Remains of a mammalian ancestor of 220 million years are found in Argentina
Probainognathia is a clade of cynodonts that includes mammals as their only living representatives. In Argentina, numerous probainognathians have been found in Carnian levels (early Late Triassic, approximately 237 to 227 million years ago) but only a single species from the Norian was known (approximately 227 to 208 million years ago). Globally,...