A new species of lizard that lived in Tunisia about fifty million years ago was discovered by Dr. Giorgos Georgalis, professor at the Institute of Systematics and Evolution of Animals of the Polish Academy of Sciences in Krakow, who, in collaboration with researchers from Germany, France and Tunisia, is researching fossil jaws and vertebrae kept in the collections of the National Bureau of Mines of Tunisia in Tunis.

“I gave the name Terastiodontosaurus (Terastiodontosaurus marcelosanchezi) to the new animal to highlight its very curious features regarding the size and shape of its teeth,” the researcher told the Athens/Macedonian News Agency.

Terastiodontosaurus, he explains, belonged to a group of lizards called Amphisvaines. These are mainly legless lizards, which live most of the time in underground burrows and rarely appear on the surface of the earth. Amphibians exist today in America, Africa, the Middle East, while in Europe they live exclusively on the Iberian Peninsula and on some islands of the Eastern Aegean.

“The fossilized jaws of Terastiodontosaurus are much larger than any other Amphisvaena and indicate that it was an animal over a meter in length, making it the largest representative of this group of lizards. It is possible that this maximum size is due to the fact that the era in which Terastiodontosaurus lived was characterized by an extremely warm climate and high temperatures, which apparently favored reptiles.”

In addition to its impressive size, Terasiodontosaurus is notable for its very peculiar teeth, which differ from any other reptile. Dr. Georgalis named it so for an obvious reason (in paleontology, animals are usually named internationally by Greek names): one tooth in the upper and lower jaws of Terastiodontosaurus was really “huge” compared to the rest of the teeth. With these teeth, Terastiodontosaurus had a powerful bite, which allowed it to crush large snails that lived in its environment.

“One tooth in the upper and lower jaw is really huge – but not in height, in length. It is very flattened and much larger than all the other teeth in the row. This is also clearly seen in the illustration, where in the upper jaw, the second tooth (counting from behind) is enormous in length in relation to all the other teeth.’

Unlike today’s Amphisvaines, Terasiodontosaurus is thought not to have lived in burrows, but on the surface of the earth. So this new species, according to Mr. Georgali, offers valuable evidence on the gigantism, evolution, diversity and lifestyle of Amphisvaina, this mysterious group of lizards, which live mainly in obscurity under the ground – between them and “our” current Amphisvaina (species Blanusstrauchi ), who lives on some of our islands (Rhodes, Symi, Kos, Leros, Kalymnos, Kastelorizo, Fourni and Samos).

The research was published in the Zoological Journal of the Linnean Society, Georgalis, GL, KT Smith, L. Marivaux, A. Herrel, EM Essid, H. Khayati Ammar, W. Marzougui, R. Temani and R. Tabuce. 2024. The world’s largest worm lizard: a new giant trogonophid (Squamata, Amphisbaenia) with extreme dental adaptations from the Eocene of Chambi, Tunisia. Zoological Journal of the Linnean Society, zlae133.