Dinosaurs that roamed what is now China some 160 million years ago had two ‘flying’ neighbors — strange creatures with long limbs, long hand, foot fingers, and wing-like membranes for tree-to-tree gliding. Named Maiopatagium furculiferum and Vilevolodon diplomylos, these prehistoric animals are the earliest known gliders in the long history of early mammals.
Maiopatagium furculiferum in Jurassic forest in crepuscular (dawn and dusk) light: a mother with a baby in suspending roosting posture, climbing on tree trunk, and in gliding. Image credit: April I. Neander, University of Chicago.
Maiopatagium furculiferum and Vilevolodon diplomylos are stem mammaliaforms, extinct relatives of living mammals, and belong to Haramiyida, an entirely extinct branch on the mammalian evolutionary tree.
The two fossils were discovered in the Tiaojishan Formation northeast of Beijing, China.
They show the exquisitely fossilized, wing-like skin membranes between their front and back limbs. They also show many skeletal features in their shoulder joints and forelimbs that gave the ancient animals the agility to be capable gliders.
The fossils are described in two papers published this month in the journal Nature by Professor Zhe-Xi Luo of the University of Chicago and co-authors.
“These Jurassic mammals are truly ‘the first in glide.’ In a way, they got the first wings among all mammals,” Professor Luo said.
“With every new mammal fossil from the Age of Dinosaurs, we continue to be surprised by how diverse mammalian forerunners were in both feeding and locomotor adaptations. The groundwork for mammals’ successful diversification today appears to have been laid long ago.”
Maiopatagium furculiferum and Vilevolodon diplomylos share similar ecology with modern gliding mammals, with some significant differences.
Today, the hallmark of most gliders is their herbivorous diet that typically consists of seeds, fruits and other soft parts of flowering plants.
But Maiopatagium furculiferum and Vilevolodon diplomylos lived in a Jurassic world where the plant life was dominated by ferns and gymnosperms like cycads, ginkgoes and conifers. This distinct diet and lifestyle evolved again some 100 million years later among modern mammals, in examples of convergent evolution and ecology.
“It’s amazing that the aerial adaptations occurred so early in the history of mammals,” said co-author David Grossnickle, a graduate student at the University of Chicago.
“Not only did these fossils show exquisite fossilization of gliding membranes, their limb, hand and foot proportion also suggests a new gliding locomotion and behavior.”
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Qing-Jin Meng et al. New gliding mammaliaforms from the Jurassic. Nature, published online August 9, 2017; doi: 10.1038/nature23476
Zhe-Xi Luo et al. New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem. Nature, published online August 9, 2017; doi: 10.1038/nature23483
