Study: Mammal-Like Reptiles May Have Existed Longer During the Cretaceous Era

Researchers have recently unearthed dozens of fossilized teeth in Kuwajima, Japan, and have identified it as a new species of tritylodontid. Tritylodontid is an animal family that is directly related to the evolution of mammals from reptiles.

Tritylodontids are also the last known family of mammal-like reptiles. Researchers from Kyoto University have found out that this group of herbivores lived much longer than what people have originally thought and existed with early mammals for several million years. The discovery led researchers to believe that mammals wiped out mammal-like reptiles soon after they emerged.

According to Science Daily, the study's author Hiroshige Matsuoka explained that tritylodontids were herbivores with a unique set of teeth, which intersects when they bite. "They had pretty much the same features as mammals -- for instance they were most likely warm-blooded -- but taxonomically speaking they were reptiles, because in their jaws they still had a bone that in mammals is used for hearing," Matsuoka continued.

While digging up a geological layer from the Cretaceous era in Kuwajima, researchers found different fossils of dinosaurs, turtles, lizards, fish, different types of plants, and Mesozoic mammals. One of those that are found has more than 250 tritylodontid teeth, the first ever of its kind to be found in Japan.

Although Matsuoka said that the belief of them dying out during the late Jurassic "made sense, because otherwise tritylodontids and the herbivorous mammals would have competed for the same niche," the new study suggests that these mammal-like reptiles may have actually survived more than 30 million years longer than what paleontologists thought, redorbit.com stated.

The discovery "raises new questions about how tritylodontids and their mammalian neighbors shared or separated ecological roles," Matsuoka added. It is the first study to use only details from excavated fossilized teeth to make sure whether or not a specie is new, and also to find where it properly belong in the evolutionary tree.

Check out the video below to further understand this eureka moment: