et Golovn., in Yudova et al., 2016, p. 70, pl. II, fig. 1-6, pl. III, fig. 1, 2, pl. IV,

fig. 1-3, text-fig. 4 a-g. Dalembia vachrameevii E. Lebed. et Herman, in Yudova et al., 2016, pl. I, fig. 3, 5. Dalembia vachrameevii auct. non E. Lebed. et Herman, in Golovneva et al., 2011, pl. 5, fig. 5, pl. 6, fig. 1-3.

Dalembia bolshakovae auct. non E. Lebed. et Herman, in Shczepetov, Golovneva, 2010, pl. VII, fig. 1, 2, 4;

text-fig. 5, a-g.

Holotype. Spec. BIN 519/63, the North-East of Russia, northern coast of the Sea of Okhotsk, Tap River, Chingandzha Formation, Coniacian; Samylina, 1984a, pl. III, fig. 2. - Pl. XXXVII, fig. 5.

Diagnosis emended. Leaves compound, odd-pinnate; petiolules thin and short; lateral leaflets are opposite, from narrowly ovate or narrowly elliptical to lanceolate and widely elliptical, lobed or dentate, 3-13 cm in length and 1,5-4 cm in width, with tapering acute triangular apices and cuneate, truncate or rounded bases; lobes short, triangular with acute or obtuse apices, often tooth-like; basal lobes are the most developed and usually have small additional teeth on the basiscopis side; apical leaflets bigger and wider than lateral ones, with more developed lobes, elliptical, ovate or rhomboidal in outline; venation pinnate, or pinnate-palmate, craspedodromous or semicraspedodromous, with 4-11 pairs of subopposite or alternate secondary veins and with numerous interstitial veins between them.

Description. The leaves are compound, odd-pinnate. The most complete specimens consist of five leaflets. The apical leaflets are larger and wider, than lateral ones. Lateral leaflets are opposite or subopposite, more elongated, then apical ones.

The lateral leaflets are lobed or with lobe-like teeth, from narrowly ovate or narrowly elliptical to lanceolate and widely elliptical, 3-13 cm in length and 1,5-4 cm in width, with tapering acute triangular apices and cuneate, truncate or rounded, sometimes decurrent, slightly asymmetric bases. The lateral leaflets have thin, short petiolules (0,5-1,3 cm) attached to the main petiole. The lobes or lobe-like teeth are short, triangular with rounded apices, 3-6 mm long. The basal lobes are the most developed and sometimes have small additional teeth on the lower side. The lobes decrease in size towards the apex of leaflet, gradually turning into teeth.

The main leaf axis is straight, thin, 1-1,5 mm in diameter. The apical leaflets are elliptical, ovate or rhomboidal in outline and have more developed lobes (up to 10-15 mm). The sinuses between the lobes are narrow, triangular in shape with a rounded apex, up to 1/2 of the leaf width.

The venation of leaflets is pinnate, or pinnate-palmate, craspedodromous or semicraspedodromous. Secondary veins are subopposite or alternate, in 4-9 pairs, subparallel, slightly curved, arising from middle vein at an angle 35-60°. The secondary veins in the middle part of lamina are usually the longest and bear several short basiscopic branches. In the lower part secondary veins are shorter and more closely spaced. Often they are bifurcate and connected by a curved anastomosis in the upper third of their length. There are numerous interstitial veins between secondary veins. They are rather long, thin and usually undulate. Tertiary venation is thin, branched-scalariform.Venation of higher orders is irregularly-reticulate.

Comparison and remarks. Earlier this species was described under the name Dalembia argentea Yudo-va et Golovn. (Yudova et al., 2016). However, a reexamination of Samylina's collections showed that identical in morphology leaflets were previously described under the name Celastrophyllum kryshtofovichii (Samylina, 1984a). In the result the new combination was created: Dalembia kryshtofovichii (Samyl.) Golovn.

The type species of the genus Dalembia is D. vachrameevii E. Lebed. et Herman (Lebedev, Herman, 1989). This species has leaflets with 2-4 pairs of long lobes and basal lobes complicated by subsidiary small lobes and large teeth. The species D. kryshtofovichii differs from D. vachrameevii in narrower lateral leaflets with less developed tooth-like lobes and numerous interstitial veins. Apical leaflets in D. vachrameevii are transversely oval with two pairs of wide, rounded lobes, while in D. kryshtofovichii they are elongated longitudinally, with three pairs of triangular lobes.

The leaves of D.pergamentii Herman et E. Lebed. is characterized by apical leaflet with 4-5 pairs of lobes complicated by numerous lobes and rounded teeth. The size and the amount of dissection of lobes decrease towards leaflet apex. Lateral leaflets have 5-7 pairs of lobes, from which second or third pair are the best developed. The depth of sinuses, dividing the lobes, corresponds to 1/3-2/3 of leaflet width. The leaves of D. pergamentii are distinguished by well-developed lobes, often with secondary lobes or additional teeth on the outer side of the lobes. In addition, in D. kryshtofovichii the basal pair of veins is usually more developed than the others, while in D.pergamentii the second pair of secondary veins is the most developed. Also, D. kryshtofovichii is characterized by numerous interstitial veins, which is not observed in D. pergamentii.

The species Dalembia bolschakovae E. Lebed. et Herman is known from one locality in Ul'ya River basin from the deposits of the Amka Formation, which is now assigned to the Coniacian (Golovneva, 2013). The leaves of D. kryshtofovichii are distinguished from the leaves of D. bolschakovae by narrower lateral leaflets

with less developed tooth-like lobes. Apical leaflets in D. bolschakovae are unknown. Leaves of D. faradjevii E. Lebed. et Herman consists of nine small leaflets (up to 4 cm long) with 4-5 pairs of lobes.

The species D. krassilovii Herman et E. Lebed. from the uppermost part of the Valizhgen Formation of Northwestern Kamchatka (Lebedev, Herman, 1989) differs from all other species of Dalembia in elongated narrow lobes, deep sinuses between them and by prominently decurrent bases of leaflets.

The leaflets in D. comparabilis (Holl.) Herman et E. Lebed. are rounded or oval with deep sinuses between lobes (1/2 from leaflet width), while in D. kryshtofovichii leaflets are more elongated with short lobes and shallow sinuses. Dalembia comparabilis was firstly described by Hollick (1930) as Cissites comparabilis Holl. from the Upper Cretaceous deposits of Yukon River, Alaska Peninsula. The age of the Kaltag and Melozi formations is now estimated as Cenomanian or late Albian-early Turonian (Patton, 1973).

The species D. jiayinensis from the Santonian Yong'ancun Formation (Northeast China) differs mostly in less developed lobes and also in predominantly cuneate decurrent base of leaflets. Its leaflets have one or two pairs of short lobes or lobe-like teeth, not complicated by additional lobes of second order (Sun et al., 2016). Sometimes leaflets may be unlobed with entire or undulate margin.

