78-614: Genus † Afrocascudo ? Delturinae Hypoptopomatinae Hypostominae Lithogeneinae Loricariinae Neoplecostominae Otothyrinae (sometimes included in Hypoptopomatinae) Genus Nannoplecostomus ( incertae sedis ) Loricariidae is the largest family of catfish (order Siluriformes), with over 90 genera and just over 680 species . Loricariids originate from freshwater habitats of Costa Rica , Panama , and tropical and subtropical South America . These fish are noted for
156-455: A rebuttal paper, acknowledging that their reconstruction took artistic liberties, proposing a possible in-life appearance for the species. They further admitted to small errors in the original study, specifically in the phylogenetic matrix and one of the figures from the supplementary data. They also concurred with Britz et al. that features of the caudal endoskeleton are not easily distinguishable. Still, they criticized Britz et al. for proposing
234-563: A sister group to the Pterygoplichthyini. Under Ambruster, six subfamilies are recognized: Delturinae , Hypoptopomatinae , Hypostominae , Lithogeneinae , Loricariinae , and Neoplecostominae . Monophyly for the family is strongly supported, except, possibly, the inclusion of Lithogenes . Lithogenes is the only genus within the subfamily Lithogeneinae. This genus and subfamily, the most basal group in Loricariidae,
312-580: 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. 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
390-421: A book published in 1950, cladistics did not flourish until its translation into English in 1966 (Lewin 1997). Today, cladistics is the most popular method for inferring phylogenetic trees from morphological data. In the 1990s, the development of effective polymerase chain reaction techniques allowed the application of cladistic methods to biochemical and molecular genetic traits of organisms, vastly expanding
468-413: A cladistic analysis is a cladogram – a tree -shaped diagram ( dendrogram ) that is interpreted to represent the best hypothesis of phylogenetic relationships. Although traditionally such cladograms were generated largely on the basis of morphological characters and originally calculated by hand, genetic sequencing data and computational phylogenetics are now commonly used in phylogenetic analyses, and
546-525: A clutch of eggs. Ancistrus males have snouts with fleshy tentacles. 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. In most Ancistrini species, sharp evertible cheek spines (elongated odontodes) are often more developed in males and are used in intraspecific displays and combat. Unusual for bony fish , many species have
624-422: A coarse impression of the complexity. A more detailed account will give details about fractions of introgressions between groupings, and even geographic variations thereof. This has been used as an argument for the use of paraphyletic groupings, but typically other reasons are quoted. Horizontal gene transfer is the mobility of genetic info between different organisms that can have immediate or delayed effects for
702-474: 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
780-460: A hypothesis, a clade can be rejected only if some groupings were explicitly excluded. It may then be found that the excluded group did actually descend from the last common ancestor of the group, and thus emerged within the group. ("Evolved from" is misleading, because in cladistics all descendants stay in the ancestral group). To keep only valid clades, upon finding that the group is paraphyletic this way, either such excluded groups should be granted to
858-489: A large number and variety of different kinds of characters are viewed as more robust than those based on more limited evidence. Mono-, para- and polyphyletic taxa can be understood based on the shape of the tree (as done above), as well as based on their character states. These are compared in the table below. Cladistics, either generally or in specific applications, has been criticized from its beginnings. Decisions as to whether particular character states are homologous ,
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#1732788021991936-473: A lot of possible trees. Assigning names to each possible clade may not be prudent. Furthermore, established names are discarded in cladistics, or alternatively carry connotations which may no longer hold, such as when additional groups are found to have emerged in them. Naming changes are the direct result of changes in the recognition of mutual relationships, which often is still in flux, especially for extinct species. Hanging on to older naming and/or connotations
1014-523: 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. 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
