Tiny Jurassic croc skull similar to Asian reptiles

012211 1a Delta croc

A tiny crocodile-like creature that died in the late Jurassic Period and whose skull was found in Delta County has been shown under a powerful new microscope to be significantly different from crocs of a similar age found in Mesa County.

If anything, in fact, the Delta County croc seems to have Asian connections.

Crocodile-like creatures have been found in the Morrison Formation, which dates to the late Jurassic Period, of both counties, but the similarities seem to end there.

In a weird twist, said John Foster, curator of paleontology at the Museum of Western Colorado’s Dinosaur Journey, the dinosaurs of the Morrison have more in common with dinosaurs of Europe.

The Delta County croc, on the other hand, seems quite similar to the Asian crocs, Foster said.

A close-up view of the croc found in Delta and another found in the Fruita Paleontological Area confirmed two differences between the creatures, Foster said. That brings to six the number of differences between the animals, which crawled the earth some 150 million years ago.

Foster examined the Delta County croc under a digital microscope at Mesa State College, the same microscope used by the Western Investigations Team, to nail down two of those differences: a small, extra tooth in the lower jaw and different contacts between two bones at the roof of the mouth, Foster said.

More eye-catching, however, are the teeth that stick out of the rock matrix holding the skull, which was about the size of a modern house cat.

The Delta County croc sported a pair of lower teeth sticking dagger-like up from the side of its lower jaw, and a curved fang hanging down from its upper.

It’s not known how the Delta County croc, with his similarities to creatures found in the sedimentary rock of China and Mongolia, happened to be buried in the mud of the Morrison Formation, not far from a crocodilian cousin who turned up after eons a few miles away in similar sediments.

It seems unlikely the Delta County croc would have traveled east, Foster said, because the Pacific Ocean was wider at that time than it is now and the Atlantic much more narrow.

“Rather, I would suspect these things came all the way over by way of Europe from the east,” Foster said.

Both the Fruita and Delta creatures still have to be recognized as new species.



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