The Cetopsidae are a small

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

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive ...

es ( order Siluriformes), commonly called the whale catfishes.

Taxonomy

This family contains five genera divided into two subfamilies, Cetopsinae and Helogeneinae. Helogeneinae was previously a family-level group, but now it has been reclassified as a subfamily of Cetopsidae. This subfamily contains four species in the genus ''

Helogenes ''Helogenes'' is a genus of whale catfish found in tropical South America. Helogeneinae is the sister taxon of Cetopsinae, the other subfamily in the family Cetopsidae. Species There are currently four recognized species in this genus: * '' ...

''. The subfamily Cetopsinae contains four genera. ''

Cetopsidium ''Cetopsidium'' is a genus of catfishes ( order Siluriformes) of the family Cetopsidae. Taxonomy ''Cetopsidium'' was described in 2005, its name coming from the ''Cetopsis'', the first described cetopsid genus, and ''idium'' which means diminu ...

'' contains six species, ''

Cetopsis ''Cetopsis'' is a genus of catfishes ( order Siluriformes) of the family Cetopsidae. Taxonomy ''Cetopsis'' is one of four genera in the subfamily Cetopsinae within the family Cetopsidae. ''Cetopsis'' is greatly expanded from when it only include ...

'' contains 21 species, ''

Denticetopsis ''Denticetopsis'' is a genus of catfishes ( order Siluriformes) of the family Cetopsidae. Taxonomy Originally ''Denticetopsis'' as described by Ferraris in 1996 was restricted to two species, ''D. royeroi'' and ''D. sauli''. These two species ha ...

'' contains seven species, and ''

Paracetopsis ''Paracetopsis'' is a genus of whale catfishes found in tropical South America. Species There are currently three recognized species in this genus: * '' Paracetopsis atahualpa'' Vari, Ferraris & de Pinna, 2005 * '' Paracetopsis bleekeri'' B ...

'' contains three species; this makes a total of 37 cetopsines. The genera have been changed as recently as 2005 with the genera ''Bathycetopsis'', ''Hemicetopsis'', and ''Pseudocetopsis'' set in

synonymy A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

with ''Cetopsis'' and the description of the new genus ''Cetopsidium''. ''Cetopsidium'' is the sister group to the rest of Cetopsinae. ''Denticetopsis'' forms the next sister group to the remaining cetopsine genera. The tribes Cetopsidiini, Denticetopsini, and Cetopsini are erected for the cetopsine genera.

Distribution

Cetopsids have a wide distribution in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

. Latitudinally, cetopsines extend from northern Colombia to central

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. They inhabit major habitats such as the

Orinoco River The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...

, Amazon River, and the

Guyanas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * G ...

. In trans-

Andean The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S l ...

South America, cetopsines are found along the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

slope from the Jurubidá River of Colombia south to the

Tumbes River The Tumbes River ( es, Río Tumbes or Río Túmbez in Peru; Río Puyango in Ecuador), is a river in South America. The river's sources are located between Ecuadorian El Oro and Loja provinces. It is the border between El Oro and Loja, and afterw ...

of northern

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...

. Along the Caribbean trans-Andean versant, species of cetopsines occur from the

Sinú River Sinú River (), is a river in northwestern Colombia that flows mostly through the Córdoba Department and into the Caribbean. The river is the third most important river after the Magdalena River and the Cauca River in the Caribbean Region. It ...

of northwestern Colombia east to the Lake Maracaibo basin of northwestern

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

. East of the Andean

Cordillera A cordillera is an extensive chain and/or network system of mountain ranges, such as those in the west coast of the Americas. The term is borrowed from Spanish, where the word comes from , a diminutive of ('rope'). The term is most commonly u ...

s, the Cetopsinae occur in the Aroa and

Yaracuy River The Yaracuy River is a river of Venezuela. It drains into the Caribbean Sea. See also *List of rivers of Venezuela This is a list of rivers in Venezuela. By drainage basin This list is arranged by drainage basin, with respective tributaries ind ...

basins along the Caribbean versant of northern Venezuela, through the Orinoco River system and the coastal rivers of the Guianas, south through the Amazon basin to the southern portions of the

Río de la Plata The Río de la Plata (, "river of silver"), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda. It empties into the Atlantic Ocean and fo ...

basin. Cetopsines also occur in the Juquiá River basin of the state of

São Paulo São Paulo (, ; Portuguese for ' Saint Paul') is the most populous city in Brazil, and is the capital of the state of São Paulo, the most populous and wealthiest Brazilian state, located in the country's Southeast Region. Listed by the Ga ...

and the São Francisco River basin of eastern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

. ''Helogenes'', the single genus of Helogeneinae, occurs through much of the Amazon basin, the southern portions of the Orinoco River basin, the coastal rivers of the Guianas, and at least the lower portions of the

Tocantins River The Tocantins River ( pt, Rio Tocantins, link=no , , Parkatêjê: ''Pyti'' ɨˈti is a river in Brazil, the central fluvial artery of the country. In the Tupi language, its name means " toucan's beak" (''Tukã'' for "toucan" and ''Ti'' for "beak ...

Description

The family Cetopsidae includes species of small- to medium-sized catfishes which share an anal fin with a long base, the lack of nasal

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the zebrafish, the black dragonfish and some s ...

, and, usually, a lack of

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

and

pectoral 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 ...

spines. In Cetopsinae, the swim bladder is highly reduced and is enclosed in a bony capsule. Cetopsines lack an

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 se ...

, while it may be present (though small) in Helogeneinae. Many species are characterized by small eyes obscured by a thick, overlying

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

that make them appear blind. The dorsal and pectoral fins usually lack spines, except in ''Cetopsidium'' (both present) and ''Denticetopsis'' (only pectoral spines present). In most species of ''Cetopsis'' and ''Cetopsidium'', mature males have a convex margin to their anal fin and elongated distal filaments of the dorsal and pectoral fin spines. The maximum length of this family is about SL in Cetopsinae. ''Cetopsidium'' species are generally smaller in body size than ''Cetopsis''. The maximum length in ''Helogenes'' species is .

Ecology

Most cetopsids feed on

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s. ''C. candiru'' and ''C. coecutiens'' are well known to have extremely voracious appetites. These fish will attack carrion, other living fish while in gillnets, and even people. Some people erroneously believe these fish are

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

like parasitic catfishes.

References

{{Taxonbar, from=Q761337 Fish of South America Catfish families Taxa named by Pieter Bleeker