A Jurassic Crocodile Fossil With Dolphin-Like Features Has Been Uncovered

Monday, 14 May 2018 - 6:20PM
Monday, 14 May 2018 - 6:20PM
A Jurassic Crocodile Fossil With Dolphin-Like Features Has Been Uncovered
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Crocodiles are an ancient species that haven't changed too much over millions of years - natural selection was never too big a threat for these apex predators

That said, their evolution isn't completely stagnant, and scientists have still been working toward a complete fossil record of the species. A big contribution to that fossil record recently came in the form of a detailed fossil discovered in northwest Hungary featuring an almost dolphin-like crocodile.

The specimen is dated at about 180 million years old, which puts it right in the middle of the Jurassic period. And it was still a major predator back then at 16.4 feet (5 meters) long, with pointed teeth, a heavily armored exterior, and a long tail fin reminiscent of a dolphin's that not every Jurassic crocodile fossil contains. The full rundown was  just published in PeerJ.

This isn't to say crocodiles evolved into dolphins or killer whales, of course - the split between mammals and reptiles happened over a hundred million years prior to this old croc. In fact, it seems like the crocodile gradually lost this tail fin over time, as it evolved to better walk on land.

Other crocodile fossils from around the same time period have been found to contain armored skin and legs meant for walking on land, while other still were found to contain only legs and fins suited for swimming around. The fact that this fossil is somewhere in between indicates that it's a missing link between these two eras of the animal. 

The fossil was first discovered in 1996, and has been sitting in storage inside a Budapest museum since then. But it was only a recent look that researchers caught on to an unusual vertebra in the tail fin which suggested the species was one we'd never seen before.

According to the study's lead author, Mark Young from the University of Edinburgh, who said the following in a statement from the university:

Opening quote
"This fossil provides a unique insight into how crocodiles began evolving into dolphin and killer whale-like forms more than 180 million years ago. The presence of both bony armour and a tail fin highlights the remarkable diversity of Jurassic-era crocodiles."
Closing quote

So, way back when, the scaly green killers looked a little bit more like friendly dolphins. Although they certainly were less smart and a whole lot meaner.
Science News