Washington: A nine-foot long, land-dwelling crocodilian ancestor may have filled one of North America’s top predator roles before dinosaurs arrived on the continent, scientists have found. Carnufex carolinensis, or the “Carolina Butcher,” walked on its hind legs and likely preyed upon smaller inhabitants of North Carolina ecosystems such as armoured reptiles and early mammal relatives.
Paleontologists from North Carolina State University and the North Carolina Museum of Natural Sciences recovered parts of Carnufex’s skull, spine and upper forelimb from the Pekin Formation in Chatham County, North Carolina. The skull of Carnufex was preserved in pieces so it was difficult to visualise what the complete skull would have looked like in real life.
To get a fuller picture of Carnufex’s skull the researchers scanned the individual bones with the latest imaging technology – a high-resolution surface scanner. Then they created a three-dimensional model of the reconstructed skull, using the more complete skulls of close relatives to fill in the missing pieces. The Pekin Formation contains sediments deposited 231 million years ago in the beginning of the Late Triassic, when what is now North Carolina was a wet, warm equatorial region beginning to break apart from the supercontinent Pangea.
“Fossils from this time period are extremely important to scientists because they record the earliest appearance of crocodylomorphs and theropod dinosaurs, two groups that first evolved in the Triassic period, yet managed to survive to the present day in the form of crocodiles and birds,” said Lindsay Zanno, assistant research professor at NC State, director of the Paleontology and Geology lab at the museum.
“The discovery of Carnufex, one of the world’s earliest and largest crocodylomorphs, adds new information to the push and pull of top terrestrial predators across Pangea,” Zanno said. Typical predators roaming Pangea included large-bodied rauisuchids and poposauroids, fearsome cousins of ancient crocodiles that went extinct in the Triassic Period. In the Southern Hemisphere, “these animals hunted alongside the earliest theropod dinosaurs, creating a predator pile-up,” said Zanno.
However, the discovery of Carnufex indicates that in the north, large-bodied crocodylomorphs, not dinosaurs, were adding to the diversity of top predator niches. “We knew that there were too many top performers on the proverbial stage in the Late Triassic,” Zanno said. “Yet, until we deciphered the story behind Carnufex, it wasn’t clear that early crocodile ancestors were among those vying for top predator roles prior to the reign of dinosaurs in North America,” Zanno added.