1092-628: A nearly complete fish collected in three pieces. It is missing parts of the head and fins. In 2024, Brito et al. described Afrocascudo saharaensis as a new genus and species of loricariid catfishes based on these fossil remains. The generic name , Afrocascudo , combines the Latin word "Afro", meaning "Africa", with the Portuguese "cascudo", the common name used in Brazil for certain armoured catfishes. The specific name , saharaensis , references
1170-475: A particular method. Datasets are tables consisting of molecular , morphological, ethological and/or other characters and a list of operational taxonomic units (OTUs), which may be genes, individuals, populations, species, or larger taxa that are presumed to be monophyletic and therefore to form, all together, one large clade; phylogenetic analysis infers the branching pattern within that clade. Different datasets and different methods, not to mention violations of
1248-720: A particular set of methods used in phylogenetic analysis, although it is now sometimes used to refer to the whole field. What is now called the cladistic method appeared as early as 1901 with a work by Peter Chalmers Mitchell for birds and subsequently by Robert John Tillyard (for insects) in 1921, and W. Zimmermann (for plants) in 1943. The term " clade " was introduced in 1958 by Julian Huxley after having been coined by Lucien Cuénot in 1940, "cladogenesis" in 1958, "cladistic" by Arthur Cain and Harrison in 1960, "cladist" (for an adherent of Hennig's school) by Ernst Mayr in 1965, and "cladistics" in 1966. Hennig referred to his own approach as "phylogenetic systematics". From
1326-457: A period, many branches may have radiated, and it may take hundreds of millions of years for them to have whittled down to just two. Only then one can theoretically assign proper last common ancestors of groupings which do not inadvertently include earlier branches. The process of true cladistic bifurcation can thus take a much more extended time than one is usually aware of. In practice, for recent radiations, cladistically guided findings only give
1404-444: A phylogenetic tree are used to justify decisions about character states, which are then used as evidence for the shape of the tree. Phylogenetics uses various forms of parsimony to decide such questions; the conclusions reached often depend on the dataset and the methods. Such is the nature of empirical science, and for this reason, most cladists refer to their cladograms as hypotheses of relationship. Cladograms that are supported by
1482-553: A powerful way to test hypotheses about cross-cultural relationships among folktales. Literature : Cladistic methods have been used in the classification of the surviving manuscripts of the Canterbury Tales , and the manuscripts of the Sanskrit Charaka Samhita . Historical linguistics : Cladistic methods have been used to reconstruct the phylogeny of languages using linguistic features. This
1560-400: A precondition of their being synapomorphies, have been challenged as involving circular reasoning and subjective judgements. Of course, the potential unreliability of evidence is a problem for any systematic method, or for that matter, for any empirical scientific endeavor at all. Transformed cladistics arose in the late 1970s in an attempt to resolve some of these problems by removing
1638-406: A priori assumptions about phylogeny from cladistic analysis, but it has remained unpopular. The cladistic method does not identify fossil species as actual ancestors of a clade. Instead, fossil taxa are identified as belonging to separate extinct branches. While a fossil species could be the actual ancestor of a clade, there is no way to know that. Therefore, a more conservative hypothesis is that
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#17327880219911716-401: A side-branch, not distinguishing whether an actual ancestor of other groupings was found. The techniques and nomenclature of cladistics have been applied to disciplines other than biology. (See phylogenetic nomenclature .) Cladistics findings are posing a difficulty for taxonomy , where the rank and (genus-)naming of established groupings may turn out to be inconsistent. Cladistics is now
1794-425: A taxonomic status change of Afrocascudo on the basis of simple comparisons without testing hypothesis (i.e. reproducing 3D renderings), and considered the interpretation of the taxon as a juvenile lepisosteiform or a holostean unlikely. In their rebuttal, Brito et al. further claimed that Afrocascudo could not be a juvenile since the type specimen is completely ossified, an indicator for maturity. They also noted
1872-425: 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. Because of their highly specialized morphology, loricariids have been recognized as a monophyletic assemblage in even
1950-1218: 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 with reduced pigmentation (appearing overall whitish) and eyes: Ancistrus 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 . Loricariids are popular aquarium 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 , omnivore , carnivore 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
