Blind Mexican catfish species spotted in the US for the first time

For the first time, a rare type of eyeless catfish native to Mexico has been spotted in the US, as a team of researchers from the University of Texas at Austin identified the creature swimming in a limestone cave at the Amistad National Recreation Area near the city of Del Rio.

Known as the Mexican blindcat (Prietella phreatophila), these endangered fish are typically less than three inches long and live in areas supported by the Edwards-Trinity Aquifer underlying the Rio Grande basin in Texas and Coahuila, UT-Austin ichthyology curator Dean Hendrickson and his colleagues explained Friday in a statement.

In May, Hendrickson’s team found two of the catfish in the limestone cave, and their discovery supports the belief that the Texas and Mexico portions of the aquifer are connected by water-filled caves located under the Rio Grande. While there have been rumored sighting of the species in Texas for decades, this is the first time that such observations can be confirmed.

The two catfish, which have since been relocated to the San Antonio Zoo, “look just like the ones from Mexico,” the ichthyologist said. It is the third species of blind catfish to be identified in the US, joining the toothless blindcat (Trogloglanis pattersoni) and the widemouth blindcat (Satan eurystomus). All three species have only been spotted in Texas.

Elusive creature captured after decades of reported sightings

First described in 1954 when it was found in wells and springs in northern Mexico, the Mexican blindcat was listed both as an endangered species by the Mexican government and as a foreign endangered species by the US Fish and Wildlife Service. For years, Hendrickson and his fellow researchers have worked to find additional populations on both sides of the border.

Jack Johnson, a National Park Service resource manager at Amistad, reported seeing some of the pinkish-white colored, slow-moving creatures during the spring of 2015. After several months of searching, he, Zara Environmental LLC biologist Peter Sprouse and a team of researchers finally once again spotted the blind catfish last month.

“Cave-dwelling animals are fascinating in that they have lost many of the characteristics we are familiar with in surface animals, such as eyes, pigmentation for camouflage, and speed,” Sprouse said. “They have found an ecological niche where none of those things are needed, and in there they have evolved extra-sensory abilities to succeed in total darkness.”

“Aquifer systems like the one that supports this rare fish are also the lifeblood of human populations and face threats from contamination and over-pumping of groundwater,” added Johnson. “The health of rare and endangered species like this fish at Amistad can help indicate the overall health of the aquifer and water resources upon which many people depend.”

While the fish have been transferred to the zoo, they are not yet on display to the public, vice president of conservation and research Danté Fenolio. For now, they will be housed in a facility specially designed for cave and aquifer species with the goal of keeping them “safe and healthy,” Fenolio said. “The fact that the zoo can participate now and house these very special catfish demonstrates the zoo’s commitment to the conservation of creatures that live in groundwater.”


Image credit: Danté Fenolio.