Stegophilinae is a subfamily of catfish

Catfish

Catfishes 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 heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

es (order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Siluriformes) of the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Trichomycteridae

Trichomycteridae

Trichomycteridae is a family of catfishes commonly known as the pencil or parasitic catfishes. This family includes the infamous candiru fish, feared by some people for its alleged habit of entering into the urethra of humans....

.

It includes twelve genera

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

, Acanthopoma, Apomatoceros, Haemomaster, Henonemus

Henonemus

Henonemus is a genus of catfishes of the family Trichomycteridae. It includes five species, H. intermedius, H. macrops, H. punctatus, H. taxistigma, and H. triacanthopomus....

, Homodiaetus

Homodiaetus

Homodiaetus is a genus of catfishes of the family Trichomycteridae. It includes four species, H. anisitsi, H. banguela, H. graciosa, and H...

, Megalocentor, Ochmacanthus

Ochmacanthus

Ochmacanthus is a genus of catfishes of the family Trichomycteridae. It includes five species, O. alternus, O. batrachostoma, O. flabelliferus, O. orinoco, and O. reinhardtii. Ochmacanthus species are distributed in South America. O. alternus and O...

, Parastegophilus

Parastegophilus

Parastegophilus is a genus of catfishes of the family Trichomycteridae. It includes two species, P. maculatus and P. paulensis. P. maculatus origiantes from the lower Paraná and Uruguay River basins in Argentina while P. paulensis is from the upper Paraná River basin in Brazil...

, Pareiodon, Pseudostegophilus

Pseudostegophilus

Pseudostegophilus is a genus of catfishes of the family Trichomycteridae. It includes two species, P. haemomyzon and P. nemurus. P. haemomyzon originates from the Orinoco River basin in Venezuela while P. nemurus is found in the Amazon River basin in Brazil and Peru. P...

, Schultzichthys

Schultzichthys

Schultzichthys is a genus of catfishes of the family Trichomycteridae. It includes two species, S. bondi and S. gracilis. S. bondi is from the Amazon and Orinoco River basins, while S. gracilis is from the Guayabero River of the Orinoco River basin in Colombia...

, and Stegophilus

Stegophilus

Stegophilus is a genus of catfishes of the family Trichomycteridae. It includes three species, S. insidiosus, S. panzeri, and S. septentrionalis. S. insidiosus originates from the São Francisco River basin in Brazil, S. panzeri is from the lower Amazon River basin in Brazil, and S...

. A monophyletic

Monophyly

In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

 group within Stegophilinae is supported by two characteristics of the lateral line

Lateral line

The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...

, including Acanthopoma, Henonemus, Megalocentor, Pareiodon, Parastegophilus, and Pseudostegophilus. Acanthopoma and Henonemus have a sister group

Cladistics

Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 relationship.

The subfamily Stegophilinae is widely distributed in the main South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

n river basins, including the Amazon

Amazon River

The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

, Orinoco

Orinoco

The Orinoco is one of the longest rivers in South America at . Its drainage basin, sometimes called the Orinoquia, covers , with 76.3% of it in Venezuela and the remainder in Colombia...

, São Francisco

São Francisco River

The São Francisco is a river in Brazil. With a length of , it is the longest river that runs entirely in Brazilian territory, and the fourth longest in South America and overall in Brazil...

, Paraná

Paraná River

The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...

-Paraguay

Paraguay River

The Paraguay River is a major river in south central South America, running through Brazil, Bolivia, Paraguay, and Argentina...

 and those of southern Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. Eight of the genera are distributed in Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

.

Stegophilines are sometimes considered candirú

Candirú

‎Candiru or candirú , also known as cañero, toothpick fish, or vampire fish, are a number of genera of parasitic freshwater catfish in the family Trichomycteridae; all are native to the Amazon River...

, and are considered parasites or semi-parasites, because of their peculiar habit of feeding on scales

Lepidophagy

Lepidophagy is a specialised feeding behaviour in fish that involves eating of scales of other fish. Lepidophagy is widespread, having been independently evolved in at least five freshwater families and seven marine families...

, mucus

Mucophagy

Mucophagy is feeding on mucus of fishes or invertebrates. It may also refer to consumption of mucus or dried mucus in primates.There are mucophagous parasites, such as some sea lice that attach themselves to gill segments of fish....

, or skin of other fishes.