Bryconops magoi
Bryconops magoi Chernoff & Machado-Allison, 2005
First described in: Chernoff, B.; Machado-Allison, A. (2005). Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Günther). <em>Zootaxa.</em> 1094(1): 1-23.
Bryconops magoi is a species of freshwater ray-finned fish belonging to the family Iguanodectidae. This species is found in South America, where 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.
Descriptions from checklists and floras indexed by GBIF
biology_ecology
Habitat. Bryconops magoi is known only from a morichal with fast moving waters over sandy bottoms. This species frequently is found in water from mid-depth to the surface, at the center of the main channel, where it schools with other characid species. Individuals feed at the surface and are attracted to allotochtonus material that falls into the water. Cursory examination shows that they feed on several groups of terrestrial insects.
Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Gunther).
description
Description. Morphometric data are given in Table 1 and a summary of meristic data appears in Table 2. A moderate to small-sized species of Bryconops, known from specimens less than 70 mm SL. Overall body shape with convex dorsum and slightly rounded belly, tapering to relatively short and deep caudal peduncle 10.5 - 13.9 (12.0 % SL). Dorsal fin origin at level of pelvic origin, almost at center of the body 49.0 - 52.3 (50.5 % SL). Head 23.6 - 27.8 (25.5 % SL); posterior margin of opercle slightly sinusoidal. Border between second and third infraorbitals with naked ventral area; third infraorbital moderatedly developed, not reaching preopercle ventrally or at angle (Fig. 5). Eye large, 8.8 - 11.3 (9.8 % SL). Snout bullet-shaped; mouth terminal, opening just ventral to horizontal diameter through orbit. Maxilla extending posteriorly not reaching posterior margin of the 2 n infraorbital., length 5.8 - 8.0 (6.8 % SL). Ventroanterior margin of maxilla not heavily recurved (Fig. 5). Outer two rows of premaxillary teeth small and not prominent. Premaxilla with 2 - 5 teeth, bearing 3 to 5 cusps. Inner premaxillary teeth uniformly five, with 5 to 7 cusps; teeth basically symmetrical. Maxil
Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Gunther).
diagnosis
Diagnosis. A species of Bryconops, subgenus Bryconops, that is distinguished from all other congeners except B. collettei by its unique color pattern, in which red coloration occupies the upper half of a diffuse caudal fin ocellus. It is further distinguished from members of the subgenus Bryconops by the following traits: pored lateral scales 43 - 47, modally 44 or 45 (> 57 in B. alburnoides, <31 in B. disruptus and B. durbini, and 44 - 48, modally 47 in B. collettei); pored lateral scales extending 2 - 3 scales beyond end of hypural plate onto caudal fin rays (pored lateral scales reaching end of hypural plate and not onto caudal fin rays in B. caudomaculatus); snout length 5.8 - 8.0 % SL, mean 6.8 % (4.2 - 5.4 %, mean 4.7 % in B. collettei); length of anal fin base 24.8 - 27.9 %, mean 26.6 % (27.3 - 29.8 % SL, mean 28.8 % in B. collettei); and total vertebrae 40 - 42, modally 41 - 42 (42 - 44, modally 42 - 43 in B. collettei).
Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Gunther).
discussion
Comparison with B. collettei. Bryconops magoi differs in body shape from B. collettei. The results of sheared principal components analysis and relative warp analysis show that all individuals of both species are discriminated by either the second sheared principal component (Fig. 6) or by the first relative warp. In both analyses all individuals of B. magoi fell at, or inside, the boundary of the 95 % confidence ellipse, whereas three individuals of B. collettei fell just outside the 95 % confidence ellipse, but with a morphology most different from B. magoi (Fig. 6). The first two eigenvectors of the PCA described 99.1 % of the variance. The second sheared PC identified a contrasting suite of traits such that B. magoi has a longer snout and B. collettei has a longer anal fin base, a larger orbit, and a greater distance between the dorsal fins (Fig. 7). RWA produced identical results to the PCA. Even though individuals of B. collettei from the Rio Iguapo have slightly longer snouts relative to other populations, there is no overlap in snout length between the species. For each of the other metric traits the differences between the species are statistically significant, but there i
Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Gunther).
From Wikipedia (CC BY-SA), quoted section by section
Description
B. magoi has a maximum size within the range of 7.0 cm (2.8 in), which places it to the smaller side of the genus Bryconops as a whole. Its caudal fin (tail fin) bears a rather diffuse ocellus (eyespot), the upper half of which is colored red; this is a similarity it shares with B. collettei. This eyespot is not well-defined, but is clear against the dark coloration of the caudal fin overall (which is dense in melanophores). Its scales are overall metallic or gray towards the back, becoming more silvery towards the belly, and it has a lateral line stripe in three colors; the base is a black band with a silver stripe beneath, finished with an iridescent-yellow line. Bryconops caudomaculatus and Bryconops collettei both bear multiple similarities to Bryconops magoi, but there are various ways to tell them apart. One of these is the pored lateral line scales, which stop at the hypural plate and do not extend onto the caudal fin itself in B. caudomaculatus; In B. magoi, they extend two to three scales beyond that point. (This is a diagnostic aspect that B. magoi shares with B. collettei.) B. magoi and B. collettei are similar in many ways as well, such as coloration (though more green in B. collettei), but their varying body shapes make them dissimilar enough to tell apart. Such aspects include a longer snout (a mean of 6.8% of the body length in magoi vs. …
Range & habitat
Bryconops magoi is found only in Venezuela, with a fairly restricted range. All paratypes were collected from the type locality: the Rio Moquete at Paso Bajito, which is located in the Francisco de Miranda Municipality, in the Venezuelan state of Anzoátegui. This is just north of the Orinoco river, the largest river in Venezuela. It demonstrates a preference for fast-moving water over sandy substrate, and is most often found swimming close to the surface, schooling with other species of fish. It is not often taken from the wild for the aquarium trade, and is not considered at risk of population depletion therein. It has not been evaluated by the IUCN. In demonstrating a preference for a blackwater habitat (many rivers in the Orinoco basin are blackwater), B. magoi also demonstrates that it does not have high-oxygen needs. Microbial activity is responsible for blackwater conditions, and microbes consume a large percentage of available dissolved oxygen in the process of decay (and said decay releases dark-colored tannins into the environment). Thus, fish with high-oxygen needs are not suited to blackwater environments, which are low-oxygen by way of the processes that characterize them.
Diet. Cursory examination shows that B. magoi feeds at the surface of the water, largely targeting insects that fall in from trees hanging above. This is a similarity it shares with congener B. …
Where it has been recorded
Recorded sightings
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geo-referenced records in GBIF, from museums, herbaria and field observers.
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In the stacks
Searching the stacks…
Every page naming Bryconops magoi in the Biodiversity Heritage Library →
From the GBIF Backbone Taxonomy and occurrence records (GBIF.org), with Wikipedia and the Source Library. GBIF species 2354271.