2028-563: Is Taubateia from the Late Oligocene - Early Miocene in Brazil . The putative Cenomanian member Afrocascudo , initially described as the earliest loricariid catfish in 2024, might represent a juvenile obaichthyid lepisosteiform , possibly a junior synonym of Obaichthys , though this has been disputed based on the complete ossification of the bones indicating full maturity and the absence of important holostean characters. Within
2106-555: 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 , Rineloricaria latirostris , to 2n = 96 in a species of Upsilodus ( Hemipsilichthys ). 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
2184-565: Is a synapomorphy of the earliest taxa to be included within Tetrapoda: did all the earliest members of the Tetrapoda inherit four limbs from a common ancestor, whereas all other vertebrates did not, or at least not homologously? By contrast, for a group within the tetrapods, such as birds, having four limbs is a plesiomorphy. Using these two terms allows a greater precision in the discussion of homology, in particular allowing clear expression of
2262-459: Is almost exclusively restricted to the genus Hypostomus , and the species from the other genera had a conserved diploid number. In some species, there is a ZZ/ZW sex-determination system . 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 , invertebrates , and detritus . Some species, notably
2340-536: Is characteristically flattened in this family. Taste buds cover almost the entire surface of the body and fin spines. Body lengths can range from 2.22 cm (0.87 in) in Nannoplecostomus eleonorae to over 100 cm (39 in) in Panaque , Acanthicus , and Pterygoplichthys . One of the most obvious characteristics of the loricariids is the suckermouth . The modified mouth and lips allow
2418-440: Is correct, then the last common ancestor of turtles and birds, at the branch near the ▼ lived earlier than the last common ancestor of lizards and birds, near the ♦ . Most molecular evidence , however, produces cladograms more like this: lizards turtles crocodilians birds If this is accurate, then the last common ancestor of turtles and birds lived later than the last common ancestor of lizards and birds. Since
Loricariidae - Misplaced Pages Continue
2496-578: Is counter-productive, as they typically do not reflect actual mutual relationships precisely at all. E.g. Archaea, Asgard archaea, protists, slime molds, worms, invertebrata, fishes, reptilia, monkeys, Ardipithecus , Australopithecus , Homo erectus all contain Homo sapiens cladistically, in their sensu lato meaning. For originally extinct stem groups, sensu lato generally means generously keeping previously included groups, which then may come to include even living species. A pruned sensu stricto meaning
2574-430: 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 ranges from 2n = 52 to 2n = 80. However, the supposed wide karyotypic diversity the family Loricariidae or the subfamily Hypostominae would present
2652-447: Is not preserved, and although its presence was argued by Brito et al. based on four rays allegedly observable as impressions, a later comment disputed this. In their phylogenetic analyses , Brito et al. (2024) recovered Afrocascudo within the diverse siluriform (catfish) clade Loricariidae . Loricariids—including Afrocascudo —are regarded as the "armoured catfishes", with around 1,220 extant species. Their results are displayed in
2730-500: Is often adopted instead, but the group would need to be restricted to a single branch on the stem. Other branches then get their own name and level. This is commensurate to the fact that more senior stem branches are in fact closer related to the resulting group than the more basal stem branches; that those stem branches only may have lived for a short time does not affect that assessment in cladistics. The comparisons used to acquire data on which cladograms can be based are not limited to
2808-504: Is similar to the traditional comparative method of historical linguistics, but is more explicit in its use of parsimony and allows much faster analysis of large datasets ( computational phylogenetics ). Textual criticism or stemmatics : Cladistic methods have been used to reconstruct the phylogeny of manuscripts of the same work (and reconstruct the lost original) using distinctive copying errors as apomorphies. This differs from traditional historical-comparative linguistics in enabling
2886-478: 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
2964-474: Is typically shared derived characteristics ( synapomorphies ) that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if
