''Bryconops collettei'' is a small freshwater fish from the rivers of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. 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.

Description

''Bryconops collettei'' is within the range of 7.8 cm (3.1 in) long in

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

, which puts it slightly to the smaller side of the genus ''

Bryconops ''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 specie ...

''. Its scales are generally silvery with a touch of

iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfl ...

green, and it has a lateral stripe in various colors: black on top, silver in the middle, and emerald-green at the bottom. One of its defining features is an indistinct red spot, or ocellus, on the upper lobe of the tail fin; this spot is rather diffuse, manifesting as a narrow ellipse or a streak rather than a strong and definite patch. Though ''Bryconops collettei'' bears similarities to congeners ''

Bryconops magoi ''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 restric ...

'' and ''

Bryconops caudomaculatus The tailspot tetra (''Bryconops caudomaculatus'') 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 ...

'', it can readily be told apart by several factors. In ''B. caudomaculatus'', the pored

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

scales stop at the hypural plate and do not extend onto the caudal fin itself, but in ''B. collettei'' they extend two to three scales beyond that point. (This is a feature that ''B. collettei'' shares with ''B. magoi''.) ''B. collettei's'' caudal ocellus is also less distinct than that of ''B. caudomaculatus''. When compared to ''B. magoi'', the general body shape is different in several ways, including ''B. collettei's'' shorter snout and longer spine, but the coloration is quite similar.

Taxonomy

''Bryconops collettei'' was first described in 2005, in a study that also named ''B. magoi'' and reestablished the characteristics that identify ''B. caudomaculatus''.''Bryconops collettei'' Chernoff & Machado-Allison, 2005
in GBIF Secretariat (2021). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2022-04-26. It is a member of the subgenus ''Bryconops'' (as opposed to the other subgenus in the genus ''Bryconops'', ''Creatochanes''), making its full scientific name ''Bryconops (Bryconops) collettei''. It is considered a part of the ''Bryconops caudomaculatus''

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

due to a history of synonymy with the species, as well as extensive morphological similarities. Like the rest of the genus ''Bryconops'', ''B. collettei'' was once considered a characin, or member of the family

Characidae Characidae, the characids or characins is a family of freshwater subtropical and tropical fish, belonging to the order Characiformes. The name "characins" is the historical one, but scientists today tend to prefer "characids" to reflect their st ...

. However, research in 2011 by Oliveira et al. moved the genera ''Bryconops'', ''

Piabucus ''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 max ...

'', and ''

Iguanodectes ''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 t ...

'' into the family

Iguanodectidae 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 ...

,Oliveira, C., Avelino, G.S., Abe, K.T., Mariguela, T.C., Benine, R.C., Orti, G., Vari, R.P., & Correa e Castro, R.M. (2011)
Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling.
''BMC Evolutionary Biology, 11: 275. doi: 10.1186/1471-2148-11-275'' which is where ''B. collettei'' currently stands. Some sources, such as

Animal Diversity Web Animal Diversity Web (ADW) is an online database that collects the natural history, classification, species characteristics, conservation biology, and distribution information on thousands of species of animals. The website includes thousands ...

and

ITIS The Integrated Taxonomic Information System (ITIS) is an American partnership of federal agencies designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagenc ...

, still list the genus ''Bryconops'' as a member of Characidae. The specific epithet "''collettei''" is in reference to Bruce B. Collette, the senior systematic zoologist at the

National Marine Fisheries Service The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the stew ...

at the time of ''B. collettei's'' description. Collette was responsible for significant contributions to systematic ichthyology and to the careers of both authors that named ''B. collettei''. In terms of a common name, ''B. collettei'' has none that are widely accepted.

Habitat and ecology

''Bryconops collettei'' is found only in

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

, with a preference for rivers that have a moderate-to-fast flow and rocky or sandy substrate. It inhabits more acidic environments, both clear and blackwater (more common in blackwater), and can often be found in schools with other species of fish. Though it is sometimes taken from the wild for the aquarium industry and its trade is not restricted, it is not in wide use, and therefore is not at considerable risk of population depletion. Due to its partial habitation of blackwater rivers, it is known that ''B. collettei'' does not need well-oxygenated waters to survive. Microbial activity is responsible for blackwater conditions, and therefore the water is low in oxygen, as microbes consume a large percentage of available dissolved oxygen in the process of inducing decay. Thus, fish with high-oxygen needs are not suited to blackwater environments. Cursory study has shown that ''B. collettei'' has a taste for terrestrial insects, but there hasn't been a great deal of diet-specific research. This is a similarity it shares with congener '' B. alburnoides'', which also eats terrestrial insects.Silva, Cylene & Ferreira, Efrem & de Deus, Cláudia. (2008)
Diet of Bryconops alburnoides and B-caudomaculatus (Osteichthyes : Characiformes) in the region affected by Balbina Hydroelectric Dam (Amazon drainage, Brazil)
Neotropical Ichthyology. 6. 237-242. 10.1590/S1679-62252008000200011. In contrast, ''B. caudomaculatus'' is known to jump out of the water in pursuit of flying insects.

References

{{Taxonbar, from=Q6416963 Fish described in 2005 Characiformes Fish of South America Fish of Venezuela