Abstract Detail

Plants at the Cretaceous-Paleogene boundary

Smith, Selena [1], Manchester, Steven [2], Kapgate, Dashrath [3], Srivastava, Rashmi [4], Matsunaga, Kelly [5], Samant, Bandana [6], Wheeler, Elisabeth [7].

Progress and challenges in understanding vascular plant diversity in the Maastrichtian-Danian Deccan Intertrappean Beds of India.

The Deccan Intertrappean Beds of India preserve a diverse biota that spanned the Cretaceous-Paleogene (K-Pg) boundary and was paleogeographically isolated, providing data on the response of a unique ecosystem to environmental changes and the role of India in the evolutionary and biogeographic history of many groups. Plants are primarily preserved in cherts, in three dimensions with anatomical structure and are represented by wood, leaves, stems, fruits, flowers, seeds, strobili, and pollen and spores. Paleobotanical localities are found primarily in the Eastern Deccan Volcanic Province and Mandla subprovince. Data on species occurrences from 34 localities, representing a subset of the total number of known localities for which we have some confidence of age, was compiled. Across all localities, the fraction of taxa represented by wood, non-wood megafossils, and palynological samples is about even. The most diverse locality is Mohgaonkalan, with >280 species described; the next highest is Mahurzari, with ~45 species, and most are <20 species. It is not clear to what extent this is real vs. an artifact of incomplete sampling; Mohgaonkalan is the classic Deccan Chert locality and has received the most attention, while many of the others are more recently discovered. In NMDS analyses, sites considered to be Maastrichtian in age are more diverse and more different from each other than Paleocene sites, with Paleocene sites showing more similarity to each other and occupying a subset of the Maastrichtian space. ~30 taxa, including many palms, do not appear to be affected by the boundary event. Both ferns and gymnosperms decrease in species diversity in Paleocene sites, with monocots seeming to form a greater fraction of the species diversity and non-monocot angiosperms remaining about the same at almost 50% of species composition. There are still numerous taxa in need of reinvestigation to fully appreciate the extent of ecosystem disturbance at different taxonomic levels, as a large number of taxa remain incertae sedis, and new specimens and localities are still being collected. We highlight the need for combining data from palynology, reproductive material, and woods, as some taxa are much more strongly represented in one record than the others. Further scrutiny to distinguish the effects of differential investigator bias from features of ecological, environmental, and/or stratigraphic significance is necessary. However, the general pattern of decline of ferns and gymnosperms – which form a small component of the flora – and replacement by the more diverse angiosperms is likely to hold.

1 - Department Of Earth & Environmental Sciences, 1100 North University Avenue, 2534 CC Little Building, Ann Arbor, MI, 48109, United States
2 - Florida Museum Of Natural History, Po Box 117800, Gainesville, FL, 32611, United States
3 - J.M. Patel College, Botany, Bhandara, M.S., 441904, India
4 - Birbal Sahni Institute for Paleobotany, Lucknow, India
5 - University Of Michigan, Earth And Environmental Sciences, 1100 N University Ave, 2534 CC Little Bldg, Ann Arbor, MI, 48109, United States
6 - Rashtrasant Tukadoji Maharaj Nagpur University, Postgraduate Department of Geology, Nagpur, 440001, India
7 - N.C. State University, Forest Biomaterials, Raleigh, NC, 27695-8005, USA

Keywords:
palm
paleocene
Cretaceous
floristic change
paleoecology.

Presentation Type: Colloquium Presentations
Session: C01, Plants at the Cretaceous-Paleogene boundary
Location: 101/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 10:45 AM
Number: C01008
Abstract ID:938
Candidate for Awards:None