The leaves of D. kryshtofovichii are similar to the leaves of Hollickia quercifolia (Holl.) Krassilov from the Santonian-Campanian deposits of the Chignik Formation in Alaska (Hollick, 1930; Krassilov, 1979) in narrow leaflets and short tooth-like lobes. But H. quercifolia is characterized by a large number of secondary veins and, accordingly, by the number of lobes (up to 10 pairs), as well as by absence of interstitial veins.

Material. Collection BIN 519, spec. 63-65, 67-70, 74, 78; collection BIN 538, spec. 44, 68, 73, 75, 101, 105, 106a, b, 127-130; collection BIN 1565, spec. 339, 342, 344, 346-355, 357, 359, 363, 365, 509, 538, 594.

Stratigraphie horizon and occurrence. Northern coast of the Sea of Okhotsk, Tap and Kananyga rivers, Chingandzha Formation, Coniacian; Viliga River basin, Gydra and Yum formations, Coniacian.

Genus IEVLEVIA Samyl., 1976 31. Ievlevia dorofeevii Samyl. Pl. XLIII, fig. 1, 2a

Ievlevia dorofeevii Samylina, 1976, p. 93, pl. XLVIII, fig. 11b, 12, 13b. - Samylina, 1989, pl. II, fig. 7.

Holotype. Spec. BIN 511/25b, the North-East of Russia, Sugoi River, Toptan Formation, lower-middle Albian; Samylina, 1976, pl. XLVIII, fig. 11b, 12, 13b.

Description. Fruits are obovate, with attenuate stipe and rounded apex, 3-4 mm long and 1,5-2 mm wide, with thin uneven in length spines, directed in different directions.

Comparison and remarks. Samylina (1976) compared these fruits with those of Ceratophyllum, which have similar sizes and spines. However, very few anatomical details have been preserved on the impressions of these fruits for a reliable comparison.

Material. Collection BIN 538, spec. 111b, 213a.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian; Balygychan-Sugoi Depression, Toptan Formation, lower-middle Albian.

Genus MENISPERMITES Lesq., 1874 32. Menispermites sibiricus (Heer) Golovn. Pl. XLI, fig. 1-5

Acer sibiricum Heer, 1878, S. 46, Taf. 10, Fig. 4b, 5a, Taf. 12, Fig. 1b. Protoacerophyllum sibiricum (Heer) Iljinskaya, 1974, p. 151, text-fig. 96, fig. 4.

Menispermites sibiricus (Heer) I. Lebed. non rite publ., in Lebedev, 1955a, p. 199, pl. 30, fig. 1. - Lebedev,

1962, p. 258, pl. 49, fig. 1. M. sibiricus (Heer) Golovneva, 2006, p. 1733, pl. I-III, text-figs 1-3.

M. kryshtofovichii Vachrameev, 1952, p. 194, pl. 14, fig. 5, 6, pl. 15, fig. 6, text-fig. 41. - Zhilin, 1974, p. 99, pl. 37, fig. 5, pl. 40, fig. 7. - Shilin, 1986, pl. 8, fig. 2, 4, pl. 9, fig. 1. - Herman, Lebedev, 1991, p. 67, pl. 2, fig. 5, text-fig. 13. - Herman et al., 2016, p. 727, pl. XXIII, fig. 10, 11, text-fig. 18. M. simonovskiensis I. Lebedev, 1962, p. 258, pl. 65, fig. 2.

M. tschulimensis I. Lebedev, 1962, p. 258, pl. 49, fig. 5. M. syrdariensis Shilin, 1986, p. 113, pl. 9, fig. 3, pl. 10, fig. 4. Menispermites sp., Philippova, 1975, p. 64, pl. 9, fig. 1; text-fig. 3. Nymphaeites tener Heer, 1878, S. 44, Taf. 13, Fig. 7. Cissites sibirensis I. Lebedev, 1955b, p. 203, pl. 31, fig. 4.

Lectotype (Golovneva, 2006). The specimen, figured by O. Heer (1878, Taf. 10, Fig. 4b), Chulym-Yenisei region of Western Siberia, Chulym River basin, Simonovo, Simonovo Formation, Cenomanian-Tu-ronian. The storage location is unknown.

Diagnosis emended (Golovneva, 2006). Leaves simple, rounded or broadly ovate in outline, usually broader than long, 3-7-lobate, with peltate-rounded, cordate or truncate base and broadly triangular obtuse apex; 6-18 cm long, 7-20 cm wide; lobes radially divergent, decreasing downwards, with additional secondary lobes or lobe-like teeth, which are rounded or triangular with obtuse apex; sinuses between lobes rounded; margin entire or irregularly coarsely dentate, varying in different leaves; venation palmate with 5(7) straight basal veins, which have several lateral branches on each side in the distal part; veins, ending in the teeth or lobes, craspedodromous, other ones form loops near the margin; peltate base innervated by

2-5 thin veins running from the beginning of basal veins; curved tertiary veins form an alternating series of meshes at right-angles to the radially arranged basal veins.

Description. The leaves are simple, entire, broadly ovate, rounded to transversely oval in outline,

3-7-lobed (usually 5-lobed), 6-18 cm long and 7-20 cm wide. The base is usually peltate, sometimes truncate or cordate; the apex is shortly acuminate or broadly rounded. The lobes are radially diverging. The upper lobe is the most developed and usually has small secondary lobes at the ends of the lower lateral veins. The length of the underlying lobes is gradually decreasing. The size of the small lower lobes is similar with size of large teeth in the upper part of the leaf. The sinuses between lobes are rounded; their depth reaches 1/5-1/3 of the diameter of the leaf lamina. The margin is entire or dentate. The teeth are large, rare, rounded, obtuse or triangular, with a blunt apex, 0,3-1 cm long, with rounded sinuses. The pelta is 0,5-2 cm high with uneven lobed edge. The venation is palmate, craspedodromous.

The large 5-lobed leaves are the most characteristic. Five powerful straight basal veins up to 1,7 mm thick depart from the petiole and terminate at the lobe apices. The three upper veins are developed somewhat stronger than the lower ones. They have 3-4 pairs of branches innervating the lobes and ending in the teeth. The lower pair of basal veins has mainly only basiscopic branches. The longest branches of the basal veins can end in small lobes of the second order, also having teeth. The upper pair of basal veins is diverged at an angle of about 45° to the middle vein, and the lower pair is diverged at an angle of about 90°. Some leaves have a third pair of basal veins. These veins extend at an angle of about 30-40° to the lower pair of basal veins in the lower part of the leaf and are approximately two times shorter and thinner than other basal veins. They can form small independent lobes or innervate the pelta. The pelta is usually innervated by 1-3 thin infrabasal veins, extending from the point of the petiole attachment.

