Volaticotherium—Mesozoic glider
10:13 pm
The cover of this past week’s issue of Nature is graced with a restoration of a newly discovered gliding mammal from the Age of Dinosaurs. The associated article inside describes Volaticotherium antiquum—”the ancient flying beast”—known from a flattened skeleton from the Daohugou beds in northeastern China. The fossil preserves traces of a big blob of hair and soft tissue that the authors interpret as a patagium—a large area of skin supported by the limbs that, when spread open in midleap, enabled Volaticotherium to glide through the treetops. Such gliding has evolved independently several times among mammals, in flying squirrels, for example, and colugos, and, (presumably) among the ancestors of bats.
Volaticotherium, however, hails from well before any of these aerial upstarts. The oldest known gliding rodent is not a squirrel but an eomyid from the Late Oligocene (~25,000,000 years ago), and the earliest known evidence for flight in bats comes from the Eocene, 51,000,000 years ago. Volaticotherium is at least 70,000,000 years older than that, and could be even older. (The age of the Daohugou beds is controversial, but lies somewhere between the Early Cretaceous (~125,000,000 years ago) and the Middle Jurassic (~170,000,000 years ago).) If the older age is correct, this would mean that Volaticotherium was experimenting with aerial locomotion before the 150,000,000-year-old Archaeopteryx, the earliest known bird.
Further reading:
Meng, J., Hu, Y., Wang, Y., Wang, X., and Li, C. 2006. A Mesozoic gliding mammal from northeastern China. Nature 444, 889–893. Editor’s summary.
A larger image of the cover art by Chuang Zhao and Lida Xing is shown at National Geographic News.
12/19 Update: Much more information on Volaticotherium (and how its discovery fits into the grand arc of Mesozoic Mammal Studies) in this article by Trevor Dykes.
“Volaticotherium, however, hails from well before any of these aerial upstarts.”
That’s putting them in their place, Matt. Nicely done. I’m still typing up my Volati-homage. John Steinbeck’s helping out. Also of interest is that this critter comes from the beds as Castorocauda, the swimming superstar. And this means the parents of Castoro managed to get the age of their baby wrong. Apparently, rather than the bone beds being below a level with some informative volcanic dust (ca. 165 million years), they’re above it. As somebody who frequently wakes up on the floor, I can empathise with that sort of mistake.