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9Палеоботаника, 2020, Т. 11, С. 74-95
Palaeobotany, 2020, Vol. 11, P. 74-95
A NEW SPECIES OF THE GENUS BIRISIA (DICKSONIACEAE) FROM THE LOWER-MIDDLE ALBIAN DEPOSITS OF SOUTHERN PRIMORYE, FAR EAST OF RUSSIA L. B. Golovneva, A. A. Grabovskiy, A. A. Zolina
Komarov Botanical Institute RAS, St. Petersburg, Russia, [email protected]
НОВЫЙ ВИД РОДА BIRISIA (DICKSONIACEAE) ИЗ НИЖНЕСРЕДНЕАЛЬБСКИХ ОТЛОЖЕНИЙ ЮЖНОГО ПРИМОРЬЯ,
ДАЛЬНИЙ ВОСТОК РОССИИ
Л. Б. Головнева, А. А. Грабовский, А. А. Золина
Ботанический институт им. В. Л. Комарова РАН, Санкт-Петербург, Россия,
Abstract. A new fern Birisia mandshurica, sp. nov. (Dicksoniaceae) from the lower-middle Albian Frentsevka Formation of southern Primorye, Far East of Russia is described. This species is characterized by short-creeping rhizomes with closely spaced stipes and bipinnate fronds with narrow linear pinnules. A reconstruction of B. mandshurica is proposed. It comes from the autochthonous locality of ferns and herbaceous angiosperms and was a part of pioneer open community, which occupied low flat plains between river channels.
Revision of ferns, described as Acanthopteris gothanii Sze from China, shows, that these ferns belongs to Birisia alata (Prynada) Samylina. The name Acanthopteris Sze should be abandoned, due to absence of spore-bearing pinnules and poor preservation of sterile pinnules in type specimens. Based on Chinese and Russian material of good preservation, we provide emended diagnoses of the genus Birisia Samylina and its type species B. alata.
Re-examination of various species of the genus Birisia revealed that this genus was widely distributed in the Cretaceous floras (from the Barremian to the Coniacian) of Eastern Siberia, New Siberian Islands, North-East and Far East of Russia, China, Japan, Alaska and Western Canada. B. alata is the most widespread species.
Key words: fossils ferns, Dicksoniaceae, Early Cretaceous, Frentsevka Formation, Far East of Russia.
Резюме. Описан новый вид папоротника Вт-з1а таийзкипса, вр. поу. (Бюквошаееае) из нижнего-среднего альба френцевской свиты, Приморье, Россия. Для этого вида характерны короткие ползучие корневища с близко расположенными черешками и дваждыперистые листья с узкими линейными перышками. Предложена реконструкция внешнего вида В. таийзкипса. Этот папоротник происходит из автохтонного местонахождения папоротников и травянистых покрытосеменных растений и был частью пионерного сообщества, занимавшего низкие плоские участки между руслами.
Ревизия папоротников, описанных как АсаМкор1епз gotкaиii из Китая, показала, что они принадлежат к виду Birisia аШа (Prynada) БатуНпа. От использования названия Acaиtкopteris предлагается отказаться из-за отсутствия спороносных перышек и плохой сохранности типовых образцов. На основе разнообразного российского и китайского материала приведены расширенные диагнозы рода Birisia БатуНпа и его типового вида В. аШа.
Ревизия находок различных видов рода Birisia показало, что этот род был широко распространен в меловых флорах Восточной Сибири, Новосибирских островов, Северо-Востока и Дальнего Востока России, Китая, Японии, Аляски и Западной Канады, начиная с баррема и до коньяка. В. аЫа является наиболее широко распространенным видом.
Ключевые слова: ископаемые папоротники, Бюквошаееае, ранний мел, френцевская свита, Дальний Восток России.
https://doi.org/10.31111/palaeobotany/2020.11.74 Received 08.09.2020; accepted for publication 25.11.2020
INTRODUCTION
The family Dicksoniaceae Schomburgk belongs to the order Cyatheales Frank (Smith et al., 2006; Christenhusz, Byng, 2016) and includes four extant genera Balantium Children, Calochlaena Maxon, Dick-sonia L'Her, and Lophosoria C. Presl (Riba, 1993; Korall et al., 2006; Lehtonen, 2011). Now this family is distributed in the islands of the Malay Archipelago, the Philippine Islands, New Guinea, southern New Zealand, southeast Australia, the Pacific Islands, and tropical Africa.
Fossil Dicksoniaceae ferns are represented by the genera Coniopteris Brongniart, Kylikipteris Harris, Eboracia Thomas, Gonatosorus Raciborski, Onychiopsis Yokoyama, Tchaunia Samylina et Philippova and Birisia Samylina (Samylina, Philippova, 1970; Samylina, 1972; Popa, van Konijnenburg-van Cittert, 1999; Taylor et al., 2009; Mehlqvist et al., 2009). They were widely distributed in the Middle Jurassic and Lower Cretaceous deposits of Europe, Asia, and North America (van Konijnenburg-van Cittert, van der Burgh, 1989). Most ancient Dicksoniaceae were recorded in the Late Triassic-Early Jurassic of Iran and belong to the genus Coniopteris (Kilpper, 1964).
The genus Birisia was erected by Samylina (1972) based on material from the Cretaceous deposits of the North-East of Russia and Siberia. The type species of the genus is Birisia alata (Prynada) Samylina from the lower-middle Albian Buor-Kemyus Formation of the Zyryanka coal basin, originally described as Cladophlebidium alatum Prynada (1938).
Besides the type species, Samylina included three species in the genus Birisia: B. ochotica Samylina, B. acutata Samylina, and B. onychioides (Vassilevskaja et Kara-Mursa) Samylina. Later, two more species were transferred to this genus: B. jelisejevii (Kryshtofovich) Philippova and B. oerstedtii (Heer) E. Lebe-dev (Philippova, 1979; Herman, Lebedev, 1991), and one new species B. samylinae E. Lebedev was described (Lebedev, 1974). The re-examination of the type material of all above-mentioned species shows that the genus Birisia comprises only three species: B. alata, B. onychioides, and B. acutata (Grabovskiy, Golovneva, 2018). Species B. ochotica and B. alata were united under the name B. alata. Species B. jelisejevii, B. samylinae and B. oerstedtii were excluded from the genus Birisia as mismatching to the generic diagnosis.
The main distinctive features of the genus Birisia, by which it can be distinguished from other genera of the Dicksoniaceae, are linear sterile pinnules and the presence of intercalated pinnules between the pinnae. Fertile pinnules of Birisia have partly reduced leaf blades and are very similar with fertile pinnules of Coniopteris. Sterile leaves of Birisia have significant similarity with those of other ferns, in particular Tchu-cotopteris Vassilevskaja (1977) and Arctopteris Samylina (1964). Spores were described previously only for B. onychioides (Vassilevskaja, Kara-Mursa, 1956).
Species of Birisia are distinguished each other in size and degree of dissection of pinnules, in shape and number of lobes, as well as the number of branches of the lateral veins inside the lobes. The pinnules of the Birisia are characterized by the significant variability and have a different structure depending on their location on the leaf blade. Therefore, for accurate species identification, it is necessary to have the complete leaves with branching of two or three orders and the fertile pinnules.
Many Chinese paleobotanists are considering the genus Birisia as a junior synonymous of the genus Acanthopteris Sze (Zhang et al., 1980; Chen et al., 1981; Chen et al., 1988; Cao, 1994; Deng, 1995, 2002; Deng, Chen, 2001). The last genus, with the type species A. gothanii Sze, was described based on two sterile leaf fragments with linear pinnules from the Lower Cretaceous Fuxin Formation, Liaoning Province, China (Sze, 1931). The age of the Fuxin Formation is determined from the late Aptian to the middle Albian (Xi et al., 2019; Xu et al., 2020). The storage location of the original material described by Sze (1931) is unknown. This material has never been re-examined and typified. The absence of spore-bearing pinnules and the poor preservation of sterile pinnules do not allow establishing the identity of the Chinese material with any of the Birisia species. Therefore, we refuse to use the name Acanthopteris for Birisia-like ferns. This name should be abandoned.
In later Chinese papers the name A. gothanii is usually used for leaves of B. alata. Some of these finds are excellently preserved, which allow to describe the anatomical structure of sporangia and spores (Deng, 1995, 2002; Deng, Chen, 2001; Deng, Lu, 2006). The leaves were found in organic connection with the rhizomes, and the general habit of Birisia plant was reconstructed. Based on the analysis of the Chinese and Russian material, we emended the diagnoses of the genus Birisia and its type species B. alata.
In this paper, we also describe a new species of the genus Birisia - B. mandshurica, sp. nov. from the lower-middle Albian Frentsevska Formation of the Partizansk Coal Basin, southern Primorye, Far East of Russia (Fig. 1A).
Fig. 1. Map of Primorye region (A) and Bolshoy Kuvshin locality near Bolshoy Kamen town (B).
MATERIAL AND METHODS
Leaves of Birisia mandshurica, sp. nov. were found in outcrop of black shales and greenish gray tuf-faceous sandstones exposed along the railroad in the base part of the Bolshoy Kuvshin Cape. Specimens come from a layer of fine-grained non-stratified sandstone about 15 cm thick which is located 14 m above the lower conglomerate layer. This outcrop was named Bolshoy Kuvshin locality (Golovneva et al., 2018). It is situated on the coast of the Ussuri Bay, in the Bolshoy Kamen Inlet near the town Bolshoy Kamen in Primorye region (Fig. 1B). The deposits were assigned to the lower-middle Albian Frentsevka Formation (Golovneva et al., 2018). The Frentsevka Formation is the upper member of the Suchan Group, which is distributed in the Partizansk Coal Basin. This formation overlies the coal-bearing rocks of the Severo-suchan Formation and is overlain by the Kangauz Formation, the lower member of the Korkino Group (Markevich et al., 2000).
