For 78 years no one knew about the nocturnal snake Hypsiglena ochrorhyncha unaocularus , and it was deleted from the list of reptile species in the world.
But a recent expedition to Isla Clarión, in Mexico, has found it again.
This snake is endemic to that island, the furthest from the Mexican mainland. For almost eight decades, no one had realized that he lived in a small habitat among volcanic rocks.
The history of its rediscovery is due to a scientific investigation by a heterogeneous team, led by Juan Esteban Martínez Gómez, from the Institute of Ecology (Inecol).
“It is an example that the islands still hold treasures of biodiversity to be discovered,” he explains. The value of the find is greater because the natural heritage of Mexico registers an accelerated deterioration and a growing number of species are in danger of extinction. Paradoxically, the Hypsiglena snake always lived in Clarión, but no one had seen it.
The first news of this species dates from 1936 , when the American naturalist Charles William Beebe traveled to the island to collect the native species. He found it one night near some rocks, something strange since most reptiles are diurnal, since the cold slows down their movements.
Beebe considered it a subspecies of the spotted night snake, but endemic to Clarión, a 1,600 km2 island in the Revillagigedo archipelago, about 1,100 kilometers from Mexico. The naturalist took a specimen that is preserved in the United States Museum of Natural History.
In 1955 there was another scientific trip to Clarion headed by Bayard Brattstrom to search for the nocturnal snake. But he did not find it and determined that it was a “labeling error”, something frequent in expeditions of the past, since they kept the species collected in the holds of the ships and many were lost or deteriorated. Hence, Hypsiglena ochrorhyncha unaocularu s was deleted from the list of extant species .
In 2012, Daniel Mulcahy, a researcher at the Department of Vertebrate Zoology at the Smithsonian Institution’s National History Museum, in Washington, began organizing a new expedition to Clarion because he was sure that the reptile existed, in light of the discoverer’s detailed notebook. original. In May 2013 the new trip was chartered and the group followed the same route as Beebe, but found nothing. Until a student of Martínez noticed a strange movement on some volcanic lava rocks and found two specimens of the snake .
After the discovery, an identification process began with DNA tests, which established that the reptile is not related to the specimens from Baja California Sur, but that its closest link to the continent is a spotted snake native to Sonora. It is, therefore, a new endemic species and not a subspecies as was thought eight decades ago.
How it got to Isla Clarión, located hundreds of kilometers from that state, is a mystery. The scientists who rediscovered it believe that thousands of years ago there was a flood of a river that dragged one or more specimens over the trunk of a tree towards the Gulf of Cortés, and from there the marine currents took them to their new home
The night snake is between 40 and 45 centimeters long, it is not poisonous and it feeds on insects and lizards. Its exact classification is in process, but it will probably be included in the list of endangered species , given the low number of specimens and its limited habitat.
Photo: Daniel Mulcahy
