Loricariidae
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The Loricariidae is the largest
family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
of
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, ...
(order Siluriformes), with 92
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 ...
and just over 680
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
. Loricariids originate from
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
habitats of
Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
,
Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...
, and tropical and subtropical
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
. These fish are noted for the bony plates covering their bodies and their
suckermouth In fish, a suckermouth is a ventrally-oriented (inferior) mouth adapted for grazing on algae and small organisms that grow on submerged objects. All Loricariidae possess a suckermouth as do the cypriniform algae eaters of the genus ''Gyrinocheilus' ...
s. Several
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 ...
are sold as " plecos", notably the suckermouth catfish, ''
Hypostomus plecostomus ''Hypostomus plecostomus'', also known as the suckermouth catfish or the common pleco, is a tropical freshwater fish belonging to the armored catfish family (Loricariidae), named for the longitudinal rows of armor-like scutes that cover the upp ...
'', and are popular as
aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...
fish.


Common names

Members of the family Loricariidae are commonly referred to as loricariids, suckermouth armoured catfishes, or armoured catfish. The name "
plecostomus Plecostomus, pleco, or plec is the common name of several species of freshwater loricariid catfish commonly sold as aquarium fish. These include: *''Hypostomus plecostomus'' *'' Hypostomus punctatus'' *'' Pterygoplichthys multiradiatus'' *'' Pte ...
", and its shortened forms "pleco" and "plec", are used for many Loricariidae, since ''Plecostomus plecostomus'' (now called ''
Hypostomus plecostomus ''Hypostomus plecostomus'', also known as the suckermouth catfish or the common pleco, is a tropical freshwater fish belonging to the armored catfish family (Loricariidae), named for the longitudinal rows of armor-like scutes that cover the upp ...
'') was one of the first loricariid species imported for the fish-keeping hobby. Some loricariids are not normally considered "plecostomus", such as ''
Farlowella ''Farlowella'' is a genus of fish in the family Loricariidae native to South America. This genus is broadly distributed in Amazon, Orinoco, Paraná and coastal rivers of the Guyana Shield. It is absent from the Pacific slope of the Andes and fro ...
'' catfish. In their native
range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...
, these fish are known as ''cascudos'' or ''acarís''.


L-numbers

Some types of loricariids are often referred to by their '
L-number The L-number system is a semi-scientific classification system of catfish based on photographs of shipments of tropical catfish of the family Loricariidae published by the German aquarium magazine DATZ (Die Aquarien- und Terrarienzeitschrift (The ...
'; this has become common since imports of loricariid catfish from South America often included specimens that had not been taxonomically described. Currently, L-numbers are used not only by fish-keeping enthusiasts, but also by biologists, since they represent a useful stopgap until a new species of fish is given a full taxonomic name. In some cases, two different L-numbered catfish have turned out to be different populations of the same species, while in other cases, multiple (but superficially similar) species have all been traded under a single L-number.


