Blindcat Catfish of North America and Mexico
The Blindcat Catfish species include freshwater fish in the Prietella, Trogloglanis, and Satan genus and belonging to the Ictaluridae family. Native to North America and Mexico. While Prietella and Noturus have been confirmed to be monophyletic sister groups.
The Blindcat either have no pigmentation or seem pink in color. While no external eyes may be visible in adults, juveniles may have eyes that appear under the skin. These eyes withdraw as the fish ages. Showing that an optic tract exists but regresses before reaching the brain. However, very little to no trace of a retina or a lens exists. Generally, the swim bladder, stomach and kidneys seem reduced. While having a weak ossification of the skeleton.
Generally, inhabit wells, still pools and shallow running waters. Preferring silt substrates in dark environments. Some of the waters where the Prietella occur include the Tamaulipas, Tamesi River Drainage, Bravo River Basin, Coahuila, Gulf of Mexico, and Texas.
While the Trogloglanis and Satan genus inhabit subterranean habitats and occur in the five artesian wells penetrating the San Antonio Pool of Edwards Aquifer in San Antonio Texas.
Species of Blindcat
The Mexican Blindcat (Prietella phreatophila) seems to be pink to white in color, with no eyes. Generally, grows to 3.6 inches in length. Further, the adipose fin joins to the unforked, straight caudal fin.
While the dorsal fin lacks a spine. The snout overhangs the mouth. Furthermore, 15 caudal rays and 10 to 14 rakers occur on the first gill arch.
The species lives in subterranean waters in caves and wells, especially the Rio Bravo Drainage in Coahuila.
This species may lie motionless or drift in the current with their breathing slowed. While pollution and extraction of the groundwater remain the main threats to the species.
The Phantom Blindcat (Prietella lundbergi), may be limited to the Tamesi River Drainage. A troglobitic species residing in caves. A pinkish white fish lacking eyes.
Generally reaches about 2.5 inches in length. While the dorsal fin lacks a spine. The snout overhangs the mouth. Meanwhile the long adipose fin joins to the caudal fin but with a posterior flat creating a deep notch between the two fins.
Further, the first gill arch consists of 17 caudal rays and 17 rakers. While a weakly forked caudal fin exists.
The Toothless Blindcat (Trogloglanis pattersoni) reaches about 4 inches in length. A vulnerable species with no pigmentation and no externally visible eyes. Their heads appear square, being broad and long.
While having not well-ossified, cartilaginous skulls. Meanwhile a sucker-like toothless mouth indicates a detritivore species.
In juveniles the eye appears under the skin. But as the fish grows the eyes withdraw even further into the skull. Showing that an optic tract exists but regresses before reaching the brain.
As may be seen, the eye remnants seem extremely reduced in size with very little to no trace of a retina or a lens.
This species has a long adipose fin which appears rounded at the end and connects to the caudal fin. While the dorsal and pectoral fins have spines.
Furthermore, a fragmented lateral line reaches between the anterior and posterior end of the adipose fin.
The fish has a reduced swim bladder and stomach which may be surrounded by deposits of adipose tissue allowing for adequate energy to be stored.
While kidney morphology exists. Furthermore, weak ossification of the skeleton exists.
The Toothless Blindcat inhabits subterranean habitats and occurs in five artesian wells penetrating the San Antonio Pool of Edwards Aquifer in San Antonio Texas. But may also be found in north-eastern caves of Mexico.
The Widemouth Blindcat (Satan eurystomus), appears to be the only representative in the Satan genus. With their closest relative being the much larger Flathead Catfish.
A vulnerable species, threatened by groundwater pollution. Generally, reaching 5.4 inches in length. They lack pigmentation and have no externally visible eyes. While having not well-ossified, cartilaginous skulls.
In juveniles the eye appears under the skin. But as the fish grows the eyes withdraw even further into the skull. Therefore, showing that an optic tract exists but regresses before reaching the brain.
As may be seen, the eye remnants seem extremely reduced in size with very little to no trace of a retina or a lens. Further, a fragmented lateral line reaches past the anterior part of the anal fin.
While the species have a few paedomorphosis traits. Which include a small sized kidney, reduced swim bladder, and ossification of the skeleton.
The Widemouth Blindcat may have been discovered inhabiting lightless underground environments in the five artesian wells penetrating the San Antonio Pool of Edwards Aquifer near San Antonio, Texas.
A top carnivore in their habitat. Diets may include crustaceans.
Conservation and Management
The Blindcat Catfish species appears to be endangered, and a vulnerable species. Generally, threatened by groundwater pollution and overfishing. Therefore, we need to contribute by keeping our environment clean and our waters unpolluted if we would like to let our children and great grandchildren see these marvelous little fish.