'Oldest land predators' Dimetrodon killed prey with 'steak-knife' teeth

Researchers have found that Dimetrodon, a carnivore that walked on land between 298 million and 272 million years ago, was a meat lover and had the first known serrated "steak knife" teeth.

Lead author Kirstin Brink along with Professor Robert Reisz from University of Toronto Mississauga's Department of Biology suggested that Dimetrodon was the first terrestrial vertebrate to develop serrated ziphodont teeth.

According to the study, ziphodont teeth, with their serrated edges, produced a more-efficient bite and would have allowed Dimetrodon to eat prey much larger than itself.

While most meat-eating dinosaurs possessed ziphodont teeth, fossil evidence suggested serrated teeth first evolved in Dimetrodon some 40 million years earlier than theropod dinosaurs.

According to Brink and Reisz's research, Dimetrodon had a diversity of previously unknown tooth structures and were also the first terrestrial vertebrate to develop cusps - teeth with raised points on the crown, which are dominant in mammals.

The study also suggests ziphodont teeth were confined to later species of Dimetrodon, indicating a gradual change in feeding habits.

The study was published in the journal Nature Communications.