Ancient vegetarian crocodile fossil unearthed

Crocodiles came in all shape and sizes in ancient times, including an 80 million-year-old pig-nosed, thick-skinned species that lived the humble life of a vegetarian.

The four-foot-long creature possessed grazer's teeth, a tank-like body and a short stubby tail. Most likely, they lived lives more like an armadillo's than a conventional crocodile's. Dubbed Simosuchus clarki, the species was first unearthed in 2000, and now appears fully described in a supplement to the Journal of Vertebrate Paleontology.

"No other crocodile looks as bizarre as this one," says paleontologist David Krause of Stony Brook (N.Y.) University, part of the team that discovered d the species. "Crocodiles evolved into a wide variety of body plans in the Age of Dinosaurs, but this one really looks unusual."

Krause and colleagues report six exceptionally well-preserved fossils of the pig-like crocodile found on the island of Madagascar. Analysis of the skull and teeth of Simosuchus led by Nathan Kley, also of Stony Brook U., confirms the creature's shortened snout served for chewing vegetation, too weak to snatch up other animals. "He was a vegetarian, no doubt," Kley says.

Some South American crocodiles from the Age of Dinosaurs, which ended about 65.5 million years ago, also show signs of eating vegetation instead of the fearsome carnivorous lives of today's crocodile, notes paleontologist Casey Holliday of the University of Missouri. "This one is unique though," he says. "And the specimens are exceptional. To actually find the teeth still in the skull tells you a lot about how these guys lived."

"This is a great critter," says paleontologist Paul Sereno of the University of Chicago, by email. "Most folks don't know how wild crocs got on the great southern landmass Gondwana during the dinosaur era---mainly because all of these crocs went extinct along with the dinosaurs 65 million years, ago, only their more aquatic croc brethren surviving."

While it was around, Simosuchus seems to have been a pretty unassuming creature, Krause suggests. Its hide appears exceptionally well-armored, which may have allowed it to survive bites from the bigger crocs and large carnivorous dinosaurs of the era that flourished on Madagascar. Given the large number of armor bones in their hides, Kley says, "they would have made terrible boots."

By Dan Vergano

Paul Sereno sent USA TODAY some further comments on the Simosuchus discoveries that puts it in perspective with some of the crocodile finds his team has made in the last decade:

Back then, during the Cretaceous Period, I have called it a special "croc world" based on what I have dug up on Africa---where small, mid and monstrous sized crocs were around every bend, competing with, pestering, and yes, even eating dinosaurs!

Now the critter in question comes from the closely related small landmass Madagascar and is a wonderfully preserved and peculiar beast. Yes, it was definitely a herbivore like some of mine from Africa. Also, it looked like a dwarf ankylosaur---the Cretaceous dinosaurs known from the northern landmass that are comepletly armored. It would not look anything like a modern croc and likely didn't have a predilection for watery habitats. Rather it is best likened to an armadillo---an armored plant eater that predators might have given up on, given the amount of work it would take to get a mouthful of meat.

Crocs on the southern landmass, like this one, evolved into creatures that are today best likened to dogs, boars, and superpredators---hence their nicknames DogCroc, BoarCroc and the dinosaur-eating SuperCroc. The Madagascar croc reminds us of how glorious and strange crocs once were before the asteroid struck, how they ranged far outside waterways to gallop, burrow and munch down vegetation.