Scientists Discover Two New Prehistoric Reptiles in North Carolina
May 19, 2015
Getting around Durham was different 230 million years ago.
On the plus side, you would have had zero chance of getting stuck in traffic on I-85, and finding parking at Duke or at the Durham Bulls Athletic Park would have been a breeze. You would, however, have constantly been on the lookout for the 9-foot-long crocodiles running around on their hind legs trying to eat you.
The Carnufex carolinensis, or “Carolina Butcher,” is one of two ancient reptiles recently discovered by North Carolina paleontologists. The other was an armored reptile called Gorgetosuchus pekinensis that most likely ate plants or grubbed for its food. These new finds give scientists more information on the dynamic of different species at this time.
Both reptiles date back to the Triassic Period period, which lasted from 251 to 199 million years ago. The Triassic saw the first dinosaurs and crocodylomoprhs, two groups that still exist today in the form of birds and crocodiles respectively.
Lindsay Zanno, Paleontology and Geology Lab Director at the North Carolina Museum of Natural Sciences and lead author of the paper on the Carnufex, says fossils from this period are extremely important because they show us the earliest forms of birds and crocodiles. They also help paint the picture of life on the supercontinent Pangea.
“The discovery of Carnufex, one of the world’s earliest and largest crocodylomorphs,” Zanno said in a press release, “adds new information to the push and pull of top terrestrial predators across Pangea.
The Carolina Butcher had the build of a top predator. At 9 feet long it could have held its own against some of the other major predators at the time, which ranged from about 6 to 20 feet long. The early crocodile walked on its hind legs as it hunted smaller reptiles.
According to Zanno, early dinosaurs were the main competitors to the top predators in the Southern Hemisphere, but the discovery of Carnufex shows that up North, large crocodylomorphs — which are not technically dinosaurs — were also part of that competition.
Determining what Carnufex looked like was a challenge, as Zanno and her colleagues did not have a complete skeleton. All they had to go on were pieces of the skull, spine, and upper arm.
But using high-resolution surface scanners, and the skulls of other crocodylomorphs as a guide, Zanno and her colleagues were able to sketch out the fearsome picture of the Carolina Butcher.
Apart from providing information on the top of the Pangean food chain, Carnufex also serves as a sort of missing link between crocodylomorphs and their ancestors, the archosaurs.
The particular brand of archosaurs that evolved into early crocodiles tended to be large, beefy top-predators, but crocodylomorphs — especially the ones in the Late Triassic and Jurassic periods — were smaller, leaner and quicker. Zanno likens them to fox-shaped alligators.
Carnufex bridges the gap between the two. It has the skeletal features of a crocodylomorph but the size, body plan and place in the food chain of its archosaur ancestors.
Zanno’s work is published in the journal Scientific Reports.
The Butcher is not the only ancient North Carolinian discovered this year. Appalachian State University geology professor Andrew Heckert discovered pieces of a new type of aetosaur (pronounced ay-YEE-toe-sore) called Gorgetosuchus pekinensis.
Like Carnufex, Gorgetosuchus is not a dinosaur but an early relative of crocodiles, hence the “suchus,” the Greek word for crocodile. Gorgetosuchus gets its name from the specific bones Heckert and his colleagues found: 19 spiny armor plates (pictured below) that would surround the reptile’s neck and back. A gorget is a piece of armor a knight would use to protect his neck and since Gorgetosuchus was heavily armored in the neck region, Heckert decided on Gorgetosuchus pekinensis or "armored-collar crocodile from the Pekin region."
Aetosaurs, like knights, were covered in these armor plates and also like knights, their armor would slow them down. Heckert says scientists can use that fact to hypothesize how these reptiles lived.
“The general concensus is they were herbivores or captured food by grubbing,” Heckert said. “Their body is more reminiscent of an armadillo than a crocodile. They had too much armor to chase things.”
Gorgetosuchus in particular was about five feet long and combines features of both early and late aetosaurs. Its body proportions are similar to primitive aetosaurs but its spiny armor plates, also called osteoderms, look more like those of evolved aetosaurs. This clearly sets it apart as its own species.
So where do these ancient reptiles keep coming from? Heckert says that North Carolina has ready access to Triassic fossils just like the more famous fossil grounds in Utah and Montana. There are three Triassic Basins strung together in North Carolina, which Heckert says are like scars left over from when Pangea split. The fossils are buried, and often covered by vegetation unlike the places out West but Heckert says the fossil-carrying rocks frequently turn up in clay pits and coal mines.
“The rocks are here, they’re just harder to find,” he said.
The Gorgetosuchus fossils were found in a brick quarry. Heckert says Natural Sciences Museum curator Vince Schneider — who worked on both the Gorgetosuchus and Carnufex discoveries — maintains a good relationship with local quarries to recover fossils when workers find them. Gorgetosuchus came in a chunk of rock and bone about the size of a football.
So while scientists in North Carolina do not often see fossils just poking out of the ground and cannot use GPS to find fossils, rock quarries and clay pits allow North Carolina scientists to tap an abundant resource of very early fossils. With any luck, a new reptile will turn up soon to join the Butcher and the Knight.
— Daniel Lane
Daniel Lane covers science, engineering, medicine and the environment in North Carolina.