Thursday, August 25, 2011

Avian Ancestors

Over at LiveScience there is a new gallery of images of avian ancestors and dinosaurs with various bird-like traits. The images are mostly artists' conceptions, with a skeletal reconstruction or fossil photograph here or there. There are some that look clearly like birds, but there are a lot more with a classic bipedal dinosaur shape, but with feathers attached. As I looked over the galleries, I was thinking about how much the image of dinosaurs has changed from what I learned when I was growing up. Back then, dinosaurs were portrayed as blandly colored and scaly, more like giant monochrome lizards than anything remotely bird-like. A large part of that has to do with recent discoveries like Gansus yumenensis and Epidexipteryx hui. Some also is a result of re-conceiving how dinosaurs looked and acted. Either way, it is fascinating to think about how bird ancestors evolved and separated from dinosaurs.

One caveat about the gallery is that it does not seem to take account of the recent revision to Archaeopteryx's status as a bird ancestor.