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14A new species of Comatricha (Myxomycetes) from southern Vietnam
Yu. K. Novozhilov1, D. W. Mitchell2
1 Komarov Botanical Institute, Prof. Popov Str., 2, St. Petersburg, 197376, Russia; yurinovozhilov@gmail.com
2 Walton Cottage, Upper Hartfield, East Sussex, TN7 4AN, England; slimelord@talktalk.net
Abstract. A new species Comatricha spinispora Novozh. et D. W. Mitch. was obtained as field collections and isolated from moist-chamber cultures from samples of ground litter. Specimens of sporocarps and substrates for moist chamber cultures were collected in deciduous monsoon tropical lowland forests (Cat Tien National Park, Vinh Cuu Nature Reserve), mixed montane tropical forests and cloudy tropical forests (Bi Dup-Nui Ba Nature Reserve) of southern Vietnam during surveys carried out in December 2010, November 2011, 2012. The morphology of representative specimens of sporocarps was examined by light and scanning electron microscopy and micrographs of relevant details are provided. Spore ornamentation consists of long spines 0.5-0.8 ^m long and 6-8 very small additional spines 0.1-0.3 ^m long densely distributed over the top part of spine surface and visible only by SEM. The stability of the taxonomic characters of the species was confirmed by several collections obtained over a period of three field seasons in field as well as in moist chamber cultures. Comatricha spinispora resembles C. rutilipedata H. Marx in overall shape and size of the sporocarps but has dark brown bottom of stalk and slightly larger spores decorated by scattered long spines. The main morphological difference between C. spinispora and Macbrideola ovoidea Nann.-Bremek. et Y. Yamam. lies in shape and colour of sporocarp and spore ornamentation.
Keywords: Amoebozoa, Comatricha spinispora, Myxogastria, Stemonitidaceae, plasmodial slime molds, myxomycetes, taxonomy, Vietnam.
Новый вид Comatricha (Myxomycetes) из южного Вьетнама Ю. К. Новожилов1, Д. В. Митчелл2
ботанический институт им. В. Л. Комарова РАН, ул. Профессора Попова, д. 2, Санкт-Петербург, 197376, Россия; yurinovozhilov@gmail.com 2 Walton Cottage, Upper Hartfield, East Sussex, TN7 4AN, England; slimelord@talktalk.net
Резюме. Новый для науки вид Comatricha spinispora Novozh. et D. W. Mitch. был выявлен в полевых сборах, а также изолирован из образцов наземного опа-да методом влажной камеры. Образцы спорокарпов и субстратов для влажных камер были собраны во время полевых исследований, проводившихся в декабре 2010 г., ноябре 2011 и 2012 гг. в листопадных муссонных пойменных тропических лесах (национальный парк Кат Тьен, заповедник Винь Кыу), смешанных горных тропических лесах и туманных тропических лесах (заповедник Би Дуп
Нуй Ба) в южном Вьетнаме. Морфология образцов спорокарпов была изучена с помощью светового и электронного сканирующего микроскопа. Орнаментация спор Comatricha spinispora состоит из длинных шипиков 0.5-0.8 мкм дл. и 6-8 дополнительных шипиков 0.1-0.3 мкм дл., плотно расположенных в верхней части основных шипиков и видимых только с помощью SEM. Стабильность таксономических признаков нового вида подтверждается несколькими коллекциями, собранными в разное время в течение трех полевых сезонов. C. spinispora по внешнему виду и размеру спорокарпов напоминает C. rutilipedata H. Marx, но в отличие от последнего имеет темно-коричневое основание ножки, несколько более крупные споры и длинные шипики вместо бородавок на поверхности спор. Основные морфологические отличия от Macbrideola ovoidea Nann.-Bremek. et Y. Yamam. относятся к форме и цвету спорокарпов, а также орнаментации спор.
