This is a new study on the evolution of birds. Its sort of a meta-analysis on existing fossil evidence. What it shows is that avian features evolved as a mosaic over tens of millions of years. Once the basic avian body plan was in place there was an explosion in the rate of evolution. From the paper: There is no great jump between nonbirds and birds in morphospace. Instead, those features that today combine to set birds apart from other vertebrates—feathers, wishbones, air sacs, and hundreds more—evolved piecemeal in Mesozoic theropods [18]. Therefore, we surmise that a Mesozoic naturalist would make no immediate distinction between a Velociraptor-type animal and an Archaeopteryx-type animal. mediafire/view/uchd1xdppf4g4la/Avian_Body_Plan.pdf
Posted on: Sat, 27 Sep 2014 19:48:08 +0000