Trichomycteridae is a family of catfishes (order Siluriformes) 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.
This family is prohibited to import into various parts of the USA.
The monophyly of Trichomycteridae is well-supported. The family is divided into eight subfamilies. The only subfamily that is not monophyletic is the largest one, Trichomycterinae. A large clade within Trichomycteridae is also suggested that includes the subfamilies Tridentinae, Stegophilinae, Vandelliinae, Sarcoglanidinae and Glanapteryginae (the so-called TSVSG clade); this large clade in turn forms a larger monophyletic group with the two genera Ituglanis and Scleronema. The latter two genera are not classified in any of the subfamilies. The basal subfamilies Copionodontinae and Trichogeninae are sister groups to each other, and together they form a clade that is sister to the rest of the Trichomycteridae.
Trichomycteridae has the greatest distribution of any catfish family. It is widely distributed throughout the Neotropics. These fish originate from freshwater in Costa Rica, Panama, and throughout South America. The family extends from Panama southward to Chile and Argentina.
The bodies of these fish are normally naked and elongate. The chin barbels are usually absent, nasal barbels are usually present, and there are usually two pairs of maxillary barbels. Most of these fish have no adipose fin, and some also lack pelvic fins.
Many trichomycterids are small enough to be considered miniatiurized (does not exceed 2.6 centimetres (1.0 in) SL). Miniaturization occurs in many of the trichomycterid subfamilies, including Trichomycterinae, Glanapteryginae, Vandelliinae (in Paravandellia), Tridentinae, and Sarcoglanidinae. Miniaturization has probably occurred four times in trichomycterid evolution, as Glanapteryginae and Sarcoglanidinae are closely related and may have a single miniaturized ancestor.
Though the family is commonly known as "parasitic catfishes", Trichomycteridae may actually include the widest range of trophic adaptations within any single catfish family. Only the two subfamilies Vandelliinae and Stegophilinae are considered to be parasitic fishes, including the infamous "candirú" or vampire catfish, feared by some people for its habit of entering into the urethra of humans. Apart from the free-living, generalized predators of small invertebrates, trophic modes represented by trichomycterids include the hematophagy (feeding on blood) in Vandelliinae, the lepidophagy (scales) and mucophagy (mucus) in some Stegophilinae and necrophagy (carrion) in others, and partial algivory (algae) in Copiondontinae.
Trichomycteridae includes species that are active swimmers (Copionodontinae and Trichogeninae), torrent dwellers (Trichomycterinae), litter leaf dwellers (Ituglanis), and sand-dwellers (Glanapteryginae and Sarcoglanidinae). Species may be restricted to elevations above 4000 metres (13000 ft) in the Andes, Andean lakes, off-shore coastal islands, lowland species known only from large rapids, leaflitter puddles, and the bottom of torrential rivers. Trichomycterids are one of the most successful groups to occupy cave habitats; it contains twelve hypogean species. Such species include Ituglanis bambui, I. epikarsticus, I. passensis, I. ramiroi, and Silvinichthys bortayro. Six of the hypogean species are of the genus Trichomycterus: Trichomycterus chaberti, T. itacarambiensis, T. santanderensis, T. spelaeus, and T. uisae.
- "Trichomycteridae". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=164269. Retrieved July 12, 2007.
- Froese, Rainer, and Daniel Pauly, eds. (2007). "Trichomycteridae" in FishBase. July 2007 version.
- Ferraris, Carl J., Jr. (2007). "Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types" (PDF). Zootaxa 1418: 1–628. http://silurus.acnatsci.org/ACSI/library/biblios/2007_Ferraris_Catfish_Checklist.pdf. Retrieved 2009-06-24.
- Datovo, Aléssio; Landim, Maria Isabel (2005). "Ituglanis macunaima, a new catfish from the rio Araguaia basin, Brazil (Siluriformes: Trichomycteridae)" (PDF). Neotropical Ichthyology 3 (4): 455–464. doi:10.1590/S1679-62252005000400002. http://www.ufrgs.br/ni/vol3num4%5CNI_v3n4p455-464lowr.pdf.
- Fernández, Luis; de Pinna, Mario C. C. (2005). Armbruster, J. W.. ed. "Phreatic Catfish of the Genus Silvinichthys from Southern South America (Teleostei, Siluriformes, Trichomycteridae)". Copeia 2005 (1): 100–108. doi:10.1643/CI-03-158R2.
- Bichuette, Maria Elina; de Pinna, Mario César Cardoso; Trajano, Eleonora (2008). "A new species of Glaphyropoma: the first subterranean copionodontine catfish and the first occurrence of opercular odontodes in the subfamily (Siluriformes: Trichomycteridae)". Neotropical Ichthyology 6 (3): 301–306. doi:10.1590/S1679-62252008000300002.
- Koch, Walter Rudolf (30 September 2002). "Revisão Taxonômica do Gênero Homodiaetus (Teleostei, Siluriformes, Trichomycteridae) (Portuguese)" (PDF). Iheringia, Sér. Zool., Porto Alegre 92 (3): 33–46. http://www.scielo.br/pdf/isz/v92n3/12975.pdf. Retrieved 2009-06-24.
- Schaefer, Scott A.; Provenzano, Francisco; de Pinna, Mario; Baskin, Jonathan N. (November 29, 2005). "New and Noteworthy Venezuelan Glanapterygine Catfishes (Siluriformes, Trichomycteridae), with Discussion of Their Biogeography and Psammophily" (PDF). American Museum Novitates (3496): 1–27. http://digitallibrary.amnh.org/dspace/bitstream/2246/5665/1/N3496.pdf. Retrieved 2009-06-24.
- Nelson, Joseph S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
- de Pinna, Mario C. C. (August 9, 1989). "A New Sarcoglanidine Catfish, Phylogeny of Its Subfamily, and an Appraisal of the Phyletic Status of the Trichomycterinae (Teleostei, Trichomycteridae)" (PDF). American Museum Novitates (2950): 1–39. http://digitallibrary.amnh.org/dspace/bitstream/2246/5105/1/N2950.pdf. Retrieved 2009-06-24.
- Castellanos-Morales, Cesar A. (2007). "Trichomycterus santanderensis: A new species of troglomorphic catfish (Siluriformes, Trichomycteridae) from Colombia" (PDF). Zootaxa 1541: 49–55. http://www.mapress.com/zootaxa/2007f/z01541p055f.pdf. Retrieved 2009-06-24.
- Castellanos-Morales, Cesar A. (2008). "Trichomycterus uisae: a new species of hypogean catfish (Siluriformes: Trichomycteridae) from the northeastern Andean Cordillera of Colombia". Neotropical Ichthyology 6 (3): 307–314. doi:10.1590/S1679-62252008000300003.