Ключевые слова: Amoebozoa, Comatricha spinispora, Myxogastria, Stemoniti-daceae, плазмодиальные слизевики, миксомицеты, таксономия, Вьетнам.
The genus Comatricha (Myxomycetes, Stemonitales), proposed originally by C. G. Preuss (1851) for Comatricha obtusata (Fr.) Preuss (= C. nigra (Pers. ex J.F. Gmel.) J. Schrot.) is based on a combination of several characters. These are the absence of a surface reticulum of capillitium and fibrous structure of the step and columella, although intermediate forms occur (Le-ontiev, 2013). At present 39 species are known in this genus (Lado, 2014).
During intensive studies of the diversity and ecology of myxomycetes in Bi Dup-Nui Ba Nature Reserve (southern Vietnam), a species of Comatricha (Myxomycetes, Stemonitales) with very small sporocarps and having distinct spinulose spores was found on ground litter in cloudy dwarf forest. Later this species appeared in moist chamber cultures prepared from samples of ground litter of various trees of Fagaceae collected in a mixed deciduous mountain forest as well as in a monsoon deciduous tropical forest in Cat Tien National Park. The spore ornamentation was different from that of any described species in the genus. This distinctive type of ornamentation suggests that it represents a species of Co-matricha new to science.
Materials and Methods
This paper is based on material obtained from moist chamber cultures of ground litter, aerial litter and bark collected from (1) Cat Tien National Park (CTNP, 11°21'-11°48' N, 107°10'-107°34' E) and adjoining forests of the Vinh Cuu Nature Reserve (VCNR, 11°03'-11°30' N, 106°54'-107°13' E), which are located at the foot of the central Vietnamese highlands in Dong Nai Province, about 130 km northeast of Ho Chi Minh City and (2) Bi Dup-Nui Ba Nature Reserve, centered in the Bi Dup Mountain massive (BDNB, 12°08' N, 108°40' E) on the Da Lat Plateau (Lam Dong Province).
All parts of CTNP and VCNR are hilly, with elevations ranging between 120 and 220 m a. s. l. (sector Nam Cat Tien) and up to 372 m a. s. l. (sector Tai Cat Tien) and 659 m a. s. l. (sector Cat Loc). There are numerous small rocky outcrops and lowlands, with the latter usually flooded for several weeks during the rainy season. Lowlands and flat-lands are especially characteristic of the eastern part of the region bordering the Dong Nai River. The general study area is characterized by a tropical monsoon climate with two distinct seasons, a rainy season extending from late April to November and a dry season that lasts from December to March. The mean annual temperature is approximately 26 °C, with rather small seasonal fluctuations. The annual rainfall varies from 1800-2500 mm, the most rain falling during August and September (400450 mm per month), when much of the park area is inundated. In contrast, there is almost no precipitation from December to March (Thinh, Anichkin, 2011).
The vegetation of CTPN is very diverse. Most of the upper canopy trees are deciduous and shed their foliage during the dry season (Blanc et al., 2000; Kuznetsov, Kuznetsova, 2011, 2013; Anichkin, Tiunov, 2011).
The topography of BDNB is dominated by a range of high mountains. This region has a monsoon climate with two separate seasons — a cool season from December to April and a warm, wet monsoon season from May to November. The rainy season extends from May to October, and the dry season encompasses the period from December to April (New et al, 2002). The predominant vegetation of the BDNB is a montane evergreen forest, with small patches of coniferous forest and mixed broadleaf-coniferous forest containing members of the Fagaceae and Magnoliaceae along with Pinus kesiya, P. dalatensis and P. krempfii (Kuznetsov et al., 2006; Tran, 2011). Above 2000 m the arborescent vegetation is diminished in stature; moreover, close to the summits and nearby exposed ridges, it grows as a mountain mossy evergreen broad-leaved forest.
The samples of substrate material used for preparing moist chamber cultures were collected in November-December of 2010-2012. The specimens were air-dried in situ and transported back to the laboratory in sealed paper bags. All the localities were geo-referenced with a portable GPS device (WGS 84 mapping data).