3042-492: The Panaque , are known for xylophagy , or the ability to digest wood . Most species of loricariids are nocturnal animals . Some species are territorial , while others, such as Otocinclus , 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
3120-735: The Late Cretaceous Douira Formation ( Kem Kem Group ) of Morocco. The genus contains a single species , A. saharaensis , known from a partial articulated specimen. The Afrocascudo holotype specimen, MHNM -KK-OT 36 a—c, was discovered in sediments of the Douira Formation (Jbel Oum Tkout locality) of the Kem Kem Group near Tafraoute Sidi Ali in Errachidia Province , southeastern Morocco. The articulated specimen consists of
3198-612: The Sahara Desert of North Africa, from which the holotype was discovered. The describers of Afrocascudo suggested that this fossil represents the oldest known catfish and, as such, the oldest known loricarioid . Before its description, the Argentinian Corydoras revelatus was the oldest known loricarioid, from the Late Paleocene (~58.5 Ma). The presence of a crown group loricarioid catfish in
Loricariidae - Misplaced Pages Continue
3276-428: The cladogram below: Diplomystidae Nematogenyidae Trichomycteridae Callichthyidae Scoloplacidae Astroblepidae Lithogenes villosus † Afrocascudo Pterygoplichthys multiradiatus However, in the same year, Britz et al. considered this taxonomic placement fallacious, and reinterpreted Afrocascudo as a juvenile obaichthyid lepisosteiform , most likely an immature individual of
3354-409: The parsimony criterion has been abandoned by many phylogeneticists in favor of more "sophisticated" but less parsimonious evolutionary models of character state transformation. Cladists contend that these models are unjustified because there is no evidence that they recover more "true" or "correct" results from actual empirical data sets Every cladogram is based on a particular dataset analyzed with
3432-494: The Late Cretaceous would indicate that the clade had already significantly diversified much earlier than was previously thought. This hypothesis has been disputed by other researchers who posit that the remains do not belong to a catfish. Afrocascudo was a small fish, with an estimated total body length of 74 millimetres (2.9 in). About 35% of the total body length is incorporated by the head. The top and sides of
3510-407: The absence of important holostean characters including the canalicules found in gar scales and the presence of teleost fish traits, such as the structure of the caudal fin, histological features, and the dorsal and lateral surfaces which are covered with bony plates and odontodes . Additionally, all principal rays of the median fins in lepisosteiforms are segmented and branched, which is different from
3588-539: The amount of data available for phylogenetics. At the same time, cladistics rapidly became popular in evolutionary biology, because computers made it possible to process large quantities of data about organisms and their characteristics. The cladistic method interprets each shared character state transformation as a potential piece of evidence for grouping. Synapomorphies (shared, derived character states) are viewed as evidence of grouping, while symplesiomorphies (shared ancestral character states) are not. The outcome of
3666-460: The body and head are covered in odontode -coated bony plates. The skull roof is triangular, with a long, pointed snout and expanded orbit region. It had approximately 30 vertebrae in total. The distal end of the caudal fin, though not entirely preserved, seems to be symmetrically rounded with 14 rays . The dorsal fin includes a small anterior spinelet, a larger spine, and 8-9 rays. The pelvic fin has six parallel rays. A physical anal fin
3744-529: 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. Members of the family Loricariidae are commonly referred to as loricariids, suckermouth catfishes, armoured catfish , or suckermouth armoured catfish. The name " plecostomus ", and its shortened forms "pleco" and "plec", are used for many Loricariidae, since Plecostomus plecostomus (now called Hypostomus plecostomus )
3822-431: The bony plates in callichthyids . (In Latin , lorica means corselet ). 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. These fish have, when they are present, a unique pair of maxillary barbels . These fish have relatively long intestines due to their usually herbivorous or detrivorous diets. The body
3900-422: The clade, or the group should be abolished. Branches down to the divergence to the next significant (e.g. extant) sister are considered stem-groupings of the clade, but in principle each level stands on its own, to be assigned a unique name. For a fully bifurcated tree, adding a group to a tree also adds an additional (named) clade, and a new level on that branch. Specifically, also extinct groups are always put on
