''Amblyopsis'' is a

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 ...

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 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 ...

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, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and hypog ...

, 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 respiratory organ that many 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 respiration on land provided they are ...

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 The pirate perch (''Aphredoderus sayanus'') is a freshwater fish that commonly inhabits coastal waters along the east coast of the United States and the backwater areas of the Mississippi Valley. This species is often found towards the bottom of ...

(''Aphredoderus sayanus''). During the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

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 In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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