The Delturinae are a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

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) of the family

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 ...

, including two

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

, ''

Delturus ''Delturus'' is a genus of armored catfishes native to rivers in Southeast and Northeast Brazil. Species There are currently four recognized species in this genus: * '' Delturus angulicauda'' ( Steindachner, 1877) * '' Delturus brevis'' Reis & ...

'' and ''

Hemipsilichthys ''Hemipsilichthys'' is a genus of catfishes belonging to the family Loricariidae. These wide-mouthed freshwater catfishes are restricted to southeast Brazil in the Paraíba do Sul, Perequê-Áçu and Taquari river basins. ''Hemipsilichthys'', a ...

''. This group is

sister A sister is a woman or a girl who shares one or more parents with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to refer to ...

to all other loricariids except ''

Lithogenes ''Lithogenes'' is a genus of South American catfish of the family Loricariidae. It is the only genus within the subfamily Lithogeneinae. Taxonomy ''Lithogenes'' is the only genus within the subfamily Lithogeneinae. This genus and subfamily, the ...

''. The geographical distribution of Delturinae, exclusively on the southeastern Brazilian Shield, indicates southeastern Brazil acts as either a refugium for basal loricariid taxa or a point of origin for the Loricariidae. Both genera can be separated from all other loricariids by the presence of a postdorsal ridge made up of raised, median, unpaired plates and the presence of an adipose fin membrane. ''Hemipsilichthys'' can be separated from ''Delturus'' by not having the anterior plates of the ridge contacting the lateral plates (juveniles of ''Delturus'' also have this condition) and by having a rectangular (vs. V-shaped) spinelet.

References

Loricariidae Taxa named by Roberto Esser dos Reis Fish subfamilies {{Loricariidae-stub