3978-443: The cladograms show two mutually exclusive hypotheses to describe the evolutionary history, at most one of them is correct. The cladogram to the right represents the current universally accepted hypothesis that all primates , including strepsirrhines like the lemurs and lorises , had a common ancestor all of whose descendants are or were primates, and so form a clade; the name Primates is therefore recognized for this clade. Within
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#17327880219914056-409: The contemporary Obaichthys . They noted significant morphological differences between this taxon and true loriicarids, and observed that the identified traits are more similar to those of Obaichthys . Britz et al. discussed their skepticism based on the erroneous phylogenetic data matrix and reconstruction of the taxon from the previous study by Brito et al., the latter of which does not closely match
4134-400: 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. Afrocascudo Afrocascudo is a controversial genus of extinct neopterygian fish, either an ancient loricariid catfish or a juvenile obaichthyid lepisosteiform of the genus Obaichthys . It is known from
4212-402: The development of cultures or artifacts using groups of cultural traits or artifact features. Comparative mythology and folktale use cladistic methods to reconstruct the protoversion of many myths. Mythological phylogenies constructed with mythemes clearly support low horizontal transmissions (borrowings), historical (sometimes Palaeolithic) diffusions and punctuated evolution. They also are
4290-655: The dorsal fin of Afrocascudo . Thus, they stood by their original conclusion that Afrocascudo represents the oldest known catfish. Afrocascudo is known from the Douira Formation (Kem Kem Group) of Morocco, which dates to the Cenomanian age of the late Cretaceous period. This locality represents a fresh water environment that would have dried seasonally. Many other fossil animals have been found in similar outcrops, such as various invertebrates, other fish, amphibians, crocodylomorphs , and dinosaurs including
4368-475: 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 , along with Amphiliidae , Trichomycteridae , Nematogenyidae , Callichthyidae , Scoloplacidae , and Astroblepidae . Some of these families also exhibit suckermouths or armor, although never in
4446-410: The exact historic relationships between the groups. The following terms, coined by Hennig, are used to identify shared or distinct character states among groups: The terms plesiomorphy and apomorphy are relative; their application depends on the position of a group within a tree. For example, when trying to decide whether the tetrapods form a clade, an important question is whether having four limbs
4524-512: The field of biology. Any group of individuals or classes that are hypothesized to have a common ancestor, and to which a set of common characteristics may or may not apply, can be compared pairwise. Cladograms can be used to depict the hypothetical descent relationships within groups of items in many different academic realms. The only requirement is that the items have characteristics that can be identified and measured. Anthropology and archaeology : Cladistic methods have been used to reconstruct
4602-494: 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
4680-481: The fossil taxon is related to other fossil and extant taxa, as implied by the pattern of shared apomorphic features. An otherwise extinct group with any extant descendants, is not considered (literally) extinct, and for instance does not have a date of extinction. Anything having to do with biology and sex is complicated and messy, and cladistics is no exception. Many species reproduce sexually, and are capable of interbreeding for millions of years. Worse, during such
4758-422: The fossilized remains. They also pointed out that Brito et al. only provided the arguments in favor of their conclusion without an extensive discussion, and that their hypotheses would all be considered doubtful if Afrocascudo is considered a non-teleost fish. As such, they argued that Afrocascudo should be considered a junior synonym of Obaichthys . Shortly after the comment by Britz, Brito et al. published
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#17327880219914836-412: The future. 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. Loricariid fossils are extremely rare. The earliest known definitive taxon
4914-407: The hierarchical relationships among different homologous features. It can be difficult to decide whether a character state is in fact the same and thus can be classified as a synapomorphy, which may identify a monophyletic group, or whether it only appears to be the same and is thus a homoplasy, which cannot identify such a group. There is a danger of circular reasoning: assumptions about the shape of
