Bryconops Allisoni
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''Bryconops'' is a genus of freshwater fish in the family
Iguanodectidae Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It contains three genera: ''Iguanodectes, Piabucus'', and ''Bryconops''. Several species in the family, such as the green line lizard tetra (' ...
from
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
. 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 (a mark near the pectoral fin), and others have a reddish ocellus, or eyespot, on one or both lobes of the dorsal fin. Many ''Bryconops'' prefer clearwater environments with a strong current, though some are partial to slow-moving blackwater, and several are endemic to their locale. The majority of species are from
Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
or
Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...
. Rivers and river basins that house species of ''Bryconops'' include the Tapajos,
Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...
,
Tocantins Tocantins () is one of the 26 states of Brazil. It is the newest state, formed in 1988 and encompassing what had formerly been the northern two-fifths of the state of Goiás. Tocantins covers and had an estimated population of 1,496,880 in 2014 ...
,
Negro In the English language, the term ''negro'' (or sometimes ''negress'' for a female) is a term historically used to refer to people of Black people, Black African heritage. The term ''negro'' means the color black in Spanish and Portuguese (from ...
, and
Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...
. Few species of ''Bryconops'' have been evaluated as far as
conservation status The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation ...
, but most of them are believed to be low-risk species. The greatest threats to population levels come almost entirely in the form of
anthropogenic hazard A hazard is a potential source of harm. Substances, events, or circumstances can constitute hazards when their nature would potentially allow them to cause damage to health, life, property, or any other interest of value. The probability of that ...
s, including mining,
dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...
construction, farmland settlement, and destruction of the
riparian zone A riparian zone or riparian area is the interface between land and a river or stream. In some regions, the terms riparian woodland, riparian forest, riparian buffer zone, riparian corridor, and riparian strip are used to characterize a ripari ...
. Nonetheless, several species are found in areas of protected forest, which decreases some of the survival pressure.


Description

Members of ''Bryconops'' are fairly small, reaching just under half a foot at a maximum. '' B. durbinae'', the smallest, reaches 3.1 cm SL (standard length, without the tail fin included), and '' B. giacopinii'', the largest, reaches 18 cm TL (total length, with the tail fin included). They are slender, somewhat compressed and elongate, described as "spindle-shaped"."THE FISH FAMILIES". Field Guide to the Fishes of the Amazon, Orinoco, and Guianas, edited by Peter van der Sleen and James S. Albert, Princeton: Princeton University Press, 2017, pp. 95-96. https://doi.org/10.1515/9781400888801-009 The mouth is often terminal. Certain morphological consistencies within the genus have contributed to its accepted status as a monophyletic
clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
, though said monophyly remains somewhat unclear, and is largely based on shared physical traits. ''Bryconops'' are most often silver or some shade therein, sometimes with a darker back and/or a greenish tint. Only three species - '' B. inpai'', '' B. marabaixo'', and '' B. sapezal'' - have a hint of blue in their scales. There is great variety in fin coloration, though they are most often some blend of hyaline, red, and dusky-gray; some species, like '' B. caudomaculatus'' (the tailspot tetra) bear an ocellus, or eyespot, on the dorsal lobe of the caudal fin. Other species, like '' B. affinis'', have an ocellus on both lobes, nearly symmetrical. The only two species to have a dark dorsal fin are '' B. chernoffi'' and '' B. piracolina''. It is uncommon, but not unheard of, for members of ''Bryconops'' to have a humeral mark, which is a spot of pigment near the dorsal fin (occasionally two spots). The scales are
cycloid In geometry, a cycloid is the curve traced by a point on a circle as it Rolling, rolls along a Line (geometry), straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette (curve), roulette, a curve g ...
, usually taller than they are wide. Most members of the genus have fairly well-defined radii on the scales; these are slightly more subdued in ''B. affinis''. The scales of the
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 epithelia ...
are pored, but the number of pored scales varies wildly from species to species, anywhere from 9 to 61. Even within a single species, '' B. disruptus'', the range is from 9 to 23. The pored scales either do or do not extend to the hypural plate, the plate that joins the fish's tail to its body, and this is a feature that can be used to tell species apart (such as ''B. caudomaculatus'', whose pored lateral scales stop at the hypural plate, versus '' B. magoi'' and '' B. collettei'', whose pored lateral scales extend 2-3 scales beyond that).


