A human tooth, on average, is 20 mm long, including the root—the part under the gums that you can’t see when someone cracks a grin. Rodolfo Garcia from the National University of Rio Negro in Argentina recently discovered the tooth from what could be the longest dinosaur ever to have roamed the Earth, and it measures in at 75 mm. The tooth belonged to a type of Sauropod, a group of plant-eating dinosaurs that lived between 200 and 65 millions years ago. In particular, this tooth was from a Titanosaur, a Sauropod who emerged much later in the fossil record as far as Sauropods go, and lived right up until the mass extinction of all dinosaurs 65 million years ago.
The tooth is 32 percent longer than any other Sauropod tooth discovered to date. However, though 75 mm seems awful long for a tooth, keep in mind that Titanosaurs weighed up to 100 tons. Since this is the longest tooth yet to have been found, this Titanosaur may have even weighed more than 100 tons. Though their teeth were long compared to ours, they were teeny compared to the enormous size of their bodies. Herbivorous dinosaurs had much smaller teeth relative to the size of their bodies than did meat-eaters, who needed huge chompers to rip into and chew tough meat.
Paleontologists are analyzing the tooth to learn more about Sauropod feeding and dietary habits. Sauropods had to ingest incredibly large quantities of food to fuel their massive bodies. For example, Mamenchisaurus was a relatively small Sauropod, weighing in at 13 tons; it ate a whopping 1,150 pounds of plants each day. Strangely enough, teeth didn’t play the main role in food digestion for Sauropods. These beasts didn’t have molars– the specimen from Rio Negro was an incisor—the only type of tooth Sauropods had—which was used for breaking off branches or leaves.
Most food breakup occurred in the mouth and stomachs, where strong digestive juices broke down mass vegetarian meals. The lack of molars made it possible for Sauropods to have very small heads, which allowed their necks to grow very long and still be able to support the head; an evolutionary advantage because Sauropods needed to stretch their necks high up and around to reach vegetation and fulfill their enormous food requirements. (Read more about Sauropod feeding habits at www.nytimes.com)
Read on at www.newscientist.com
Find this study in the journal Cretaceous Research
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