A New Snake Species Was Named "Unbelievable." The Taxonomists Were Not Wrong.

Rarely does a new species get named after the reaction it provoked in the people who found it. Calamaria incredibilis is an exception: when researchers confirmed it was something entirely new, they reached for the Latin word for "unbelievable."

The snake is a newly described reed snake from southern China whose stubby, blunt-tipped tail so closely mimics its own head that locals have long called it the two-headed snake. It is not, for the record, two-headed. Evolution just thought that would be funnier.

A study published in Zoosystematics and Evolution formally describes the species from just two specimens collected in Guangxi, China, where it had previously been misidentified as a known relative, Calamaria pavimentata. The snake belongs to a group of small, burrowing reed snakes notoriously difficult to tell apart, most spending the majority of their lives underground, which makes them hard to study and harder still to classify.

Confirmation required a close look at scale counts, tail proportions, coloration and DNA, plus micro-CT scanning to produce 3D images of the skull, confirming that its anatomy did not match anything previously described. Calamaria incredibilis differs from its nearest relatives by more than 12 percent genetically, a meaningful gap for a group where many species are nearly identical on the outside.

The Guangxi region, sitting at the junction of southern China and northern Indochina, features limestone karst landscapes, varied elevations and a complex geological past that has likely kept animal populations isolated long enough for new species to evolve. The research team notes that many historical records of Calamaria pavimentata across the region almost certainly contain specimens that were never properly identified.

If one "two-headed" reed snake could be hiding in plain sight, others may still be waiting.

Read the full story at Discover Magazine, May 27, 2025

Hot Take: The taxonomy of burrowing reed snakes seems to be an ongoing negotiation with a group of animals that would clearly prefer not to be classified.