The locality Bolshoy Kuvshin was discovered by the geologist A. Oleynikov and then studied by pal-aeobotanists V. Krassilov and E. Volynets (Krassilov, Volynets, 2008), who described two new species of tiny herbaceous angiosperms from there: Achaenocarpites capitellatus Krassilov et Volynets and Ternari-carpites floribundus Krassilov et Volynets. New excavations at this locality were made from 2017 to 2020 by L. Golovneva, P. Alekseev, E. Bugdaeva, E. Volynets, A. Grabovskiy, D. Zolin and A. Zolina.
Remains of B. mandshurica, sp. nov. are preserved as brownish or dark gray impressions, yielding no structurally preserved material. They are represented by creeping rhizomes, sterile and spore-bearing leaves. Spores have not survived.
All specimens are stored in the paleobotanical collection of the Federal Scientific Center of the East Asia Terrestrial Biodiversity FEB RAS in Vladivostok (former Institute of Biology and Soil Science), and are given the prefix IBSS 320-. The material was studied under a Zeiss Stemi 2000-C binocular microscope, and photographed using a digital Nikon Coolpix P7700 camera at low-angle illumination or in water.
Graphic reconstruction of fern-angiosperm herbaceous community was made using Terragen 4 and Xfrog programs by P. Alekseev. Reconstruction of Birisia mandshurica, sp. nov. was drawing in the program Adobe Photoshop CS5.1 by A. Zolina.
Type material of Birisia alata and Birisia onychioides is kept at the Central Scientific-Research Geological Exploration Museum in St. Petersburg (coll. no. CNIGR Museum 5350 and 9498), and holotype of Birisia acutata is kept at the Komarov Botanical Institute RAS in St. Petersburg (coll. no. BIN 508).
Ferns, described under the name Acanthopteris gothanii, were reported from many localities of northeastern China (Zhang et al., 1980; Chen et al., 1981, 1988; Cao, 1994; Deng, 1995; Deng, Chen, 2001). The best material, represented by leaves attached to horizontal rhizomes, and by spores in situ, come from the Lower Cretaceous Huolinhe Formation, the Huolinhe Basin, Inner Mongolia and from the Lower Cretaceous Xiaoming'anbei Formation, the Tiefa Basin, Liaoning (Deng, 1995, 2002; Deng, Chen, 2001; Deng, Lu, 2006).
SYSTEMATICS Division POLYPODIOPHYTA Class POLYPODIOPSIDA Order CYATHEALES Frank Family DICKSONIACEAE Schomburgk, 1849 Genus BIRISIA Samylina, 1972
Type species: Birisia alata (Prynada) Samylina.
Species composition: B. acutata Samylina, B. onychioides (Vassilevskaja et Kara-Mursa) Samylina, B. mandshurica, sp. nov.
Diagnosis emended. Rhizome horizontal, short-creeping with closely spaced stipes; fronds produced singly, bipinnate to tripinnate, linear-lanceolate or lanceolate with acute or attenuate apices; pinnules linear with toothed or lobed margin, rarely entire; basal basiscopic lobes decurrent to the pinna rachis and basal basiscopic pinnules decurrent to the leaf rachis or intercalated; pinnule venation pinnate, usually simple or forked; fertile pinnae with reduced pinnules; sori apical, rounded or elliptical; indusium transitional from bivalvate to cup-like; sporangia globular or elliptical, with long stalk; annulus vertical, incomplete, about % of the circumference of the sporangium, each sporangium yielding 64 spores; spores trilete, sub-triangular in polar view, sides slightly convex or concave, laesurae thick, nearly reaching equator; exine smooth or with fine granules.
Birisia alata (Prynada) Samylina Cladophlebidium alatum Prynada, 1938, p. 34, pl. I, pl. II, fig. 5a, 6a.
