A crocodile with teeth like razors ruled the lands now known as North Carolina around 230 million years ago, before dinosaurs arrived in the area.
Carnufex carolinensis, or 'Carolina butcher' hunted armored reptiles and primitive mammals, and was likely a highly-successful hunter in its habitat. Fossils of the creature, which walked on its hind legs, were discovered in the Pekin Formation in North Carolina.
"People don't think about how many different predators were around in the Triassic, and that crocs really ruled before dinosaurs," Lindsay Zanno of North Carolina State University said.
The butcher crocodile lived during the late Triassic Period. At this time, the area was located near the equator, as part of Pangaea. The animal likely thrived as a top predator in the region, without competition from dinosaurs.
Grooves and pits in the skull of Carnufex are similar to modern crocodiles, but these features are not seen in early ancestors of the animals. The shape of the teeth and cheekbones resemble those found in meat-eating theropod dinosaurs. This combination of features suggested to researchers that the fossils they found represent a previously-unknown species.
When it was discovered, the skull of the ancient hunter was shattered into several pieces. Researchers scanned the fragments, and created a 3D virtual model of the animal, filling in missing parts with digital recreations based on related species.
At the time the butcher crocodile was prowling the land, a number of top predators were vying for dominance. This new discovery shows that ancestors of crocodiles were among the species that were most successful at dominating the landscape.
A mass extinction at the end of the Triassic Period wiped out most of the the large predators, leaving behind just theropods and smaller relatives of crocodiles. Predatory dinosaurs then became the top predator in the area for 135 million years.
"Theropods were ready understudies for vacant top predator niches when large-bodied crocs and their relatives bowed out. Predatory dinosaurs went on to fill these roles exclusively for the next 135 million years," Zanno said.
As dinosaurs became more common in the region following the end of the era, ancient crocodile-like creatures evolved into smaller forms, filling an ecological niche similar to that of small predatory mammals today.
"As theropod dinosaurs started to make it big, the ancestors of modern crocs initially took on a role similar to foxes or jackals, with small, sleek bodies and long limbs. If you want to picture these animals, just think of a modern day fox, but with alligator skin instead of fur," Susan Drymala of North Carolina State University told the press.
Discovery of the fossil and analysis of the fossil were detailed in the journal Scientific Reports.
Photo: Ravi Jandhyala | Flickr