High Teeth Replacement Rate Helped the World's Largest Dinosaur Survive Jurassic Period

The Sauropods, weighing 100 tons, were among the largest and the most successful dinosaurs to ever walk on Earth. A new research has shown that these dinosaurs could constantly replace their teeth that probably contributed to their evolutionary success.

These dinosaurs appeared very early in the Jurassic period and lived for millions of years. Popular Sauropds include Diplodocus, Apatosaurus (formerly Brontosaurus- also mentioned in the movie The Jurassic Park) and the heaviest of them all, the heavyweight Argentinosaurus.

The new study of fossil records by Michael D'Emic, PhD, and colleagues from Stony Brook University shows that the ability to replace teeth helped the dinosaur feed on a variety of vegetation and avoid inter-species fight over food sources. These dinosaurs spread around the world, with the only exception being, the Antarctica. Other researchers had earlier found that the teeth helped these dinosaurs survive, but weren't sure how the mechanism worked.

The current study published in PLOS One, shows how the constant up-gradation of the teeth, just like sharks and crocodiles, helped the dinosaurs live-off various plants. These dinosaurs would have fed on a humongous amount of vegetation that led to wear and tear of the teeth. Replacing teeth helped them eat more and not fight with other species for food source.

"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 Dr. D'Emic, Research Instructor in the Department of Anatomical Sciences at Stony Brook University School of Medicine. "We determined that for the gigantic sauropods, each tooth took just a few months to form. Effectively, sauropods took a 'quantity over quality' approach."

Also, the saurapods didn't chew food the way we do, instead they'd just rip the food in smaller bits and swallowed them.

"At least twice during their evolution, sauropods evolved small, peg-like teeth that formed and replaced quickly," said Dr. D'Emic in a news release. "This characteristic may have led to the evolutionary success of sauropods."

The research team used microscopic sections of the fossil specimens along with computed tomography (CT) scanning to measure the teeth replacement time in these animals. They even measured enamel thickness and crown formation in teeth samples of Camarasaurus and Diplodocus (dinosaurs that once roamed in North America).

They could easily count the number of growth lines in the teeth. These growth lines are thinner than a strand of human hair and their tally gives an estimate of tooth formation.

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