Described in Mallorca the world's oldest ancestor of mammals

Gorgonopsians are an extinct group of synapsids that lived during the Permian, between 270 and 250 million years ago. They belong to the evolutionary lineage that would give rise to the first mammals 50 million years later. They were warm-blooded animals like modern mammals, but, unlike most of them, they laid eggs. They were carnivorous and were the first animals to develop the characteristic saber teeth. They were often the superpredators of the ecosystems in which they lived, and their appearance would be similar to a dog, but without ears or fur.

The remains recovered in Mallorca belong to a small to medium-sized animal, approximately one meter in length, and come from a site located in the municipality of Banyalbufar (Serra de Tramuntana, Mallorca, Spain). Excavations were carried out in three different campaigns during which a large quantity of material was recovered. “The large number of bone remains is surprising. We have found everything from fragments of skull, vertebrae, and ribs to a very well-preserved femur. In fact, when we started this excavation, we never thought we would find so many remains of an animal of this type in Mallorca,” explains Rafel Matamales, curator of the Museu Balear de Ciències Naturals (MUCBO | MBCN) and research associate at the Institut Català de Paleontologia Miquel Crusafont (ICP), and first author of the article.

Its location of the specimen in the Balearic Islands is an unusual fact in itself. The known remains of gorgonopsians prior to this discovery belonged to very high latitudes such as Russia or South Africa. Its age has also surprised the researchers who conducted the study. “It is probably the oldest gorgonopsian on the planet. The one we found in Mallorca is at least 270 million years old, and the other records of this group worldwide are, at the very least, slightly younger,” points Josep Fortuny, senior author of the article and leader of the Computational Biomechanics and Evolution of Life History research group at the ICP.

Among the excavated fossil remains, a nearly complete leg stands out, which has allowed researchers to study how the animal moved. Unlike reptiles, which have a more ancestral locomotion with their legs more spread out, gorgonopsians had their legs positioned more vertically and, therefore, moved in a way that was intermediate between reptiles and mammals. This system is more efficient for walking and especially for running. The recovered saber teeth confirm its diet. “We know that this is a carnivorous animal, a characteristic shared by all gorgonopsians worldwide. The saber teeth are a common feature in large predators of ecosystems, and what we have found was likely one in the environment in which it lived,” emphasizes Àngel Galobart, researcher at the ICP and director of the Museu de la Conca Dellà.

When Mallorca Was Not an Island

During the Permian, approximately 270 million years ago, Mallorca was not an island but was part of the supercontinent Pangaea. It was located at an equatorial latitude, where countries like Congo or Guinea can be found today. The climate was monsoonal, alternating between wet and very dry seasons. It has been found that the site where the fossils were found was a floodplain with temporary ponds where gorgonopsians and other fauna drank. Among the animals that cohabited in this ecosystem were moradisaurine captorhinids, an ancient group of herbivorous reptiles to which the Tramuntanasaurus tiai belongs, which may have been part of the gorgonopsians' diet.

Despite the small area that occupy, the Balearic Islands have an exceptional fossil record. The most studied and well-known fossils are from the Pleistocene and Holocene. However, the fossil record from other periods is considerably less known. Nonetheless, remarkable fossils have been found, such as the world's oldest mosquito, nearly a thousand species of ammonoids (cephalopods related to squids), ancestors of horses and hippos, giant sharks, and large coral reefs.

In addition to Matamales, Fortuny, and Galobart, the study also involved Eudald Mujal, researcher at the Staatliches Museum für Naturkunde Stuttgart (Germany), Tiago Simões, from the Princeton University (USA), Christian Kammerer from the North Carolina Museum of Natural Sciences (USA), and Kenneth Angielczyk from the Field Museum of Natural History (USA). The study has been supported by the project "Mallorca abans dels dinosaures: estudi dels ecosistemes continentals del Permià i Triàsic amb especial èmfasi en les restes de vertebrats" from the Institut Català de Paleontologia Miquel Crusafont (ICP) and funded by the Departament de Cultura i Patrimoni (Consell Insular de Mallorca) and the CERCA program of the Generalitat de Catalunya.

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