Deepa Agnihotri

A Dicroidium flora from the Triassic of Allan Hills, South Victoria Land, Transantarctic Mountains, Antarctica

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.

Thecamoebians (Testate Amoebae) Straddling the Permian-Triassic Boundary in the Guryul Ravine Section, India: Evolutionary and Palaeoecological Implications.

Exceptionally well-preserved organic remains of thecamoebians (testate amoebae) were preserved in marine sediments that straddle the greatest extinction event in the Phanerozoic: the Permian-Triassic Boundary. Outcrops from the Late Permian Zewan Formation and the Early Triassic Khunamuh Formation are represented by a complete sedimentary sequence at the Guryul Ravine Section in Kashmir, India, which is an archetypal Permian-Triassic boundary sequence [1]. Previous biostratigraphic analysis provides chronological control for the section, and a perspective of faunal turnover in the brachiopods, ammonoids, bivalves, conodonts, gastropods and foraminifera. Thecamoebians were concentrated from bulk sediments using palynological procedures, which isolated the organic constituents of preserved thecamoebian tests. The recovered individuals demonstrate exceptional similarity to the modern thecamoebian families Centropyxidae, Arcellidae, Hyalospheniidae and Trigonopyxidae, however, the vast majority belong to the Centropyxidae. This study further confirms the morphologic stability of the thecamoebian lineages through the Phanerozoic, and most importantly, their apparent little response to an infamous biological crisis in Earth’s history.

An Early Permian Glossopteris flora from the Umrer Coalfield, Wardha Basin, Maharashtra, India

Tewari, R., Pandita, S.K., Agnihotri, D., Pillai, S.S.K. & Bernardes-De-Oliveira, M.E.C., September 2012. An Early Permian Glossopteris flora from the Umrer Coalfield, Wardha Basin, Maharashtra, India. Alcheringa 36, 359–376. ISSN 0311-5518. A rich and well-preserved Glossopteris-dominated plant fossil assemblage is described from the Barakar Formation of the Makardhokra and Umrer open-cast projects, Umrer Coalfield, Nagpur District, Wardha Basin, Maharashtra, India. The assemblage includes equisetalean axes, cordaitalean leaves (Noeggerathiopsis hislopii), Gangamopteris clarkeana and diverse Glossopteris leaves and a fertile organ assigned to Scutum sp. cf. S. leslii. The flora, although similar to that of the Barakar Formation of the Damodar Basin complex (the reference basin system with respect to the qualitative and quantitative distribution of Indian Permian plant taxa), exhibits unique characteristics and is Artinskian to Kungurian in age. Besides supplementing knowledge of the broader Wardha Basin flora, this is the first systematic documentation of the Glossopteris flora from the Barakar Formation of this basin.

Morphological and stratigraphical significance of lower Gondwana plant fossils of Mohpani Coalfield, Satpura Gondwana Basin, Madhya Pradesh

Plant fossils from the coal bearing Barakar Formation exposed in Gottitoria open cast mine of Mohpani Coalfield, Satpura Gondwana Basin are described for the first time. The assemblage is represented by Glossopteris communis, G. indica, G. stenoneura, Gangamopteris angustifolia, G. cyclopteroides, G. karharbariensis, G. major, seeds of Cordaicarpus zeilleri and equisetaceous stems. The dominance of the species of Gangamopteris over the species of Glossopteris and absence of Noeggerathiopsis indicate the floral affinity with the flora of Lower Barakar Formation of Lower Gondwana.