Science, just Science News

The news items in here are created by the SJS team. Any comments left in here are the sole responsibility of those making the comment and may not reflect the views of the SJS campaign or it's contributors.


February 25, 2006

Jurassic Beaver found

Science, Just Science - News

Another gap in the fossil gap closes?

A full version of this article appears in New Scientist

http://www.newscientist.com/article.ns?id=dn8769

'Jurassic beaver' find stuns experts

Original article printed in New Scientist 19:00 23 February 2006

By Jeff Hecht


The discovery of a new, remarkably preserved fossil of a beaver-like mammal that lived 164 million years ago is shaking palaeontologists’ understanding of early mammals.

This makes it the largest mammal ever found in the Jurassic Period, from 200 million to 145 million years ago.

Palaeontologists had long thought the mammals living under the feet of the dinosaurs were tiny shrew-like animals. But recent discoveries have challenged this notion.

Full pelt

In 2005, Repenomamus giganticus from China showed that land mammals had reached a metre in length about 130 million years ago, during the Cretaceous Period.

But the newly found fossil reveals that early mammals were also far more diverse than thought. The discoveries "are completely reconfiguring our understanding of Mesozoic mammals," says Hans-Dieter Sues of the Smithsonian Institution's National Museum of Natural History.

Castorocauda was preserved in exquisite detail, flattened in sediments at the bottom of an ancient lake. Hair impressions surround the body, which includes a 20-centimetre-long flat, beaver-like tail. Two slabs of sedimentary rock include most of the body and part of the skull.

The animal had "a full mammalian pelt, with guard hairs and under fur, and scales on the tail" like a modern beaver, says Zhe-Xi Luo of the Carnegie Museum of Natural History in Pittsburgh, US, and one of the team.

It is the earliest mammal known to live partly in the water. The creature probably lived like a modern platypus, says Luo, "digging a tunnel to nest and lay eggs, and going from the tunnel into the water to feed".

, ,

0 Comments:

Post a Comment

Links to this post:

Create a Link

<< Home