''Epalzeorhynchos'' is a small

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

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 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 ...

Cyprinidae Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest verte ...

. Its members are – like some other cyprinids – known as "

freshwater shark Bullshark Beqa Fiji 2007

Freshwater sharks are sharks able to ...

s" or simply "sharks". They are, however,

freshwater 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 ...

members of the

Osteichthyes Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage ...

lineage which is distinct from the Chondrichthyes lineage of sharks. The description of these animals as "shark" is most likely a reference to the shark-like shape of these popular cyprinids. The genus ''Epalzeorhynchos'' may be placed in the

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...

Garrini Labeoninae is a doubtfully distinct subfamily of ray-finned fishes in the family Cyprinidae of order Cypriniformes. They inhabit fresh water and the largest species richness is in the region around southern China, but there are also species else ...

of the Labeoninae, or in

subtribe Subtribe is a taxonomic category ranking which is below the rank of tribe and above genus. The standard suffix for a subtribe is -ina (in animals) or -inae (in plants Plants are predominantly photosynthetic eukaryotes of the kingdom Plant ...

Garraina of tribe Labeonini, if these are considered a tribe of subfamily

Cyprininae The Cyprininae are one of at least 11 subfamilies of cyprinid fish. It contains three genera in its strictest definition but many more are included depending on which authority is defining it, especially if the Labeobarbinae is not considered to ...

. It is not yet resolved which is a more appropriate representation of their

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

Description and ecology

In size and shape ''Epalzeorhynchos'' generally resemble the Indian loaches (''Botia''), which, although they are also

cypriniform Cypriniformes is an order of ray-finned fish, including the carps, minnows, loaches, and relatives. Cypriniformes is an Order within the Superorder Ostariophysi consisting of "Carp-like" Ostariophysins. This order contains 11-12 families, ...

s, are far too distantly related to have anything other than

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

be responsible for this similarity. Alternatively, ''Epalzeorhynchos'' might be considered a plumper version of '' Crossocheilus'', which includes the well-known Siamese algae eater (''C. siamensis'') and is a very close relative. Their coloration is also reminiscent of some ''Crossocheilus'', or of the Mekong loaches (''Yasuhikotakia''), depending on the particular ''Epalzeorhynchos'' species. Unlike actual

shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...

s, ''Epalzeorhynchos'' "

freshwater shark Bullshark Beqa Fiji 2007

Freshwater sharks are sharks able to ...

s" are

. Thus, they have gill covers that can actively pump water over the gills, enabling them to breathe comfortably while at rest. As typical for Garrini, they spend much time on or near the ground – though not quite as much as the related true

gudgeon A gudgeon is a socket-like, cylindrical (i.e., ''female'') fitting attached to one component to enable a pivoting or hinging connection to a second component. The second component carries a pintle fitting, the male counterpart to the gudgeon, ...

s of the Gobioninae or the loaches of the cypriniform

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Cobitoidea Loaches are fish of the superfamily Cobitoidea. They are freshwater, benthic (bottom-dwelling) fish found in rivers and creeks throughout Eurasia and northern Africa. Loaches are among the most diverse groups of fish; the 1249 known species of C ...

. Still, they usually only move for prolonged distances during migration to their

spawn Spawn or spawning may refer to: * Spawn (biology), the eggs and sperm of aquatic animals Arts, entertainment, and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** '' Spawn: Ar ...

ing grounds.Kottelat (1996) Epalzeorhynchos kalopterus1

This genus feeds mainly on aufwuchs,

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

and small

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

and

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

matter. Their mouthparts are not as

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

ic as that of many other Garrini; they do not have a pronounced rostral cap, but in addition to the two barbels on the rostrum they retain another pair of barbels at the rear edges of the lower maxilla. The upper lip carries a short bristly ridge, while the lower one has a sizeable hard edge with which they can scrape food off hard substrate like rocks or logs. Three species are frequent in the

aquarium fish Lists of aquarium life include lists of fish, amphibians, invertebrates and plants in freshwater, brackish and marine aquariums. In fishkeeping, suitable species of aquarium fish, plants and other organisms vary with the size, water chemistry and ...

