Carnivorous ancestor of today’s short-tailed opossum identified

The short-tailed possums, a genus of marsupials classified as Monodelphis of which today there are 24 species, are fairly peaceful animals, slightly larger than a mouse, widespread especially in South America.

Now a new study, published in the Journal of Mammalian Evolution, confirms the existence of a ferocious direct relative of this animal that lived about 4 million years ago in the same areas of South America. We speak of Sparassocynus, a carnivorous relative of Monodelphis, whose remains have been found for more than a century even if its evolution has never been well studied, at least until this new study.

The research, conducted by Robin Beck, a researcher at the University of Salford, and by Matías Taglioretti, a paleontologist at the Museo Municipal de Ciencias Naturales “Lorenzo Scaglia” in Argentina, has identified several proofs that Sparassocynus is one of the ancestors of the today’s short-tailed opossums. In particular the scientists analyzed the remains of the skull, remains found near some cliffs along the Atlantic coast of Argentina.

It is an individual not fully grown as it still has traces of milk teeth. The researchers analyzed different characteristics comparing them with the evidence taken from the DNA of today’s short-tailed opossums and showed that this animal is closely related to today’s short-quota opossums. It was a carnivore that probably ate other rodents and small vertebrates and was larger than today’s short-tailed opossums about five times.

Today’s opossums are much more “quiet” animals and eat only small insects. The Sparassocynus survived in areas of South America up to 2.5 million years ago and is possibly extinct due to the arrival of the weasels from North America.