April I. Neander/University of Chicago

Meet the mammals that soared through Jurassic skies

Tens of millions of years before bats took wing, tiny mammals were gliding from tree to tree in what is now eastern China, new fossils suggest. The fossilized remains of two species include traces of fur as well as hints of skin membranes used to parachute from one perch to another. Those membranes apparently stretched down to the wrists and ankles of each species, a configuration similar to that seen in many of today’s “flying” mammals. One of the animals (artist’s concept, above) was about the size of the modern-day flying squirrels of North America, the researchers report today in Nature. The scientists have dubbed that creature Maiopatagium, from the Latin for “mother with skin membrane.” Fossils of the other new species, found in rocks of a similar age a few dozen kilometers away, suggest that creature—dubbed Vilevolodon, roughly from the Latin for “toothed glider”—was about as large as a midsized mouse. The long digits on both species’ feet suggest that they were strong climbers and may have even been able to roost while hanging beneath limbs or on rocks, as modern-day bats do. Although these flying mammals may have supplemented their diet with insects, they likely fed mostly on the soft parts of ferns, gingkoes, and other vegetation; the flowers, fruits, and seeds that are favorite foods of some modern-day gliders didn’t evolve until long after Maiopatagium and Vilevolodon lived, the researchers note.