Dinosaur Teeth Reveal Evolutionary Success of Sauropods

Dinosaurs once roamed over vast expanses of the Earth, adapting and thriving on our planet. These creatures were some of the most successful animals during their time and now, scientists may have discovered why. It turns out that rapid tooth replacement by sauropods may have led to their evolutionary success.

Sauropods are some of the largest dinosaurs in the fossil record. Mostly herbivores, these creatures digested massive amounts of foliage in order to maintain their immense sizes. Yet chomping all of that vegetation wears teeth down over time, grinding them to the point where they're almost useless. In order to find out exactly how these sauropods may have eaten enough despite this fact, scientists decided to take a look at fossils.

The researchers developed a novel method to estimate to estimate sauropod tooth formation and replacement rate without destructively sampling the teeth by making microscopic sections. Using these estimates, the scientists could track the evolution of tooth formation and replacement rates through time in species whose fossil remains are too rare to section. They then used computed tomography (CT) scanning and microscopic anatomical methods in order to measure tooth formation time, replacement rate, crown volume and enamel thickness.

"The microscopic structure of teeth and bones records aspects of an animal's physiology, giving us a window into the biology of long-extinct animals," said Michael D'Emic, one of the researchers, in a news release. "We determined that for gigantic sauropods, each tooth took just a few months to form. Effectively, sauropods took a 'quantity over quality' approach."

In fact, sauropods replaced teeth faster than any other type of dinosaurs--rather like sharks and crocodiles. This allowed the dinosaurs to keep their teeth fresh as they endured the constant wear from grinding the enormous amounts of vegetation every day.

"A nearly 100-foot-long sauropod would have had a fresh tooth in each position about once every one to two months, sometimes less," said D'Emic.

The findings show a little bit more about sauropods and even give a new view of this group of dinosaurs, which were once thought to be more primitive than other dinosaur groups. In addition, the new research shows that these creatures exhibited varied approaches to feeding since the tooth replacement rate, size and shape varied from species to species.

The findings are published in the journal PLOS One.