A research team discovered in Patagonia the fossil of a small mammal the size of a mouse that rubbed shoulders with the dinosaurs. The animal with crushed teeth was previously unknown to the community of paleontologists.
The Yeutherium pressor was about being the size of a gray mouse and weighed between 30 and 40 grams. He lived in the upper Cretaceous, about 74 million years ago. It is the smallest mammal ever identified in this South American region. Capital importance for paleontology, because the animal is only the third species of mammal of the mesozoic – or age of dinosaurs – discovered in Chile.
The fossil consists of “a small piece of jaw with a molar and the crown and the root of two other molars”, explains to AFP Hans Puschel, at the head of the team of scientists of the University of Chile and the Millennium Nucleus Research Center, which is interested in the evolutionary transitions of the first mammals (Evotem).
The announcement of this find took place last week in a article Posted by the British scientific journal Proceedings of the Royal Society B.
Scientists identified it in the Río de Las Chinas valley, a river in the Magallanes region, in the south of the country, some 3000 kilometers from Santiago.
The Yeutherium pressor was a mammal capable of laying eggs – like today’s ornithorynques – and carrying your young in a pocket like kangaroos or opossums. It was therefore not similar to modern mammals, but rather a line prior to the common ancestor of placentaires and marsupial.
Special teeth
Its name comes from “Yeut”, which means hill or mountain in Aonikenk, the language of the Aboriginal people of Patagonia, and “Therium” in Greek, for animals.
“Pressor”, that is “the one who presses”, in Latin, refers to the shape of his teeth with rounded and crenellated ridges. This suggests that its diet was made up of relatively hard plant foods. It will allow paleontologists to better understand the evolutionary transition of this dental morphology specializing in grinding.
According to the team, it is impossible to linkYeutherium closely to an existing species, as it does not belong to any line of mammals currently present.
Like the dinosaurs who lived at the same time as him, this little mammal disappeared at the end of the Cretaceous, some 66 million years ago.
Stéphanie Jaquet and ATS