In the laboratory, cultures were prepared by placing pieces of paper towel in Petri dishes (9 cm diam.) in such a way that most of the bottom surface of each dish (ca. 60 cm2) was covered. Cultures were flooded with distilled water, and after 24 hrs the excess water was poured off. Small amounts of water were added to the cultures at regular intervals to keep the substrates moist, and the cultures were maintained for up to three months
under diffuse daylight at room temperature (22-23 °C) and examined for the presence of myxomycetes on six occasions (days 2-4, 6-8, 11-14, 20-22, 40-44 and 85-90). The pH of the wet substrate was determined using an Hanna model 9024 pH meter with a flat surface electrode HI-1413 (with measurements taken for three pieces of substrate) during the first examination (days 2-4, pH 6.01 ± 0.24 for all cultures producing new species, n = 7). Sporocarps of the new species usually appeared within 20-22 days after the moist chamber cultures were started, with the last sporocarps being found at days 40-44. Voucher specimens are deposited in the collection of the first author in the Mycological Herbarium of the Komarov Botanical Institute (St. Petersburg, LE).
Air-dried sporocarps were studied with a Zeiss Axio Imager A1 light microscope with differential interface contrast (DIC), a Stemi 2000 dissection microscope and a JSM-6390 LA scanning electron microscope (SEM) in the Komarov Botanical Institute. For microscopy, sporocarps were preserved as permanent slides in polyvinyl lactophenol. The freeware program CombineZ was used to create stacked images under a Ste-mi 2000 dissection microscope. Microscopic measurements were made with the program Axio Vision 4.8.0.0 (Carl Zeiss Imaging Solutions GmbH, free licence). Spore features (diameter and spore ornamentation) were determined for 10 spores per specimen for each of the specimens examined in detail. Observations of the spore ornamentation by SEM have been made after applying the critical point drying technique (Singer et al., 2005). Specimens for electron microscopy were mounted on copper stubs using double-sided sticky film and sputter-coated with gold. Colour notations in parentheses are from the ISCC-NBS colour-name charts illustrated with centroid colours (Anonymous, 2012).
Comatricha spinispora Novozh. et D. W. Mitch., sp. nov. (Plate I).
MycoBank: MB 808697
Sporocarps scattered or in small groups, up to 1.0 mm total height (Plate I, a). Sporothecae subglobose to ovoid (Plate I, b), 0.15-0.4 mm diam. Stalk 60-70 % of the total height, black above, brown or reddish-brown in the expanded basal part in transmitted light (Plate I, e). Columella tapered, reaching to near the apex of the sporotheca (Plate I, e). C a p i 11 i t i u m arising from the length of the columella, dark brown, sinuous, with few free ends at the periphery (Plate I, c,f, h). Peridium evanescent but remaining as a small collar. Hypothallus discoid, redish or occasionally confluent beneath small groups. Spore-mass greyish yellowish pink (gy.yPk 32). Spores pinkish grey (pkGy) in transmitted light (7.0)7.5-8.0(8.5) ^m diam. (Plate I, c, d). Spore ornamentation
consists of spines 0.5-0.7 ^m in length (Plate I, g) and small spine-like protuberances 0.1-0.3 ^m in length densely distributed over the top part of spine surface and visible only by SEM (Plate I, i).
Holotype: Vietnam, Lam Dong Province, Bi Dup-Nui Ba Nature Reserve, Da Lat Plateau, dense mountain evergreen forest with Fagaceae, 12°11'07.7" N, 108°40'52.7" E, 1445 m a. s. l., on ground litter of leaves of undetermined trees of Fagaceae, 01.11.2011, Novozhilov, LE 286575.