Birisia alata (Prynada) Samylina, 1972, p. 97, pl. I, fig. 5, 6. - Samylina, 1976, p. 23, pl. II, fig. 3, 4, pl. V, fig. 1, pl. XV. - Spicer, Herman, 2001, fig. 17, A-C. - Grabovskiy, Golovneva, 2018, p. 36, pl. I, fig. 1-6, pl. II, fig. 1, 3-6, 8-12, pl. III, fig. 1-3, pl. IV, fig. 1-6. Birisia ochotica Samylina, 1972, p. 94, pl. II, fig. 1-3. - Samylina, 1976, p. 24, pl.VI, fig. 1, 2, pl. VII, fig. 1. -
Herman et al., 2016, p. 674, pl. II, fig. 1-3, pl. III, fig. 1-4. Acanthopteris gothanii auct. non Sze, 1931 - Chen et al., 1981, p. 46, pl. 1, fig. 1-3. - Chen et al., 1988, p. 39, pl. 9, fig. 1-5, pl. 10, fig. 1, 2, pl. 12, fig. 1, pl. 62, fig. 5-7. - Deng, 1995, p. 28, pl. 13, fig. 1-4, pl. 14, fig. 2-6, pl. 15, fig. 1-4, pl. 17, fig. 5. - Deng, Chen, 2001, p. 92, pl. 51, fig. 1, pl. 52, fig. 1, 2, pl. 53, fig. 1-8, pl. 54, fig. 1-4, pl. 55, fig. 1-5, pl. 56, fig. 1-6, pl. 57, fig. 1-9, pl. 58, fig. 1-8, pl. 59, fig. 1-7, pl. 60, fig. 1-7, pl. 61, fig. 1-6, pl. 62, fig. 1-6, pl. 63, fig. 1-6, pl. 64, fig. 1-6, Text-fig. 20. - Deng, 2002, pl. I, fig. 1-4, pl. II, fig. 2, 3. - Deng, Lu, 2006, pl. 2, fig. 1-5, pl. 3, fig. 1-3. Birisia jelisejevii auct. non (Kryshtofovich) Philippova: Philippova, Abramova, 1993, p. 49, pl. I, fig. 3, 4, pl. II, fig. 12.
Birisia onychioides auct. non (Vassilevskaja et Kara-Mursa) Samylina, 1964, p. 60, pl. VIII, fig. 1, 2, pl. IX,
fig. 1-5. - Samylina, 1976, p. 24, pl. III, fig. 1-3, pl. IV, fig. 1.- Scott, Smiley, 1979, pl. 2, fig. 2. Cladophlebis oerstedtii auct. non (Heer) Seward: Kryshtofovich, 1958, p. 29, pl. III, fig. 1, 2. Coniopteris inenarabilis auct. non (Hollick) Scott, Smiley, 1979, pl. 2, fig. 1.
Holotype. Spec. CNIGRM 5350/31, North-East of Russia, Zyryanka River, Buor-Kemyus Formation, lower-middle Albian; Prynada, 1938, pl. I.
Diagnosis emended. Rhizome short-creeping with closely spaced stipes; fronds produced singly, bi-pinnate to tripinnate, linear-lanceolate; young leaves circinate; sterile ultimate pinnae alternate or less commonly opposite; up to 15 cm long and 3,5 cm wide; sterile pinnules linear, tapering apically, with toothed or lobed margin, rarely entire; up to 35 mm long and up to 10 mm wide; (width to length ratio 1:4-1:8), lobed pinnules with 5-12 pairs of lobes (usually with 5-8 pairs); lobes linear-lanceolate to broadly lanceolate with acute apices; pinnule venation pinnate, usually simple, or forked 2-3 times; fertile pinnae with reduced pinnules; sori apical, rounded or elliptical, 1-2 mm in diameter; indusium transitional from bivalvate to cup-like; sporangia globular or elliptical, 200-250 |im in diameter, with long stalk; annulus vertical, incomplete, about % of the circumference of the sporangium, consisting of about 20-25 thickened cells; each sporangium yielding 64 spores; spores trilete, sub-triangular in polar view, sides slightly convex or concave, laesurae thick, nearly reaching equator; exine smooth or with fine granules.
Stratigraphie horizon and occurrence. North-East of Russia: Buor-Kemyus Formation, lower-middle Albian; Galimyi Formation, lower-middle Albian; Krivorechenskaya Formation, upper Albian-lower Turonian; Arman and Zarya formations, Turonian-Coniacian.
Northeastern China: Huolinhe Formation, Inner Mongolia, Lower Cretaceous; Xiaoming'anbei, Shahai and Fuxin formations, Liaoning, Lower Cretaceous.
Alaska: Kukpowruk and Corwin formations, Albian-Cenomanian.
Birisia aeutata Samylina
Birisia acutata Samylina, 1972, p. 96, pl. I, fig. 1-4, pl. II, fig. 3. - Grabovskiy, Golovneva, 2018, p. 37, pl. II, fig. 7. Coniopteris onychioides auct. non Vassilevskaja et Kara-Mursa: Samylina, 1964, p. 60, pl. VIII, fig. 3, 4.
Holotype. Spec. BIN 508/245, North-East of Russia, Zyryanka River, Buor-Kemyus Formation, lower-middle Albian; Samylina 1972, pl. I, fig. 3.
