Hypostomus
Encyclopedia
Hypostomus is the largest genus
of the armored catfish family Loricariidae
. It includes the popular freshwater aquarium
fish
Plecostomus
(formerly Plecostomus plecostomus). There is a lot of confusion as to the precise taxonomic structure of the Loricariidae.
Hypostomini of the subfamily Hypostominae
, and is the type genus
of Hypostominae. The type species
of Hypostomus is H. guacari.
With the inclusion of Aphanotorulus, Cheiridodus, Cochliodon, Isorineloricaria, Squaliforma, and Watawata, the genus Hypostomus is by far the largest genus of Loricariidae, and the second largest genus of catfish. However, a good way to split up the genus further is unclear. Species level taxonomy of Hypostomus is still poorly known as well as the phylogenetic relationships within and of the genus. It has been shown that the genus does not form a natural group. However, small monophyletic
groups are known to exist within the genus Hypostomus, such as the H. unicolor group and the H. cochliodon group. Aphanotorulus, Isorineloricaria, and Squaliforma are considered separate genera by some authors based on molecular information.
Studies conducted with representatives of some genera of Hypostominae showed that within this group, the diploid number ranges from 2n = 52 to 2n = 80. However, the supposed wide karyotypic diversity that the family Loricariidae or the subfamily Hypostominae would present is almost exclusively restricted to the genus Hypostomus, and the species from the other genera had a conserved diploid number.
habitats of South America
. They are found throughout most of the range of loricariids except for drainages west of the Atrato River
. They are essentially ubiquitous throughout their range. Maximum diversity in number of species of Hypostomus occurs in rivers of the Paraná
-Paraguay
system.
Hypostomus species are found in almost all aquatic habitats, from large rivers to small rivulets. The typical habitat would be relatively fast moving water over a shallow gravel bed. Most species are lowland, sluggish stream- and lake-dwellers usually found associated with submerged wood; however, many species may be found among rocks in piedmont to mountain streams with moderate to swift flow. Members of Hypostomus may be found over a range of substrates such mud, detritus, gravel, and sand. Many species spawn in hollows dug into mud banks or within hollow logs.
. They use their mouth as well as the pectoral, pelvic, and caudal fin areas, to interact with the rocky river-bottom. The comb-toothed inferior mouth of the Hypostomus is able to grasp green algae on the river bottom. With the help of the suckermouth, which anchor the fishes, in conjunction with the arched design of pectoral and pelvic fin spines, they are also able to remain upright while exploring this substratum. In addition, their large, concave caudal fin is associated with fast locomotion over short distances.
Also like other loricariids, Hypostomus species exhibit plates of armor over their body. The colouration among Hypostomus species varies. They may have a white ground color and black spots, or brown and spotted, or even black with red, gold, or white spots. Abdomen also varies in color from white to black and may be spotted or not. The caudal fin is forked with the lower lobe longer than upper. Most species have stout bodies, but some do have thinner, elongate bodies.
In most species, males develop hypertrophied odontode
s on the leading edge of the pectoral fin spine and the end of the spine may become swollen. In some species, the males may also develop hypertrophied odontodes on the body during the breeding season.
Hypostomus species are well-known for the ability to breathe air. This is achieved through a slightly-modified stomach that is larger and thinner than in non-air breathers. To breathe air, Hypostomus must orient itself vertically.
Species of the H. cochliodon group are fairly large loricariids that reach about 30 centimetres (12 in) SL
. Their colouration is typically dark brown with spots generally developed over most surfaces; however, most species of this group have been observed to have a well-developed ability to alter color according to substrate. Except for H. sculpodon, these species tend to have a deep body at the dorsal fin origin; this makes the body appear humped.
Along with Panaque
, species of the H. cochliodon group are unique among loricariids for xylophagy
, or the ability to digest wood, accomplished through specialized spoon-shaped teeth. In H. hemicochliodon and H. sculpodon appear to be intermediate between other species of Hypostomus and the H. cochilodon group by feeding less on wood and lacking specialized teeth; many other Hypostomus will occasionally eat wood, but wood only amounts to a very small fraction of their diet.
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...
of the armored catfish family Loricariidae
Loricariidae
Loricariidae is the largest family of catfish , with almost 700 species and new species being described each year. Loricariids originate from fresh water habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and...
. It includes the popular freshwater aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
Plecostomus
Plecostomus
Hypostomus plecostomus is the scientific name for a type of freshwater tropical Central and South American fish belonging to the family Loricariidae. They are large algae eaters, and to differentiate them from small algae eaters, they are often referred to as plecostomus, often abbreviated as...
(formerly Plecostomus plecostomus). There is a lot of confusion as to the precise taxonomic structure of the Loricariidae.
Taxonomy and phylogeny
Hypostomus is the only genus in the tribeTribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
Hypostomini of the subfamily Hypostominae
Hypostominae
Hypostominae is a subfamily of catfishes of the family Loricariidae.Studies conducted with representatives of some genera of Hypostominae showed that within thisgroup, the diploid number ranges from 2n = 52 to 2n = 80...
, and is the type genus
Biological type
In biology, a type is one particular specimen of an organism to which the scientific name of that organism is formally attached...
of Hypostominae. The type species
Biological type
In biology, a type is one particular specimen of an organism to which the scientific name of that organism is formally attached...
of Hypostomus is H. guacari.
