A tiny animal measuring 20 cm in length, similar to a mouse, with a skull smaller than 4 cm and teeth measuring about 2 mm, which roamed the central region of Rio Grande do Sul, is today considered the oldest mammal on the planet.
The discovery was made by researchers from UFRGS (Federal University of Rio Grande do Sul), based on a microscopic analysis of the jaws and teeth of fossils found in Faxinal do Soturno, about 50 km from Santa Maria.
The city is one of the 22 municipalities in the state of Rio Grande do Sul located in the occurrence area of the so-called Santa Maria Formation, a geological unit known for over a century worldwide for the presence of vertebrate fossils.
In the case of fossil "mice", these animals, scientifically named Brasilodon quadrangularis, are believed to have lived between 225 and 220 million years ago, at the end of the Triassic period (which lasted from 250 to 200 million years).
Translated by Cassy Dias