Diagnosis (Grabovskiy, Golovneva, 2018). Sterile pinnules small, from 6 to 15 mm long and from 1 to 3 mm wide, with 3-7 acute teeth, without lobes; sporangia and spores unknown.
Stratigraphie horizon and occurrence. North-East of Russia, Zyryanka River, Buor-Kemyus Formation, lower-middle Albian.
Birisia onychioides (Vassilevskaja et Kara-Mursa) Samylina
Birisia onychioides (Vassilevskaja et Kara-Mursa) Samylina, 1972, p. 95. - Grabovskiy, Golovneva, 2018, p. 37, pl. V, fig. 1-4.
Coniopteris onychioides Vassilevskaja et Kara-Mursa, 1956, p. 38, pl. I-III, text-fig. 1-5. - Vassilevskaja, 1958, p. 62, pl. V, fig. 7, pl. VIII, fig. 1, pl. IX, fig. 1, 2, pl. XI, fig. 2. - Vassilevskaja, Pavlov, 1963, pl. XI, fig. 3, pl. XIX, fig. 5, 6, pl. XXXI, fig. 6-8, 9a.
Holotype. Spec. CNIGRM 9498/44, Siberia, Lena River basin, Eksenyakh Formation, Aptian; Vassilevskaja, Kara-Mursa 1956, pl. II, fig. 1.
Diagnosis (Grabovskiy, Golovneva, 2018). Sterile pinnules from 8 to 35 mm long and from 3 to 5 mm wide, mostly divided into lobes, or dentate in the upper part of the frond; lobed pinnules with 8-15 pairs of lobes with acute or rounded apices, each lobe entering one vein, sometimes branched. Sporangia unknown. Spores trilete, sub-triangular in polar view, sides slightly convex or concave; laesurae thick, nearly reaching equator; exine smooth or with fine granules.
Stratigraphic horizon and occurrence. Siberia, Lena River basin: Eksenyakh Formation, Aptian; Bu-lun Formation, Barremian; Ukinsk Formation, Albian.
Birisia mandshurica Golovneva, Grabovskiy et Zolina, sp. nov. Pl. I, fig. 1-4, Pl. II, fig. 1-4, Pl. III, fig. 1-4, Pl. IV, fig. 1-6, Pl. V, fig. 1-5
Etymology - after region Manchuria.
Holotype (designated here). Spec. IBSS 320/485, Far East of Russia, Primorye, Frentsevka Formation, lower-middle Albian. - Pl. I, fig. 1, Pl. II, fig. 4.
Diagnosis. Rhizome short-creeping with closely spaced stipes; fronds produced singly, bipinnate, linear-lanceolate; sterile pinnules linear, narrow, 6-25 mm long, 0,8-2,5 mm wide (width to length ratio 1:81:10), with dentate margin; fertile pinnae with reduced pinnules; sori apical, rounded or elliptical, 1-2 mm in diameter; sporangia and spores unknown.
Description. Material is represented by fragments of sterile and fertile leaves, some of them attached to rhizomes. The large, linear-lanceolate fronds were produced singly, arising upwards from horizontal short-creeping rhizomes.
Rhizomes are short and thick, up to 10 cm long and 0,8-1,0 cm in diameter, without ribs and scales. The roots are not preserved. Stipes are closely spaced, flattened, smooth or ribbed, up to 8 cm long and 0,5-0,8 cm in diameter near the base. Distance between stipes is 0,5-1,0 cm.
Fronds are bipinnate, linear-lanceolate, with acute or attenuate apices, up to 18 cm long and up to 17 cm wide. The rachises of pinnae are thick, straight, up to 5 mm wide, with thin longitudinal central rib.
The pinnae are usually subopposite, rarely alternate, up to 18 pairs, diverging from rachis at an angle of 30-50° (near the frond base up to 70°). They are linear, gradually tapering toward the apices, up to 12 cm long and 0,7-2,5 cm wide near their bases. The pinnae occur at some distance from one another or touch by margins.
There are 20-30 pinnules on each side of the sterile pinna in the middle part of the frond. They are linear, gradually tapering toward the apices, densely spaced, diverging from rachis at an angle of 30-45°, 6-25 mm long, 0,8-2,5 mm wide, alternate or subopposite, with acute apex, sessile base and dentate margin. A single vein enters the pinnule. The venation is pinnate, with 7-10 pairs of short lateral veins. The proximal basiscopic pinnule of each pinna is decurrent to the leaf rachis. The intercalated pinnules are similar with the normal ones in size and shape. In small pinnae near the frond apex the pinnules gradually transform into linear-lanceolate lobes or triangular big teeth. The proximal basiscopic lobes also are decurrent to the rachis. They are linear-lanceolate or triangular.
