Iguanodectidae | |
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Bryconops caudomaculatus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Characiformes |
Family: | Iguanodectidae Eigenmann, 1909 |
Genera | |
See the text |
Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It is home to the subfamily Iguanodectinae (Eigenmann, 1909) and the monotypic Bryconops clade. Several species in the family, such as the green line lizard tetra (Iguanodectes spilurus), the tailspot tetra (Bryconops caudomaculatus), and the orangefin tetra (Bryconops affinis), are sometimes taken as aquarium fish.
Iguanodectids are generally small, and are brightly colored or reflective, making them moderately-popular ornamental fish. They range from 3.1 cm to 15 cm SL (standard length). [1] [2] [3] They are rather narrow in shape, somewhat resembling minnows; ichthyologist Carl H. Eigenmann compared them to smelt. [4]
Iguanodectids are found in South America, spread all across the northern half of the continent. [5] [6] Though they primarily inhabit freshwater, Iguanodectid fishes are known to tolerate brackish water as well. [7] Habitat destruction, by way of land development and aquaculture, is the biggest threat to members of Iguanodectidae, though evaluated species are mostly considered least concern by the International Union for the Conservation of Nature (IUCN). [8]
Iguanodectidae is in the order Characiformes, with three extant genera - Bryconops , Iguanodectes , and Piabucus . [6] [9] Said genera used to be classified in the family Characidae, but have since been reclassified in order to keep Characidae monophyletic. [10]
Species include:
Iguanodectes (Cope, 1872)
Piabucus (Oken, 1817)
Bryconops is the most speciose genus, with 21 valid species. [1] Iguanodectes is next-largest with 8, and Piabucus has the fewest at 3. [2] [3]
Iguanodectes and Piabucus are largely considered to make up the subfamily Iguanodectinae, with Bryconops becoming its own separate clade, but this is a matter of debate. Several sources accept the subfamily Iguanodectinae as its own entity, [11] [12] but others consider it synonymous with Iguanodectidae [13] [14] or simply don't acknowledge it, [15] uniting the genera therein. ITIS considers it synonymous with Characidae, which is a reflection of its older classification. [16]
Iguanodectinae, when first officially classified by Carl H. Eigenmann in 1909, was placed in the family Characidae, and only contained the genus Iguanodectes; [17] by 1929, it had grown to include the genus Piabucus. [4] Through the year 1977, this remained the case. [18] In 2011, Iguanodectinae was found to be closely related to Bryconops, and the two clades were combined in Iguanodectidae. [10]
The family Iguanodectidae was resurrected from Eigenmann's work in the year 2011 by Oliveira et al. to contain Iguanodectinae and Bryconops. [7] [10] Iguanodectinae itself was classified in 1909, and therefore Iguanodectidae is often considered to originate in the same year, despite the recent nature of the study. [15]
The family name "Iguanodectidae" originates in the genus name "Iguanodectes", which used to be its sole representative. [17] The origin of such was not made clear upon its nomination, but is assumed to be from "iguana", the lizard, and "dectes", meaning "bite", in reference to the general dentition's almost lizard-like formation. [19] The common name "lizard bite tetra" has been proposed in reference to this, though this has not been widely accepted as of 2022. [7] [20]
Though data is limited, it is known that Bryconops colanegra, [21] Bryconops colaroja, [22] and Piabucus dentatus [23] are seen in the ornamental fish trade. Iguanodectes geisleri is rare, but is sold under the name "red line lizard tetra". [24] One of its congeners, Iguanodectes spilurus, is called the "green line lizard tetra", and is sensitive to poor water conditions. [25]
Bryconops is a genus of freshwater fish in the family Iguanodectidae from South America. It consists of small fish, all under half-a-foot long, with slender bodies and silvery scales, though there is some mild color variation. Several species can be identified by way of a humeral patch, and others have a reddish ocellus, or eyespot, on one or both lobes of the dorsal fin.
Iguanodectes is a genus of freshwater fish found in tropical South America, with eight currently described species. They are all small tetras, none longer than 5 inches, and often have attractive silvery or striped scales, which makes them a target for the ornamental fish industry. Alongside the genus Piabucus, it is in the subfamily Iguanodectinae, which in turn is in the family Iguanodectidae. The genus Bryconops, which is also in Iguanodectidae, makes up a sister clade to Iguanodectinae.
Piabucus is a genus of freshwater tetras in the family Iguanodectidae. All three species are found in South America, largely the Amazon and its major tributaries. None of them are longer than half a foot long, with the largest reaching a maximum size of 12.9 cm (5.1 in), and they are slender, with relatively deep chests and long pectoral fins. Their scales are pale or silvery, with lateral lines that stand out.
Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. It has two genera, Piabucus and Iguanodectes. Some species in the subfamily are taken from the wild for aquariums, like the red- and green-line lizard tetras. There is minor, but ongoing, debate regarding its taxonomy.