Material examined: Vietnam, Dong Nai Province, Tan Phu District, Cat Tien National Park, right bank of the Dong Nai River (upper reach), the south Vietnamese lowland dense monsoon semideciduous tropical secondary forest, 11°25'53.9" N, 107°25'34.0" E, 125 m a. s. l., on ground litter (in moist chamber culture), 28.11.2012, Novozhilov, LE 297269; road to the Bao Sao lake, 11°26'15.5" N 107°25'18.9" E, 152 m a. s. l., on ground litter (in moist chamber culture), 16.11.2011, Novozhilov, LE 297952; near meteorological station, on ground litter (in moist chamber culture), 22.11.2012, Novozhilov, LE 297953. Lam Dong Province, Bi Dup-Nui Ba Nature Reserve, Da Lat Plateau, dense mountain evergreen forest with Fagaceae, cordon Giang Ly, 12°11'12.3" N, 108°40'54.0" E, 1520 m a. s. l., on ground litter (in moist chamber culture), 02.11.2011, Novozhilov, LE 288064; cordon Hon Giao, at the beginning of the trail, mountain evergreen cloudy forest, 12°11'15.2" N, 108°42'50.8" E, 1652 m a. s. l., on ground litter, field collections, 04.11.2011, Novozhilov, LE 286619, LE 286620; in moist chamber culture: LE 288052, LE 288068, LE 288070, LE 288090; cordon Hon Giao, mountain evergreen cloudy forest, 12°11'19.7" N, 108°42'50.1" E, 1707 m a. s. l., on ground litter, in moist chamber culture, 04.11.2011, Novozhilov, LE 288073, LE 288092, LE 288093, LE 288095, LE 288096, LE 288098.
Differentiation: Macroscopically the new species is most resembling Comatricha rutilipedata Marx and Macbrideola ovoidea Nann.-Bremek. et Y. Yamam. C. spinispora differs from C. rutilipedata (Marx, 1999) by the lack of many free ends in capillitium net, brown colour of the bottom of the stalk and mostly by subglobose and ovoid shape of sporo-theca. Spores of C. rutilipedata ornamented by scattered warts («Warzen» in the original description) whereas spores of C. spinispora ornamented by scattered long spines (Plate I, g, i). Spores of C. spinispora mostly resemble those of M. ovoidea (Nannenga-Bremekamp, Yamamoto, 1983; M. Tamaya-ma, pers. comm.). Both species have spores ornamented with spines 0.5-0.8 ^m long with coral-like tips consisting of 6-8 very small additional spines which are visible only under high magnification (x 2000-3000, eg. SEM). However C. spinispora differs from M. ovoidea by its much longer stipes of sporocarps, shape of sporotheca (subglobose or ovoid vs. subcylindrical) and color of spore mass (pinkish-grey vs. purplish-brown).
Acknowledgments
We gratefully acknowledge the technical support (SEM) provided by Ludmila A. Kartzeva (Komarov Botanical Institute RAS, St. Petersburg). The authors are grateful to the administration of the Joint Russian Vietnamese Tropical Research and Technological Centre of the Cat Tien National Park and to A. N. Kuznetzov and A. E. Anichkin for their assistance in the organization of fieldwork. We also wish to thank Mitsunori Tamayama for comments on taxonomy of Macbrideola ovoidea. Expeditions and laboratory work were supported by the Russian Found for Basic Research (grant № 13-04-00839-a) and the Program Ecolan-1.2 of the Russian-Vietnamese Tropical Scientific and Technological Centre.
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Plate I. Comatricha spinispora Novozh. et D. W. Mitch. (LE 286575, holotype). a — colony of sporocarps (dissection microscope = DM); b — opened sporocarp (DM); c — capillitium and spores (differential interference-contrast lens = DIC); d — spores (DIC); e — sporocarp (DIC); f— sporocarp (SEM); h — capillitium (SEM); g — spore (SEM); i — spore ornamentation (SEM). Scale bars: a, b, e, f — 100 ^m; c, d, h —
10 ^m; g, i — 1 ^m.