Fertile pinnules have a reduced blades. They can be found anywhere, but are usually concentrated in the upper part of the frond. Fertile pinnae are usually shorter and narrower, then sterile ones. Fertile pinnules are simple or branched 1-2 times. Sori are located in the upper parts of the lobes near the ends of the veins, rounded or elliptical, 1-1,5 mm in diameter. Sporangia and spores are not preserved.
Material. Collection IBSS 320, spec. 167, 480-491, 504, 506-520.
Stratigraphic horizon and occurrence. Far East of Russia, Primorye, Frentsevka Formation, lower-middle Albian.
DISCUSSION
Comparison with fossil taxa
Species of Birisia are distinguished each other in size and degree of dissection of sterile pinnules, and in shape and number of lobes. Rhizomes were currently described for B. alata (Deng, 1995; Deng, Chen, 2001; Deng, 2002; Deng, Lu, 2006) and for B. mandshurica (this paper). The structure of rhizomes in these two species practically does not different. Spores were studied also for two species: for B. onychioides (Vassilevskaja, Kara-Mursa, 1956) and for B. alata (Deng, Chen, 2001; Deng, 2002; Deng, Lu, 2006). Their sizes and morphology are very similar. Structure of sori and sporangia are known only for B. alata (Deng, 2002; Deng, Lu, 2006).
Birisia mandshurica, sp. nov. is the most similar to the type species of the genus Birisia - B. alata. New species differs from the latter by smaller size of leaves and by smaller and narrower pinnules. In B. alata leaves are usually tripinnate, very rarely bipinnate. In B. mandshurica all leaves are bipinnate. Sterile pinnules in B. alata are toothed or lobed, rarely entire, up to 35 mm long and up to 10 mm wide, lobed pinnules have 5-12 pairs of linear-lanceolate or broadly lanceolate lobes with acute apices. B. mandshurica is characterized only by dentate pinnules. They are smaller and narrower, then in B. alata (width to length ratio is 1:4-1:8 in B. alata and 1:8-1:10 in B. mandshurica). The morphology of fertile pinnules, sori and short-creeping rhizomes in both species is similar. Sporangia and spores in B. mandshurica are unknown.
B. onychioides is distinguished from B. mandshurica by tripinnate leaves, and by predominance of large lobed pinnules with slightly contracted bases. Pinnules of B. acutata have no lobes, like pinnules of B. man-dshurica, but the first species differs by very small sizes of fronds and pinnules (pinnules 6-5 mm long and 1-3 mm wide with 3-7 acute teeth in B. acutata and 6-25 mm long and 0,8-2,5 mm wide with 6-13 acute teeth in B. mandshurica).
Sterile leaves of Birisia have significant similarity with those of some other ferns, in particular Tchucoto-pteris and Arctopteris.
The genus Tchucotopteris with type species T. ustinovii Vassilevskaja was described from the Nyrvakinot Unit of Eastern Chukotka (Vassilevskaja, 1977). It has linear dentate or lobed pinnules with acute apex like Birisia. The proximal basiscopic pinnule of each pinna is decurrent to the leaf rachis. However sori of Tchucotopteris are linear, marginal, covered by a false indusium formed from the reflexed margin of the leaf. This structure of spore-bearing pinnules is characteristic of the Pteridaceae family. Leaves of Arctopteris are characterized by wider tongue-shaped pinnules, which often merge at the base, and also by marginal sori with false indusium (Samylina, 1964; Golovneva, 2018).
Reconstruction and palaeoecological interpretation
Deposits of the Frentsevka Formation near the Bolshoy Kuvshin Cape are represented by alluvial-lacustrine floodplain facies intercalated with coarse-grained sandstones and conglomerates, representing deposits of braided rivers flowing down from the upland where is now located the Ussuri Bay (Sharudo,
1960). The locality contains numerous remains of diverse herbaceous angiosperms with an admixture of the ferns Onychiopsis psilotoides (Stokes et Webb) Ward and Birisia mandshurica. Many specimens are represented by almost complete plants or big fragments with attached roots, leaves and fruits. The plant remains are often folded, rolled and cross bedding planes. Herbaceous angiosperms were small (10-30 cm high) and very delicate. Their complete preservation in rather coarse sediment indicates the absence of water transport. They were deposited very close to their original location. Stronger fern leaves were often left standing in organic connection to the horizontal rhizomes. It is likely that this fossil-bearing layer was formed during catastrophic flooding event (Golovneva et al., 2018). Thus, this locality can be considered as autochthonous, reflecting the vegetation which grew near to the burial place. We interpreted this vegetation as an open fern-angiosperm herbaceous community, which occupied low flat plains between river channels and was adapted to colonize fresh sediments in periodically flooded areas (Golovneva et al., 2018). Reconstruction of this fern-angiosperm community is shown in Fig. 2.
