I've been so slammed with work that I've just now been able to dig into the details on the new prosauropod Aardonyx celestae, discovered in South Africa. Aardonyx was described in The Proceedings of the Royal Society B on November 11 and the lead author is Adam Yates, who writes the essential paleoblog Dracovenator. His excitement over the publication is obvious when you read his post. This is a perfect example of a scientist using his blog for the public benefit. His post breaks everything down into digestible bits, and without the hyperbole and knuckleheadedness the traditional media likes to throw in for extra flavor.
Aardonyx is one of those special creatures that sits somewhere in between two lineages. All dinosaurs are believe to have evolved from a bipedal common ancestor. The bipedal Aardonyx displays skeletal features which are consistent with what we would expect to see in a family of dinosaurs for whom large size is being naturally selected for. At some point, the increasing size of sauropods would have necessitated the greater weight-bearing capabilities of quadrupedalism. Aardonyx appears to be one of those dinosaurs who could employ either stance as the situation required.
Here's a video of coauthor Dr. Matt Bonnan of Western Illinois University explaining how Aardonyx was discovered and the implications:
There's a lot more great information at Western Illinois University's Aardonyx site. Also, just noticed a story in one of the Chicago papers about Bonnan.