Sciworks Radio
Sciworks Radio
The Carolina Butcher : 2-legged Crocodile Ancestor before the Dinosaurs

Crocodiles and their ancestors were around a hundred million years before the dinosaurs. One of the largest of the early crocodile family was discovered right here in North Carolina.

It has been investigated and described by Dr. Lindsay Zanno, Director of the Paleontology and Geology lab at the Museum of Natural Sciences in Raleigh, and Research Assistant Professor in the Department of Biological Sciences, at NC State University.

The Carolina Butcher

Or Carnufex Carolinensis, to use the traditional Latin.

…is a new species of ancient crocodile from here in North Carolina. It’s a transitional animal. It’s kind of like a missing link between crocodiles and their closest relatives, Rauisuchids, and Rauisuchids looked a lot like Tyrannosaurs. Some of them walked on two legs. We sort of leaned toward the two legged hypotheses because the front arms are very short in relationship to the skull. However the hind legs could be really short too, and it could just be a really weird creature, so we won’t know for sure until we find the rest of it.

This crocodile ancestor might have walked around North Carolina on two legs, like a nightmare, but the real story is what it tells us about life after Earth’s biggest mass extinction. The loss of 90% of all species marked the end of the Permian and start of the Triassic Geologic periods, 252 Million years ago.

The evolution of triassic animals that came after that extinction event is very interesting. We see the origin of all kinds of groups of animals: turtles, groups of lizards, reptiles, mammals, dinosaurs, crocodiles and all of these kinds of animals that we’re really familiar with in our modern ecosystem. And a great diversity of different kinds of animals filling these predatory roles. So Carnufax shows us that even early crocodilamorphs grew to great sizes and filled top predator roles in the Triassic.

…Like T-Rex in the Jurassic. There were dinosaurs around during the end of the Triassic but they were small tasty meals to Carnufax and other predators.

Things were doing really well when another mass extinction hit at the end of the triassic and again changed the face of ecosystems on the planet. And animals like Carnufax and a lot of other large predators that were living at the time didn’t make it through that extinction event. So after that what we see is dinosaurs sort of taking over and filling all the rolls that used to be occupied by a variety of different animals. Crocodiles become very small. They become secondary predators, more like a jackal or fox, and dinosaurs take over all of these large predator rolls. North Carolina has a very important part of this story to tell. Fossils that we’re finding are some of the oldest evidence of these types of animals anywhere in the world. So Carnufax may be one of the oldest crocodile line animals that we’ve ever found.

So, why do paleontologists bother studying these ancient animals and their ecosystems?

We have this perspective on extinction that reflects scenarios that have already happened. It’s really important because we’re in the middle of a mass extinction right now. The rate at which species are disappearing is on par with what we’ve seen in the past with the mass extinction events. Species don’t have time to adapt and to survive. Most of this is human caused either directly by habitat destruction or indirectly by forcing climate change at rapid rates. Climate is always changing. We live on a dynamic planet. Temperatures go up and down sea levels go up and down. Right now those changes are happening way too fast. And when they happen fast like that animals don’t have time to adapt to those changing conditions and that’s when we see extinction. That’s what happened in all the mass extinction events. We see massive climate change on short time scales. Whether it’s volcanism or asteroid impacts, things that exceed the normal rates of change the planet can accommodate.

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First aired Sep 11, 2015.