Taxonomy and evolution

Because of their highly specialized morphology, loricariids have been recognized as a
monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
assemblage in even the earliest classifications of the Siluriformes, meaning they consist of a natural grouping with a common ancestor and all of its descendants. Loricariidae is one of seven families in the superfamily
Loricarioidea Loricarioidea is a superfamily of catfishes ( order Siluriformes). It contains the six families Trichomycteridae, Nematogenyiidae, Callichthyidae, Scoloplacidae, Astroblepidae, and Loricariidae. Some schemes also include Amphiliidae. This s ...
, along with Amphiliidae,
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 hum ...
, Nematogenyidae,
Callichthyidae Callichthyidae is a family of catfishes (order Siluriformes), called armored catfishes due to the two rows of bony plates (or scutes) along the lengths of their bodies. It contains some of the most popular freshwater aquarium fish, such as many ...
,
Scoloplacidae ''Scoloplax'' is the only genus in the catfish (order Siluriformes) family Scoloplacidae, the spiny dwarf catfishes. Species The six currently recognized species in this genus are: * ''Scoloplax baileyi'' Rocha, Lazzarotto & Rapp Py-Daniel, ...
, and
Astroblepidae ''Astroblepus'' is a genus of fish in the family Astroblepidae found in South America and Panama. This genus is the only member of its family. These catfishes are primarily found in torrential streams in the Andean area. ''Astroblepus pholeter'' ...
. Some of these families also exhibit suckermouths or armor, although never in the same individual, as in loricariids. This is the largest
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, ...
family, including about 684 species in around 92 genera, with new species being described each year. However, this family is in flux, and revisions are likely. For example, the subfamily Ancistrinae is accepted as late as the 2006 edition of Nelson's ''
Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...
''; it later becomes grouped as a tribe, because of its recognition as a sister group to the Pterygoplichthyini. Under Ambruster, six subfamilies are recognized:
Delturinae The Delturinae are a subfamily of catfishes (order Siluriformes) of the family Loricariidae, including two genera, ''Delturus'' and ''Hemipsilichthys''. This group is sister to all other loricariids except ''Lithogenes''. The geographical distrib ...
,
Hypoptopomatinae The Hypoptopomatinae are a subfamily of catfishes (order Siluriformes) of the family Loricariidae, composed of 17 genus, genera and approximately 80 species. This subfamily represents about one-tenth of all loricariid species. It has been divide ...
,
Hypostominae The Hypostominae are a subfamily of catfishes of the family Loricariidae. Most members are restricted to tropical and subtropical South America, but there are also several species (in genera ''Ancistrus'', '' Chaetostoma'', ''Lasiancistrus'', '' ...
,
Lithogeneinae ''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 ...
,
Loricariinae Loricariinae is a subfamily of the family Loricariidae of catfish (order Siluriformes). This subfamily is divided into two tribe (biology), tribes and about 30 genus, genera. They are mainly native to freshwater habitats in South America, but the ...
, and
Neoplecostominae Neoplecostominae is a subfamily of South American catfishes of the family Loricariidae. Species of this subfamily live in high-mountain and swift-flowing river habitats. Taxonomy This subfamily is the most basal clade in Loricariidae with the ...
. Monophyly for the family is strongly supported, except, possibly, the inclusion of ''
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 ...
''. ''Lithogenes'' is the only genus within the subfamily Lithogeneinae. This genus and subfamily, the most basal group in Loricariidae, is the sister group to the rest of the family. Neoplecostominae are the most basal group among the loricariids with the exception of Lithogeneinae. However, the genera of Neoplecostominae do not appear to form a monophyletic assemblage. The two subfamilies Loricariinae and Hypoptopomatinae appear to be generally regarded as monophyletic. However, the monophyly and composition of the other subfamilies are currently being examined and will likely be altered substantially in the future. The Hypostominae are the largest subfamily of Loricariidae. It is made up of five
tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...
s. Four of the five tribes, Corymbophanini,
Hypostomini ''Hypostomus'' is a genus of catfish in the family Loricariidae. They are native to tropical and subtropical South America. '' H. plecostomus'' is the popular freshwater aquarium fish formerly known as ''Plecostomus plecostomus''. The taxonomic ...
,
Pterygoplichthyini Pterygoplichthyini is a tribe of catfishes ( order Siluriformes) of the family Loricariidae. It includes two genera, ''Pterygoplichthys'' and the currently undescribed genus referred to as the ''Hemiancistrus annectens'' group, This group was ea ...
, and
Rhinelepini Rhinelepini is a tribe of fishes in the subfamily Hypostominae of the armored suckermouth catfish family Loricariidae. Taxonomy This tribe is a well diagnosed monophyletic group currently containing three genera: '' Pogonopoma'', '' Pseudorin ...
, include about 24 genera. The fifth and largest tribe,
Ancistrini Ancistrini is a tribe of catfishes of the family Loricariidae. Most are restricted to tropical and subtropical South America, but there are also several genus (''Ancistrus'', '' Chaetostoma'', ''Hemiancistrus'' and ''Lasiancistrus'') in southern ...
(formerly recognized as its own subfamily), includes 30 genera. Loricariid
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s are extremely rare. The
fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
of Loricariidae extends back to the upper
Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
. Within the superfamily
Loricarioidea Loricarioidea is a superfamily of catfishes ( order Siluriformes). It contains the six families Trichomycteridae, Nematogenyiidae, Callichthyidae, Scoloplacidae, Astroblepidae, and Loricariidae. Some schemes also include Amphiliidae. This s ...
, the Loricariidae are the most
derived Derive may refer to: * Derive (computer algebra system), a commercial system made by Texas Instruments * ''Dérive'' (magazine), an Austrian science magazine on urbanism *Dérive, a psychogeographical concept See also * *Derivation (disambiguatio ...
; in this superfamily, the trend is toward increasingly complex jaw morphology, which may have allowed for the great diversification of the Loricariidae, which have the most advanced jaws.


