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. 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.
Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, 226007, India.
Vartika
V
Singh
Department of Geology, University of Jammu, Jammu, 180006, India.
Sundeep K
SK
Pandita
Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, 226007, India.
Rajni
R
Tewari
Department of Marine Sciences, Texas A&M University at Galveston, Galveston, Texas, 77553, United States of America.
Peter J
PJ
van Hengstum
Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, 226007, India.
Suresh S K
SS
Pillai
Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, 226007, India.
Deepa
D
Agnihotri
Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, 226007, India.
Kamlesh
K
Kumar
Directorate of Geology and Mining, Jammu and Kashmir Government, Srinagar, 190002, India.
G D
GD
Bhat
D000656:Amoeba / Q000145:classification*; D044822:Biodiversity; D005075:Biological Evolution; D005580:Fossils; D019015:Geologic Sediments / Q000469:parasitology*; D007194:India; D010163:Paleontology