Scientists discover new Mesozoic mammal

PITTSBURGH, Oct. 12 (UPI) -- Chinese and U.S. paleontologists say they've discovered a new Mesozoic mammal whose ear structure shows how mammalian ear evolution occurred.

The international team of paleontologists discovered the new species that lived 123 million years ago in what is now Liaoning Province in northeastern China.

The scientists said the well preserved fossil of the newly discovered animal, Maotherium asiaticus, offers insight into how the mammalian middle ear evolved.

The researchers said such discoveries provide evidence of how developmental mechanisms impacted the morphological evolution of the earliest mammals and shed light on how complex structures arise in evolution because of changes in developmental pathways.

"What is most surprising, and thus scientifically interesting, is this animal's ear," said Zhe-Xi Luo, associate director of science and research at the Carnegie Museum of Natural History. "Mammals have highly sensitive hearing, far better than the hearing capacity of all other vertebrates, and hearing is fundamental to the mammalian way of life. The mammalian ear evolution is important for understanding the origins of key mammalian adaptations."

Maotherium asiaticus fed on insects and worms and lived on the ground, researchers said. It had about a five-inch-long body and weighed approximately 0.15 to 0.17 pounds.

The research that included Qiang Ji of the Chinese Academy of Geological Sciences and Xinliang Zhang of China's Henan Provincial Geological Museum is detailed in the journal Science.