February 7, 2014
Steak-Knife Teeth First Appeared In Land Animals 300M Years Ago
Lee Rannals for redOrbit.com - Your Universe Online
A carnivorous dinosaur that roamed the Earth nearly 300 million years ago was the first terrestrial vertebrate to develop “steak-knife” teeth.
The Dimetrodon was a dinosaur that walked on land between 298 million and 272 million years ago, and the latest study, published in Nature Communications, shows the ancient reptile wasn’t afraid to bite off more than it could chew.
Researchers found that Dimetrodon was the first meat-eating dinosaur to develop serrated ziphodont teeth. These vicious teeth enabled Dimetrodon to have a more-efficient bite, which helped it take down prey much larger than itself. Most meat-eating dinosaurs at this point possessed non-serrated ziphodont teeth, so the latest study suggests that serrated teeth first evolved with Dimetrodon, which thrived about 40 million years earlier than theropod dinosaurs.
"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," Kirstin Brink, of the University of Toronto Mississauga's Department of Biology, said in a statement.
Scientists say that Dimetrodon was at the top of the food chain in the Early Permian Period and this dinosaur could be considered the forerunner of mammals. Before this study, Dimetrodon were known to have a diversity of tooth structures and were considered to be the first terrestrial vertebrate to develop teeth with raised points on the crown, or cusps.
The new study suggests ziphodont teeth were confined to later species of Dimetrodon, which could be due to a gradual change in feeding habits during the time.
"This research is an important step in reconstructing the structure of ancient complex communities," Robert Reisz, a professor at the University of Toronto Mississauga's Department of Biology, said in a statement. "Teeth tell us a lot more about the ecology of animals than just looking at the skeleton."
He added that this type of study is allowing scientists to piece together how the members of these ancient animals interacted. The changes in tooth structure unveiled by the study indicates a change in feeding style and trophic interactions.
"The steak knife configuration of these teeth and the architecture of the skull suggest Dimetrodon was able to grab and rip and dismember large prey," Reisz said. "Teeth fossils have attracted a lot of attention in dinosaurs but much less is known about the animals that lived during this first chapter in terrestrial evolution."