The tertiary venation is ramified-percurrent, looped along the sinuses and large teeth. The venation of the fourth order is orthogonal-reticulate.

Comparison and remarks. The genus Menispermites includes entire and lobed leaves with palmate craspedodromous venation, often peltate. It was established by L. Lesquereux (1874) from the Upper Cretaceous Dakota Formation (Kansas, United States), from which three species were originally described. Later Knowlton (1919) selected M. obtusilobus Lesq. as the type species. In leaf morphology Menispermites resembles the leaves of the modern genus Menispermum (order Ranunculales). However, closely related morphotypes occur in the other families (for example, Nymphaeaceae or Piperaceae). Therefore Menisper-mites is considered as a genus of uncertain systematic position.

The remains of Menispermites sibiricus were first found by N. A. Lopatin (1876) near village Simonovo on the Chulym River (Western Siberia). Heer (1878) described them under the name Acersibiricum. Subsequently, I. V. Lebedev (1955a) collected a more representative collection from this locality and transferred this species from the modern genus Acer to the genus Menispermites. Zhilin (1974) considered the name Menispermites sibiricus (Heer) I. Lebed. as invalid, since Lebedev did not give the correct reference to the basionym. A little earlier V. A. Vachrameev (1952) described identical lobed peltate leaves from the Al-bian deposits of Kuldenentemir (Kazakhstan) as M. kryshtofovichii Vachr., and this name was rather widely used. The recent revision of peltate leaves from Siberia and Kazakhstan allowed to restore the combination

Menispermites sibiricus (Heer) Golovn., since Heer's species epithet is valid and priority for this species (Golovneva, 2006).

From the type species M. obtusilobus, the species M. sibiricus is distinguished by the predominance of 5-lobed peltate leaves, by presence of large teeth along with lobes and by five powerful basal veins. M. ob-tusilobus is characterized by three-lobed or unlobed leaves, by very small pelta and by entire or wavy margin.

Several species of Menispermites have been described from the Grebenka flora from the upper Albi-an-lower Turonian Krivorechenskaya Formation (Philippova, Abramova, 1993; Golovneva et al., 2015). M. minutus (Krysht.) Shczep., Herman et Belaya differs from M. sibiricus in the lobeless nonpeltate leaves with seven to nine basal veins, dentate-sinuate margin, and protruding glands at the ends of teeth. The species M. marcovoensis Philipp. is characterized by fan-shaped leaves with rounded upper margin, 7-11 primary veins and crenate-lobed (scalloped) teeth. The species M. vasetskii Philipp. is characterized by ovate leaves with rounded base, 5-7 primary veins and large triangular lobe-like teeth with rounded apices. The leaves of M. orientalis Golovn. are characterized by broadly ovate shape with deeply cordate base, 9-11 primary veins and by crenate margin.

The species M. sachalinensis Krysht. from the Zhonkier flora of Sakhalin (Campanian) (Kryshtofovich, Baikovskaya, 1960; Krassilov, 1979) differs from M. sibiricus in a wavy margin with weakly pronounced lobes, and M. favosus Krassilov from the Boshnyakovo flora of Sakhalin (Paleocene) in a rounded leaf shape, absence of lobes, brochidodromous venation and in the presence of glands.

Material. Collection BIN 1565, spec. 358, 375, 376, 381, 383, 554.

Stratigraphic horizon and occurrence. Northern coast of the Sea of Okhotsk, Kananyga River, Chin-gandzha Formation, Coniacian; Arman Formation, upper Turonian; Chulym-Yenisei region, Cenomanian-Turonian; Lena-Vilyuy Depression, Cenomanian-Turonian; Kazakhstan, Cenomanian-Turonian; Northwestern Kamchatka, Turonian-Coniacian.

Genus QUEREUXIA Krysht. ex Baik., 1963 33. Quereuxia angulata (Newb.) Krysht. ex Baik.

Pl. XL, fig. 4a, pl. XLII, fig. 1-5

Quereuxia angulata (Newb.) Krysht. ex Baik., in Shczepetov, 1991b, pl. 93, fig. 5, 6, pl. 94, fig. 1-7. -

Philippova, Abramova, 1993, p. 177, pl. 55, fig. 4-9, pl. 56, fig. 6-8, pl. 57, fig. 5, pl. 58, fig. 9, pl. 60,

fig. 7, pl. 63, fig. 10, pl. 66, fig. 10. - Philippova, 2011, pl. 5, fig. 9-13. - Golovneva, 2018, p. 159, pl. 46,

fig. 1-7, pl. 51, fig. 7, pl. 52, fig. 3a, 4a, 7b, pl. 55, fig. 7. - Akinin et al., 2019, pl. 6, fig. 1.

Description. Surface leaves are arranged in flat floating rosettes, which are formed by 5-7 pairs of leaves opposite to each other. The leaves of the inner 2-3 pairs are simple; the other ones are compound, with 3, 5 or 7 leaflets. The material from the Chingandzha Formation contains simple leaves and isolated leaflets.

Simple leaves are almost orbicular, ovate, widely elliptical or transversely widely elliptical, slightly asymmetric, with a rounded base. Leaflets of compound leaves are angular, oblong-ovate or obovate, usually slightly asymmetrical. Their base is truncated or rounded; the apex is rounded or obtuse. Leaf sizes range from 0,5 to 1,6 cm in length. The margin is serrate, entire near the base of leaflet. The teeth are simple, small, with an acute apex, adpressed in the lower part of the leaflet and widely triangular in the upper part.

The venation is pinnate, craspedodromous; 4-5 pairs of secondary veins depart from the middle vein at an acute angle (30-35°). They branch 2-3 times unequally dichotomously or have basiscopic branches. The tertiary venation is reticulate and consists of narrow oblong areolae elongated along the secondary veins. A prominent marginal vein is formed by the coalescence of secondary and tertiary veins near the margin.

Comparison and remarks. The remains of this species are widespread in the Upper Cretaceous and Tertiary deposits of the Northern Hemisphere. Leaflets from the Upper Cretaceous deposits are distinguished by smaller sizes. According to other features, the fossils from the Upper Cretaceous deposits of Central and Eastern Chukotka do not differ from the Paleogene ones.

Material. Collection BIN 538, spec. 19, 20, 21, 23-25, 27, 29, 49; collection BIN 1565, spec. 325, 326, 329, 330.

Stratigraphic horizon and occurrence. Upper Cretaceous and Paleogene of Eurasia and North America.

