Widemouth blindcat  (Satan eurystomus)

A bizarre looking fish, the appearance of the widemouth blindcat reflects the unique habitat it occupies. Living in dark, underground waters, the widemouth blindcat lacks eyes and its smooth, scaleless skin possesses no dark pigments and so appears white or pink in colour (3) (4). The head and snout are broad and flat (3), with long, whisker-like barbels (fleshy projections) around the mouth (4). It has a long, high adipose fin on the back, and a strong spine in front of the dorsal and pectoral fins (4). It occupies the same underground pools as the toothless blindcat, but can be easily distinguished by its well developed jaw teeth (3).

Occurs only in the San Antonio Pool of the Edwards Aquifer, in and near San Antonio in Bexar County, Texas (3).

The widemouth blindcat is a subterranean freshwater fish, inhabiting underground pools at depths of 305 to 582 meters (5).

Due to the inaccessibility of its habitat, little is known about the widemouth blindcat. It is known to eat shrimp, amphipods, and isopods, and may also prey on the toothless blindcat, Trogloglanis pattersoni (5). The widemouth blindcat possesses a well-developed lateral line (a row of receptors that can detect movement via vibrations in water), which is thought to be the primary sense with which it locates prey (6). It is this, along with the frequent presence of crustacean skeletons in its gut, and its muscular stomach, that suggests that the widemouth blindcat may be the top carnivore in the Edwards Aquifer system (6).

As the widemouth blindcat occurs only in one underground pool, any change in the pool environment could rapidly impact the entire population, making this species very vulnerable to extinction. The widemouth blindcat inhabits water that is removed for human use (7), particularly for the enormous city of San Antonio. As San Antonio continues to grow at a rapid rate, ground water extraction has an increasing impact on the blindcat's habitat (8). In addition, as human populations rise, so does the probability of contamination of the Edwards Aquifer from agricultural and industrial runoff, such as fertilisers, pesticides and heavy metals (5) (7).

In addition to the IUCN classifying the widemouth blindcat as Vulnerable (1), the Texas Parks and Wildlife Department consider this species to be Threatened (9). Controls are placed on water extraction from the Edwards Aquifer by federal and state authorities, offering the toothless blindcat a little protection (8). However, to fully protect this little-known species and the unique aquatic ecosystem it inhabits, further studies and long-term monitoring are required to inform conservation actions (8).

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk