New Species of Giant Fossil Turtle Discovered in Alabama

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Appalachemys ebersolei resting on an estuarine shoreline next to the theropod dinosaur Saurornitholestes. Artwork by Gabriel Ugueto.

CONTRIBUTED BY ASMS

MOBILE —

Last week, a team of scientists announced the discovery of a new species of freshwater turtle that lived alongside the dinosaurs, 83 million years ago. The scientists who made this discovery are Dr. Andrew D. Gentry of the Alabama School of Mathematics and Science in Mobile, Alabama, Dr. James F. Parham of the University of California Fullerton and Caitlin Kiernan of McWane Science Center in Birmingham, Alabama.

The official name of the new turtle is Appalachemys ebersolei in honor of Alabama paleontologist Jun Ebersole. The fossilized remains were originally found in southern Alabama during the mid-1980s and held in the collection at the Alabama Museum of Natural History in Tuscaloosa, Alabama, for more than 30 years before being recognized as significant by Parham, the museum’s former curator.

“I was aware of the specimen for more than a year after becoming curator but never examined it closely because it was mislabeled as a common species,” Parham said. “When I finally opened the cabinet where it was stored, I knew immediately that it was important. I’ll never forget that moment.”

The study revealed that Appalachemys was a member of a poorly known group of fossil turtles known as macrobaenids, which inhabited the rivers and estuaries of North America and Asia roughly 55 to 95 million years ago. At nearly a meter long, Appalachemys was one of the largest freshwater turtles to ever live in North America.

“The size of the animal is really astonishing,” Gentry said. “We’ve known for quite some time that sea turtles reached immense proportions during the Cretaceous, but generally freshwater turtles were, and still are, much smaller.”

Researchers think Appalachemys’ massive size may have evolved due to a combination of the tropical climate in Alabama during that time and as a means of avoiding predation.

The fossil of Appalachemys ebersolei. Scale bar = 10 cm.

“There was certainly no shortage of large predators in Alabama during the Cretaceous,” Gentry said. “Giant crocodiles, carnivorous dinosaurs and mosasaurs were all predators that Appalachemys would have had to contend with. Having a thick shell and being as big as possible would have been helpful, but it’s impossible to say if predation was the reason Appalachemys got so big.”

Appalachemys is the latest in a growing list of new species identified from Alabama museum collections in the past decade.

“The discovery of Appalachemys underscores the importance of museum collections and demonstrates how historically collected fossils can still lead to important scientific  advancements,” Gentry said. “Thanks to our temperate climate and ample rainfall, Alabama has always been a biodiversity hotspot. We have a pretty good idea of the species living here today, but when it comes to the ancient life of Alabama, we’ve barely scratched the surface.” 

The study, titled “A large non-marine turtle from from the Upper Cretaceous of Alabama and a review of North American Macrobaenids”, was published last week in the journal Anatomical Record and can be viewed online at: The Anatomical Record – Wiley Online Library.

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