Distribution and habitat

The family Loricariidae is vastly distributed over both the east and west sides of the
Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...
mountains, however, most species are generally restricted to small geographic ranges. They are primarily found in
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
habitats of
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, but several loricariines and hypostomines are native to
Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...
, and two species ('' Fonchiiichthys uracanthus'' and ''
Hemiancistrus ''Hemiancistrus'' is a genus of suckermouth armored catfishes. These species are native to South America. The taxonomy of this genus is complex and unclear, and major work has to be done. Many of these fish are popular aquarium fish. Taxonomy ...
aspidolepis'') are native to
Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
. Species occur in swift-flowing streams from the lowlands up to in elevation. They can also be found in a variety of other freshwater environments. They can be found in torrential mountain rivers, quiet brackish estuaries, black acidic waters, and even in subterranean habitats.


Description and biology

This family has extremely variable color patterns and body shapes. Loricariids are characterized by bony plates covering their bodies, similar to the bony plates in callichthyids. (In
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
, ''lorica'' means
corselet In women's clothing, a corselet or corselette is a type of foundation garment, sharing elements of both bras and girdles. It extends from straps over the shoulders down the torso, and stops around the top of the legs. It may incorporate lace in ...
). These fish exhibit a
ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...
suckermouth, with
papilla Papilla (Latin, 'nipple') or papillae may refer to: In animals * Papilla (fish anatomy), in the mouth of fish * Basilar papilla, a sensory organ of lizards, amphibians and fish * Dental papilla, in a developing tooth * Dermal papillae, part of ...
e (small projections) on the lips. When present, the
adipose fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
usually has a spine at the forward edge. These fish have, when they are present, a unique pair of maxillary barbels. These fish have relatively long intestines due to their usually
herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
or detrivorous diets. The body is characteristically flattened in this family.
Taste bud Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as lingual papillae, papillae found on the upper surface of the tongue, soft palate, upper e ...
s cover almost the entire surface of the body and fin spines. Body lengths can range from in '' Nannoplecostomus eleonorae'' to over in ''
Panaque The genus ''Panaque'' contains a small number of small to medium-sized South American suckermouth armoured catfishes that are notable for being among the very few vertebrates that feed extensively on wood. In addition, algae and aufwuchs are a ...
'', '' Acanthicus'', and ''
Pterygoplichthys ''Pterygoplichthys'', sometimes collectively known as janitor fish, is a genus of South American armored catfishes. These fish are commonly known as sailfin armoured catfish or sailfin plecs, especially in the aquarium trade. Etymology ''Pte ...
''. One of the most obvious characteristics of the loricariids is the
suckermouth In fish, a suckermouth is a ventrally-oriented (inferior) mouth adapted for grazing on algae and small organisms that grow on submerged objects. All Loricariidae possess a suckermouth as do the cypriniform algae eaters of the genus ''Gyrinocheilus' ...