CONCLUSION

1. The Chingandzha flora from the volcanic-sedimentary deposits of the Chingandzha Formation (the Okhotsk-Chukotka volcanic belt, North-East of Russia) includes 23 genera and 33 species. Angiosperms are rather diverse in comparison with the other OCVB floras. Representatives of the families Platanaceae and Cercidiphyllaceae predominate. Two new species (Taxodium viligense Golovn. and Cupressinocladus shelikhovii Golovn.) are described, and two new combinations (Arctopteris ochotica (Samyl.) Golovn. and Dalembia kryshtofovichii (Samyl.) Golovn.) are created.

2. Riparian vegetation along rivers was formed by Pseudoprotophyllum cordatum. The floodplains were probably occupied by forests dominated by various species of the genus Trochodendroides and by groves, consisting of Metasequoia or Ginkgo. Plants from the genera Araliaephyllum, Dalembia, Menispermites most likely formed undergrowth in the lowland forests. Better drained parts of river valleys and lower slopes were occupied by Sequoia forests. Forests of Taxodium inhabited lowland wetlands. Probably ferns did not form independent open communities, and grew under the canopy of forests. Aquatic vegetation is represented by the genus Quereuxia. Horsetails and liverworts settled on fresh sandy and silty sediments.

3. The Chingandzha flora is distinct from other floras of the OCVB in predominance of flowering plants and in the absence of the Early Cretaceous relicts such as Podozamites, Phoenicopsis, and cycado-phytes. The Chingandzha and the Aleeky floras have many common taxa, which were widespread in the Late Cretaceous of the North-East of Russia. Species Cladophlebis inaequipinnulata and Dalembia kryshto-fovichii are known only for these two floras.

4. According to its systematic composition and paleoecological features, the Chingandzha flora is close to the floras from the coal-bearing deposits of the coastal lowlands of the Anadyr Province: the Penzhina (late Turonian), Kaivayam (Coniacian) floras of Northwestern Kamchatka and the Tylpegyrgynay (Conia-cian) flora of the Pekulney Ridge. Among these floras, the Chingandzha flora has the greatest similarity with the Tylpegyrgynay flora. Most likely, this flora was developed in a large river valley, which had a connection with the coastal lowlands from the east side of the belt.

5. The age of the Chingandzha flora is determined as the Coniacian. This flora is assigned to the Anadyr Province of the Siberian-Canadian floristic realm and to the Kaivayam phase of the flora evolution. The Chingandzha flora is correlated with the Coniacian Aleeky flora from the Viliga-Tumany interfluve area and with other Coniacian floras of the OCVB: the Chaun flora of the Central Chukotka, the Kholchan flora of the Magadan Region and the Ul'ya flora of the Ul'ya Depression.

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Nosova, N., Golovneva, L. B. 2014. The Mesozoic genus Protophyllocladus Berry (Pinopsida). - Rev. Pa-laeobot. Palynol., 210: 77-88. https://doi.org/10.1016/j.revpalbo.2014.07.003

Oishi, S., Huzioka, K. 1941. Studies on the Cenozoic plants of Hokkaido and Karafuto. - Jour. Fac. Sci., Hokkaido Univ., 7: 103-115.

Oostendorp, C. 1987. The Bryophytes of the Palaeozoic and Mesozoic. - Bryophytorium bibliotheca, 34: 1-112.

Patton Jr., W. W. 1973. Reconnaissance geology of the Northern Yukon-Koyukuk Province, Alaska. - U. S. Geol. Surv. Prof. Pap., 774-A: 1-17. https://doi.org/10.3133/pp774A

Philippova, G. G. 1972. Novye melovye rasteniya iz basseina reki Palyavaam [New Cretaceous plants from the Palyavaam River basin]. - Kolyma, 2: 36-38. (in Russian).

Philippova, G. G. 1975. Fossil angiosperms from the Arman River basin. - Iskopaemye Flory Dal'nego Vostoka. Vladivostok: DVNTs AN SSSR, p. 60-75. (in Russian).

Philippova, G. G. 1989. Otkritie senonskoi flory na reke Grebenka (pravoberezh'e reki Anadyr) [Discovery of the Senonian flora in the Grebenka River (right bank of the Anadyr River)]. - Kolyma, 11: p. 8-10. (in Russian).

Philippova, G. G. 1991. New angiosperms from the Coniacian deposits of the northern Pekul'nei Ridge. -Paleontol. J., 3: 85-93. (in Russian).

Philippova, G. G. 2010. Cretaceous stratigraphy and floral assemblages of the northern Pekulney Range (Chukotka). Magadan: NEISRI FEB RAS, 203 p. (in Russian).

Philippova, G. G. 2011. Stratigrafiya i vozrast vulkanogennykh otlozheniy levoberezhia r. Palyavaam (Tsen-tralnaya Chukotka) [Stratigraphy and age of volcanic deposits on the left bank of the Palyavaam River (central Chukotka)]. - Vestnik SVNTs DVO RAN, 2: 5-16. (in Russian).

Philippova, G. G., Abramova, L. N. 1993. Pozdnemelovaya flora Severo-Vostoka Rossii [The Late Cretaceous Flora of the North-East of Russia]. Moscow: Nedra, 348 p. (in Russian).

Samylina, V. A. 1964. Mesozoic flora from the left bank of the Kolyma River (Zyryanka coal basin). Part 1. Eq-uisetales, Polypodiales, Bennettitales. - Acta of the Komarov Botan. Inst., ser. 8, 5: 39-79. (in Russian).

Samylina, V. A. 1967. On the final stages of the history of the genus Ginkgo L. in Eurasia. - Botanicheskii Zhurnal, 52 (3): 303-316. (in Russian).

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Samylina, V. A. 1984b. O melovoi flore s r. Kananyga (Severnoe Priokhot'e) [About Cretaceous flora of the Kananyga River (Northern coast of the Sea of Okhotsk)]. - Stratigrafiya i paleontologiya paleozoiskikh i mezozoiskikh otlozhenii Severo-Vostoka SSSR. Moscow: Nauka, p. 178-190. (in Russian).

Samylina, V. A. 1988. Arkagalinskaya stratoflora Severo-Vostoka Azii [The Arkagala Stratoflora of Northeastern Asia]. Leningrad: Nauka, 131 p. (in Russian).

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Shchepetov, S. V. 1988. Stratigrafiya melovykh kontinental'nykh nakoplenii Omsukchanskogo raiona (Severnoe Priokhot'e) [Nonmarine Cretaceous stratigraphy of the Omsukchan district (the Northern coast of the Sea of Okhotsk)]. Magadan: SVKNII DVO AN SSSR, 60 p. (in Russian).

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PLATE I Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-6 - Jungermannites sp.:

1 - spec. BIN 538/205, x5;

2 - spec. BIN 1565/191, x5;

3 - spec. BIN 538/201, x5;

4 - spec. BIN 538/207, x10;

5 - spec. BIN 538/203, x5;

6 - spec. BIN 538/209, x5.

