This little dinosaur had feathery wings 150 million years ago—but definitely couldn't fly

This charming little fellow is Eosinopteryx brevipenna, a feathered dinosaur that lived during the Jurassic period more than 150 million years ago. Recently unearthed in northwestern China, Eosinopteryx suggests the evolution of flight is more complex than we suspected.

Eosinopteryx was a tiny little guy, measuring only about a foot long. That's actually not unduly small for a feathered dinosaur — and, thus, a potential ancestor of birds — as the most famous of the lot, Archaeopterx, itself only measured about a foot and eight inches long. But Eosinopteryx is diminutive in other ways, and that's what caught the attention of University of Southampton paleontologist Dr. Gareth Dyke.

In particular, it appears to have had significantly fewer feathers on its legs and tail than Archaeopteryx and other early feathered dinosaurs. Not only did it have a small wingspan, but the bones in its wings were actually put together such that it would have been impossible for Eosinopteryx to flap its wings, let alone to fly. Its wings still would have had their uses down on the ground, but it's clear Eosinopteryx took an evolutionary path that had nothing to do with flying, feathers notwithstanding.

According to Dr. Dyke, that means that, even 150 million years ago, feathers served lots of different adaptive purposes, with flight only one of many reasons why these generally tiny dinosaurs would evolve plumage. And while Eosinopteryx decidedly doesn't threaten Archaeopteryx's claim as the first bird-like creature to attain flight, this discovery might well mean that flight isn't what defines these most primitive of birds. Speaking to the BBC, Dr. Dyke adds:

"This discovery sheds further doubt on the theory that the famous fossil Archaeopteryx - or 'first bird' as it is sometimes referred to - was pivotal in the evolution of modern birds. Our findings suggest that the origin of flight was much more complex than previously thought. It's such a well preserved complete skeleton of a small dinosaur. It would have lived in a forested, swampy environment. I imagine it running around and jumping around from tree trunk to tree trunk, maybe using its wings to speed up its running."

Nature Communications via BBC News. Image via Royal Belgian Institute of Natural Sciences.