Finds of carnivores preying on one another are rare in the fossil record. Yet for two big Triassic reptiles, a case of predation has shown a great deal about how their rather carnivore-heavy ecosystem may have worked. The victim is a rauisuchian, a largely terrestrial carnivore while the attacker is a phytosaur, a reptile once thought to have been highly aquatic. Both animals are crocodile-like archosaurs or crurotarsans. Remains of the duel between the two creatures were scientifically described by Dr. Stephanie Drumheller from the University of Tennessee at Knoxville, and Michelle R. Stocker and Sterling J. Nesbitt of Virginia Tech.
The well-known Chinle Formation has revealed one of the best Triassic assemblages ever, dating back to about 210 million years ago. At the time the supercontinent of Pangaea was still around, with the Chinle having preserved one of the wetter regions of this massive landmass. The area was full of life, including some of the early dinosaurs and conifer trees towering 60 meters in height.
The research was published in the November 2014 issue of the German scientific journal Naturwissenschaften. Evidence of the conflict comes from the rauisuchian’s incomplete femur, in which the phytosaur’s tooth is still embedded. This initial attack proved not to be fatal, with the tooth having broken off. The injury seems to have healed over time. CT scans and 3D models of the bone showed that the same animal had been attacked not once but twice by phytosaurs, a surprising turn of events.