Who Flew First?

Meet Anchiornis. It’s a rather remarkable looking little creature; a scrawny little dinosaur with abundant feathering, including “leg wings” and an

Anchiornis: The Critter in Question

extravagantly fluffy tail. As the newest announcement at the annual Society of Vertabrate Paleontology meeting  this little dinosaur is kicking up quite a stir.

Why? It all has to do with three things; its age, its linneage, and wether or not it could fly.

First, its age. Anchiornis is from the middle Jurassic, the second great epoch in the age of the dinosaurs and the one in which feathered theropods (meat eating dinosaurs) are positively known to have emerged. There’s another famous feathered dinosaur from the middle Jurassic; Archeopteryx, the famous “first bird.”

Here’s the thing though. Archeopteryx came later then our new friend Anchiornis. And that’s interesting for a lot of reasons; among them the new, sneaking suspicion that “the first bird” may not, in fact, be the first.

But here the evidence makes things a bit more twisted. Archeopteryx is what is known as an “avialian”–a protobird. In the tangled game of theropod taxonomy, its rather unclear where exacly avialians lie in relation to other families. So when Anchiornis was intitially reported as an avialian, the lamentations of taxonomists were loud and prolonged. “How the hell do we fit this thing in with Archeopteryx?” They cried in despair. But when a new and better skeleton was found, something else came to light. Anchiornis was not an avialian. It was a troodont.

To put this in context, troodonts are primarily Cretaceous animals; they are a sister family of the famed dromeaosaurs, or raptors. Both families are rare

The Bird Family Tree: Anchornis fits uneasily at the juncture between dromeosaurs and troodonts. And this is the simplified version. You can see why Taxonomists tend to get headaches.

in the Jurassic, and when they do show up it’s only in the latest portions of the epoch. But here we have a recognizable troodont, extravagantly feathered, quite a few millenia earlier then it should be. It clouds an important issue of whom is related to whom. The Middle Jurassic was the time when the dromeaosaurs (primitive beasts such as Microraptor), the troodonts (Anchiornis), and the avialians (Archeopteryx) were all splitting off from each other, and now the genealogical waters have been muddied.

Taking all of this into account, the next question is obvious; could Anchiornis fly? Did it beat Archeopteryx and other avialians into the air? Unfortunately, no. There are a few reasons why, and they primarily lie with wings structure. While all troodonts, dromeosaurs and avialians appear to have been feathered and equipped with the “leg wings” that make Microraptor and Anchiornis so distinctive looking, that doesn’t mean they were doing anything in particular with them. Anchiornis had wings, but the

Two methods of early flight: Microraptor glides like a Biplane, while the Hawk demonstrates powered flight as Archeopteryx may have used it.

feathers were arranged symetrically, which provides little to no lift. It had none of the gliding specializations of Microraptor, and lacked the adaptations for powered flight exemplified by Archeopteryx. It actually appears that the troodonts weren’t beating anyone; they were in fact some of the last off the ground, if they ever made it at all.

So there we have it; a confusing little beast, muddying up an important taxanomic issue in the study of bird origins. For now, at least, Archeopteryx can rest easy on its perch as the first powered flier. The discovery of Anchiornis simply helps fill in the tree underneath it.

Stay tuned: The Annual SVP meeting is going on, and some cool announcements should be coming out of it. I’ll blog about them as they come.