Loricariidae
Template:Short description Template:Automatic taxobox
Loricariidae is the largest family of catfish (order Siluriformes), with over 90 genera and just over 680 species.<ref name="Nelson"/> Loricariids originate from freshwater habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and their suckermouths. Several genera are sold as "plecos", notably the suckermouth catfish, Hypostomus plecostomus, and are popular as aquarium fish.
Common namesEdit
Members of the family Loricariidae are commonly referred to as loricariids, suckermouth catfishes, armoured catfish, or suckermouth armoured catfish.<ref name="Nelson">Template:Cite book</ref> The name "plecostomus", and its shortened forms "pleco" and "plec", are used for many Loricariidae, since Plecostomus plecostomus (now called Hypostomus plecostomus) was one of the first loricariid species imported for the fish-keeping hobby.<ref name=Fenner/>
Some loricariids are not normally considered "plecostomus", such as Farlowella catfish.
In their native range, these fish are known as cascudos or acarís.<ref name="Oliveira">Template:Cite journal</ref>
L-numbersEdit
{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Some types of loricariids are often referred to by their 'L-number'; 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.<ref name="lnumber">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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. Template:Citation needed
Taxonomy and evolutionEdit
Because of their highly specialized morphology, loricariids have been recognized as a monophyletic 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.<ref name=loricariinae>Template:Cite journal</ref> Loricariidae is one of seven families in the superfamily Loricarioidea, along with Amphiliidae, Trichomycteridae, Nematogenyidae, Callichthyidae, Scoloplacidae, and Astroblepidae. Some of these families also exhibit suckermouths or armor, although never in the same individual, as in loricariids.<ref name="Nelson"/>
This is the largest catfish family, including about 684 species in around 92 genera, with new species being described each year.<ref name="Nelson"/> However, this family is in flux, and revisions are likely.<ref name="Nelson"/> For example, the subfamily Ancistrinae is accepted as late as the 2006 edition of Nelson's Fishes of the World; it later becomes grouped as a tribe, because of its recognition as a sister group to the Pterygoplichthyini.<ref name="Nelson"/><ref name="Oliveira"/><ref name="Armbruster">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Under Ambruster, six subfamilies are recognized: Delturinae, Hypoptopomatinae, Hypostominae, Lithogeneinae, Loricariinae, and Neoplecostominae.<ref name="Armbruster"/><ref name=delturinae>Template:Cite journal</ref>
Monophyly for the family is strongly supported, except, possibly, the inclusion of Lithogenes.<ref name="ferraris">Template:Cite journal</ref> 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.<ref name="Schaefer2003">Template:Cite journal</ref> Neoplecostominae are the most basal group among the loricariids with the exception of Lithogeneinae.<ref name="Alves"/> However, the genera of Neoplecostominae do not appear to form a monophyletic assemblage.<ref name="Pereira">Template:Cite journal</ref> 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.<ref name="ferraris"/> The Hypostominae are the largest subfamily of Loricariidae. It is made up of five tribes. Four of the five tribes, Corymbophanini, Hypostomini, Pterygoplichthyini, and Rhinelepini, include about 24 genera. The fifth and largest tribe, Ancistrini (formerly recognized as its own subfamily), includes 30 genera.<ref name=guahiborum>Template:Cite journal</ref>
Loricariid fossils are extremely rare. The earliest known definitive taxon is Taubateia from the Late Oligocene-Early Miocene in Brazil.<ref name="Malabarba">Template:Cite journal</ref> The putative Cenomanian member Afrocascudo, initially described as the earliest loricariid catfish in 2024,<ref name=Afrocascudo/> might represent a juvenile obaichthyid lepisosteiform, possibly a junior synonym of Obaichthys,<ref>Template:Cite journal</ref> though this has been disputed based on the complete ossification of the bones indicating full maturity and the absence of important holostean characters.<ref>Template:Cite journal</ref> Within the superfamily Loricarioidea, the Loricariidae are the most derived; 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.<ref name="Schaefer1986">Template:Cite journal</ref>
