''Helogenes'' 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 whale catfish found in tropical South America. Helogeneinae is the

sister taxon 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 ...

of Cetopsinae, the other subfamily in the family Cetopsidae.

Species

There are currently four recognized species in this genus: * '' Helogenes castaneus'' ( Dahl, 1960) * '' Helogenes gouldingi''

Vari Vari () is a southern suburb of Athens and former municipality in East Attica, Greece along the Athens coast. The ancient Athenian deme of Anagyrous was situated here. Since the 2011 local government reform it is part of the municipality Vari-Vo ...

& H. Ortega, 1986 * '' Helogenes marmoratus'' Günther, 1863 * '' Helogenes uruyensis'' Fernández-Yépez, 1967

Distribution

''Helogenes'' species occur through much of the

Amazon River basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...

, the southern portions of the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

River basin, the coastal rivers of the

Guianas The Guianas, also spelled Guyanas or Guayanas, are a geographical region in north-eastern South America. Strictly, the term refers to the three Guianas: Guyana, Suriname, and French Guiana, formerly British Guiana, British, Surinam (Dutch colo ...

, and at least the lower portions of the

Tocantins River The Tocantins River ( , Parkatêjê dialect, 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"). It ...

Description

In ''Helogenes'', the

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

base is short, the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

base is elongate, the dorsal and

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s lack spines, the adipose fin is usually present, but is reduced or absent in one population of one species. ''Helogenes'' species grow to about 4.3–7.3 centimetres (1.7–2.9 in) SL.

Ecology

''Helogenes'' species feed on

allochthonous River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.Angelier ...

insects. The only species for which details of the ecology are known is ''H. marmoratus'' (refer to article for that species).

References

{{Authority control Cetopsidae Fish of the Amazon basin Catfish genera Taxa named by Albert Günther Freshwater fish genera