Bryconops allisoni | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Characiformes |
Family: | Iguanodectidae |
Genus: | Bryconops |
Species: | B. allisoni |
Binomial name | |
Bryconops allisoni | |
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.
The holotype, or first collected specimen, of Bryconops allisoni was 7.25 cm SL (standard length). Other collected specimens range from 2.76 to 6.86 cm. [1] This makes it slightly smaller than other members of the genus, which usually range from 6 to 8 cm SL. [2] The body is generally slender, deepest in the region of the dorsal fin, and the snout is relatively long, about 23-29% of the length of the head. [3]
The scales of B. allisoni are silvery with a greenish iridescence, and parts of the snout are tinted brown. [3] (Silver or greenish coloration is not uncommon in the genus as a whole.) [4] It bears an iridescent-green lateral stripe that turns black when it advances onto the caudal fin, and the caudal fin also has a red blotch of pigment just above this stripe; the dorsal fin may have a spot of red, and the adipose fin is red entirely. The pelvic, anal, and dorsal fins are almost completely clear with scattered chromatophores (color cells). [3]
The presence of a stripe on the caudal peduncle on the caudal fin is a feature shared with B. chernoffi , B. inpai , and B. melanurus , but various factors differentiate said species. In B. inpai and B. melanurus, the stripe is longer, advancing onto the dorsal lobe of the caudal fin, and B. allisoni has more predorsal scales than B. chernoffi (10-12 vs. 8–9, respectively). [3] [4]
Mature males of B. allisoni are equipped with bony hooks on select fin-rays. [3] This is a feature seen in many other members of Bryconops, though the specific appearance may vary depending on the species, sometimes more accurately being described as barbs or spines; [5] for instance, hooks are well-defined on the anal fin of congener B. munduruku , but there are smaller spines on munduruku's dorsal and pelvic fins. [6] Otherwise, there are no documented morphometric or coloration differences between males and females.
Bryconops allisoni has been considered a member of the genus Bryconops since its description in 2019. There are two subgenera in Bryconops, Bryconops and Creatochanes, [6] and B. allisoni exhibits synapomorphies of both; multicuspid teeth on both maxillae and well-denticulated gill rakers from Creatochanes, but a shorter jaw structure associated with Bryconops. Therefore, B. allisoni's subgeneric status is yet undetermined. [3] It is still considered a member of the genus Bryconops incertae sedis . [7]
The specific name "allisoni" is in honor of Venezuelan ichthyologist Antonio Machado-Allison, who has written or co-authored a large amount of literature concerning the taxonomy of Bryconops. [7]
Bryconops allisoni is only known from the lower rio Tapajós, appearing solely in small, right-bank tributaries. [3] It is the most recent species described therein; excluding B. allisoni, there are thought to be at least nine species cited from the middle and lower Tapajós basin. The congener B. munduruku specifically was also originally described from a right-bank tributary of the Tapajós, [6] and B. allisoni occurs syntopically with congener B. melanurus. [3]
Bryconops allisoni has not been evaluated by the IUCN. Based on patterns seen in other members of the genus, it may be under threat of various anthropogenic hazards, including illegal mining and farmland settlement. [8] The Tapajós main has been subject to such intense mining activity in the past that portions of it have turned entirely brown due to sediment addition and disturbance.[ citation needed ] However, its type locality, the Corredor Ecológico stream, is a tributary of the Tapaós located in the Tapajos National Forest, a large area of protected land. [3] Therefore, there are already measures in place that may aid in its survival as a species.
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.
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.
Bryconops cyrtogaster is a midsize species of freshwater fish found in the Oyapock river in French Guiana and Brazil. It is overall silver, with an indistinct dark patch at the base of the tail fin that spreads onto the fin rays slightly. Originally described in 1926 under a different baisonym, it was the subject of a redescription in June 2020.
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 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 gracilis is a small species of freshwater fish from the rivers of South America. It is one of multiple species for which the common name "lambari" is used. Though not well-studied, it has been re-described in recent years in order to differentiate it from Bryconops alburnoides, a congener to which it bears a strong resemblance.
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 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 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.
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 tocantinensis is a small freshwater fish from the rivers of Brazil. It has yellow-gold scales on its back and white scales on its belly, with a bright-silver stripe marking the divide between the two. It gets the name "tocantinensis" from its endemism to the upper Tocantins basin drainage - specifically, the Conceição River.
Bryconops transitoria is a small freshwater fish that lives in the rivers of South America. It is a poorly-studied member of the genus Bryconops with few records and vague distribution accounts, though it is believed to be endemic to the Rio Tapajós. It was originally thought to be a subspecies of congener Bryconops melanurus, but is now accepted as its own species.
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 chernoffi is a species of freshwater fish that inhabits the rivers of Brazil. Specifically, it is found in the Rio Maicuru and Rio Ipixuna; the latter is a tributary of the former, which is a tributary of the Amazon river main. B. chernoffi demonstrates a preference for clear-water streams with sandy and rocky bottoms.
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.
Bryconops marabaixo is a small freshwater fish from the lower Amazon basin, native to the Rio Jari. It is small and silvery, with a dark-gray back, and its fins are mostly clear, though the caudal fin has a dark stripe on the lower margin of the dorsal lobe, and a spot of red pigment just above that. Like many other members of Bryconops, it has a humeral spot, which is a mark near each pectoral fin.
Bryconops rheoruber is a species of freshwater fish from the rivers of Brazil. Its back scales are tan-to-cream, and its belly is silvery; the divide between the two colors is marked by a broad iridescent-silver stripe. Its fins are a mixture of pale, clear, and reddish, which contributed to its specific name. "Rheo" means "flow" or "current" in Greek, and "ruber" means "red" in Latin.
Bryconops sapezal is a small freshwater fish native to the Rio Tapajós basin of Brazil. It is one of the more recent additions to its genus, described in 2018, and has a name that means "covered in sapê", or thatching. This originates from the Sapezal municipality of Mato Grosso, Brazil, which is type locality of B. sapezal.
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