Fossils of Prehistoric Mammal Found in the Regions of Mexico

American scientists found fossils of a prehistoric mammal, with a beaver-like appearance, that lived more than 60 million years ago. The creature survived on Earth after an asteroid destroyed all nonavian dinosaurs, allowing huge, plant-eating animals to further evolve. This relatively large mammal lived in Central America during the dangerous dinosaur-killing time, by crushing green plants with its tremendous molars.

Though little, this mammal is an interesting discovery for paleontology, as the scientists said. It is part of an ancient family of rodent-like animals, known as multituberculates, named after several cusps growing on their teeth. These animals roamed next to dinosaurs, but have been capable to endure the huge extinction of the Cretaceous era. They lived for another 25 million years before vanishing too, according to the experts who studied them

The recently found fossils have more than 60 million years, being dated right after the dinosaur-extinction catastrophe caused by an asteroid that hit our planet. This mammal only lived in Mexico’s current regions after the global annihilation, so it is very interesting to find a pretty big animal the size of a beaver.

During the prehistoric era, mammals were very small, about the dimension of mice or even tinier. They were not capable to grow larger than that, certainly because they were living next to dinosaurs that were dominating those larger areas.

However, once all nonavian dinosaurs disappeared from the surface of the Earth, mammals became a lot more present and took over their surroundings where dinosaurs once roamed. A few multituberculates got quite big, with a weight of up to 220 lbs. These creature were not monsters by any means but, for that distant era, they were rather huge.

Scientists named the newly found mammal Kimbetopsalis simmonsae, relating to the place where they discovered it. The ancient term “psalis” means “cutting shears”, referring to the animal’s unusual strong teeth. Kimbetopsalis simmonsae had a weight of around 88 lbs. and likely had a length of 1.5 feet from head to the tip of its tail

A teeth analysis revealed that the creature’s molars were huge and rectangle-shaped, having more cusps than the teeth of its relatives, as American researchers have noticed. Each one of these cusps had crenelations or small ridges. All cusps were worn through use and, depending on their form and style of wear, experts know that they were used for crushing food.

Thanks to these new fossils and the others discovered before them, this species is part of a subfamily of multituberculates, called taeniolabidoids. The subgroup started to evolve right before the prehistoric mass extinction, and lived all over North America and Asia, until around 55 million years ago. It is still uncertain why they became extinct, as scientists have multiple theories on this cause.

In comparison, other species of multituberculates lived for another 25 million years after the taeniolabidoids disappeared. Scientists have developed a few explanations on why these mammals suddenly vanished. They assume that these creatures were competing against large rats, another family of creatures that were quickly expanding during those days.

 

Image source: Sci-News.com