More dinosaur than we thought
Familiar to many, you can know how old a tree is and how fast it has grown by counting the number of rings in a cross section. Well, you can do the same with the long bones of vertebrates.
Now Gregory M. Erickson and co-workers published a paper in which they did just that to a specimen of one of the most famous fossil forms around: Archaeopterix. Watch Mark Norell, paleontologist from the American Museum of Natural History and co-author of the paper, explain the results:
