New fossil worm lizard with jaws capable of cracking snails

Nov. 22 () –

A new fossil species of worm lizard discovered in Tunisia exhibits jaws that were capable of breaking snails and forward and backward mobility.

Terastiodontosaurus marcelosanchezi, which lived about 50 million years ago, is the largest known species of the Amphisbaenia group, with a cranial length of more than five centimeters.

Unlike today’s predominantly subterranean worm lizards, this species may also have been a surface dweller. The fossil shows extreme dental features, including strong jaws and specialized tooth enamel, indicating that it fed on snails, a diet that has persisted for more than 56 million years.

Worm lizards (Amphisbaenia) are aptly named, as at first glance these scaly reptiles resemble a worm with a head on both ends. However, what is reminiscent of a creature from Greek mythology is actually an evolutionary trick: Worm lizards can crawl both forward and backward with their blunt, rounded tail ends.

Among other things, they use their body shape, which resembles that of an earthworm, to traverse narrow passages in the soil that they dig themselves.

“Our discovery in Tunisia, with a cranial length estimated at more than five centimeters, is the largest known species of worm lizard,” explains in a statement Professor Georgios L. Georgalis of the Institute of Animal Systematics and Evolution of the Polish Academy of Sciences in Krakow, first author of the study. “All indications are that the new species is related to the extant checkerboard worm lizard.”

Unlike extant Amphisbaenia, which are adapted to a subterranean lifestyle, the new species Terastiodontosaurus marcelosanchezi was probably too large to live exclusively in burrows. Therefore, the researchers assume that the animal also spent a significant amount of time on the surface.

Co-author Dr Krister Smith from the Senckenberg Research Institute and the Natural History Museum in Frankfurt adds: “If worm lizards could grow as large as snakes, then the new species would be comparable to Titanoboa, which measures up to 13 meters long. that is, significantly larger than its closest relatives. “We think the unusual body size is related to the higher temperatures in this period of Earth’s history.”

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 extreme dental morphology, including a huge tooth in the upper jaw, flat molars, and a number of other features, which distinguish it from all other amphisbaenians.

“Visually, you can imagine the animal as a ‘sandworm’ from the science fiction novels ‘Dune’ and its film adaptation. Based on the structure of the teeth and the unusually thick enamel, We can deduce that the animals had enormous muscular strength in their jaws“explains Georgalis.

“We know that today’s checkerboard worm lizards like to eat snails by breaking their shells. We can now assume that this lineage specialized in feeding on snails more than 56 million years ago and could effortlessly tear them open with its powerful jaws. This feeding strategy is therefore extremely consistent: it has defied all environmental changes and accompanies the lineage to this day,” adds Smith.