The oldest known ancestor of mammals lived at least 270 million years ago in what is now Mallorca. About one meter long, it was a predator with sharp fangs and a appearance not very different from that of a dog, although without hair or ears. This has been described by an international research led by archaeologists from Mallorca and Catalonia based on a large number of fossil remains, which has even allowed to detail how it moved.
The authors, presenting their findings this Tuesday in an article from the journal Nature Communications, still do not dare to say whether it is a new species or not. The richness of fossil remains unearthed at the site (a tusk, parts of the skull, vertebrae, ribs, and a perfectly preserved femur) has, however, allowed them to confirm that the animal is the oldest known gorgonopsid.
The gorgonopsids were a group of extinct predatory animals that inhabited the supercontinent Pangaea before the dominance of the dinosaurs. Halfway between reptiles and mammals, they shared characteristics of both but did not belong to either class. They are indeed considered the oldest ancestors of mammals.
The gorgonopsid found in Mallorca is the first known animal to have sharp fangs, similar to those of dogs
鈥淚t has been unexpected,鈥� repeats Josep Fortuny, a researcher at the Catalan Institute of Paleontology Miquel Crusafont (ICP), in statements to bet365赔率. 鈥淯ntil now, this group of animals was exclusively known in high latitudes, such as Russia and South Africa,鈥� he explains, 鈥渁nd the fossils were millions of years younger.鈥� The oldest specimen found so far was 265 million years old, compared to the 270 or 280 of the one found in Mallorca.
Such was the surprise of the researchers upon identifying the remains of the unearthed animal that, to confirm their hypothesis, they contacted Christian Kammerer from the North Carolina Museum of Natural Sciences in the United States, considered the foremost expert worldwide on gorgonopsians. 鈥淗is immediate response was that he was already looking for plane tickets, and about ten days later, we had him with us in Mallorca because he couldn't believe it,鈥� Fortuny describes.
Kammerer confirmed the identity of a fossil that revolutionizes the study of mammal evolution, as it proposes an equatorial origin for its oldest ancestor - 270 million years ago, when what is now Mallorca was part of the supercontinent Pangea at the level of present-day Congo, and had a monsoonal climate. 鈥淭here was a theoretical study that said there was a lack of fossil record, and teams were looking for gorgonopsians at higher latitudes, but no one expected them to appear in our area,鈥� explains the expert, who advocates for continued exploration in Mediterranean areas, 鈥渂ecause we may have missed present groups.鈥�
Indeed, the gorgonopsid appeared unexpectedly, when paleontologists were working at a site in Banyalbufar, a municipality in the Serra de Tramuntana in Mallorca, where a few months earlier they had described a new species of reptile that they named the 鈥渢ramuntanasaurio.鈥� They believe that 270 million years ago, seasonal floods in the area created temporary ponds where animals would drink. They suggest that the gorgonopsids likely fed on these other reptiles.
Like a dog without hair or ears
Neither reptile nor mammal, the gorgonopsid was warm-blooded, but it laid eggs
鈥淚f you saw this animal walking down the street, it would resemble a medium-sized dog, perhaps the size of a husky, but something wouldn't quite add up,鈥� explained Ken Angielczyk, curator at the Field Museum of Natural History in Chicago, United States, who took part in the study. 鈥淚t had no fur or canine ears,鈥� he exemplified. Additionally, it laid eggs, as if it were a reptile.鈥�
On the other hand, it was warm-blooded鈥攎aintaining a constant body temperature regardless of the external temperature鈥攁nd had its legs more or less vertically positioned under the body, allowing for more efficient movement. Both are characteristics of mammals, just like some structures described in its jaw that, millions of years later, would eventually evolve into the bones of the middle ear.
鈥淚t is a very primitive animal, but it does not have unique characteristics,鈥� something essential to describe a new species, details Fortuny, from the ICP. 鈥淲e are preparing a new research project to take this individual to a synchrotron, scan it at high resolution, and be able to see its interior, in a way that allows us to observe characteristics that will enable us to establish a new species,鈥� he describes with an eye on the future.
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