The blind swamp eel (''Ophisternon infernale'') is a species of

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

in the family Synbranchidae. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

where it lives in cave systems and is known in

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Cana ...

as the '. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has rated this

cavefish Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and hypog ...

as "

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

Taxonomy

The blind swamp eel was first described by the American

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of Octobe ...

Carl Leavitt Hubbs Carl Leavitt Hubbs (October 19, 1894 – June 30, 1979) was an American ichthyologist. Biography Youth He was born in Williams, Arizona. He was the son of Charles Leavitt and Elizabeth (née Goss) Hubbs. His father had a wide variety of jobs (f ...

in 1938, the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

having been collected two years earlier by A.S.Pearse. Hubbs named the fish ''Pluto infernalis'' because he liked to associate creatures living underground with the devil, who supposedly dwelt underground, and gave diabolical names to cave fishes; ''infernale'' comes from the Latin for

Hell In religion and folklore, hell is a location in the afterlife in which evil souls are subjected to punitive suffering, most often through torture, as eternal punishment after death. Religions with a linear divine history often depict hell ...

. The fish was later transferred to the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Ophisternon ''Ophisternon'' is a genus of swamp eels found in fresh and brackish waters in South and Southeast Asia, New Guinea, Australia, Middle America and West Africa. Two species are blind cave-dwellers.Romero, A., editor (2001). ''The Biology of Hyp ...

'', the swamp eels. The genus name is derived from the Greek, "ophis", meaning a serpent, and "sternon", meaning chest. Synonyms for this species include ''Furmastix infernalis'' and ''Synbranchus infernalis''.

Description

The blind swamp eel is an elongated, wormlike fish with no pigment, no scales and no visible eyes. It seems likely that it is derived from the marbled swamp eel (''Synbranchus marmoratus'') and became adapted for life underground. It grows to a

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

of and the bulbous head bears numerous sensory pores.

Distribution

The blind swamp eel is endemic to the

Yucatán Peninsula The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...

in Mexico where it inhabits freshwater in sinkholes and limestone caves. It lives in shallow water in the muddy substrate or under stones. It has only been found in 7% of the caves investigated, and where it is found, it coexists with the

Mexican blind brotula The Mexican blind brotula (''Typhliasina pearsei'') is a species of viviparous brotula endemic to Mexico, where it is found in sinkholes and caves. It is known as ''sak kay'' in Mayan and ''dama blanca ciega'' in Spanish. This cavefish grows to ...

(''Typhliasina pearsei''), and often with the catfish ''

Rhamdia guatemalensis ''Rhamdia'' is a genus of three-barbeled catfishes found in Mexico, Central and South America. These catfishes are nocturnal, opportunistic carnivores, found in a wide range of freshwater habitats. This genus includes a number of troglobitic me ...

''.

Ecology

The blind swamp eel feeds on the faeces of bats and swallows and on shrimps. The male swamp eel excavates a mucus-lined burrow in which the eggs are laid, and the male guards the nest.

Status

The chief threats faced by this swamp eel is from pollution from untreated sewage and waste water which may seep into the aquifer, and from human disturbance. The

has rated this eel as being an "

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

". This is on the basis that the area occupied by this species is limited in extent, and the number of individuals is thought to have declined drastically over the last ten years, and is likely to continue doing so, due to a decrease in the quantity and quality of suitable habitat.

References

{{DEFAULTSORT:Blind Swamp Eel Cave fish Ophisternon Endemic fish of Mexico Taxa named by Carl Leavitt Hubbs Fish described in 1938 Taxonomy articles created by Polbot