Secrets of a strange snake-like worm revealed by CT scans

Amphibians are strange creatures. Like worms with vertebrae, scales, a large central tooth and sometimes small forearms, these reptiles live underground, digging tunnels and feeding on almost anything they encounter, much like a miniature version of the monstrous sandworms from “Dune”.

Although they are found throughout much of the world, little is known about the behavior of amphisbae in the wild, as they cannot be observed in their natural habitat under sand and soil. But thanks to two articles published in the March issue of The anatomical filenew light is shed on these animals and their specialized anatomy.

Using a micro-CT scanner at the University of Texas at Austin’s Jackson School of Geosciences, researchers performed a detailed comparative analysis of 15 southern African amphisbenes and a bone-by-bone description of each cranial anatomical characteristic of the species Zygaspis quadrifrons. According to the researchers, these are the most detailed studies of southern African amphisbenes to date.

By scanning these specimens, the researchers were able to render individual bones as large 3D printed models. This allowed them to closely examine bones such as the tabulosphenoid, which is almost entirely inside the skull and almost impossible to see without this technology, said Christopher J. Bell, the lead author of the article which looked at the subject. anatomy of the Zygaspis skull and professor at the Jackson School.

“You could place three Zygaspis quadrifron skulls on the nail of my little finger. We can now look at these very small vertebrate organisms in a degree of detail we’ve never had before,” Bell said.

The research began more than 15 years ago when Patrick J. Lewis, co-author of both papers and professor of paleobiology at Sam Houston State University, led a team to Botswana on a mission aimed at trapping and studying animals of all kinds. By digging and sampling the environment, they began to capture amphisbens. At the time, Lewis didn’t know much about them. When one of his students handed him one, he said he was surprised that something that looked so much like a worm could be so powerful.

“They wriggle and try to escape and move in a way that worms just aren’t able to do. They’re much more like little snakes in the way they move and interact. It’s just surprising for something so small. You don’t. “I don’t expect that behavior,” Lewis said.

Some of the most striking images from these CT scans highlight sutures in the skull: deep, thin waves that “cling” to each other, Lewis described. The images also render in exquisite detail the strange, singular central tooth of amphisbaenas, which interlocks with the two lower teeth.

“Combined with amphisbae’s powerful jaw muscles, this gives them a ferocious bite for an animal of their size. They can bite and tear off pieces of their prey,” Bell said.

Antonio Meza, lead author of the paper examining the different amphisbae species and a first-year doctoral student at Arizona State University, said snakes and other reptiles are born with an egg tooth which allows them to come out of their shell.

“But in amphisbaenas, they just kept it,” he said.

Meza’s analysis also confirmed sexual dimorphism in Zygaspis quadrifrons, with females being larger than males in this species.

With little biological and ecological data available on amphisbae, studying their anatomy is the best way for researchers to learn more about these bizarre animals and the hidden lives they lead beneath the surface.