. The modified mouth and lips allow the fish to feed, breathe, and attach to the substrate through suction. The lips were once believed to be unable to function as a sucker while respiration continued, as the inflowing water would cause the system to fail; however, respiration and suction can function simultaneously. Inflowing water passing under the sucker is limited to a thin stream immediately behind each maxillary barbel; the
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
e in loricariids support only small maxillary barbels and are primarily used to mediate the lateral lip tissue in which they are embedded, preventing failure of suction during inspiration. To achieve suction, the fish presses its lips against the substrate and expands its oral cavity, causing negative pressure. Also, unlike most other catfishes, the
premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...
e are highly mobile, and the lower jaws have evolved towards a medial position, with the teeth pointed rostroventrally; these are important evolutionary innovations. The fish rotates its lower and upper jaws to scrape the substrate. Of the two, the lower jaws are more mobile. Loricariid catfishes have evolved several modifications of their digestive tracts that function as accessory respiratory organs or
hydrostatic Fluid statics or hydrostatics is the branch of fluid mechanics that studies the condition of the equilibrium of a floating body and submerged body "fluids at hydrostatic equilibrium and the pressure in a fluid, or exerted by a fluid, on an imme ...
organs. These complex structures would have been independently evolved a number of times within the family. This includes an enlarged stomach in the Pterygoplichthyini, ''Hypostomus'', and ''
Lithoxus ''Lithoxus'' is a genus of suckermouth armored catfishes native to tropical South America. Taxonomy ''Lithoxus'' is supported as a monophyletic sister to '' Exastilithoxus''. Together, these two genera form a well-supported clade. Species ...
'', a U-shaped diverticulum in Rhinelepini, and a ring-like diverticulum in ''
Otocinclus ''Otocinclus'' is a genus of catfish in the family Loricariidae native to South America, commonly known as "dwarf suckers" or "otos". This genus, like other loricariids, is characterized by rows of armour plating covering the body, as well as the ...
''. It may be noted that even loricariids with unmodified stomachs have a slight ability to breathe air. Considerable
sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
occurs in this family, most pronounced during the breeding season. For example, in ''
Loricariichthys ''Loricariichthys'' is a genus of catfishes ( order Siluriformes) of the family Loricariidae. Taxonomy This genus is part of the ''Loricariichthys'' group within the subfamily Loricariinae; this group also includes the genera '' Furcodontichthy ...
'', the male has a large expansion of its lower lip, which it uses to hold a clutch of eggs. ''
Ancistrus ''Ancistrus'' is a genus of nocturnal freshwater fish in the family Loricariidae of order Siluriformes, native to freshwater habitats in South America and Panama. Fish of this genus are common in the aquarium trade where they are known as bushyn ...
'' males have snouts with fleshy tentacles. In loricariids,
odontode Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to th ...
s develop almost anywhere on the external surface of the body and first appear soon after hatching; odontodes appear in a variety of shapes and sizes and are often sexually dimorphic, being larger in breeding males. In most
Ancistrini Ancistrini is a tribe of catfishes of the family Loricariidae. Most are restricted to tropical and subtropical South America, but there are also several genus (''Ancistrus'', '' Chaetostoma'', ''Hemiancistrus'' and ''Lasiancistrus'') in southern ...
species, sharp evertible cheek spines (elongated odontodes) are often more developed in males and are used in intraspecific displays and combat.


