Jurassic 'beaver' is new fossil record.

This article presents information about the discovery of a new fossil of a semi-aquatic cousin of modern mammals called Castorocauda lutrasimilis, which lived 164 million years ago. Looking like a cross between a platypus, river otter and beaver, this ancient mammal would have been almost half a meter long from nose to tail and weighed about half a kilogram. If the date of the fossil is confirmed, it makes Castorocauda the largest mammaliaform ever found from the Jurassic period, which lasted from 200 to 145 million years ago. It also sports the oldest known fur.