The first mammals evolved about 200 million years ago, in the early days of the dinosaurs, but they emerged from a much older group, the therapsids, which although they did not resemble mammals, already presented some subtle features of what would be these animals. They were protomammals.
Now, a team of scientists has found on the Spanish island of Mallorca the oldest fossil therapsid ever discovered: a predator similar to a medium-sized saber-toothed dog. The details were published this Tuesday in the journal Nature Communications.
The new fossil, which does not yet have a species name, belongs to an extinct group, called gorgonopsianswhich lived in the Permian between 270 and 250 million years ago and that 50 million years later would give rise to the first mammals.
“Gorgonopsians are more related to mammals than to any other living animal and although they do not have modern descendants, nor are they our direct ancestors, they are related to species that were”explained Ken Angielczyk, of the Negaunee Integrative Research Center at the Field Museum and co-author of the article.
Furthermore, until now, the oldest known gorgonopsians were thought to have lived about 265 million years ago, but the new fossil is from 270-280 million years ago, so “it is very likely the oldest gorgonopsian on the planet.” ”, highlighted Josep Fortuny, main author of the article and head of the group at the Institut Català de Paleontologia Miquel Crusafont (ICP).
Mallorca in Pangea, an equatorial latitude
The location of the specimen in the Balearic Islands is an unusual fact in itself, since until now, the remains of gorgonopsians had been found in very high altitudes, such as Russia or South Africa.
But, in the Permian, about 270 million years ago, Mallorca was part of the supercontinent of Pangea, was located at an equatorial latitude – what would be the Congo or Guinea today – and had a monsoon climate with two seasons (wet and dry). .
The site, located in the municipality of Banyalbufar, in the Sierra de Tramuntana (Mallorca), was excavated in three campaigns in which a surprising number of bone remains were found.
“We found everything from skull fragments, vertebrae and ribs to a very well preserved femur. We never thought that we would find so many remains of an animal of this type in Mallorca,” explained Rafel Matamales, curator of the Museu Balear de Ciències Naturals (MUCBO|MBCN) and first author of the article.
A saber-toothed predator
The bones allowed the researchers to reconstruct the animal’s appearance and a little about its life.
“If you saw this animal walking down the street, it would look a little like a medium-sized dog, maybe the size of a husky, but it wouldn’t be quite right. He had no fur or dog ears.”Angielczyk explained.
But this animal had saber teeth, which suggests that it was a large predator in its time. In fact, it is the oldest animal that scientists have found with “blade-long” canine teeth, the researcher described.
Analysis of the bones suggests that it is probably the oldest gorgonopsian on the planet, dating back at least 270 million years, while “the other records of this group around the world are, at least, slightly younger,” Fortuny noted. .
For scientists, the discovery of this new fossil is another piece of the puzzle of mammal evolution, because the fact that this gorgonopsian is tens of millions of years older than its closest relatives changes the understanding of the evolution of therapsids, a milestone important on the path to the appearance of mammals, and in turn tells us something about where we come from.
“Before the time of the dinosaurs, there was an era of ancient mammalian relatives. Most of those ancient mammalian relatives looked very different from what we have today. “They were very diverse and performed many different ecological functions,” Angielczyk said.