Omega iris

Unusual for
bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilag ...
, many species have a modified
iris Iris most often refers to: *Iris (anatomy), part of the eye *Iris (mythology), a Greek goddess * ''Iris'' (plant), a genus of flowering plants * Iris (color), an ambiguous color term Iris or IRIS may also refer to: Arts and media Fictional ent ...
called an omega iris. The dorsal segment of the iris expands downward over the pupil to form a loop which can expand and contract, called an iris operculum; when light levels are high, the pupil reduces in diameter and the loop expands to cover the center of the pupil, giving rise to a
crescent A crescent shape (, ) is a symbol or emblem used to represent the lunar phase in the first quarter (the "sickle moon"), or by extension a symbol representing the Moon itself. In Hinduism, Lord Shiva is often shown wearing a crescent moon on his ...
-shaped, light-transmitting partial pupil. This feature gets its name from its similarity to an upside-down uppercase
Greek letter The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BCE. It is derived from the earlier Phoenician alphabet, and was the earliest known alphabetic script to have distinct letters for vowels as w ...
omega Omega (; capital: Ω, lowercase: ω; Ancient Greek ὦ, later ὦ μέγα, Modern Greek ωμέγα) is the twenty-fourth and final letter in the Greek alphabet. In the Greek numeric system/isopsephy (gematria), it has a value of 800. The wo ...
(Ω). The origins of this structure are unknown, but breaking up the outline of the highly visible eye has been suggested to aid
camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...
in what are often highly mottled animals. Species in the tribe
Rhinelepini Rhinelepini is a tribe of fishes in the subfamily Hypostominae of the armored suckermouth catfish family Loricariidae. Taxonomy This tribe is a well diagnosed monophyletic group currently containing three genera: '' Pogonopoma'', '' Pseudorin ...
are an exceptional group among loricariids, having a circular iris. The presence or absence of the iris operculum can be used for identification of species in the subfamily
Loricariinae Loricariinae is a subfamily of the family Loricariidae of catfish (order Siluriformes). This subfamily is divided into two tribe (biology), tribes and about 30 genus, genera. They are mainly native to freshwater habitats in South America, but the ...
.


Genetics

As of 2000, only 56 loricariid species have been cytogenically investigated. The basal
diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...
number of
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s is 2n = 54 in this family, but with a wide variation in the chromosome number in this fish group, ranging from 2n = 36 in the
Loricariinae Loricariinae is a subfamily of the family Loricariidae of catfish (order Siluriformes). This subfamily is divided into two tribe (biology), tribes and about 30 genus, genera. They are mainly native to freshwater habitats in South America, but the ...
, '' Rineloricaria latirostris'', to 2n = 96 in a species of ''Upsilodus'' (''
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 ...
''). Most members of the Ancistrini and Pterygoplichthyini have 52 chromosomes. Karyotypic evolution by means of centric fusions and centric fissions seems to be a common feature among loricariids; this is demonstrated by a higher number of biarmed chromosomes in species with lower diploid number and many uniarmed chromosomes in species with higher diploid numbers. Studies conducted with representatives of some genera of Hypostominae showed, within this group, the
diploid number Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...
ranges from 2n = 52 to 2n = 80. However, the supposed wide karyotypic diversity the family Loricariidae or the subfamily Hypostominae would present is almost exclusively restricted to the genus ''
Hypostomus ''Hypostomus'' is a genus of catfish in the family Loricariidae. They are native to tropical and subtropical South America. '' H. plecostomus'' is the popular freshwater aquarium fish formerly known as ''Plecostomus plecostomus''. The taxonomic ...
'', and the species from the other genera had a conserved diploid number. In some species, there is a ZZ/ZW
sex-determination system A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most organisms that create their offspring using sexual reproduction have two sexes. In some species there are hermap ...
.


