Degree Name

MS (Master of Science)

Program

Biology

Date of Award

8-2013

Committee Chair or Co-Chairs

Dr. Yu-Sheng (Christopher) Liu

Committee Members

Dr. Foster Levy, Dr. Tim McDowell

Abstract

The Late Hemphillian (latest Miocene or earliest Pliocene, 7-4.5 Ma) Gray Fossil Site in northeastern Tennessee is interpreted to represent a lacustrine paleokarst fed by a river or stream. This research focuses on the morphological and systematic relations of Nyssa endocarps (fruit pits) from the fossil site to extinct and extant Nyssa species. A combination of metric and nonmetric traits allows recognition of a new species: Nyssa grayensis sp. nov. This fossil species shares the most similarities with the extant Nyssa ogeche Bartram ex Marshall from southeast North America and the Eocene fossil Nyssa eolignitica Berry from western Tennessee. Affinities with Nyssa ogeche Bartram ex Marshall suggest a warmer winter climate than the present and periodically fluctuating water levels. Fossil vertebrates (Alligator, Heloderma, Hesperotestudo) and plants (Fossil relatives of Ilex vomitoria, Quercus virginiana, Taxodium, Acer leucoderme) with modern counterparts distributed in areas with mild winters support this interpretation.

Document Type

Thesis - Open Access

Copyright

Copyright by the authors.

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