This is one of several ribs that were worked on this summer from a Theropod called Daspletosaurus. This cretaceous predator could reach lengths of approximately 8-9 meters and lived between 77-74 million years ago.
The ribs from this specimen are unique in the fact that many of them show signs of healed bone where a fracture had occurred. This is in fact a belly-rib called a gastralia, which were ribs that were suspended in the flesh on the underside of a theropods body. This shows evidence that the dinosaur injured itself, either through falling or interactions with another dinosaur, and broke several of its belly-ribs. He survived however and the bone healed, producing a large callus where new bone joined the two broken pieces back together
I will be posting more pictures of other ribs up soon, but for now enjoy these few pictures and have fun pondering. How do you think it injured itself? post your answers in the comments below!