Underground snake discovered in the Balsas River basin, in Puebla

In the dry soils of the Balsas River basin, in Puebla, a snake hitherto unknown to science was identified, so unique that it not only represents a new species, but a new genus. It is about Collarcoatl tlallian underground and elusive snake that had gone unnoticed.

Based on genetic, morphological and anatomical analyses, the research published in the journal PLOS One demonstrated that these specimens do not belong to any previously described genus, but rather to their own evolutionary lineage within the group of snakes. Sonorini.

For Antonio Yolocalli Cisneros Bernal, professor at the Faculty of Sciences of the National Autonomous University of Mexico and director of Totlok, a civil association focused on species conservation, the finding confirms that Mexico continues to be a global epicenter of biodiversity and reveals how much there is still to be known about the country’s dry ecosystems.

“Describing species is relatively common in herpetology, the science that studies amphibians and reptiles; between five and six are described each year. However, a new genus is much more complicated, because it is a category higher up. It is like having a larger container, where one can place several species,” he said.

Another aspect of this research is that, unlike other taxa that have been described by English, French or Americans, this is the first genus described only by Latin Americans.

In Mexico, 34 genera of fossorial snakes have been reported, whose main characteristic is that they spend most of their lives underground and, therefore, are especially difficult to observe. Among the genera detected in the country, four are endemic (Conopsis, Geagras, Pseudoficimia y Sympholis) and together they are known as burrowing snakes of the tribe Sonorini.

However, the two snake specimens Sonorini found during scientific exploration could not be assigned to any known genus of the tribe nor to another taxon of snakes. Collarcoatl tlalli It has a slightly raised snout, formed by a frontal scale that slopes upward and gives it a “snub-nosed” appearance.

In addition, the belly has more than 150 scales and the tail is made up of just over 35 pairs of scales, a pattern different from that of its close relatives. In the skull, the bones above the nose are short and robust and the back of the head lacks a bony crest, contributing to a more compact shape.

To conclude that it was a new genus and species, scientists analyzed its external and internal morphology using digital calipers and CT scans. The data obtained was compared with other Mexican genres, which confirmed the differences.

Likewise, DNA extraction and a phylogenetic analysis of the tribe were carried out. Sonorini. The results allowed us to reconstruct the “family tree” of this group of Mexican snakes and clearly showed how they relate to each other. It was confirmed that the specimens found in the Balsas basin, in Puebla, form their own compact group.

The data revealed that Yaka-coatl tlalli is related to the snake Pseudoficimia frontalisbut at the same time it is different. Both are related to another rare species, Sympholis lippienswhich places the new snake on a very specific branch of the evolutionary tree.

The name Yakacoatl comes from Nahuatl yacatlwhich means nose, referring to its pronounced rostral scale, which resembles a pointed nose, and coatlwhich means snake, while tlalli It is earth and alludes to the presumed fossorial habits of the species.

Because the two specimens were found dead, much of their natural history is unknown. Some morphological characteristics lead specialists to infer a diet specialized in arthropods: centipedes, spiders and scorpions. But there is no diagnosis of its state of conservation, although it is estimated that it could be vulnerable to human disturbance of the territory.

“Although there are genera that are highly tolerant to disturbances and have relatively high abundances, we consider that this is not the case for Collarcoatl tlalli. Based on the morphological evidence and the locality of the discovery, we believe that this species usually inhabits xeric areas of the area, buried under rocks or logs,” the article reports.

Mexico has the second richest reptile biodiversity in the world, surpassed only by Australia. There are more than 950 recognized species of Mexican reptiles, of which more than 50 percent are considered endemic to the country, a number that increases every year thanks to new discoveries.

From 2020 to date, at least 58 taxa of Mexican snakes have been resurrected, described or elevated based on the detection of new populations previously unknown to science. With the recognition of Yakacoatlthere are now 16 genera of snakes endemic to Mexico, representing 18 percent of the snake diversity currently known in the country.

This new genus and species demonstrates that scientific exploration has not ended even in landscapes that have been studied for decades.