Monday, January 05, 2009
Carl Zimmer has a fascinating item on the ever- more- blurry line between birds and non- avian Dinosaurs. It seems the Paleognathes-- the bird group commonly known as ratites, composed of the big flightless birds like Ostriches and the odd related but flying South American group known as Tinamous-- have retained the brooding habits of such "true" Dinosaurs as Oviraptors and Troodonts. In all these groups, the MALES brood. As you can see by looking at the cladogram, Paleognathes are separate from all other extant birds and retain this archaic trait from a long while back. Read it all.