Two Majungasaurus hunting down a Rapetosaurus. (ABelov2014 via Wikicommons under CC BY-SA 3.0)
The Smithsonian has a story about tooth replacement in theropod dinosaurs. A new study published in the journal PLOS ONE has found that Majungasaurus probably replaced its teeth every 56 days. This is faster than the previous highest tooth replacement rate which was about 100 days in Jurassic carnivores Allosaurus and Ceratosaurus. This new rate is about 14 times faster than Tyrannosaurus rex, which is thought to replace it's teeth about once every 2 years. These rate were based on the number of shed teeth found for each species.
Like all toothy dinosaurs, prehistoric carnivores replaced their teeth throughout their lives. New cutlery constantly grew in their jaws to push old or broken teeth out of the way. And a new study published today in PLOS ONE reveals how often three Mesozoic meat eaters replaced their chompers. The evidence that these carnivores grew new teeth several times a year also can tell us new things about how these animals hunted and fed.
The research, published by Adelphi University paleontologist Michael D’Emic and colleagues, continues previous work that examined the teeth of herbivorous dinosaurs. In 2013 D’Emic and coauthors calculated that the long-necked Jurassic herbivores Camarasaurus and Diplodocus replaced one tooth every 62 days and 35 days, respectively. Plant food can be abrasive, wearing down teeth quickly, and so herbivorous dinosaurs required a constantly renewed supply. But what about the carnivores?
While at Stony Brook University, D’Emic saw a wealth of Majungasaurus teeth that had been shed while the dinosaurs were alive. This dinosaur was the apex predator of its time, reaching about 20 feet in length and weighing roughly a ton. “There are lots of other species known from the same formation and area in Madagascar, but their shed teeth are not incredibly abundant, so I thought there must be something unique about Majungasaurus itself,” D’Emic says.