Bryconops alburnoides is a small freshwater fish, approximately 6 inches long at its largest, that lives in the rivers of South America. It has a slender body, with a yellowish dorsal fin and yellow-tinged back scales that fade into silver on its belly. It is largely an insectivore that picks land-dwelling insects from the riverbanks, though it eats much more whenever rain washes prey into the water.
The tailspot tetra is a freshwater fish that lives in the coastal river regions of upper South America. Both its common and scientific names reference the distinct spot of color present on the tail fin, which is one of its defining characteristics. It is a small fish, reaching 4.8 in at its longest. Despite its small size, it is an active swimmer, with a preference for fast-flowing waters.
Bryconops colanegra is a small, slender-bodied species of freshwater fish from South America, about 3.5 in long. It has a black tail fin that bears hints of red, and its scales are dark along the back, transitioning to a silver belly. It is endemic to a single river system in Venezuela, the Rio Caroní.
Bryconops colaroja is a small species of fish endemic to tributaries and creeks of the Cuyuni River basin in Venezuela. The specific epithet "colaroja" means "red tailed", and it gets this name from its most distinctive feature - a deep red caudal fin, largely unique amongst members of its genus.
Bryconops collettei is a small freshwater fish from the rivers of South America. It is mostly silvery, with notable green iridescence on its sides, and a diffuse ocellus (eyespot) on the upper lobe of the caudal fin. Before its distinction as a separate species, specimens of B. collettei were misidentified as specimens of Bryconops caudomaculatus due to several morphological similarities, including a caudal ocellus and generally similar fin coloration.
Bryconops disruptus is a small freshwater fish of the family Iguanodectidae. It is only found in the Rio Negro in South America. Like the rest of the genus Bryconops, B. disruptus is silvery in color, with a relatively deep chest and a notable set of teeth. The specific epithet "disruptus" refers to the incomplete lateral line.
Bryconops durbinae, sometimes listed under the name Bryconops durbini, is a small species of freshwater fish in the family Iguanodectidae. It is the smallest species of the genus Bryconops, and is endemic to the Tapajós river basin in Brazil.
Bryconops inpai is a small freshwater fish native to the rivers of South America. It only lives in two particular river systems - the Casiquiare and Negro - which means that its range is restricted to the northern half of the continent. It has indistinct humeral spots, and is bluish-silver in life, which is unusual for members of Bryconops; they are more often plain silver or greenish-silver.
Bryconops magoi is a small species of fish from South America. It is only found in Venezuela, along with sister species Bryconops collettei. Its tail-fin markings help to differentiate it from various congeners, as does its fairly restricted range. It is most closely related to B. collettei and Bryconops caudomaculatus, and it was once considered synonymous with the latter; specimens of B. magoi and B. collettei both were routinely misidentified as B. caudomaculatus before being given species distinction.
Bryconops piracolina is a small fish that inhabits the waters of Brazil. It is slender and silvery in color, like many fish in Bryconops, but can be distinguished from other members by way of its dorsal fin, which has a black patch of color extending up from the fin-base; congeners usually have light pigment in the dorsal fin, or a brighter color.
Bryconops vibex is a small freshwater fish from the rivers of Venezuela, known solely from the Rio Cataniapo. The body is slender, though with an element of sturdiness, and it has one humeral spot by each pectoral fin. It bears visual similarities to several congeners, but can be differentiated by way of many factors.
Bryconops florenceae is a small freshwater fish that inhabits the rivers of South America. Comprehensive research is lacking due to B. florenceae being the most recently described of the genus, but researchers believe it to be a relatively widespread species. It is found throughout the Maroni, Mana, and Sinnamary river basins, which defines its range within Suriname and French Guiana.
Iguanodectes geisleri, the red-line lizard tetra, is a species of freshwater fish from South America. It is a small species, largely herbivorous with some omnivorous traits, that prefers to live in schools and is partial to shallow waters, especially in blackwater habitats. Some aspects of its body plan are unique amongst its genus, including the position and length of the anal fin.
Iguanodectes gracilis is a small species of freshwater fish from South America. It is known solely from the Rio Negro river system, which restricts its range only to Brazil. The name "gracilis" is in reference to a slender body shape, alongside the diminutive nature of I. gracilis - it is the smallest member of the genus Iguanodectes.
Iguanodectes spilurus, the green-line lizard tetra, is a small characiform fish from the rivers of South America. It is not a well-studied species, but research is available, including data from hobbyists that keep it as an ornamental fish. It has a distinct lateral stripe of reflective-green scales, and lacks any red markings therein; red is common in congeners' lateral stripes.
Piabucus caudomaculatus is a small freshwater fish inhabiting the rivers of South America. It was the first member of the family Iguanodectidae to be reported from Bolivia, and it remains endemic to the region, found solely in the Mamoré river basin. It displays a preference for slow-moving waterways and has a largely insectivorous diet.