Archaeopteryx No Longer First Bird

Sorry, the title is a tad hyperbolic but it fits with the article. A re-evaluation of Archaeopteryx has led to its removal from the subclass Aves and placed within the theropod dinosaurs. A large group of these had feathers and it is from this group that true birds arose. As the story in the Independent notes, however:

The reclassification of Archaeopteryx is expected to be exploited by creationists, who are likely to pick up on the fact that scientists are appearing to change their mind about the fossil's iconic status as the first bird, but this would be wrong, said Lawrence Witmer, professor of anatomy at Ohio University.

The reclassification does not alter the fact that Archaeopteryx possessed features that are both reptilian and avian, nor does it change the fact that birds evolved from feathered dinosaurs, he said. "What this does is change our view of Archaeopteryx. For 150 years it's been our oldest and most prominent bird. Part of the reason why we should care about this is that Archaeopteryx is probably one of the most famous fossils ever," Professor Witmer said. "It changes a lot inhttp://www.blogger.com/img/blank.gif terms of how we view early birds, and how early birds evolved."

Indeed the evidence is now so strong that birds evolved from theropod dinosaurs that recently the class aves was redesignated as a subclass of reptilia. The new fossil is thought to be around 155 million years old and is called Xiaotingia. Pharyngula has a nice rundown on what the new fossil means.

----------------
Now playing: Steve Hackett - Cavalcanti
via FoxyTunes

Tyrannosaurus Rex and Trichomonosis: The Dinosaur to Bird Avalanche of Evidence Continues

The Chicago Sun-Times has an article on what may have killed the famous Tyrannosaur named Sue, which currently resides in the Field Museum. According to the story, by David Newbart:

Theories abound on what led to the demise of the Field Museum’s most famous specimen: shortly after the Tyrannosaurus rex was found, some wondered if a series of holes in the back of her massive skull were bite marks suffered during a ferocious battle with another meat-eating dinosaur.

But researchers have honed in on a culprit far smaller: a throat infection caused by a single-celled organism.

Writing in Tuesday’s edition of the online journal of Public Library of Science One, researchers from the University of Wisconsin and elsewhere theorize that the parasitic infection could have led to an autoimmune response that eventually could have led Sue to starve to death 67 million years ago.

Now the punch line: the infection shows evidence of being caused by the Trichomonosis bacteria which is found in only one other sub-class: birds. Given all of the other palaeontological evidence that the the theropod dinosaurs and Aves share a common ancestry, what are the odds they would share the same kind of infection by chance?

----------------
Now playing: Amy Grant - Lead Me On
via FoxyTunes