An endangered blind catfish, previously only known to inhabit caves in Mexico, has been discovered living in a deep limestone cave in Texas.
The pair of Mexican blindcats, Prietella phreatophila, which were first spotted in the cave at Amistad National Recreation Area near Del Rio, in April last year, have been collected and relocated by a team of experts to San Antonio Zoo.
The Mexican blindcat reaches just 7.5cm/3in in length and is known to live only in areas supported by the Edwards-Trinity Aquifer that underlies the Rio Grande basin in Texas and the northern Mexican state of Coahuila. The new finding lends weight to a theory that water-filled caves below the Rio Grande may connect the Texas and Mexico portions of the aquifer.
"Since the 1960s there have been rumours of sightings of blind, white catfishes in that area, but this is the first confirmation," said Dean Hendrickson of The University of Texas at Austin, who identifed the fish. "I’ve seen more of these things than anybody, and these specimens look just like the ones from Mexico."
Mexican blindcats are a pale pink colour because their blood can be seen through the translucent skin, and they dwell exclusively in groundwater.
The species was originally described in 1954 and was subsequently listed as an endangered species by the Mexican government, and as a foreign endangered species by the U.S. Fish and Wildlife Service. Hendrickson led efforts to locate additional blindcat sites in Mexico and Texas for years but only located them in Mexico on previous expeditions.
The fish are not yet on public display. They will be kept in a special facility designed to accommodate cave and aquifer species at the San Antonio Zoo’s Department of Conservation and Research.
The finding brings the number of blind catfish species within the U.S. to three, all found only in Texas. The two other species of blind catfish in Texas, the Toothless blindcat, Trogloglanis pattersoni, and the Widemouth blindcat, Satan eurystomus, live in part of the Edwards Aquifer complex, the deep Edwards pool below the city of San Antonio.