Distribution and habitatEdit
The family Loricariidae is vastly distributed over both the east and west sides of the Andes mountains, however, most species are generally restricted to small geographic ranges.<ref name=pogonopoma>Template:Cite journal</ref> They are primarily found in freshwater habitats of South America, but several loricariines and hypostomines are native to Panama, and two species (Fonchiiichthys uracanthus and Hemiancistrus aspidolepis) are native to Costa Rica.<ref>Template:Cite journal</ref> Species occur in swift-flowing streams from the lowlands up to Template:Convert in elevation.<ref name=Nelson/> They can also be found in a variety of other freshwater environments.<ref name="Fenner"/> They can be found in torrential mountain rivers, quiet brackish estuaries, black acidic waters, and even in subterranean habitats.<ref name=loricariinae/>
Description and biologyEdit
This family has extremely variable color patterns and body shapes.<ref name=loricariinae/> Loricariids are characterized by bony plates covering their bodies, similar to the bony plates in callichthyids. (In Latin, lorica means corselet).<ref name=FishBase>{{#invoke:Cite taxon|main|fishbase|genus=|species=|subspecies=}}</ref> These fish exhibit a ventral suckermouth, with papillae (small projections) on the lips. When present, the adipose fin usually has a spine at the forward edge.<ref name="Nelson"/> These fish have, when they are present, a unique pair of maxillary barbels.<ref name="Nelson"/><ref name=loricariinae/> These fish have relatively long intestines due to their usually herbivorous or detrivorous diets.<ref name="Nelson"/> The body is characteristically flattened in this family.<ref name=loricariinae/> Taste buds cover almost the entire surface of the body and fin spines.<ref name="Sabaj"/> Body lengths can range from Template:Convert in Nannoplecostomus eleonorae to over Template:Convert in Panaque, Acanthicus, and Pterygoplichthys.<ref name=pogonopoma/>
One of the most obvious characteristics of the loricariids is the suckermouth. 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 maxillae 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 inspirationTemplate:Vague. To achieve suction, the fish presses its lips against the substrate and expands its oral cavity, causing negative pressure.<ref name="Geerinckx">Template:Cite journal</ref>
Also, unlike most other catfishes, the premaxillae are highly mobile, and the lower jaws have evolved towards a medial position, with the teeth pointed rostroventrally; these are important evolutionary innovations.<ref name="Schaefer1986"/> The fish rotates its lower and upper jaws to scrape the substrate. Of the two, the lower jaws are more mobile.<ref name="Geerinckx"/>
Loricariid catfishes have evolved several modifications of their digestive tracts that function as accessory respiratory organs or hydrostatic 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, a U-shaped diverticulum in Rhinelepini, and a ring-like diverticulum in Otocinclus. It may be noted that even loricariids with unmodified stomachs have a slight ability to breathe air.<ref name="Armbruster1998">Template:Cite journal</ref>
Considerable sexual dimorphism occurs in this family, most pronounced during the breeding season. For example, in Loricariichthys, the male has a large expansion of its lower lip, which it uses to hold a clutch of eggs.<ref name="Sabaj"/> Ancistrus males have snouts with fleshy tentacles.<ref name="Sabaj"/> In loricariids, odontodes 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.<ref name="Sabaj"/> In most Ancistrini species, sharp evertible cheek spines (elongated odontodes) are often more developed in males and are used in intraspecific displays and combat.<ref name="Sabaj"/>
Omega irisEdit
Unusual for bony fish, many species have a modified iris 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-shaped, light-transmitting partial pupil.<ref name="Douglas"/> This feature gets its name from its similarity to an upside-down uppercase Greek letter omega (Ω). The origins of this structure are unknown, but breaking up the outline of the highly visible eye has been suggested to aid camouflage in what are often highly mottled animals.<ref name="Douglas">Template:Cite journal</ref> Species in the tribe Rhinelepini are an exceptional group among loricariids, having a circular iris.<ref name=rhinelepini>Template:Cite journal</ref> The presence or absence of the iris operculum can be used for identification of species in the subfamily Loricariinae.<ref name=loricariinae/>
