Life reconstruction of the dicynodont Dicynodon. Aside from the tusks in the upper jaw, most dicynodonts possessed a turtle-like beak that they used to chew their food. Image by Marlene Hill Donnelly. Credit: Marlene Hill Donnelly
SciTechDaily has a story about animal tusks. Throughout history, many animals have sported tusks, from modern day elephants to the dicynodonts of the Permian. A new paper in the journal Proceedings of the Royal Society B looks at the evolutionary history of tusks.
A wide variety of animals have tusks, from elephants and walruses to five-pound, guinea pig-looking critters called hyraxes. But one thing tusked animals have in common is that they’re all mammals — there are no known fish, reptiles, or birds with tusks. In a new study in Proceedings of the Royal Society B, paleontologists traced the first tusks back to ancient mammal relatives that lived before the dinosaurs, and to do so, they had to define what makes a tusk a tusk in the first place.
“Tusks are this very famous anatomy, but until I started working on this study, I never really thought about how tusks are restricted to mammals,” says Megan Whitney, a researcher at Harvard University and the lead author of the study.
“We were able to show that the first tusks belonged to animals that came before modern mammals, called dicynodonts,” says Ken Angielczyk, a curator at Chicago’s Field Museum and an author of the paper. “They’re very weird animals.”
The dicynodonts mostly lived before the time of the dinosaurs, from about 270 to 201 million years ago, and they ranged from rat-sized to elephant-sized. Modern mammals are their closest living relatives, but they looked more reptilian, with turtle-like beaks. And since their discovery 176 years ago, one of their defining features has been the pair of protruding tusks in their upper jaws. The name dicynodont even means “two canine teeth.”
