New Discovery of 96-Million-Year Old Turtle Species and Hints at Intercontinental Migrations

Map of North America during the Cenomanian age (96 million years ago) showing the four turtle families newly discovered at the Arlington Archosaur Site (AAS). The AAS fossil assemblage includes a diverse combination of native North American turtle lineages alongside those that migrated from Asia or the Southern hemisphere. One of these species, “Trinitichelys” maini is a new species to science, described here for the first time.
Credit: Brent Adrian, M.F.A.

New 96-million-year old turtles from Texas connect North America with Asia and the Southern Hemisphere, suggesting vast intercontinental migrations during this time.

The Arlington Archosaur Site (AAS) of Texas preserves remnants of an ancient Late Cretaceous river delta that once existed in the Dallas-Fort Worth area. Known for discoveries of fossil crocodiles and dinosaurs, a multi-institution research team has described four extinct turtle species, including a new river turtle named after AAS paleontologist Dr. Derek Main and the oldest side-necked turtle in North America. These new turtles include an intriguing combination of native North American forms alongside Asian and Southern Hemisphere immigrants, suggesting extensive intercontinental migration of turtles during this time.

Originally discovered by amateur fossil hunter Art Sahlstein in 2003, the AAS is a prolific fossil locality found in the middle of a suburban subdivision. The AAS preserves remnants of an ancient Late Cretaceous river delta around 96 million years ago in what is today the Dallas-Fort Worth area. It preserves a record of a freshwater wetland that sat near the shore of a large peninsula, including a diverse assemblage of crocodile relatives, dinosaurs, amphibians, mammals, fish, invertebrates, and plants, several of which are also new species awaiting description. “Until this discovery, there were very few turtle fossils from this time period discovered in Appalachia,” says Dr. Heather Smith, one of the authors of the paper. The research team describing these discoveries includes Brent Adrian, M.F.A., Heather F. Smith, Ph.D., and Ari Grossman, Ph.D., from Midwestern University in Glendale Arizona, and Christopher Noto, Ph.D., from University of Wisconsin-Parkside.

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