Ecology

The suckermouth exhibited by these catfish allows them to adhere to objects in their habitats, even in fast-flowing waters. The mouth and teeth also are adapted to feed on a variety of foods, such as
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
,
invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s, and
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
. Some species, notably the ''
Panaque The genus ''Panaque'' contains a small number of small to medium-sized South American suckermouth armoured catfishes that are notable for being among the very few vertebrates that feed extensively on wood. In addition, algae and aufwuchs are a ...
'', are known for
xylophagy Xylophagy is a term used in ecology to describe the habits of an herbivorous animal whose diet consists primarily (often solely) of wood. The word derives from Greek ''ξυλοφάγος'' (''xulophagos'') "eating wood", from ''ξύλον'' (') ...
, or the ability to digest
wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...
. Most species of loricariids are
nocturnal animal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...
s. Some species are
territorial A territory is an area of land, sea, or space, particularly belonging or connected to a country, person, or animal. In international politics, a territory is usually either the total area from which a state may extract power resources or a ...
, while others, such as ''
Otocinclus ''Otocinclus'' is a genus of catfish in the family Loricariidae native to South America, commonly known as "dwarf suckers" or "otos". This genus, like other loricariids, is characterized by rows of armour plating covering the body, as well as the ...
'', prefer to live in groups. Air-breathing is well known among many loricariids; this ability is dependent on the risk of hypoxia faced by a species; torrent-dwelling species tend to have no ability to breathe air, while low-land, pool-dwelling species, such as those of ''Hypostomus'', have a great ability to breathe air. ''Pterygoplichthys'' is known for being kept out of water and sold alive in fish markets, surviving up to 30 hours out of water. Loricariids are facultative air breathers; they will only breathe air if under stress and will only use their gills in situations when oxygen levels are high. The dry season is a likely time for this; there would be little food in the stomach, which would allow its use for air breathing. Loricariids exhibit a wide range of reproductive strategies, including cavity spawning, attachment of eggs on the underside of rocks, and egg-carrying. Parental care is usually good, and the male guards the eggs and sometimes the larvae. The eggs hatch after four to 20 days, depending on the species. Three species known from subterranean habitats are true
troglobites A troglobite (or, formally, troglobiont) is an animal species, or population of a species, strictly bound to underground habitats, such as caves. These are separate from species that mainly live in above-ground habitats but are also able to live u ...
with reduced
pigmentation A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compoun ...
(appearing overall whitish) and eyes: ''
Ancistrus ''Ancistrus'' is a genus of nocturnal freshwater fish in the family Loricariidae of order Siluriformes, native to freshwater habitats in South America and Panama. Fish of this genus are common in the aquarium trade where they are known as bushyn ...
cryptophthalmus'', ''A. galani'' and ''A. formoso''. Similar adaptions with reduced pigmentation are known from two loricariids found in deep water in large Amazonian rivers, '' Peckoltia pankimpuju'' and '' Panaque bathyphilus''.Lujan, N.K., and C. Chamon (2008). ''Two new species of Loricariidae (Teleostei: Siluriformes) from main channels of the upper and middle Amazon Basin, with discussion of deep water specialization in loricariids. Ichthyological Exploration of Freshwaters. 19: 271–282.''


In the aquarium

Loricariids are popular
aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...
fish, where they are often sold as "plecs", "plecos" or "plecostomus". These fish are often purchased because of their algae-eating habits, though this role may not be carried out. Loricariid are either
vegetarian Vegetarianism is the practice of abstaining from the consumption of meat (red meat, poultry, seafood, insects, and the flesh of any other animal). It may also include abstaining from eating all by-products of animal slaughter. Vegetarianism m ...
,
omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...
,
carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
or wood-eaters. A great many species of loricariids are also sold for their ornamental qualities, representing many body shapes and colors. Most species of loricariids are nocturnal and will shy away from bright light, appreciating some sort of cover to hide under throughout the day. As they often originate from habitats with fast-moving water, filtration should be vigorous. A number of species of loricariids have been bred in captivity.


References


External links


THE LORICARIIDAE by Dr. Jonathan Armbruster
- useful website including a taxonomic key.
Planet Catfish
Catalogue of loricariid catfishes
Plecostomus.org
{{Authority control Fish of South America Extant Miocene first appearances Catfish families Taxa named by Constantine Samuel Rafinesque