Fossil Trachemys (Testudines: Emydidae) from the Late Hemphillian of Eastern Tennessee and Its Implications for the Evolution of the Emydidae.

摘要

Trachemys (Testudines: Emydidae) represents one of the most well-known turtles today. The evolution of Trachemys, while being heavily documented with various fossil representatives, is not well understood. Numerous fossils from the Gray Fossil Site in northeastern Tennessee are helping to elucidate the taxon's evolution. The fossil Trachemys at the Gray Fossil Site represent a new species. A review of previously named Trachemys taxa reveals that a huge majority of them are not valid or have been previously misinterpreted. A phylogenetic analysis preformed on modern emydids and supposed fossil representatives of those genera also shows the evolution of a portion of the modern turtle fauna. While some fossils are nested within modern clades, a large number of the fossil turtles studied fall within their own clade. This may mean that these fossils represent an extinct lineage and less fossil representatives of modern turtles are known than previously thought.