4992-427: The large theropods Carcharodontosaurus and Spinosaurus . Cladistics Cladistics ( / k l ə ˈ d ɪ s t ɪ k s / klə- DIST -iks ; from Ancient Greek κλάδος kládos 'branch') is an approach to biological classification in which organisms are categorized in groups (" clades ") based on hypotheses of most recent common ancestry . The evidence for hypothesized relationships
5070-497: 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 premaxillae 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
5148-487: The latter contains Tarsiiformes and Anthropoidea. Lemurs and tarsiers may have looked closely related to humans, in the sense of being close on the evolutionary tree to humans. However, from the perspective of a tarsier, humans and lemurs would have looked close, in the exact same sense. Cladistics forces a neutral perspective, treating all branches (extant or extinct) in the same manner. It also forces one to try to make statements, and honestly take into account findings, about
5226-412: The lowlands up to 3,000 m (9,800 ft) 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. This family has extremely variable color patterns and body shapes. Loricariids are characterized by bony plates covering their bodies, similar to
5304-419: The mentioned assumptions, often result in different cladograms. Only scientific investigation can show which is more likely to be correct. Until recently, for example, cladograms like the following have generally been accepted as accurate representations of the ancestral relations among turtles, lizards, crocodilians, and birds: turtles lizards crocodilians birds If this phylogenetic hypothesis
5382-455: The most commonly used method to classify organisms. The original methods used in cladistic analysis and the school of taxonomy derived from the work of the German entomologist Willi Hennig , who referred to it as phylogenetic systematics (also the title of his 1966 book); but the terms "cladistics" and "clade" were popularized by other researchers. Cladistics in the original sense refers to
5460-464: The outline of the highly visible eye has been suggested to aid camouflage in what are often highly mottled animals. Species in the tribe Rhinelepini 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 . As of 2000, only 56 loricariid species have been cytogenically investigated. The basal diploid number of chromosomes
5538-444: The primates, all anthropoids (monkeys, apes, and humans) are hypothesized to have had a common ancestor all of whose descendants are or were anthropoids, so they form the clade called Anthropoidea. The "prosimians", on the other hand, form a paraphyletic taxon. The name Prosimii is not used in phylogenetic nomenclature , which names only clades; the "prosimians" are instead divided between the clades Strepsirhini and Haplorhini , where
5616-432: The reciprocal host. There are several processes in nature which can cause horizontal gene transfer . This does typically not directly interfere with ancestry of the organism, but can complicate the determination of that ancestry. On another level, one can map the horizontal gene transfer processes, by determining the phylogeny of the individual genes using cladistics. If there is unclarity in mutual relationships, there are
5694-466: The same individual, as in loricariids. This is the largest catfish 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 ; it later becomes grouped as a tribe, because of its recognition as
5772-408: 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 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 ,
5850-788: 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. 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. 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 . Species occur in swift-flowing streams from
5928-461: The terms worms or fishes were used within a strict cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically , outside of cladistics, e.g. as a ' grade ', which are fruitless to precisely delineate, especially when including extinct species. Radiation results in the generation of new subclades by bifurcation, but in practice sexual hybridization may blur very closely related groupings. As
6006-410: The time of his original formulation until the end of the 1970s, cladistics competed as an analytical and philosophical approach to systematics with phenetics and so-called evolutionary taxonomy . Phenetics was championed at this time by the numerical taxonomists Peter Sneath and Robert Sokal , and evolutionary taxonomy by Ernst Mayr . Originally conceived, if only in essence, by Willi Hennig in
6084-579: Was one of the first loricariid species imported for the fish-keeping hobby. Some loricariids are not normally considered "plecostomus", such as Farlowella catfish. In their native range , these fish are known as cascudos or acarís . 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
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