Pittsburgh-Area Scientists Help Discover New Mammal From The Age Of The Dinosaurs

Jun 18, 2018

Pittsburgh-area scientists are part of an international group to discover a new squirrel-like mammal from the time of the dinosaurs. 

Ambolestes zhoui it is the most complete fossil of a relative of placental mammals found from the Mesozoic Era. It was unearthed in Inner Mongolia, a region of northeast China, in a quarry that, 126 million years ago, was a lake.

Placental mammals are the largest and most diverse of the three subdivisions on the mammalian family; among them are primates, rodents, ungulates like deer and pigs, and carnivores like cats and bears.  

Artist's rendering of Ambolestes zhoui.
Credit Carnegie Museum of Natural History

The other two subdivisions include the egg-laying monoterms, like the platypus, and marsupials, such as kangaroos and opossums. 

Scientists believe Ambolestes zhoui was an insect-eater. The specimen measures roughly 10 inches in length and has a long snout. 

“We can say that Ambolestes zhoui was an animal that was an adept climber,” said John Wible, curator of mammals, at the Carnegie Museum of Natural History. “[It] may not have lived full time in the trees, but certainly had the capability of running around in the trees.”

Wible helped the team analyze the fossilized skeleton and understand the implications of the discovery. He was recruited by Shundong Bi, an evolutionary biologist at Indiana University of Pennsylvania, who was part of the excavation team.

Wible said the fossil is so intact that even the delicate hyoid bone, located in the throat, was present.   

“You never see it in a fossil. It jumped off the screen at me,” he said. “Oh my God! This is amazing.”

Wible said he hopes the discovery of this hyoid apparatus will create an interest in researching swallowing, mastication and vocalization in mammals. He also said this fossil will give scientists insights into the origins of the mammalian family tree. 

The speciment is now at the Tianyu Museum of Natural History, in Shandong Province, China.

The findings were published in the journal Nature.

90.5 WESA receives funding from the Carnegie Museum of Natural History.