Researchers discover 50-million-year-old animal from Tunisia could crack snail shells with its powerful jaws.
The discovery of Terastiodontosaurus marcelosanchezi in Tunisia reveals the largest worm lizard species, combining unique surface-dwelling habits with a 56-million-year-old snail-eating specialization, showcasing extraordinary evolutionary consistency.
Discovery of a New Fossil Species
An international team of researchers has uncovered a new fossil species of worm lizard in Tunisia, named Terastiodontosaurus marcelosanchezi. This discovery marks the largest known member of the Amphisbaenia group, with a skull measuring over five centimeters. Unlike modern worm lizards, which primarily live underground, this ancient species may have spent time on the surface due to its size. Its fossil reveals remarkable dental adaptations, including powerful jaws and specialized tooth enamel, suggesting a diet centered on snails—a feeding habit that has persisted for over 56 million years.
Unusual Traits of Worm Lizards
Worm lizards, or Amphisbaenia, get their name from their striking resemblance to a worm with heads at both ends. This appearance, evocative of creatures from Greek mythology, is actually an evolutionary adaptation. With their rounded, blunt tail ends, worm lizards can move forward and backward with ease. Their worm-like bodies are ideally suited for navigating tight underground spaces that they dig themselves, enabling them to thrive in their burrowing lifestyles.
International Research Collaboration
An international team led by Prof. Dr. Georgios L. Georgalis from the Institute of Systematics and Evolution of Animals at the Polish Academy of Sciences, Krakow, with researchers from the Senckenberg Research Institute and Natural History Museum in Frankfurt, the Institut des Sciences de l’Évolution de Montpellier, the Muséum national d’Histoire naturelle in Paris, and the National Office of Mines in Tunis, has now described a previously unknown fossil species from the group of worm lizards in a new study.
“Our discovery from Tunisia, with an estimated skull length exceeding five centimeters, is the largest known worm lizard species,” explains Georgalis. “All evidence indicates that the new species is related to the modern-day checkerboard worm lizard.”
Giant Worm Lizard: Life Above and Below Ground
Unlike the recent Amphisbaenia, which are adapted to a subterranean lifestyle, the new species Terastiodontosaurus marcelosanchezi was probably too large to live exclusively in burrows. The researchers therefore assume that the animal also spent a significant amount of time on the surface.
Co-author PD Dr. Krister Smith from the Senckenberg Research Institute and Natural History Museum Frankfurt adds, “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 long – in other words, significantly larger than its closest relatives. We think that the unusual body size is related to the higher temperatures in this period of the Earth’s history.”
Advanced Dental Adaptations of a Prehistoric Predator
Using micro-computed tomography, the research team documented the particular anatomy of the new species, which dates back to the Eocene. The worm lizard is characterized by an extreme dental morphology – including a massive tooth in the upper jaw, flat molars, and a number of other features – which distinguishes it from all other Amphisbaenia.
“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,” explains Georgalis.
We know that today’s checkerboard worm lizards like to eat snails by breaking open their shells. We can now assume that this lineage specialized in feeding on snails over 56 million years ago and could crack them open effortlessly with their powerful jaws. This feeding strategy is therefore extremely consistent – it has defied all environmental changes and accompanies the lineage to this day,” adds Smith in summary.
Reference: “The world’s largest worm lizard: a new giant trogonophid (Squamata: Amphisbaenia) with extreme dental adaptations from the Eocene of Chambi, Tunisia” by Georgios L Georgalis, Krister T Smith, Laurent Marivaux, Anthony Herrel, El Mabrouk Essid, Hayet Khayati Ammar, Wissem Marzougui, Rim Temani and Rodolphe Tabuce, 21 November 2024, Zoological Journal of the Linnean Society.
DOI: 10.1093/zoolinnean/zlae133
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