Paleontologists have revealed a giant new species of prehistoric "worm lizard" with a powerful bite that is the largest of its kind found to date.
The newly identified creature, named Terastiodontosaurus marcelosanchezi, lived approximately 50 million years ago during the Eocene epoch, a study reported.
Researchers described the species based on fossils uncovered during recent fieldwork in the Djebel Chambi National Park, Tunisia, in North Africa. Its appearance has even been likened to that of the infamous "sandworms" from Frank Herbert's Dune science fiction novels.
The study authors report that T. marcelosanchezi is the largest known worm lizard species ever to have lived, with an estimated length likely exceeding 3 feet.
Worm lizards, or amphisbaenians, are a group of typically limbless, burrowing reptiles resembling worms that include a number of extinct and living species.
"This is large for amphisbaenian standards, considering that these, mostly limbless, lizards are relatively small- to medium-sized and spend most of their time underground," study lead author Georgios Georgalis, with the Institute of Systematics and Evolution of Animals at the Polish Academy of Sciences, told Newsweek.
While amphisbaenians are generally not considered to be "true" lizards, these reptiles belong to the order Squamata alongside snakes and lizards.
Worm lizards are well adapted for underground life, with elongated bodies, reduced or no limbs, rudimentary eyes and tough, ring-like scales. They also have specialized muscles that enable them to move in both directions, either head-first or tail-first— and powerful jaws they use to feed on insects and small invertebrates.
The latest description of Terastiodontosaurus is based on the fossils of at least 11 different individuals, of different sizes. All fossils are represent the remains of jaws and vertebrae.
Unlike its modern relatives, Terastiodontosaurus likely spent much of its time on the ground surface. The authors of the study, published in the Zoological Journal of the Linnean Society, suggest that it was probably too large to live exclusively in burrows.
The researchers also observed dental features in the fossils, such as strong jaws and thick tooth enamel, which suggest that the species feasted on snails. The characteristics indicate that it would have been capable of "effortlessly" crushing a wide variety of snail shells.
"Visually, you can imagine the animal as a 'sandworm' from the 'Dune' science fiction novels and their movie adaptation. Based on the tooth structure and the unusually thick enamel, we can deduce that the animals had enormous muscle strength in their jaws," Georgalis said in a press release.
Based on the available fossils, the estimated skull length of Terastiodontosaurus is more than around 2 inches. Extrapolating from this and using comparisons with related creatures, the authors propose that the species is the largest known worm lizard—extinct or living.
"If worm lizards could grow as large as snakes, then the new species would be comparable to the Titanoboa, which is up to 13 meters [around 43 feet] long—in other words, significantly larger than its closest relatives," study co-author Krister Smith from the Senckenberg Research Institute and Natural History Museum in Frankfurt, Germany, said in a statement.
"We think that the unusual body size is related to the higher temperatures in this period of the Earth's history."
These higher temperatures apparently favored large sizes for different reptile groups, according to Georgalis.
The study demonstrated that Terastiodontosaurus is closely related to the modern-day checkerboard worm lizard, which is endemic to North Africa. This species and Terastiodontosaurus both belong to a small family of worm lizards known as the Trogonophids.
While trogonophids share common characteristics with other worm lizards, they possess distinctive features in their skull structure, tooth arrangement, tail morphology, geographic distribution and burrowing behavior that distinguish them from other amphisbaenians.
In the study, the researchers documented "extreme" and "unique" dental features—including a massive tooth in the upper jaw and flat molars—that enabled them to describe Terastiodontosaurus as a new worm lizard species.
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Reference
Georgalis, G. L., Smith, K. T., Marivaux, L., Herrel, A., Essid, E. M., Ammar, H. K., Marzougui, W., Temani, R., & Tabuce, R. (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, 202(3). https://doi.org/10.1093/zoolinnean/zlae133
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