trade; '' E. munense'' is the only member of the genus that rarely (if ever) makes its way into the trade. The demand for these colourful fishes is high, and breeding is almost impossible to achieve in the home aquarium. The popular species are thus bred on an industrial scale in

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

. Today all

red-tailed black shark The red-tailed black shark (''Epalzeorhynchos bicolor''; syn. ''Labeo bicolor''), also known as the redtail shark and redtail sharkminnow, is a species of freshwater fish in the carp family, Cyprinidae. Despite its name, it is more closely rela ...

s (''E. bicolor''), all flying foxes (''E. kalopterus''), and most

rainbow shark The rainbow shark (''Epalzeorhynchos frenatum'') is a species of Southeast Asian freshwater fish from the family Cyprinidae. It is also known as the ruby shark, red-fin shark, red-finned shark, rainbow sharkminnow, green fringelip labeo, whitefi ...

s (''E. frenatum'') seen in the aquarium trade are believed to be farm-bred. The main problem for their status is

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, a ...

ming of rivers between the fishes' usual haunts and the breeding grounds. While otherwise a considerable take of wild ''Epalzeorhynchus'' could be sustained, dams will literally stand in the way of successful reproduction, and such isolated subpopulations are easily extinguished by

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...

Water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water ...

is also problematic. Due to these threats, the red-tailed black shark is very rare and was believed to be

extinct in the wild A species that is extinct in the wild (EW) is one that has been categorized by the International Union for Conservation of Nature as known only by living members kept in captivity or as a naturalized population outside its historic range due ...

, but a tiny wild population is now known, leading to its current

IUCN 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 ...

rating as critically endangered. Among the remaining, ''E. munense'' is vulnerable, the rainbow shark is considered safe, and the flying fox is

data deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...

(its status is unclear based on 2009 knowledge).

Species

A mere four

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 ...

are placed in this

: *''

Epalzeorhynchos bicolor The red-tailed black shark (''Epalzeorhynchos bicolor''; syn. ''Labeo bicolor''), also known as the redtail shark and redtail sharkminnow, is a species of freshwater fish in the carp family, Cyprinidae. Despite its name, it is more closely relate ...

'' ( H. M. Smith, 1931) (red-tailed black shark, redtail shark, red-tailed labeo, redtail sharkminnow) *'' Epalzeorhynchos frenatum'' ( Fowler, 1934) (rainbow shark, rainbow sharkminnow) *'' Epalzeorhynchos kalopterus'' (

Bleeker Bleeker is a Dutch occupational surname. Bleeker is an old spelling of ''(linnen)bleker'' ("linen bleacher").Epalzeorhynchos munense'' ( H. M. Smith, 1934) (redfin shark) In addition to these, '' Akrokolioplax bicornis'' was included in ''Epalzeorhynchos'' until 2006.Zhang, E. and M. Kottelat. (2006). ''Akrokolioplax, a new genus of Southeast Asian labeonine fishes (Teleostei: Cyprinidae).'' Zootaxa 1225, 21-30.

Footnotes

References

* (2007): Evolutionary origin of Lake Tana's (Ethiopia) small ''Barbus'' species: indications of rapid ecological divergence and speciation. '' Anim. Biol.'' 57(1): 39-48. (HTML abstract) * * * (2007): An overview of labeonin relationships and the phylogenetic placement of the Afro-Asian genus ''Garra'' Hamilton, 1922 (Teleostei: Cyprinidae), with the description of five new species of ''Garra'' from Ethiopia, and a key to all African species. '' Zool. J. Linn. Soc.'' 150(1): 41-83. PDF fulltext
{{Taxonbar, from=Q135495 Cyprinidae genera Freshwater fish genera Taxa named by Pieter Bleeker Cyprinid fish of Asia