A Dicroidium flora from the Triassic of Allan Hills, South Victoria Land, Transantarctic Mountains, Antarctica
2013; Taylor & Francis; Volume: 37; Issue: 2 Linguagem: Inglês
10.1080/03115518.2013.736799
ISSN1752-0754
AutoresSankar Chatterjee, Rajni Tewari, Deepa Agnihotri,
Tópico(s)Plant and Fungal Species Descriptions
ResumoAbstract Chatterjee, S., Tewari, R. & Agnihotri, D., 2013. A Dicroidium flora from the Triassic of Allan Hills, South Victoria Land, Transantarctic Mountains, Antarctica. Alcheringa 37, 207-219. ISSN 0311-5518. A heterogenous and well-preserved assemblage of Triassic plants, including pteridophytes and gymnosperms, is described from the Lashly Formation of the Allan Hills, South Victoria Land, Antarctica. The pteridophytes include the sphenopsids Calamites aliwalensis, unidentified calamitalean axes, Neocalamites carreri and Neocalamites sp. The gymnosperms include Corystospermales, Peltaspermales and Pinales. Corystosperms dominate the megafloral assemblage and include Dicroidium odontopteroides, D. crassinervis, D. fremouwensis, D. coriaceum subsp. dutoitii, together with a microsporangiate structure Pteruchus sp. Peltaspermales include microsporangiate and ovuliferous reproductive structures namely Townrovia polaris and Matatiella dejerseyi, respectively. Conifers are represented by Heidiphyllum elongatum foliage and an unidentified cone. The megafossil assemblage is similar to those recorded from the late Early Triassic of New South Wales and Antarctica, Middle Triassic of Argentina, New Zealand and southeast Queensland, Middle to Late Triassic of South Africa, India, northern Argentina and Australia, early to middle Late Triassic of the central Transantarctic Mountains, Antarctica, and Late Triassic of Chile and North Victoria Land, East Antarctica. The records of Calamites aliwalensis, Neocalamites carreri, Dicroidium fremouwensis, Pteruchus sp., Townrovia polaris, Matatiella dejerseyi and a conifer cone are the first of these taxa from the Allan Hills. Recent finds from the Permian beds of India and Jordan indicate a much earlier origin of Dicroidium than previously suspected. Persistence of greenhouse conditions from the end of the Permian through the Triassic allowed the rich and diverse Dicroidium forests to develop in the polar regions of Antarctica. Sankar Chatterjee [sankar.chatterjee@ttu.edu], Texas Tech University, Lubbock, TX 79401, USA; Rajni Tewari [rajni.tewari@gmail.com], Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow 226007, India; Deepa Agnihotri [deepa_302033@yahoo.com], Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow 226007, India. Received 9.4.2012; revised 20.9.2012; accepted 2.10.2012. 本文描述了采自南极洲南维多利亚大陆Allan Hills的Lashly组的三叠纪植物组合, 包括蕨类植物和裸子植物。它们是异源的, 保存完好。蕨类植物包括契叶植物Calamites aliwalensis、未鉴定的芦木茎轴、Noecalamites carreri和Neocalamites sp.。裸子植物包括Corystospermale、Peltaspermales及Pinales。大植物组合以corystosperms占优势, 包括Dicroidium odontopteroides、D. crassinervis、D. fremouwensis、D. coriaceum subsp. dutoitii, 其它还有微孢子囊结构Pteruchus sp. 。Peltaspermales包括微孢子囊和胚珠生殖构造, 分别命名为Townrovia polaris 和Matatiellade jerseyi。松树以Heidiphyllum elongatum树叶及未鉴定的果球为代表。这个大植物组合与新南威尔士和南极洲的早三叠世晚期的, 阿根廷、新西兰和昆士兰东南部的中三叠世的, 南非、印度、阿根廷北部和澳大利亚的中-晚三叠世的, 南极洲横断山脉中部的晚三叠世早-中期, 智利和东南极洲北维多利亚大陆的晚三叠世的植物群相似。Calamites aliwalensis、Neocalamites carreri、Dicroidium fremouwensis、Pteruchus sp.、Townrovia polaris、Matatiellade jerseyi及松果的记录在Allen Hills 属首次发现。最近在印度和约旦二叠纪地层中的新发现说明Dicroidium的起始比原先想象的要早得多。从二叠纪末至整个三叠纪, 温室条件的持续使得南极洲极区的Dicroidium林生长茂盛且多样。 Key words: Dicroidium floraTriassicLashly FormationAllan HillsAntarcticapalaeogeographypalaeoclimatology Acknowledgements We thank Naresh C. Mehrotra, director, Birbal Sahni Institute of Palaeobotany for providing the necessary facilities to carry out this research and Bill Mueller for photography. Sincere thanks are due to Steve McLoughlin and Benjamin Bomfleur for critically reading the manuscript and providing constructive suggestions. The research was funded by the National Science Foundation.
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