The Trichomycterinae 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 botanical subfamily names with "-oideae", and zo ...

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

es (order Siluriformes) of the family

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

. It includes six

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, '' Bullockia'', '' Hatcheria'', '' Rhizosomichthys'', and '' Eremophilus'', all

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

, '' Silvinichthys'' with seven

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, and '' Trichomycterus'', with over 170 species. The former five genera are diagnosed by putatively apomorphic characters, whereas ''Trichomycterus'' is defined by the lack of those specializations and is likely not

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. This subfamily has historically served as much of a wastebasket for trichomycterids that lack the specializations of the other subfamilies. Species of Trichomycterinae dwell in headwaters and small, cold clear water streams running over stony beds. Due to the patchy distribution of their habitats, trichomycterines generally have restricted geographic distributions, thus display a high level of

endemism Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

References

Trichomycteridae Catfish of South America Ray-finned fish subfamilies {{Trichomycteridae-stub