PLATE II Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1 - Hepaticites sp. 1, spec. BIN 538/217a, x2. 2, 4 - Hepaticites sp. 2:

2 - spec. BIN 1565/227, x2; 4 - spec. BIN 1565/221, x2. 3 - Hepaticites sp. 3, spec. BIN 1565/223, x4.

PLATE III Chingandzha flora, Coniacian Kananyga (1-5) and Chingandzha (6) rivers, Chingandzha Formation

1, 2 - Hepaticites sp. 3:

1 - spec. BIN 1565/230, x5;

2 - spec. BIN 1565/377, x5.

3 - Jungermannites sp., spec. BIN 538/206, x5.

4 - Hepaticites sp. 4, spec. BIN 538/241, x10.

5 - Equisetum sp., spec. BIN 1565/155, x1.

6 - Cladophlebis inaequipinnulata Samyl., spec. BIN 1565/516, x2.

PLATE IV Chingandzha flora, Coniacian Chingandzha (1-5) and Tap (6) rivers, Chingandzha Formation

1-5 - Cladophlebis inaequipinnulata Samyl.:

1 - spec. BIN 1565/545, x2;

2 - spec. BIN 1565/547, x2;

3 - spec. BIN 1565/516, x3;

4 - spec. BIN 1565/550, x2;

5 - spec. BIN 1565/514, x2.

6 - Osmunda tapensis Samyl., spec. BIN 519/1, holotype, x2.

PLATE V Chingandzha flora, Coniacian Tap River, Chingandzha Formation

1-5 - Coniopteris tschuktschorum (Krysht.) Samyl.:

1 - spec. BIN 524/3, x2;

2 - spec. BIN 524/4, x2;

3 - spec. BIN 519/6, x2;

4 - spec. BIN 519/10, x1;

5 - spec. BIN 519/9, x2.

PLATE VI Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Coniopteris opposita Samyl.:

1 - spec. BIN 1565/174b, x3;

2 - spec. BIN 538/174, holotype, x5;

3 - spec. BIN 1565/189, x3;

4 - spec. BIN 538/172, x3;

5 - spec. BIN 538/171, x5.

PLATE VII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Coniopteris opposita Samyl.:

1 - spec. BIN 1565/504, x2;

2 - spec. BIN 1565/572, x3;

3 - spec. BIN 1565/488, x3;

4 - spec. BIN 1565/486, x4;

5 - spec. BIN 1565/220, x3.

PLATE VIII Chingandzha flora, Coniacian Kananyga (1-4) and Chingandzha (5) rivers, Chingandzha Formation

1-4 - Arctopteris ilirnensis Golovn.:

1 - spec. BIN 1565/201, x2;

2 - spec. BIN 1565/197, x2;

3 - spec. BIN 1565/199, x2;

4 - spec. BIN 1565/216, x2.

5 - Sagenopteris variabilis (Velen.) Velen., spec. BIN 1565/585, x2.

PLATE IX Chingandzha flora, Coniacian Tap River, Chingandzha Formation

1, 4 - Arctopteris ochotica (Samyl.) Golovn., spec. BIN 524/1, holotype: 1 - *2; 4 - *1.

2, 3 - Cladophlebis inaequipinnulata Samyl.:

2 - spec. BIN 519/15, x2;

3 - spec. BIN 524/6, x2.

PLATE X Chingandzha flora, Coniacian Tap (1-3, 7), Kananyga (4, 5) and Chingandzha (6) rivers, Chingandzha Formation

1 -3, 7 - Cladophlebis inaequipinnulata Samyl.:

1 - spec. BIN 519/12, holotype, x2;

2 - spec. BIN 519/13, x2;

3 - spec. BIN 519/18, x2; 7 - spec. BIN 519/19, x2.

4 - Asplenium cf. rigidum Vassilevsk., spec. BIN 1565/203, x4. 5, 6 - Asplenium dicksonianum Heer:

5 - spec. BIN 1565/202, x2;

6 - spec. BIN 547/36, x2.

PLATE XI Chingandzha flora, Coniacian Kananyga (1, 6-9) and Chingandzha (2-5) rivers, Chingandzha Formation

1 - Lobifoliagleichenioides Golovn. et Grabovskiy, spec. BIN 1565/500, x2. 2-9 - Ginkgo ex gr. adiantoides (Ung.) Heer:

2 - spec. BIN 547/29, x1;

3 - spec. BIN 547/4, x1;

4 - spec. BIN 547/3, x1;

5 - spec. BIN 1565/524, x1;

6 - spec. BIN 1565/158, x2;

7 - spec. BIN 1565/147, x2;

8 - spec. BIN 1565/146, x2;

9 - spec. BIN 1565/152, x2.

PLATE XII Chingandzha flora, Coniacian Kananyga (1-4, 7, 9) and Chingandzha (5, 6, 8, 10) rivers, Chingandzha Formation

1-4 - Ginkgo ex gr. adiantoides (Ung.) Heer:

1 - spec. BIN 1565/357a, x2;

2 - spec. BIN 1565/142, x2;

3 - spec. BIN 1565/148, x2;

4 - spec. BIN 1565/141, x2. 5-10 - Ginkgo ex gr. sibirica Heer:

5 - spec. BIN 547/48, x1;

6 - spec. BIN 547/51, x1;

7 - spec. BIN 538/160, x1;

8 - spec. BIN 547/6, x1;

9 - spec. BIN 1565/502, x1;

10 - spec. BIN 1565/522, x1.

PLATE XIII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-4 - Sequoia ochotica Yudova et Golovn.:

1 - spec. BIN 1565/437, x4;

2 - spec. BIN 1565/451, holotype, x2;

3 - spec. BIN 1565/66, x2;

4 - spec. BIN 1565/447, x2.

PLATE XIV Chingandzha flora, Coniacian Kananyga (1, 2, 4-6) and Chingandzha (3) rivers, Chingandzha Formation

1-6 - Sequoia ochotica Yudova et Golovn.:

1 - spec. BIN 1565/468, x4;

2 - spec. BIN 1565/460, x2;

3 - spec. BIN 1565/528, x4;

4 - spec. BIN 1565/74, x2;

5 - spec. BIN 1565/408, x2;

6 - spec. BIN 1565/ 417, x2.

PLATE XV Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Sequoia ochotica Yudova et Golovn.:

1 - spec. BIN 1565/450, x2;

2 - spec. BIN 1565/430, x 2;

3 - spec. BIN 1565/84, x2;

4 - spec. BIN 1565/90, x2;

5 - spec. BIN 1565/432, x2.

