A mysterious snake that perplexed biologists since it was discovered in the stomach of another snake in southern Mexico 42 years ago has been designated as a new species.
A team from the University of Texas at Arlington have named the tropical reptile Cenaspis aenigma – Latin for ‘enigmatic dinner snake’. The humorous moniker not only pays homage to the specimen’s unconventional origins but also references how much we have yet to learn about the species.
In their official description, published in the Journal of Herpetology, the scientists used the decades-old preserved remains (which had been languishing in storage) to detail Cenaspis' unique physical features. However, they were unable to report anything definitive about the snake’s behavior or life cycle, because, despite many attempts over the years, no one has ever found a living specimen.
According to National Geographic, the sole dinner snake known to science was found when a palm fruit harvester, working in the untamed rainforest of Chiapas, killed a venomous Central American coral snake. That snake’s body was eventually passed on to scientists, who were tickled to find only lightly digested remains of a smaller, 25.8-centimeter (10-inch) snake inside.
The serendipitous discovery quickly morphed into a longstanding puzzle when no one could identify what species the last meal belonged to and field researchers dispatched to the same section of forest returned empty-handed.
“This enigmatic little snake possesses a unique suite of characters that defies placing it in any known genus and clearly distinguishes it from all known genera,” the authors explain.
They note that one of Cenaspis’ most unusual features is a pattern of irregular triangular stripes located on the underside of the body. The morphology of the skull and tooth count – 14 in the upper jaw – also separate it from other known genera in the region.
Based on features of the teeth and skeleton, the team speculates that Cenaspis is a non-venomous burrowing snake that feeds on hard-bodied chitinous insects and arthropods.
"The dorsal colour is rather unremarkable, being uniformly pale brown," they wrote. "This colour and lack of dorsal pattern is not unusual for burrowing species; however, the ventrals are marked with three series of dark rectangular to triangular markings forming essentially three stripes for the length of the body, and the subcaudals are marked with a single midventral band extending the length of the tail.
"Why a secretive burrowing snake would have such a distinctive ventral pattern is unknown. The ventral pattern is not replicated in any other Middle American snake."
But it was the structure and flower-like appendages of the hemipenis – the two-pronged male sexual organ – and the undivided scales on the underside of the tail that truly made lead author Jonathan Campbell and his colleagues scratch their heads.
“Neither of these characteristics is known for any other colubroid of the Western Hemisphere,” the group wrote. Colubridae is the largest family of snakes on Earth, with approximately 1,760 member species found on every continent except Antarctica.
Speaking to National Geographic, Campbell said that Cenaspis’ discovery demonstrates that many more interesting, undescribed snakes could be sneaking around the tropics and that conserving the rich habitats that give rise to such evolutionary diversity should be a top priority.
