THE first fossils discovered in China shook the family trees of birds and dinosaurs. Now the latest find is shaking our own. The fossil is 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 metre long from nose to tail and weighed about half a kilogram – about the size of a grey squirrel. If the date of the fossil is confirmed, it makes Castorocauda the largest “mammaliaform”, or mammal-like animal, ever found…
