Is it a Bird? Is it a… Dinosaur?

Archaeopteryx, Archie to his friends & fans, is the world’s most famous ‘transitional fossil’. Until very recently Archie was believed to be a proper bird, definitely on the bird side of the dinosaur/bird transition. Very akin to dinosaurs and other ‘saurians’ – crocodilians, thecodonts, dinosauromorphs, and other diapsids – but definitely a bird. The bony tail, the mouth full of teeth and the lack of specifically ‘birdy’ bits of anatomy should have made people pause to consider a better definition of what makes a bird. Feathers won’t do. Lots of dinosaurs have those, or something like them.

Now Archie has another feature in common with his non-avian dinosaurian kin… slow-growth. Reported here in the New York Times, the latest examination of Archie’s bones indicate it grew at dinosaur pace NOT bird pace. Interesting. So just what makes Archie a bird?

The journal paper the NYT reported on is:

Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx

…available for free from the PLoS.

Archie remains justly famous as a ‘transitional form’ between the other ‘reptiles’ and birds. He’s just not as birdy as we once thought.