''Nematogenys inermis'' is a species of mountain catfish, the only extant

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 ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Nematogenyiidae. This species 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 ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

where it is found in

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

s in central Chile. This species grows to a length of NG. The body is naked (without scales) and elongated. The three pairs of

barbel Barbel may refer to: *Barbel (anatomy), a whisker-like organ near the mouth found in some fish (notably catfish, loaches and cyprinids) and turtles *Barbel (fish), a common name for certain species of fish **''Barbus barbus'', a species of cyprinid ...

s are the chin (mental) barbels, maxillary barbels, and nasal barbels. No

adipose 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 s ...

is present. The

opercle The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four b ...

lacks spines. The Nematogenyidae and

Trichomycteridae Trichomycteridae is a family of catfishes commonly known as pencil catfishes or parasitic catfishes. This family includes the candiru fish (''Vandellia cirrhosa''), feared by some people for its alleged habit of entering into the urethra of hum ...

are

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

s that together form a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

sister to the families

Callichthyidae Callichthyidae is a family of catfishes ( order Siluriformes), called armored catfishes due to the two rows of bony plates (or scutes) along the lengths of their bodies. It contains some of the most popular freshwater aquarium fish, such as many ...

Scoloplacidae ''Scoloplax'' is the only genus in the catfish (order Siluriformes) family Scoloplacidae, the spiny dwarf catfishes. Species The six currently recognized species in this genus are: * ''Scoloplax baileyi'' Rocha, Lazzarotto & Rapp Py-Daniel, ...

Astroblepidae ''Astroblepus'' is a genus of fish in the family Astroblepidae found in South America and Panama. This genus is the only member of its family. These catfishes are primarily found in torrential streams in the Andean area. ''Astroblepus pholeter'' ...

, and

Loricariidae The Loricariidae is the largest family of catfish (order Siluriformes), with 92 genera and just over 680 species. Loricariids originate from freshwater habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are not ...

. One extinct species, '' Nematogenys cuivi'', has been described in this genus.

References

Endemic fauna of Chile Catfish of South America Fish described in 1848 {{catfish-stub