03 - 17
COLUMBUS, Ga. – Ancient bite marks and fossilized feces discovered in Georgia are providing new details about a giant crocodile that roamed the Southeast United States about 79 million years ago.
The giant reptile, called Deinosuchus, reached at least 29 feet long in Georgia and preferred living in a shallow water environment and could take down dinosaurs its own size, as new findings show.
“We’re sure (Deinosuchus) ate a lot of sea turtles, but it’s evident it sometimes preyed on dinosaurs too,” said Columbus State paleontologist, Professor David Schwimmer who recently completed two studies on the giant croc with one of his students, Samantha Harrell.
Schwimmer and Harrell gave a combined presentation on the bite marks and the fossilized dung, called coprolites, at the March 13-16 Geological Society of America Northeastern-Southeastern annual meeting in Baltimore. Additionally, the coprolite study is being published as “Coprolites of Deinosuchus and other Crocodylians from the Upper Cretaceous of Western Georgia, USA” in a special symposium volume of the New Mexico Museum of Natural History and Science Bulletin, a publication of international interest.
The studies detail how bite marks on dinosaur bones discovered in various locations around the country, and large fossilized dung droppings discovered near Columbus, Ga., have been linked to the Deinosuchus.
The dung fossils are the first such documented samples from the Deinosuchus and help confirm the giant, ancient croc preferred living in the marine shallows. Meanwhile, the separate bite mark findings reveal aspect of the creature’s eating habits.
“In some cases we’re talking about a 29-foot Deinosuchus taking down a 29-foot dinosaur,” Schwimmer said.
A likely victim, Appalachiosaurus montgomeriensis — a relative of Tyrannosaurus rex — was discovered near Montgomery, Ala., and named in 2005 by Schwimmer and a pair of colleagues.
Schwimmer is regarded an expert on both the Deinosuchus and the Late Cretaceous paleontology of the southeastern United States. The status was affirmed with his 2002 book, King of the Crocodylians: The Paleobiology of Deinosuchus.
In spring 2009 Schwimmer asked Harrell to take command of a project as an independent study course to gather and analyze fossilized feces he had started to recover from a fossil hot spot along the banks of the Hannahatchee Creek in Stewart County, a major tributary of the Chattahoochee River, south of where the Piedmont meets the Coastal Plain.
Harrell, a senior geology major from Girdler, Ky., worked with 20 samples of fossil crocodylian dung. She attributed six of the large spindle shaped masses, 8-13 centimeters long, to Deinosuchus.
Harrell explained coprolites are studied in order to convey information about the lifestyles of the dead and buried. She discovered sand and lots of shell fragments, signifying the crocs lived in a shallow, brackish, warm-water environment — likely near the mouth of a river where it opened to a sea with sandy shoreline and an abundance of sea turtles for its diet.
The unusual nature of Harrell’s project drew the attention of Georgia Public Broadcasting, which highlighted Harrell’s research as part of its Dinosaur Week series last September. The series also featured Schwimmer in a pair of separate stories.
Harrell plans to pursue graduate study in paleontology. Schwimmer said Harrell is already off to a fast start in her field. “It’s a rare and outstanding accomplishment for an undergraduate to be the lead author of a study in an international journal.”
Harrell also will present her coprolite research as part of the March 27 Georgia Academy of Sciences annual meeting hosted by Columbus State University.