Bryconops disruptus

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Bryconops disruptus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Iguanodectidae
Genus: Bryconops
Species:
B. disruptus
Binomial name
Bryconops disruptus

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.

Contents

Description

Bryconops disruptus is one of the smallest members of Bryconops , measuring about 6.4 cm (2.5 in) in standard length. [1] The only species smaller is Bryconops durbinae , which reaches 3.1 cm (1.2 in) in standard length. [2] It is similar in coloration to Bryconops caudomaculatus , including a similar caudal ocellus (an eyespot on the tail fin), but is overall a darker silver and has a more consistently incomplete lateral line. [3] The number of pored lateral line scales varies wildly, ranging from 9 to 23. [4]

Due to the presence of a caudal ocellus, B. disruptus bears an outward resemblance to B. caudomaculatus, and its small size and general shape make it reminiscent of B. durbinae. [5] However, it can be told apart by various factors; these include fewer precaudal vertebrae (16 in B. disruptus versus 17–18 in B. caudomaculatus) and the lack of a caudal ocellus in B. durbinae. [3]

Taxonomy

Bryconops disruptus has been identified as a member of the genus Bryconops since its description in February 1997. [3] Originally, the genus Bryconops was considered a member of the family Characidae, but research in 2011 prompted a move into the family Iguanodectidae, alongside the genera Piabucus and Iguanodectes . [6] B. disruptus is currently classified as an iguanodectid. [7] [8]

Bryconops caudomaculatus, a closely related congener, is at the center of an informal species complex that formed around a history of mistaken identity or synonymy. [5] B. disruptus is a part of this species complex, having drawn multiple comparisons to B. caudomaculatus in its original description. [3]

The specific epithet "disruptus" is in reference to the lateral line, which is regularly incomplete or interrupted. [9] B. disruptus has no accepted common names. [10]

Habitat and ecology

Bryconops disruptus solely inhabits the Rio Negro, a blackwater tributary of the Amazon river. [1] The Rio Negro has very low mineral content, and is very acidic, with a pH ranging from 2.9 to 4.2. [11] The riverbed is stable, with low erosion and very few suspended particulates in the water, and the flora and fauna are generally sparse outside of species like B. disruptus. [12]

Blackwater habitats generally have low oxygen content, which shows that B. disruptus does not need well-oxygenated waters to survive. This is because blackwater conditions are caused by the decay of plant matter leaching tannins into the water, and the microbial activity responsible for said decay consumes a great deal of the available dissolved oxygen. [13] [14] [15]

Bryconops disruptus's preference for acidic and/or blackwater environments is something it shares with more than a few of its congeners. One of these is Bryconops collettei , which is found both in more acidic blackwaters and rather less acidic clear waters. [16] Another example is Bryconops colaroja , which inhabits waters in the Guiana Shield that lean towards acidity. [17]

Conservation status

The Rio Negro is the world's largest blackwater river, which means that B. disruptus has a wide native range. [18] Though B. disruptus hasn't been evaluated by the IUCN, [1] there is no concern that it will run out of habitable territory anytime soon.

Related Research Articles

<i>Bryconops</i> Genus of fishes

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.

<span class="mw-page-title-main">Iguanodectidae</span> Family of fish

Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It is home to the subfamily Iguanodectinae and the monotypic Bryconops clade. Several species in the family, such as the green line lizard tetra, the tailspot tetra, and the orangefin tetra, are sometimes taken as aquarium fish.

<span class="mw-page-title-main">Orangefin tetra</span> Species of fish

The orangefin tetra is a small species of freshwater fish from South America that belongs to the family Iguanodectidae. Though common in its native range, it seems to prefer fast-flowing and shallow creeks. It is an active swimmer that feeds on plant material and various invertebrates, sometimes jumping out of the water to catch prey above the surface.

<i>Bryconops alburnoides</i> Species of fish

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.

<span class="mw-page-title-main">Tailspot tetra</span> Species of fish

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.

<i>Bryconops colaroja</i> Species of fish

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.

<i>Bryconops collettei</i> Species of fish

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 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.

<i>Bryconops giacopinii</i> Species of fish

Bryconops giacopinii is a mid-sized species of freshwater fish in the family Iguanodectidae. It is the largest member of the genus Bryconops, and is therefore difficult to confuse with any of its congeners. With a diet that consists largely of land-dwelling insects, it serves as an important link between the terrestrial and aquatic aspects of its native range.

Bryconops humeralis is a small freshwater fish distributed across northern South America. The name "humeralis" means "relating to the shoulder", in reference to the distinct humeral patches that the fish sports. It is slightly longer than average in terms of the genus Bryconops, though still firmly within the standard range, and is slightly more slender than is usual for its congeners.

Bryconops imitator is a small freshwater fish that lives in the rivers of South America. It is a small, silvery fish with a bright red tail fin that is known to eat invertebrates, like insects and freshwater zooplankton.

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.

<i>Bryconops magoi</i> Species of fish

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.

<i>Bryconops melanurus</i> Species of fish

Bryconops melanurus, sometimes called the tail-light tetra, is a small species of freshwater fish from South America that primarily preys on insects. It lives in small schools and is an active swimmer, which means that it requires open space in its habitat. Nonetheless, it does not demonstrate a strong preference for any one biotope within its native range.

Bryconops munduruku is a small freshwater fish of the family Iguanodectidae that lives in the rivers of South America. Its adipose fin is black, with a clear base, and it has two humeral spots, which is a feature it shares with few congeners. Its fins are a variety of yellow, red, black, and clear, and mature males have hooks on select fin-rays.

<i>Bryconops piracolina</i> Species of fish

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 allisoni is a species of freshwater fish known from the rivers of Brazil. It is a recent addition to the genus (2019), currently considered a member incertae sedis. Its name honors Antonio Machado-Allison, an ichthyologist responsible for a great deal of work on the genus Bryconops.

<i>Bryconops florenceae</i> Species of fish

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.

References

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  4. Guedes, Tharles L. O.; Oliveira, Everton F.; Lucinda, Paulo H. F. (14 March 2016). "A new species of Bryconops (Ostariophysi: Characiformes: Characidae) from the upper rio Tocantins drainage, Brazil". Neotropical Ichthyology. 14 (2). doi: 10.1590/1982-0224-20150176 .
  5. 1 2 Chernoff, Barry; Machado-Allison, Antonio (2005-12-13). "Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Günther)". Zootaxa. 1094 (1): 1–23. doi:10.11646/zootaxa.1094.1.1 . Retrieved 3 April 2022.
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