Remains of B. mandshurica are also relatively complete and well-preserved. They include sterile and fertile fronds and creeping rhizomes. Rhizomes with attached stipes are associated with the fronds. Based on these fossils we proposed a whole-plant reconstruction of B. mandshurica (Fig. 3). It was herbaceous rhizomatous fern up to 30-40 cm in height. Leaves were bipinnate with relatively short and thick stipes. Closely spaced stipes suggests that leaves tended to form clumps from 5-10 fronds. The fertile pinnae were borne at the upper part of the frond, or only some of the pinnules of a pinna were fertile.
Palaeogeography
The most ancient species of this genus is B. onychioides from the Lena River basin, Eastern Siberia. It was recorded from the Barremian Bulun Formation, the Aptian Eksenyakh and Ogoner-Yuryakh formations, and the Albian Ukinsk Formation (Vassilevskaja, Kara-Mursa, 1956; Vassilevskaja, 1958; Vassilevs-kaja, Pavlov, 1963).
This species was also reported from the Lower Cretaceous Tamodani, Oguchi, Chinaboradani and Mekkodani formations of Japan (Kimura, 1975, 1979). However, our examination of figured material
Fig. 2. Reconstruction of the fern-angiosperm open herbaceous community.
Fig. 3. Reconstruction of B. mandshurica Golovneva, Grabovskiy et Zolina.
(Kimura, 1975) shows, that these specimens most likely should be assigned to B. alata. Specimens, described by Samylina as B. onychioides from the lower-middle Albian Buor-Kemyus Formation, Kolyma River basin (Prynada, 1938; Samylina, 1964) and from the lower-middle Albian Galimyi Formation, Balygychan-Su-goi depression (Samylina, 1976) also belong to B. alata. Fragments of ferns, figured under the name B. onychioides from the Albian Balyktakh Formation, Kotelnyi Island, New Siberian Islands (Kuzmichev et al., 2018; Domogatskaya, Herman, 2019) are characterized by a different morphology and cannot be attributed to the genus Birisia.
B. alata is the most widespread species, which is known from the North-East of Russia, China, Japan and Alaska (Fig. 4). In the North-East of Russia it was found in the lower-middle Albian Buor-Kemyus Formation, Kolyma River basin (Prynada, 1938; Samylina, 1964), the lower-middle Albian Galimyi Formation, Balygychan-Sugoi depression (Samylina, 1976), upper Albian-lower Turonian Krivorechenskaya Formation, Grebenka River (Kryshtofovich, 1958; Philippova, Abramova, 1993), and in the Turonian-Coniacian Arman Formation of the Arman River basin (Samylina,1972; Herman et al., 2016; Grabovskiy, Golovneva, 2018).
B. alata was widely distributed in the Lower Cretaceous of northeastern China, where was reported under the name Acanthopteris gothanii (Zhang et al., 1980; Zheng, Zhang, 1982; Chen et al., 1988; Cao, 1994; Deng, 1995, 2002; Deng et al., 1997; Yang, 2003), and in Japan under the name B. onychioides (Kimura, 1975, 1979). However, the preservation of most specimens is not good enough for a confident species determination. In many cases, they do not have spore-bearing pinnules. The most complete material comes from the Xiaoming'anbei Formation, the Tiefa Basin (Chen et al., 1988; Deng, Chen, 2001; Deng, Lu, 2006), the Huolinhe Formation, the Huolinhe Basin (Deng, 1995; Deng, Chen, 2001), and the Shahai and Fuxin formations, the Fuxin Basin (Chen et al., 1981; Chen et al., 1988; Deng, Chen, 2001).
In Alaska, B. alata (named as Coniopteris inenarabilis (Hollick) Scott, Smiley and C. onychioides) was found in the Albian-Cenomanian deposits of the Kukpowruk and Corwin formations (Scott, Smiley, 1979; Spicer, Herman, 2001).
The sterile and fertile leaves of Birisia under the name Acanthopteris gothanii were described by Wan (1996) from the lower Albian Gates Formation, Western Canada. However, more complete material is needed to species identification of these specimens. From the Albian Balyktakh Formation, New Siberian Islands, fragmented leaves of B. alata were figured as Coniopteris aff. saportana (Heer) Vachrameev (Domogatskaya, Herman, 2019, Fig. 3, Ab, B, F).
