According to a new study published this month in the German journal Naturwissenschaften, aquatic dinosaurs and land-based dinosaurs used to fight with each other aggressively.

Researches from Virginia Tech and the University of Tennessee found a 200 million old tooth lodged in the thigh bone of the largest predator of Triassic period.The bone was discovered at the University of California Museum in Paleontology.

The tooth belongs to a semi-aquatic phytosaur and it was lodged in the thigh bone of a terrestrial rauisuchid, a creature about 25 feet long and four feet tall at the hip.

The tooth was then recreated using a 3D printer and CT scans of the bone. It was found that the tooth was buried about two inches deep then healed over, indicating that the rauisuchid survived the initial attack.

Rauisuchids were the land-based dinosaurs while phytosaurs thrived in water. About 210 million years ago when the supercontinent of Pangea was starting to break up, phytosaurs and rauisuchids were at the top of the food chain.

The discovery of this tooth clearly indicates that both the predators interacted with one another, while it was believed that Rauisuchids and its water-dwelling counterpart has no reason to come in contact.

This also shows the evidence that phyosaur may have hunted on land as well as in the water. It was believed that phytosaurs were dominant predators of the sea because they were very large and are similar to modern crocodiles.

Dr. Stephanie Drumheller of the University of Tennessee at Knoxville said, "These rauisuchids were the largest predators in their environments. You might expect them to be the top predators as well, but here we have evidence of phytosaurs, who were smaller, semi-aquatic animals, potentially targeting and eating these big carnivores".