Fossil Evidence Reveals Oldest Predators on Earth Possessed ‘Steak-Knife’ Teeth

The Dimetrodon, a carnivorous predator that roamed the Earth between 298 million and 272 million years ago, was the first to have serrated ziphodont teeth, otherwise known as "steak-knife" teeth, according to a University of Toronto Mississauga study.

The study was authored by Kirstin Brink and Professor Robert Reisz and was published in Nature Communications. The researchers found that these serrated ziphodont teeth gave the Dimetrodon the ability to eat prey much larger than itself.

Fossil evidence revealed that the Dimetrodon possessed the "serrated" teeth 40 million years before the first theropod dinosaurs. Most meat-eating dinosaurs that evolved during these millions of years had ziphodont teeth. But the Dimetrodon was the first, and it stood at the top of the terrestrial food chain during the Early Permian Period.

"Technologies such as scanning electron microscope (SEM) and histology allowed us to examine these teeth in detail to reveal previously unknown patterns in the evolutionary history of Dimetrodon," said Brink, the lead author of the study, in this EurekAlert! article.

The Dimetrodon were also the first terrestrial vertebrate to develop cusps, which are the now-dominant feature of mammal teeth. Cusps are teeth with raised points on the crown, which give animals the ability to further break down meat and tougher foods. The researchers studied the changes in Dimetrodon teeth over 25 million years of evolution and found that ziphodont teeth indicated a gradual change in feeding habits, suggesting that more of their species were carnivores as time went on.

"Teeth tell us a lot more about the ecology of animals than just looking at the skeleton," said Reisz. "We already know from fossil evidence which animals existed at that time but now with this type of research we are starting to piece together how the members of these communities interacted."

"Interacted" is probably a more politically correct scientific term since the serrated ziphodont teeth allowed the Dimetrodon to grab, rip and dismember large prey.

To read more about this study, visit this EurekAlert! article.