To say that it is evolution at work is to make an assumption based on a belief rather than any actual supporting evidence.
I am not sure what response you think I should make. It is a fossil, but as best as I can tell, any assumptions about it are exactly that, assumptions and any belief that it represents anything more than an interesting fossil, is based on a belief in evolution, not any actual fact or hard evidence.
You gave no specific reference to your dinosaur, but I am assuming that you are talking about this one:
http://www.msnbc.msn.com/id/7736120/
The article presents the information as if it were known, supported fact. I did some further research on the animal and could find no hard data to support the claims made in the story. Perhaps you can point me in the right directon or answer a couple of questions yourself since you seem to be up on the discovery.
Can you describe to me the method by which it was factually determined who this dinosaur's ancestors were and who its decendent's were and are?
Can you describe the method by which it was determined that it is fact that its ancestors were meat eaters and that its decendents became vegetarians?
It is a rather large assumption to assume that all animals with flat teeth are vegetarians and all animals with sharp teeth are carnivores. The tendency may lean in that direction, but it is unscientific to make the assumption. Based on that sort of thinking, what do you suppose a paleontologist might make of a set of gorilla dentition? Based on that logic, the gorilla must be a fierce carnivore.
Since they can't say who the fossil's ancestors were, and who its decendents were, I might ask why they assume that it was evolving from a carnivore into a vegetarian rather than from a vegetarian into a carnivore? Based on the actual evidence, why might one direction be favored over the other?
If you are interested in fact, then the fact is that the story that arose from the fossil is just that. A story.