Trichomycteridae
Encyclopedia
Trichomycteridae is a family
of catfish
es (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.
and 207 species
. It is the second-most diverse family of the superfamily Loricarioidea
. Numerous species still remain undescribed.
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.
, Panama
, and throughout South America
. The family extends from Panama southward to Chile
and Argentina
.
s 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 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.
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 metre
s (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.
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...
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) commonly known as the pencil or parasitic catfishes. This family includes the infamous candiru
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...
fish, feared by some people for its alleged habit of entering into the urethra
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...
of humans.
This family is prohibited to import into various parts of the USA.
Taxonomy
Trichomycteridae comprises about 41 generaGenus
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...
and 207 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. It is the second-most diverse family of the superfamily Loricarioidea
Loricarioidea
Loricarioidea is a superfamily of catfishes . It contains the six families Trichomycteridae, Nematogenyiidae, Callichthyidae, Scoloplacidae, Astroblepidae, and Loricariidae. Some schemes also include Amphiliidae...
. Numerous species still remain undescribed.
The monophyly
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...
of Trichomycteridae is well-supported. The family is divided into eight subfamilies. The only subfamily that is not 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...
is the largest one, Trichomycterinae. A large clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
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
Ituglanis
Ituglanis is a genus of catfishes of the family Trichomycteridae. Their greatest diversity seems to occur in the Amazon River basin. Most species inhabit leaf litter, while four species have been described from caves....
and Scleronema. The latter two genera are not classified in any of the subfamilies. The basal subfamilies Copionodontinae
Copionodontinae
Copionodontinae is a subfamily of catfishes of the family Trichomycteridae. It includes two genera, Copionodon and Glaphyropoma.-Classification:...
and Trichogeninae are sister
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...
groups to each other, and together they form a clade that is sister to the rest of the Trichomycteridae.
Distribution
Trichomycteridae has the greatest distribution of any catfish family. It is widely distributed throughout the Neotropics. These fish originate from freshwater in Costa RicaCosta Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
, Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, and throughout 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...
. The family extends from Panama southward to Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
and Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
.
Description
The bodies of these fish are normally naked and elongate. The chin barbels are usually absent, nasal barbelBarbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...
s 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 in) SL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
). 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.
Ecology
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 parasiticParasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
fishes, including the infamous "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...
" or vampire catfish, feared by some people for its habit of entering into the urethra
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...
of humans. Apart from the free-living, generalized predators of small invertebrates, trophic modes represented by trichomycterids include the hematophagy
Hematophagy
Hematophagy is the practice of certain animals of feeding on blood...
(feeding on blood) in Vandelliinae, the lepidophagy
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...
(scales) and mucophagy
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....
(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 metre
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
s (13000 ft) in the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
, 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
Trichomycterus is a genus of catfishes, the largest genus in the family Trichomycteridae with over 100 species currently described.-Taxonomy:This genus is defined by the lack of specializations found in other trichomycterids and is certainly polyphyletic...
: Trichomycterus chaberti, T. itacarambiensis, T. santanderensis, T. spelaeus, and T. uisae.