With the inclusion of Aphanotorulus, Cheiridodus, Cochliodon, Isorineloricaria, Squaliforma, and Watawata, the genus Hypostomus is by far the largest genus of Loricariidae, and the second largest genus of catfish. However, a good way to split up the genus further is unclear. Species level taxonomy of Hypostomus is still poorly known as well as the phylogenetic relationships within and of the genus. It has been shown that the genus does not form a natural group. However, small 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...
groups are known to exist within the genus Hypostomus, such as the H. unicolor group and the H. cochliodon group. Aphanotorulus, Isorineloricaria, and Squaliforma are considered separate genera by some authors based on molecular information.
Studies conducted with representatives of some genera of Hypostominae showed that within this group, the diploid number ranges from 2n = 52 to 2n = 80. However, the supposed wide karyotypic diversity that the family Loricariidae or the subfamily Hypostominae would present is almost exclusively restricted to the genus Hypostomus, and the species from the other genera had a conserved diploid number.
Distribution and habitat
Hypostomus species originate from freshwaterFresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
habitats of 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...
. They are found throughout most of the range of loricariids except for drainages west of the Atrato River
Atrato River
The Río Atrato is a river of northwestern Colombia. It rises in the slopes of the Western Cordillera and flows almost due north to the Gulf of Urabá , where it forms a large, swampy delta....
. They are essentially ubiquitous throughout their range. Maximum diversity in number of species of Hypostomus occurs in rivers of the 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...
system.
Hypostomus species are found in almost all aquatic habitats, from large rivers to small rivulets. The typical habitat would be relatively fast moving water over a shallow gravel bed. Most species are lowland, sluggish stream- and lake-dwellers usually found associated with submerged wood; however, many species may be found among rocks in piedmont to mountain streams with moderate to swift flow. Members of Hypostomus may be found over a range of substrates such mud, detritus, gravel, and sand. Many species spawn in hollows dug into mud banks or within hollow logs.
Description and ecology
As in all loricariids, Hypostomus species have a suckermouthSuckermouth
In fishes, a suckermouth is a ventrally-oriented mouth adapted for grazing on algae and small organisms that grow on submerged objects....
. They use their mouth as well as the pectoral, pelvic, and caudal fin areas, to interact with the rocky river-bottom. The comb-toothed inferior mouth of the Hypostomus is able to grasp green algae on the river bottom. With the help of the suckermouth, which anchor the fishes, in conjunction with the arched design of pectoral and pelvic fin spines, they are also able to remain upright while exploring this substratum. In addition, their large, concave caudal fin is associated with fast locomotion over short distances.
Also like other loricariids, Hypostomus species exhibit plates of armor over their body. The colouration among Hypostomus species varies. They may have a white ground color and black spots, or brown and spotted, or even black with red, gold, or white spots. Abdomen also varies in color from white to black and may be spotted or not. The caudal fin is forked with the lower lobe longer than upper. Most species have stout bodies, but some do have thinner, elongate bodies.
In most species, males develop hypertrophied odontode
Odontode
Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They comprise a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to that of teeth. They generally do not have the same...
s on the leading edge of the pectoral fin spine and the end of the spine may become swollen. In some species, the males may also develop hypertrophied odontodes on the body during the breeding season.
Hypostomus species are well-known for the ability to breathe air. This is achieved through a slightly-modified stomach that is larger and thinner than in non-air breathers. To breathe air, Hypostomus must orient itself vertically.
Species of the H. cochliodon group are fairly large loricariids that reach about 30 centimetres (12 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:...
. Their colouration is typically dark brown with spots generally developed over most surfaces; however, most species of this group have been observed to have a well-developed ability to alter color according to substrate. Except for H. sculpodon, these species tend to have a deep body at the dorsal fin origin; this makes the body appear humped.
Along with Panaque
Panaque
The genus Panaque contains a small number of small to medium sized South American armoured catfishes that are notable for being among the very few vertebrates that feed extensively on wood. In addition, algae and aufwuchs are an important part of the diet, and they use their rasping teeth to...
, species of the H. cochliodon group are unique among loricariids for xylophagy
Xylophagy
Xylophagy is a term used in ecology to describe the habits of an herbivorous animal whose diet consists primarily of wood. The word derives from Greek ξυλοφάγος "eating wood", from ξύλον "wood" and φαγεῖν "to eat", an ancient Greek name for a kind of a worm-eating bird...
, or the ability to digest wood, accomplished through specialized spoon-shaped teeth. In H. hemicochliodon and H. sculpodon appear to be intermediate between other species of Hypostomus and the H. cochilodon group by feeding less on wood and lacking specialized teeth; many other Hypostomus will occasionally eat wood, but wood only amounts to a very small fraction of their diet.
Species
Species list according to Armbruster. Newer species are referenced.
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Hypostomus plecostomus Hypostomus plecostomus, the suckermouth catfish or common pleco, is a tropical fish belonging to the armored catfish family , named for the armor-like longitudinal rows of scutes that cover the upper parts of the head and body... |
Hypostomus punctatus The Suckermouthed Catfish is a tropical fish known as a Plecostomus belonging to the armored suckermouth catfish family . Hypostomus punctatus is a freshwater fish native to South America, in the coastal drainages of southeastern Brazil... |