New snake species discovered in another snake’s belly

Scientists have discovered a species of snake unlike any seen before, but this special serpent wasn't found sliding through its forested habitat in tropical Mexico. The newfound animal made its scientific debut in a more unconventional place: inside another snake’s belly.

Newly described in a recent paper in the Journal of Herpetology, the creature has been dubbed Cenaspis aenigma, which translates to “mysterious dinner snake.” The name derives from the Latin cena (dinner), aspis (a snake variety), and enigma.

This species has unique features that separate it from its relatives, including the shape of its skull, the covering of its hemipenis—its reproductive structure—and the scales under its tail.

Hiding in the wild

Based on certain features of its skeleton and teeth, scientists think Cenaspis is a burrowing snake that likely feeds on insects and spiders. Incredibly, however, the creature has never been found alive—so it’s hard to know precisely what it eats or how it lives, says Jonathan Campbell, a herpetologist at the University of Texas at Arlington who led the research team.

The snake, you see, has evaded detection for 42 years. In 1976, in the southern Mexican state of Chiapas, palm-harvesters working deep in one of the region’s forests found a Central American coral snake—a vibrantly colored species with neurotoxic venom. When researchers obtained it, they found that its last meal was smaller serpent.

This ten-inch-long male snake was something special, as it didn’t match any known species, so the specimen was preserved in a museum collection. The research team returned to the area at least a dozen times over several decades, but came up empty handed.

“This provides evidence of just how secretive some snakes can be,” says Campbell. “Combine their elusive habits with restricted ranges and some snakes do not turn up often.”

Campbell doesn’t think that the snake’s disappearing act is from a post-70s extinction. Rather, he thinks Cenaspis is still out in Chiapas somewhere, but a burrowing lifestyle coupled with other secretive habits make it difficult to find.

Odd features

The underside of the creature is adorned with three series of triangular blotches that make irregular stripes; very few New World snakes have similar striping. It also has 14 short, stout teeth in its upper jaw; most members of its family have more or less than that.

But Cenaspsis’s hemipenes are its most bizarre attribute. Most of its relatives have hemipenes festooned with spines along the organ’s body, some decorated at the end with cup-like structures called calyces. The new species’ appendage is spineless, and absolutely covered in calyces, making it look like some kind of otherworldly honeycomb.

The snake is unique enough that it qualifies not only as a new species, but a new genus (which is a group of closely related species—for example, the genus Canis includes Canis lupus, the gray wolf, but also other animals like coyotes and jackals).

Sara Ruane—a herpetologist and evolutionary biologist at Rutgers University-Newark not involved in this study—is impressed by the finding.

“This is an excellent contribution to herpetology and reminds us all that you never know what new information you may get when doing field collections and taking a closer look at what is already in museums—and why such collections are important,” says Ruane.

Kevin de Queiroz—zoologist and curator of the collection of Amphibians and Reptiles at the Smithsonian’s National Museum of Natural History—agrees.

“It's always interesting to find a species that is new to science, and even more so when it appears not to be particularly closely related to any currently known species.”

But neither Ruane or de Queiroz are surprised that it was a coral snake that had located the ill-fated Cenaspis before human researchers did. These animals are adept specialists at hunting and eating small snakes, and Cenaspis isn’t the first species to be discovered inside one; it’s happened a few times before. But as far as Campbell knows, “This is the first time a new genus has been found in the stomach of a coral snake.”

While little is known about the biology of the “dinner snake,” the species’ strange, Russian-nesting-doll discovery provides an important lesson about the world’s biodiversity, much of which remains unseen and unrecognized.

“[The discovery] tells us that there are likely still Neotropical snake species remaining to be discovered that are relatively isolated evolutionarily,” says de Queiroz.

For Campbell, the uniqueness of Cenaspis suggests its habitat is likewise special, and irreplaceable—and worth being considered as a park or protected area.