Ellen Thomas, research professor of earth and environmental sciences, is the co-author of “Pteropoda (Mollusca, Gastropoda, Thecosomata) from the Paleocene-Eocene Thermal Maximum of the United States Atlantic Coastal Plain,” published in Palaeontologia Electronica, Article 19 (3) in October 2016.
The Paleocene Epoch lasted 65 to 54.8 million years ago and the Eocene Epoch lasted from 56 to 33.9 million years ago, and was a period of rapid global warming.
The response of many organisms to the Paleocene-Eocene Thermal Maximum (PETM) has been documented, but marine mollusks are not known from any deposits of that age. For the first time, Thomas and her co-authors describe a PETM assemblage of pteropods (planktic mollusks), consisting of six species representing three genera (Altaspiratella, Heliconoides and Limacina). Four species could be identified to species level, and one of these, Limacina novacaesarea sp. nov., is described as new. Only the genus Heliconoides was previously known from pre-Eocene sediments, with a single Campanian specimen and one latest Paleocene species.