PLATE XVI Chingandzha flora, Coniacian Kananyga (1, 2, 7-9) and Chingandzha (3-6) rivers, Chingandzha Formation

1-9 - Sequoia ochotica Yudova et Golovn.:

1 - spec. BIN 1565/421, x2;

2 - spec. BIN 538/67, x2,5;

3 - spec. BIN 1565/529, x1;

4 - spec. BIN 547/60, x1;

5 - spec. BIN 1565/531a, x1;

6 - spec. BIN 547/61, x1;

7 - spec. BIN 1565/61, x2;

8 - spec. BIN 1565/166, x1;

9 - spec. BIN 1565/370, x2.

PLATE XVII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Sequoia ochotica Yudova et Golovn.:

1 - spec. BIN 1565/443, x2;

2 - spec. BIN 1565/76, x2;

3 - spec. BIN 538/52, x1;

4 - spec. BIN 1565/75, x2;

5 - spec. BIN 1565/481, x2.

PLATE XVIII Chingandzha flora, Coniacian Kananyga (1, 3, 4, 8) and Chingandzha (2, 5-7) rivers, Chingandzha Formation

1-8 - Metasequoia sp.:

1 - spec. BIN 1565/96, x2;

2 - spec. BIN 547/33, x2,5;

3 - spec. BIN 1565/60a, x2;

4 - spec. BIN 1565/94, x2;

5 - spec. BIN 1565/565a, x2;

6 - spec. BIN 547/91, x2;

7 - spec. BIN 1565/567, x2;

8 - spec. BIN 1565/97, x2.

PLATE XIX Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1, 4 - Taxodium viligense Golovn.:

1 - spec. BIN 1565/82b, x2; 4 - spec. BIN 1565/84b, x4.

2, 3 - Metasequoia sp.:

2 - spec. BIN 538/454, x2;

3 - spec. BIN 1565/457, x2.

PLATE XX Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Taxodium viligense Golovn.:

1 - spec. BIN 1565/473, x2;

2 - spec. BIN 1565/125, x2,5;

3 - spec. BIN 1565/479, x2;

4, 5 - spec. BIN 1565/470: 4 - x4; 5 - x2.

PLATE XXI Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-4 - Taxodium viligense Golovn.:

1 - spec. BIN 1565/466a, holotype, x2;

2 - spec. BIN 1565/466b, x2;

3 - spec. BIN 1565/476b, x2;

4 - spec. BIN 1565/429, x1.

PLATE XXII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Taxodium viligense Golovn.:

1 - spec. BIN 1565/512b, x2;

2 - spec. BIN 538/138, x2;

3 - spec. BIN 538/64, x2;

4 - spec. BIN 1565/422a, x2;

5 - spec. BIN 1565/422b, x2.

PLATE XXIII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-7 - Cupressinocladus shelikhovii Golovn.:

1 - spec. BIN 1565/182, x2;

2 - spec. BIN 1565/172, x2;

3 - spec. BIN 538/171, x2;

4 - spec. BIN 1565/176, x2;

5 - spec. BIN 538/137, x1,2;

6 - spec. BIN 1565/173, x2;

7 - spec. BIN 1565/183, holotype, x2.

PLATE XXIV Chingandzha flora, Coniacian Chingandzha (1, 2), Kananyga (3-5) and Tap (6) rivers, Chingandzha Formation

1, 2 - Sequoia ochotica Yudova et Golovn.:

1 - spec. BIN 547/74, xl;

2 - spec. BIN 547/73, x2.

3-6 - Pseudoprotophyllum cordatum Samyl.:

3 - spec. BIN 538/15, x2;

4 - spec. BIN 1565/409, x1;

5 - spec. BIN 538/136, holotype, x1;

6 - spec. BIN 519/45, x1.

PLATE XXV Chingandzha flora, Coniacian Tap (1-5) and Kananyga (6-9) rivers, Chingandzha Formation

1-5 - Protophyllocladus subintegrifolius (Lesq.) Berry:

1 - spec. BIN 519/54, x2;

2 - spec. BIN 519/56a, x2;

3 - spec. BIN 519/55, x2;

4 - spec. BIN 519/61, x2;

5 - spec. BIN 519/56b, x2.

6-9 - Pseudoprotophyllum cordatum Samyl.:

6 - spec. BIN 1565/286, x1;

7 - spec. BIN 1565/256, x1,5;

8 - spec. BIN 1565/317, x1;

9 - spec. BIN 538/221, x1.

PLATE XXVI Chingandzha flora, Coniacian Chingandzha River, Chingandzha Formation

1-5 - Pseudoprotophyllum cordatum Samyl., leaves with cordate (1, 2, 4), rounded (3) and cuneate (5) bases:

1 - spec. BIN 547/164, x1;

2 - spec. BIN 547/5, x1;

3 - spec. BIN 547/13, x1;

4 - spec. BIN 547/9, x1;

5 - spec. BIN 547/8a, x1.

PLATE XXVII Chingandzha flora, Coniacian Kananyga (1, 2) and Chingandzha (3) rivers, Chingandzha Formation

1-3 - Pseudoprotophyllum cordatum Samyl.:

1 - spec. BIN 1565/291, xl;

2 - spec. BIN 1565/312, x1;

3 - spec. BIN 547/14, x1.

PLATE XXVIII Chingandzha flora, Coniacian Tap (1, 4) and Chingandzha (2, 3) rivers, Chingandzha Formation

1-4 - Pseudoprotophyllum cordatum Samyl., leaves with peltate (1, 4) and cordate (2, 3) bases:

1 - spec. BIN 519/48, x1;

2 - spec. BIN 547/5, x1;

3 - spec. BIN 547/136, x1,5;

4 - spec. BIN 519/44, x1.

PLATE XXIX Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-3 - Pseudoprotophyllum cordatum Samyl., leaves with cordate (1), truncate (2) and rounded (3) bases:

1 - spec. BIN 1565/498, x1;

2 - spec. BIN 1565/364, x1;

3 - spec. BIN 1565/387, x1.

PLATE XXX Chingandzha flora, Coniacian Kananyga (1-4, 6, 7) and Tap (5) rivers, Chingandzha Formation

1-7 - Pseudoprotophyllum cordatum Samyl., leaves with cordate (1, 2, 4-7) and truncate (3) bases:

1 - spec. BIN 1565/257, x1;

2 - spec. BIN 1565/261, x1;

3 - spec. BIN 1565/314, x1;

4 - spec. BIN 1565/284, x1,5;

5 - spec. BIN 519/49b, x1;

6 - spec. BIN 1565/258, x1;

7 - spec. BIN 1565/394, x1.

PLATE XXXI Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-13 - Trochodendroides tumanensis Yudova:

1 - spec. BIN 1565/403, x1;

2 - spec. BIN 1565/511, x1;

3 - spec. BIN 1565/27, holotype, x1;

4 - spec. BIN 1565/244, x2;

5, 7 - spec. BIN 538/150: 5 - leaf margin, x3, 7 - x1;

6, 8 - spec. BIN 1565/3: 6 - leaf margin, x3, 8 - x1; 9 - spec. BIN 1565/14, x1;

10, 13 - spec. BIN 1565/496: 10 - leaf margin, x3, 13 - x1;

11 - spec. BIN 538/108, x1;

12 - spec. BIN 1565/21, x1.

PLATE XXXII Chingandzha flora, Coniacian Kananyga (1-3, 5, 6, 8, 9) and Chingandzha (4, 7) rivers, Chingandzha Formation

1-9 - Trochodendroides deminii Yudova et Golovn.:

1 - spec. BIN 1565/37, x1;

2 - spec. BIN 1565/234, x1;

3 - spec. BIN 1565/1, x1;

4 - spec. BIN 547/140, x1;

5 - spec. BIN 1565/44, x1;

6 - spec. BIN 1565/233, holotype, x1;

7 - spec. BIN 547/139, x1;

8 - spec. BIN 1565/508, x1;

9 - spec. BIN 1565/40, x1.

PLATE XXXIII Chingandzha flora, Coniacian Kananyga (1, 2, 6, 7), Tap (3, 5) and Chingandzha (4, 8) rivers, Chingandzha Formation

1, 2 - Trochodendroidespeculneensis Philipp., spec. BIN 1565/10: 1 - leaf margin, x10; 2 - x2. 3, 5 - Trochodendroides sp.: 3 - spec. BIN 519/81, x1;

5 - spec. BIN 519/80, x1.

4 - Trochodendroides deminii Yudova et Golovn., spec. BIN 547/138, x1. 6-8 - Trochodendroides tumanensis Yudova:

6 - spec. BIN 1565/497, x1;

7 - spec. BIN 1565/402, x1;

8 - spec. BIN 547/118, x1.

PLATE XXXIV Chingandzha flora, Coniacian Kananyga (1, 2, 4-6) and Chingandzha (3) rivers, Chingandzha Formation

1 - Pseudoprotophyllum cordatum Samyl., spec. BIN 1565/410, x1. 2, 3 - Trochodendroides tumanensis Yudova:

2 - spec. BIN 538/90, x1;

3 - spec. BIN 547/7, x1.

4 - Araliaephyllum speciosum Philipp., spec. BIN1565/495d, x2. 5, 6 - Araliaephyllum devjatilovae Philipp.:

5 - spec. BIN 1565/493, x2;

6 - spec. BIN 1565/495c, x2.

PLATE XXXV Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-4 - Araliaephyllum devjatilovae Philipp.:

1 - spec. BIN 1565/385a, x1;

2 - spec. BIN 1565/382, x1;

3 - spec. BIN 1565/371, x1;

4 - spec. BIN 1565/372, x1.

PLATE XXXVI Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-3 - Araliaephyllum speciosum Philipp.:

1 - spec. BIN 1565/495a, x2;

2 - spec. BIN 1565/385b, x2;

3 - spec. BIN 1565/378, x2.

PLATE XXXVII Chingandzha flora, Coniacian Kananyga (1-4) and Tap (5-7) rivers, Chingandzha Formation

1-7 - Dalembia kryshtofovichii (Samyl.) Golovn.:

1 - spec. BIN 538/106a, lateral leaflet, x2;

2 - spec. BIN 538/101, lateral leaflet, x2;

3 - spec. BIN 538/106b, lateral leaflet, x2;

4 - spec. BIN 538/105, lateral leaflet, x2;

5 - spec. BIN 519/63, holotype, lateral leaflet, x1;

6 - spec. BIN 519/74, lateral leaflet, x1;

7 - spec. BIN 519/64, lateral leaflet, x1.

PLATE XXXVIII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-6 - Dalembia kryshtofovichii (Samyl.) Golovn.:

1 - spec. BIN 1565/355, apical and lateral leaflets, x2;

2 - spec. BIN 1565/357, lateral leaflet, x2;

3 - spec. BIN 1565/348, lateral leaflet, x1;

4 - spec. BIN 1565/594, apical leaflet, x2;

5 - spec. BIN 1565/594, lateral leaflet, x2;

6 - spec. BIN 1565/342, apical and two lateral leaflets, x2.

PLATE XXXIX Chingandzha flora, Coniacian Kananyga (1-5) and Tap (6) rivers, Chingandzha Formation

1-6 - Dalembia kryshtofovichii (Samyl.) Golovn.:

1 - spec. BIN 1565/351, tooth-like lobes and interstitial veins, *5;

2 - spec. BIN 1565/594, apical leaflet, tertiary and quaternary venation, *4;

3 - spec. BIN 1565/509, apical and lateral leaflets, *2;

4 - spec. BIN 1565/350, lateral leaflet, x2;

5 - spec. BIN 538/73, apical leaflet, *1;

6 - spec. BIN 519/78, lateral leaflet, secondary and tertiary venation, *2.

PLATE XL Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-3, 5 - Dalembia kryshtofovichii (Samyl.) Golovn.:

1 - spec. BIN 1565/353, lateral leaflet, x1;

2 - spec. BIN 538/75, lateral leaflet, x1;

3 - spec. BIN 1565/352, lateral leaflet, x2; 5 - spec. BIN 1565/354, apical leaflet, x2.

4a - Quereuxia angulata (Newb.) Krysht. ex Baik., spec. BIN 538/19a, x4. 4b - Jungermannites sp., spec. BIN 538/19b, x4.

PLATE XLI Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Menispermites sibiricus (Heer) Golovn.: 1, 2 - spec. BIN 1565/358: 1 - x1, 2 - x3;

3 - spec. BIN 1565/554, x3;

4 - spec. BIN 1565/381, x1;

5 - spec. BIN 1565/383, x1.

6 - Dalembia kryshtofovichii (Samyl.) Golovn., spec. BIN 1565/346, apical leaflet, x2.

PLATE XLII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1-5 - Quereuxia angulata (Newb.) Krysht. ex Baik.:

1 - spec. BIN 538/20, x2;

2 - spec. BIN 538/29, x4;

3 - spec. BIN 538/25a, x4;

4 - spec. BIN 528/23, x4;

5 - spec. BIN 538/25b, x4.

6, 7 - Dalembia kryshtofovichii (Samyl.) Golovn.:

6 - spec. BIN 538/130, lateral leaflet, x2.

7 - spec. BIN 1565/363, lateral leaflet, x3.