GeneticsEdit
As of 2000, only 56 loricariid species have been cytogenically investigated.<ref name="Oliveira"/> The basal diploid number of chromosomes is 2n = 54 in this family,<ref name="Artoni">Template:Cite journal</ref> but with a wide variation in the chromosome number in this fish group, ranging from 2n = 36 in the Loricariinae, Rineloricaria latirostris, to 2n = 96 in a species of Upsilodus (Hemipsilichthys).<ref name="Artoni"/> Most members of the Ancistrini and Pterygoplichthyini have 52 chromosomes.<ref name="Oliveira"/> 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.<ref name="Kavalco">Template:Cite journal</ref> Studies conducted with representatives of some genera of Hypostominae showed, within this group, the diploid number 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, and the species from the other genera had a conserved diploid number.<ref name="Alves">Template:Cite journal</ref> In some species, there is a ZZ/ZW sex-determination system.<ref name="Oliveira"/><ref name="Kavalco"/>
EcologyEdit
The suckermouth exhibited by these catfish allows them to adhere to objects in their habitats, even in fast-flowing waters.<ref name=loricariinae/> The mouth and teeth also are adapted to feed on a variety of foods, such as algae, invertebrates, and detritus.<ref name=loricariinae/> Some species, notably the Panaque, are known for xylophagy, or the ability to digest wood.<ref name=wood>Template:Cite journal</ref>
Most species of loricariids are nocturnal animals. Some species are territorial, while others, such as Otocinclus, prefer to live in groups.<ref name="Fenner"/>
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.<ref name="Armbruster1998"/> Pterygoplichthys is known for being kept out of water and sold alive in fish markets, surviving up to 30 hours out of water.<ref name="Armbruster1998"/> 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.<ref name="Armbruster1998"/>
Loricariids exhibit a wide range of reproductive strategies, including cavity spawning, attachment of eggs on the underside of rocks, and egg-carrying.<ref name="Sabaj">Template:Cite journal</ref> Parental care is usually good, and the male guards the eggs and sometimes the larvae.<ref name="Sabaj"/> The eggs hatch after four to 20 days, depending on the species.<ref name="Fenner"/>
Three species known from subterranean habitats are true troglobites with reduced pigmentation (appearing overall whitish) and eyes: Ancistrus cryptophthalmus, A. galani and A. formoso.<ref>Romero, A., editor (2001). The Biology of Hypogean Fishes. Developments in Environmental Biology of Fishes. Template:ISBN</ref><ref>Sabino, J., and E. Trajano (1997). A new species of blind armoured catfish, genus "Ancistrus", from caves of Bodoquena region, Mato Grosso do Sul, southwestern Brazil (Siluriformes, Loricariidae, Ancistrinae). Revue française d'Aquariologie Herpétologie 24(3-4): 73–78</ref><ref>Template:Multiref2</ref> Similar adaptions with reduced pigmentation are known from two loricariids found in deep water in large Amazonian rivers, Peckoltia pankimpuju and Panaque bathyphilus.<ref>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.</ref>
In the aquariumEdit
Loricariids are popular aquarium fish, where they are often sold as "plecs", "plecos" or "plecostomus".<ref name="Nelson"/> These fish are often purchased because of their algae-eating habits, though this role may not be carried out.<ref name="Fenner">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Loricariid are either vegetarian, omnivore, carnivore or wood-eaters.<ref name="Planetcatfish1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name="Fenner"/>
A number of species of loricariids have been bred in captivity.<ref name="Fenner"/>
ReferencesEdit
External linksEdit
Template:Sister project Template:Sister project
- THE LORICARIIDAE by Dr. Jonathan Armbruster - useful website including a taxonomic key.
- Planet Catfish Catalogue of loricariid catfishes
- All Catfish Species Inventory page for Loricariidae
- Plecostomus.org