Hypsiglena unaocularis, commonly known as the Clarión nightsnake, was first described by American naturalist William Beebe during his voyage to Clarión Island in 1936. Beebe encountered a single specimen, and the snake was not seen again in decades. Now researchers have confirmed the existence of the species, after collecting DNA samples from snakes on Clarión, which is part of the Revillagigedo Islands group.
Daniel Mulcahy, a researcher for the National Museum of Natural History in Washington, was convinced that the snake might still exist, and he and Juan Martinez Gomez of Mexico's Ecology Institute planned an expedition to the Revillagigedo Islands to find it. Martinez Gomez, an expert on the Revillagigedos, helped to form a plan for locating the nightsnake, using Beebe's original field notes as a guide.
Martinez Gomez commented, "Basically, following those directions, we essentially put ourselves in his place." One of Martinez Gomez' graduate students spotted the snake, the first seen alive since 1936. The team performed a DNA analysis to declare the animal as its own species, which revealed that it closely resembles snakes from Mexico's Sonora-Sinaloa coast more than 500 miles away. Martinez Gomez thinks that the snakes may have floated on a tree trunk from the Mexican mainland to the island.
Clarión Island is currently occupied by a small outfit of Mexican marines, and civilian visits to the area require a military escort, which has made it difficult to document the wildlife native to the region. This, along with a lack of sightings since Beebe's 1936 find, caused scientists to presume that Beebe had provided an incorrect locality for the specimen
Here is an old-school documentary on the wildlife of Clarión Island, with native species include the Clarión Burrowing Owl, the Clarión Wren, the Clarión Mourning Dove and the Clarion Island Whipsnake:
The National Museum of Natural History commented that Mulcahy "uncovered the controversy surrounding the inclusion of this snake in the scientific record, and found that it appears to be the only species ever to be discarded due to a presumed locality error."
Image via YouTube