''Amblyopsis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of small (up to long) fish in the family

Amblyopsidae The Amblyopsidae are a fish family commonly referred to as cavefish, blindfish, or swampfish. They are small freshwater fish found in the dark environments of caves (underground lakes, pools, rivers and streams), springs and swamps in the easter ...

that are

endemic Endemism is the state of a species being found only 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 foun ...

to the central and eastern United States. Like other

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, Troglomorphism, troglomorphic fish, troglobitic fish, stygobitic fish, phreat ...

, they lack pigmentation and are blind. The most recently described species was in 2014. Uniquely among fish, ''Amblyopsis'' brood their eggs in the

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

chambers (somewhat like

mouthbrooder Mouthbrooding, also known as oral incubation and buccal incubation, is the care given by some groups of animals to their offspring by holding them in the mouth of the parent for extended periods of time. Although mouthbrooding is performed by a va ...

s). It was formerly incorrectly speculated that the same brooding behavior existed in other genera in the family and in the pirate perch (''Aphredoderus sayanus''). During the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

period, the modern Ohio river was a barrier of dispersal and created a great genetic variation, leading to two phylogenetically distinct lineages from the species Amblyopsis.

Species

There are currently 3

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of this genus: * '' Amblyopsis hoosieri'' Niemiller, Prejean & Chakrabarty, 2014 (Hoosier cavefish) * ''

Amblyopsis rosae The Ozark cavefish, ''Troglichthys rosae'', is a small subterranean freshwater fish endemic to the United States. It has been listed as a threatened species in the US since 1984; the IUCN currently lists the species as Near Threatened, though it ...

'' C. H. Eigenmann, 1898 (Ozark cavefish) * '' Amblyopsis spelaea'' DeKay, 1842 (northern cavefish)

References

Bibliography

Amblyopsidae Cave fish Fish described in 1842 Taxa named by James Ellsworth De Kay {{Percopsiformes-stub