PLATE XLIII Chingandzha flora, Coniacian Kananyga River, Chingandzha Formation

1, 2a - Ievlevia dorofeevii Samyl.: 1 - spec. BIN 538/111b, x4; 2a - spec. BIN 538/213a, x4. 2b - Jungermannites sp., spec. BIN 538/213b, x4. 3 - undetermined fruit 1, spec. BIN 519/83, x3. 4, 5 - undetermined fruit 2:

4 - spec. BIN 1565/338a, x4;

5 - spec. BIN 1565/338b, x4.

6 - undetermined fruit 3, spec. BIN 1565/577, x4.

7 - undetermined fruit 4, spec. BIN 1565/512a, x4.

PLATE XLIV Aleeky flora, Coniacian Merenga River, Gydra Formation (1-4, 6, 7, 9), Elan Creek, Kananyga Formation (5), Zlobny Creek, Kananyga Formation (8)

1, 2, 6 - Coniopteris tschuktschorum (Krysht.) Samyl.:

1 - spec. BIN 810/2 and 810/3, x2;

2 - spec. BIN 810/8, x10;

6 - spec. BIN 810/9, x2.

3 - Metasequoia sp., spec. BIN 810/1, x2. 4, 5 - Cladophlebis inaequipinnulata Samyl.:

4 - spec. BIN 810/27, x2;

5 - spec. BIN 1556/9, x2.

7, 9 - Sequoia ochotica Yudova et Golovn.:

7 - spec. BIN 810/4, x2; 9 - spec. BIN 810/15, x2.

8 - Birisia alata (Prynada) Samyl., spec. BIN 812/68, x2.

PLATE XLV Aleeky flora, Coniacian Teukich Creek, Gydra Formation

1-5 - Hausmannia bipartita Samyl. et Shczep.:

1 - spec. BIN 546/1, holotype, xl;

2 - spec. BIN 546/7, xl;

3 - spec. BIN 546/3-1, x1,5;

4 - spec. BIN 546/3-2, x1;

5 - spec. BIN 546/6, x2.

PLATE XLVI Aleeky flora, Coniacian Teukich Creek, Gydra Formation

1, 5 - Lobifolia alikensis Shczep. et Golovn.:

1 - spec. BIN 546/36, x2; 5 - spec. BIN 546/25, x2.

2, 4 - Asplenium dicksonianum Heer:

2 - spec. BIN 546/101, x2; 4 - spec. BIN 546/87, x2.

3 - Pityolepis sp., spec. BIN 546/136, x3.

PLATE XLVII Aleeky flora, Coniacian Teukich Creek, Gydra Formation

1 - Arctopteris ilirnensis Golovn., spec. BIN 546/136, x1,5. 2-5 - Lobifolia alikensis Shczep. et Golovn.: 2 - spec. BIN 546/31b, x5; 3, 4 - spec. BIN 546/31a, holotype: 3 - x5; 4 - x2; 5 - spec. BIN 546/36, x10.

PLATE XLVIII Aleeky flora, Coniacian Teukich Creek, Gydra Formation (1, 4, 6-8),

Elan Creek, Kananyga Formation (2, 3), Merenga River, Kananyga Formation (5, 9)

1 - Arctopteris ilirnensis Golovn., spec. BIN 546/77, *1,5.

2 - Tchaunia lobifolia Philipp., spec. BIN 1557/26b, *2.

3 - Cladophlebisgrandis Samyl., spec. BIN 1557/33, *2.

4 - Sagenopteris variabilis (Velen.) Velen., spec. BIN 546/130, *2.

5 - Equisetum sp., spec. BIN 812/60, *2.

6 - Sequoia ochotica Yudova et Golovn., spec. BIN 546/116, *1.

7 - Phoenicopsis ex gr. angustifolia Heer, spec. BIN 546/55, *1.

8 - Ginkgo ex gr. sibirica Heer, spec. BIN 546/42, *1.

9 - Ginkgo ex gr. adiantoides (Ung.) Heer, spec. BIN 812/63, *2.

PLATE XLIX Aleeky flora, Coniacian Teukich Creek, Gydra Formation (2, 7), Elan Creek, Kananyga Formation (1, 4, 9), Merenga River, Kananyga Formation (3, 8), Zlobny Creek, Kananyga Formation (6), Aleeky River, Yum Formation (5)

1, 2, 9 - Ginkgo ex gr. sibirica Heer:

1 - spec. BIN 1556/4, x1;

2 - spec. BIN 546/49-2, x2; 9 - spec. BIN 1553/12, x1.

3 - Taxodium amguemense (Efimova) Golovn., spec. BIN 812/38, x2.

4 - Araucarites subacutensis Philipp., spec. BIN 1553/2, x2. 5, 6 - Sequoia ochotica Yudova et Golovn.:

5 - spec. BIN 811/16, x2,5;

6 - spec. BIN 812/50, x2.

7 - Sciadopitys (?) sp., spec. BIN 546/49-1, x1.

8 - Heilungia sp., spec. BIN 812/1, x2.

PLATE L Aleeky flora, Coniacian Teukich Creek, Gydra Formation (5), Elan Creek, Kananyga Formation (2, 4), Merenga River, Kananyga Formation (1, 3), Zlobny Creek, Kananyga Formation (6, 7)

1 - Picea sp., spec. BIN 812/61, x2.

2 - Pityophyllum sp., spec. BIN 1556/6, x1. 3, 6, 7 - Sequoia ochotica Yudova et Golovn.:

3 - spec. BIN 812/10, x2;

6 - spec. BIN 812/12, x2;

7 - spec. BIN 812/42, x2.

4 - Sphenobaiera sp., spec. BIN 1556/1, x1.

5 - Dalembia kryshtofovichii (Samyl.) Golovn., spec. BIN 546/40-1, x2.

PLATE LI Aleeky flora, Coniacian Teukich Creek, Gydra Formation

1-5, 6a - Nelumbites extenuinervis Upchurch, Crane et Drinnan: 1-5 - spec. BIN 546/45-1: 1, 3 - x5; 2, 4 - x1,5; 5 - x5; 6a - spec. BIN 546/51-2a, x2. 6b - Pteris sp., spec. BIN 546/51-2b, x2.

PLATE LII Aleeky flora, Coniacian Teukich Creek, Gydra Formation (1-5),

Aleeky River, Yum Formation (7, 8), Merenga River, Kananyga Formation (6)

1, 3, 7 - Trochodendroides tumanensis Yudova: 1 - spec. BIN 546/53, x2; 3 - spec. BIN 546/57, x2; 7 - spec. BIN 811/17, x2. 2 - Trochodendroides deminii Yudova et Golovn., spec. BIN 546/59, x2. 4 - Pseudoprotophyllum (?) sp., spec. BIN 546/146, x1. 5, 6 - Menispermites sp.:

5 - spec. BIN 546/149, x2;

6 - spec. BIN 812/65, x2.

8 - Dicotylophyllum sp. 1, spec. BIN 811/9, x2.