The oceans, coastlines and rivers of 135 million years ago crawled with crocodiles. Fossils of these beasts run the gamut from small to giant, but the ones known to science have all shared the long snout associated with modern crocs. Until now. Researchers say they have unearthed the remains of a large crocodile that looks very unlike its brethren in having a short, stubby snout.

"This species was very unusual because other marine crocodiles that were around at the same time have very delicate features--long, skinny snouts and needle-like teeth," says Diego Pol, a bioinformatics researcher at Ohio State University who used a computer program to figure out where on the reptile family tree this creature, dubbed Dakosaurus andiniensis, belongs. "This croc was just the opposite. It had a short snout and large teeth with serrated edges."

Yet features of its nostrils and eye socket, and a distinctive groove in its jaw mark it as a croc. And although D. andiniensis may have been the funny-looking cousin at family gatherings in Cretaceous bays, its fellow marine crocodiles would have been wise not to mess with their fearsome relative, which measured 13 feet long and boasted a one-and-a-half foot jaw studded with four-inch sawing teeth.

Zulma Gasparini and Luis Spalletti of the National University of La Plata in Argentina found two skulls of the odd beast in 1996 on an expedition in western Argentina. The bones turned up in rocks hailing from what was once the bottom of a Pacific Ocean bay off the coast of the ancient southern supercontinent, Gondwana. Whereas other crocs are believed to have specialized in eating fish and other agile prey, based on their relatively gracile jaws and teeth, the scientists surmise that D. andiniensis--with its stout jaw and massive teeth--likely ate much larger beasts, such as pliosaurs, ichthyosaurs and other marine reptiles. A report detailing the finding appeared in the most recent Science Express.