Bryconops colaroja
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| Bryconops colaroja | |
|---|---|
 | |
| Preserved specimen | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Characiformes |
| Family: | Iguanodectidae |
| Genus: | Bryconops |
| Species: | B. colaroja |
| Binomial name | |
| Bryconops colaroja Chernoff & Machado-Allison, 1999 | |
Bryconops colaroja is a small species of freshwater ray-finned fish belonging to the family Iguanodectidae. This fish is 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 colaroja is one of the smaller members of the genus Bryconops, measuring around 7.8 cm (3.1 in) in standard length.[2] In general, the genus Bryconops has a similar body shape to sister genus Piabucus, described as resembling a minnow or smelt.[3] Its scales are mostly greenish-silver, slightly darker on the back than on the rest of the body. The uniform gradient of the scales, lacking prominent markings, is a feature that can be used to differentiate it from other members of the genus; for example, B. colanegra and B. melanurus have distinct blotches of pigmentation in the cheek and eye region.[4]
Bryconops colaroja is the only member of the genus Bryconops to have a caudal fin that is completely red, aside from congener Bryconops imitator (which gets its name from its similarity to B. colaroja).[5][6] The margins of the fin rays are the only places where melanophores are present, making dark lines radiate inwards from the fin margin.[4] This distinct color is the origin of the fish's scientific name; "cola" means "tail", and "roja" means "red".[7] It is sometimes called the redtailed bryconops because of this,[8] but this is not in wide use, and B. colaroja has no accepted common name.[9]
Though Bryconops colaroja has gill rakers that are notably denticulated - that is, adorned with toothlike protrusions - its congener B. colanegra is known to have gill rakers with higher denticulation.[4] The teeth are multicuspid, which is a feature that the Bryconops clade shares with sister clade Iguanodectinae.[10]
Taxonomy
Bryconops colaroja was described in 1999 as a part of the subgenus Creatochanes, making its full name Bryconops (Creatochanes) colaroja.[4] It has no synonyms, nor is it often mistaken for its congeners, aside from B. imitator.[11] The red tail makes it fairly easy to identify.
Bryconops colaroja, as with all members of the genus Bryconops, was once considered a part of the family Characidae, and is still listed there by some sources.[12][13] However, research in 2011 by Oliveira et al. moved the genera Bryconops, Iguanodectes, and Piabucus to the family Iguanodectidae,[14] which is where B. colaroja currently stands.[2][11]