The widemouth blindcat (''Satan eurystomus'') is a species of

North American freshwater catfish North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is ...

endemic to Texas in the United States. It is the only species in the genus ''Satan''.

Description

It was first discovered inhabiting a well, and is adapted for a lightless underground environment. Like other cavefish, the widemouth blindcat lacks pigmentation and has no externally visible eyes. The eye remnants are extremely reduced in size with very little or no trace of a retina or lens; the optic tract is present, but always regresses before reaching the brain. The

swim bladder The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled Organ (anatomy), organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their curren ...

in these fish is reduced, and the skull is mostly cartilaginous and not well- ossified, unlike the adults of most larger ictalurids. The

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

is fragmentary and never reaches past the anterior part of the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

. This species also has a few paedomorphic traits (indicated by small size, kidney morphology, and weak ossification of the skeleton). This species grows to about TL.

Taxonomy

The widemouth blindcat's closest relative is the much larger flathead catfish (''Pylodictis olivaris'').

Distribution and habitat

Along with the related toothless blindcat (''Trogloglanis pattersoni''), this species is distributed in five artesian wells penetrating the San Antonio Pool of the Edwards Aquifer in and near San Antonio, Texas. These fish have been found with crustacean exoskeletons in their stomachs, and may be the

top carnivore An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic le ...

in their habitat.

Conservation

The widemouth blindcat is a vulnerable species, and is threatened by groundwater pollution.

References

{{Taxonbar, from=Q3760645 Ictaluridae Cave fish Endemic fauna of Texas Freshwater fish of the United States Fish described in 1947 Taxa named by Carl Leavitt Hubbs

Description

Taxonomy

Distribution and habitat

Conservation

See also

References