The discovery of a single bone suggests the "king of the land" and "king of the sea" interacted with each other 210 million years ago, contrary to previous beliefs.
During this period the subcontinent of Pangea was starting to separate, and dog-sized dinosaurs were no longer at the top of the food chain, Virginia Tech reported. Reptiles called Phytosaurs and Rauisuchids ruled both the land and the sea, but researchers believed these major predators did not have contact with each other; the discovery of a single bone suggests otherwise.
"Phytosaurs were thought to be dominant aquatic predators because of their large size and similarity to modern crocodylians," said Stocker, "but we were able to provide the first direct evidence they targeted both aquatic and large terrestrial prey."
The evidence is an aquatic phytosaur tooth lodged in the leg bone of a land-based rauisuchid. The tooth had been lodged about two inches deep and was healed over, suggesting the ancient reptile survived the attack.
"Finding teeth embedded directly in fossil bone is very, very rare," said Stephanie Drumheller of the University of Tennessee. "This is the first time it's been identified among phytosaurs, and it gives us a smoking gun for interpreting this set of bite marks."
The findings reveal a food web from over 200 million years ago. Observations of the auisuchid thigh bone employing a CT scan and 3-D printer suggest the ancient reptile was preyed on at least twice in its life.
"This research will call for us to go back and look at some of the assumptions we've had in regard to the Late Triassic ecosystems. The distinctions between aquatic and terrestrial distinctions were over-simplified and I think we've made a case that the two spheres were intimately connected," said Michelle Stocker, a vertebrate paleontologist with the Virginia Tech's Department of Geosciences.
The findings were published in September in the German journal Naturwissenschaften.
