Three new mammal species from dinosaur era discovered

In rocky outcroppings near a cornfield in northern China, paleontologists have unearthed three species of squirrel-like mammals that lived at the same time as the dinosaurs.

Remarkably complete skeletons of the three new species – Shenshou lui, Xianshou linglong and Xianshou songae – were found in pieces of sandstone that date back 160 million years. Their discovery lends support to the theory that the population of mammals that lived among the dinosaurs was more diverse than previously thought.

“There was this idea that mammals were these miserable small little things living in the shadow of the dinosaurs, and that picture has changed quite a lot,” said paleontologist Jin Meng, a curator at the American Museum of Natural History in New York.

The three new mammals, all members of the new group Euharamiyida, range in size from a house mouse to a squirrel. They had long, thin fingers, tails that were longer than their bodies, and light, fragile skeletons, which all suggest they lived in the trees of the Jurassic forest. Their diet probably consisted of insects, nuts and fruit.

A paper describing the newly discovered animals was published Tuesday in the journal Nature.

These small furry creatures belong to an extinct group called Haramiyida that is known by the strange shape of its members’ molar teeth. Most mammals today are derived from an ancient mammal that had molars with three cusps arranged in a triangular shape. The Haramiyidas have two rows of cusps on their molars.