A pair of prehistoric discoveries amazing came to light this week, on the one hand in Brazil they found fossil remains of a prehistoric mouse over 225 million years old and on the other hand, an otter almost as big as a lion was found.
In the first case, in Brazil, jaw bones of a mouse about 20 centimeters that lived 225 million years ago, delays the time of origin of mammals: the Brasilodon.
“Evidence of how the dentition was built during the time of development is crucial and definitive in proving that brazilodonts were mammals. Our paper raises the level of the debate about what defines a mammal and shows that it was a much earlier time of origin in the fossil record than previously known,” he says in a statement Moya Meredith Smithcontributing author and Professor Emeritus of Evolution and Development of Dentoskeletal Anatomy.
Examining dentitions found in Brasilodon quadrangularis fossils from southern Brazil, dating to around 225 million years ago (Late Triassic/Norian), the research team uncovered evidence of a single set of replacement teeth. This is a key feature of mammals known as diphodonty.
Another finding was the Enhydriodon omoensis, after the Lower Omo Valley in southwestern Ethiopia, where it was discovered. It is the giant otter, which lived 6 million years ago and with an estimated weight of 200 kilograms.
An article describing the animal has just appeared in the French science journal Comptes Rendus Palevol.
“The peculiar thing, apart from its massive size, is that [los isótopos] in its teeth suggest it was not aquatic, like all modern otters,” study co-author Kevin Uno, a geochemist at the Columbia Climate School’s Lamont-Doherty Earth Observatory, said in a statement. “We found that it had a diet of land animals, which also differs from modern otters.”