The scientific article, published in the scientific journal "Papers In Paleontology", describes the discovery of the new species “Cambelodon torreensis”, a mammal from the Portuguese Upper Jurassic that researchers believe may have walked the earth around 100 million years ago.

The discovery, which brought information “about the evolution of primitive mammals, as well as their diet and chewing mechanics”, was studied by Portuguese, Brazilian and Belgian researchers, in work developed mainly by Víctor Carvalho during his master's dissertation in Paleontology at NOVA FCT.

Speaking to Lusa news agency, research supervisor Bruno Camilo said that it was “a very rare discovery”, both due to its location, almost in a kind of natural trap”, and the quantity of “bones”, including teeth and the jaw of a mammal from the Order Multituberculata, an extinct group.

Discovered in Cambelas, in the municipality of Torres Vedras, in the district of Lisbon, the new species, named “Cambelodon torreensis”, belonged to the group of mammals that would have managed to survive on land due to some peculiarities such as “bizarre teeth”.

“They were very small animals, the size of a squirrel, quadrupeds,” described Bruno Camilo, adding that their dentition “seems to suggest that they were omnivores, with a generalist diet.

“There is nothing vaguely similar to them today,” says Ricardo Araújo, in a statement in which he highlights that “the discovery of Cambelodon offers absolutely new data on the origin of this group.”

The fossil found in Cambelas was analyzed using nanotomography at the Instituto Superior Técnico, and it was “possible to identify that the specimen was a young individual, still with preserved baby teeth”.

A rare discovery that allowed “distinguishing the tooth replacement pattern of this species, that is, the order in which the teeth are replaced” explained Víctor Carvalho, lead author of the article.

“Among modern mammals and multituberculates, tooth replacement is predominantly done from front to back (incisors first, then canines, premolars and, finally, molars). Cambelodon has reverse tooth replacement, that is, from back to front and in a non-sequential manner.”

This replacement is extremely rare: only two other specimens of multituberculates are known in the entire world, one species found in China, and another in Portugal, in the Guimarota mine, as the text reads.

Cambelodon was classified as a member of the Pinheirodontidae family, a group of multituberculates created almost 30 years ago based on fossils found in Portugal.

Since then, representatives of this family have also been identified in Spain, Germany and England, but all are known only from isolated teeth.

The fossil was discovered in 2022, in an area “where there are at least three small dinosaurs”, said Bruno Camilo, adding that the complete block, which is part of the collection of the Natural History Society (SHN) of Torres Vedras, is being studied, and the fossils should be exhibited at the paleontology research center, in Santa Cruz, Torres Vedras.