B. acutata is known only from the lower-middle Albian Buor-Kemyus Formation, Kolyma River (Samylina, 1972).
Fig. 4. Localities of Birisia in the Cretaceous deposits of Russia and northeastern China: 1 - Partizansk Basin, Bolshoy Kuvshin Cape, Primorye, Frentsevka Formation, lower-middle Albian; 2 - Lena River, Yakutia, Eksenyakh Formation, Aptian; 3, 4 - Zyryanka Basin, Kolyma River basin, Buor-Kemyus Formation, lower-middle Albian; 5 - Arman River, Magadan Region, Arman Formation, Turonian-Coniacian; 6 - Omsukchan Basin, Balygychan-Sugoi depression, Magadan Region, Galimyi Formation, lower-middle Albian; 7 - Grebenka River, Chukotka, Krivorechenskaya Formation, upper Albian-lower Turonian; 8 - Huolinhe Basin, Inner Mongolia, Huolinhe Formation, Lower Cretaceous; 9 - Fuxin Basin, Liaoning Province, Shahai and Fuxin formations, Aptian-Albian; 10 - Tiefa Basin, Liaoning Province, Xiaoming'anbei Formation, Lower Cretaceous.
B. mandshurica, described in this paper, comes from the lower-middle Albian Frentsevka Formation, Primorye region.
CONCLUSION
Revision of ferns, described as Acanthopteris gothanii in China, shows, that these ferns belongs to Birisia alata. The name Acanthopteris should be abandoned, due to absence of spore-bearing pinnules and poor preservation of sterile pinnules in type specimens. The storage location of the original material described by Sze (1931) is unknown. Based on Chinese and Russian material, the diagnoses of the genus Birisia and its type species B. alata were emended.
Re-examination of different findings of the genus Birisia revealed that this genus was widely distributed in the Cretaceous floras of Eastern Siberia, New Siberian Islands, North-East and of Far East of Russia, China, Japan, Alaska and Western Canada, ranging from the Barremian to the Coniacian. B. alata is the most widespread species.
Birisia mandshurica is the most similar to B. alata. New species differs from the latter by bipinnate fronds and by smaller and narrower pinnules. A whole-plant reconstruction of B. mandshurica is proposed. It was herbaceous rhizomatous fern up to 30-40 cm in height with bipinnate leaves and relatively short and thick stipes. Closely spaced stipes suggests that leaves tended to form clumps from 5-10 fronds. The fertile pinnae were borne at the upper part of the frond, or only some of the pinnules of a pinna were fertile. B. mandshurica was a part of pioneer open herbaceous community, consisting of ferns and angiosperms, which occupied low flat plains between river channels.
ACKNOWLEDGEMENTS This study was supported by the Russian Foundation for Basic Research, project No 19-04-00943 and carried out within the framework of the institutional research project AAAA-A19-119030190018-1.
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PLATE I
1-4 - Birisia mandshurica Golovneva, Grabovskiy et Zolina, sp. nov.:
1 - spec. IBSS 320-485, bipinnate leaf with fertile pinnae, holotype, *1,5;
2 - spec. IBSS 320-480, fragment of sterile pinnae, *2;
3 - spec. IBSS 320-491', sterile pinnae, x1,5;
4 - spec. IBSS 320-482, fertile pinnae, x1,5.
PLATE II
1-4 - Birisia mandshurica Golovneva, Grabovskiy et Zolina, sp. nov.:
1 - spec. IBSS 320-484, leaf fragment with decurrent pinnules, *3;
2 - spec. IBSS 320-481, bipinnate frond, x1;
3 - spec. IBSS 320-480, bipinnate frond, x1;
4 - spec. IBSS 320-485, fertile pinnae, holotype, *3.
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PLATE III
1-4 - Birisia mandshurica Golovneva, Grabovskiy et Zolina, sp. nov.:
1 - spec. IBSS 320-520a, leaf fragment with intercalated pinnules, *2;
2 - spec. IBSS 320-513, bipinnate frond, *2;
3 - spec. IBSS 320-520b, pinnules in the upper part of the frond, *3;
4 - spec. IBSS 320-520c, pinnules in the upper part of the frond, *3.
PLATE IV
1-6 - Birisia mandshurica Golovneva, Grabovskiy et Zolina, sp. nov.:
1 - spec. IBSS 320-515, fertile pinnae, *2;
2 - spec. IBSS 320-487, fertile pinnae and intercalated fertile pinnules, *2;
3 - spec. IBSS 320-520', leaf fragment with intercalated pinnule,*2;
4 - spec. IBSS 320-482', fertile and sterile pinnae, *2.
5 - spec. IBSS 320-620, creeping rhizome with closely spaced stipes, *2.
6 - spec. IBSS 320-506, closely spaced stipes, *1.
PLATE V
1-5 - Birisia mandshurica Golovneva, Grabovskiy et Zolina, sp. nov.:
1 - spec. IBSS 320-520', fragments of sterile bipinnate fronds, *1;
2 - spec. IBSS 320-504', fertile pinnae, x2;
3 - spec. IBSS 320-509, leaf fragment with decurrent or intercalated pinnules,*1;
4 - spec. IBSS 320-517, fertile pinnae, x2;
5 - spec. IBSS 320-482', fertile pinnae, x1.