Taxonomy

''Bryconops'' was long considered to belong to the family
Characidae Characidae, the characids, is a family of freshwater subtropical and tropical fish belonging to the order Characiformes. They are found throughout much of Central and South America, including such major waterways as the Amazon and Orinoco Riv ...
''
incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
''. It is still listed there by some resources, such as ADW 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 ...
. Characidae is an enormously varied family, with many genera in a similar position. However, research in 2011 examined morphological and
phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
evidence, and prompted taxonomists to move ''Bryconops'' to a different family,
Iguanodectidae Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It contains three genera: ''Iguanodectes, Piabucus'', and ''Bryconops''. Several species in the family, such as the green line lizard tetra (' ...
. This was also done to keep Characidae monophyletic. The genera ''
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 maxi ...
'' and '' Iguanodectes'' are in Iguanodectidae as well, and were also moved based on the 2011 research. ''Piabucus'' and ''Iguanodectes'' come together to make up a
subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...
, Iguanodectinae; Bryconops is considered its own monophyletic clade. The family Iguanodectidae is a revival from some of the works of
Carl H. Eigenmann Carl Henry Eigenmann (March 9, 1863 – April 24, 1927) was a German-American ichthyology, ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited wit ...
, a prolific German-American ichthyologist. ''Bryconops'' has two
subgenera In biology, a subgenus ( subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the ge ...
: ''Bryconops'' and ''Creatochanes''. The latter was considered its own standalone genus before being synonymized with ''Bryconops'' and turned into a subgenus in 1999. Members of ''Bryconops'' usually have no teeth to either side of the
maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...
ry, or a single conical tooth on one side. ''Creatochanes'', in contrast, is characterized partially by the presence of 1-3 teeth to both sides of the maxillary. Another difference is in the length of the maxillary bone; in ''Bryconops'', it does not reach the junction of the second and third infraorbital bones, but in ''Creatochanes'' it does. A third difference is in the ossification and denticulation of the
gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of th ...
s, which is strong in ''Creatochanes'' and poor in ''Bryconops''. ''Creatochanes'' is the more speciose of the two. Altogether, there are 27 recognized species in the genus ''Bryconops''. This makes it the largest genus in its family; ''Iguanodectes'' has 8, and ''Piabucus'' has 3. It continues to grow into the 21st century, with new species having been described as recently as 2019 ('' B. hexalepis''), 2020 ('' B. marabaixo''), and 2021 ('' B. florenceae'').


Species

In alphabetical order, the species are: * '' Bryconops affinis'' ( Günther, 1864) (Orangefin tetra) * '' Bryconops alburnoides'' ( Kner, 1858) * '' Bryconops allisoni'' ( C. S. de Oliveira,
Canto The canto () is a principal form of division in medieval and modern long poetry. Etymology and equivalent terms The word ''canto'' is derived from the Italian word for "song" or "singing", which comes from the Latin ''cantus'', "song", from th ...
& F. R. V. Ribeiro, 2019)
* '' Bryconops caudomaculatus'' ( Günther, 1864) (Tailspot tetra) * '' Bryconops chernoffi'' ( Oliveira,
Lima Lima ( ; ), founded in 1535 as the Ciudad de los Reyes (, Spanish for "City of Biblical Magi, Kings"), is the capital and largest city of Peru. It is located in the valleys of the Chillón River, Chillón, Rímac River, Rímac and Lurín Rive ...
, & Bogotá-Gregory, 2018)
* '' Bryconops colanegra'' (
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
& Machado-Allison, 1999)
* '' Bryconops colaroja'' (
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
& Machado-Allison, 1999)
* '' Bryconops collettei'' (
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
& Machado-Allison, 2005)
* '' Bryconops cyrtogaster'' (
Norman Norman or Normans may refer to: Ethnic and cultural identity * The Normans, a people partly descended from Norse Vikings who settled in the territory of Normandy in France in the 9th and 10th centuries ** People or things connected with the Norma ...
, 1926)
* '' Bryconops disruptus'' ( Machado-Allison &
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
, 1997)
* ''
Bryconops durbinae ''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 Endemism, endemic to the Tapajós, Ta ...
'' ( C. H. Eigenmann, 1908) * '' Bryconops florenceae'' ( Oliveira, Ota, Sabaj, & Py-Daniel, 2021) * '' Bryconops giacopinii'' ( Fernández-Yépez, 1950) * '' Bryconops gracilis'' ( C. H. Eigenmann, 1908) * '' Bryconops hexalepis'' ( Guedes, Oliveira, & Lucinda, 2019) * '' Bryconops humeralis'' ( Machado-Allison,
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
& Buckup, 1996)
* '' Bryconops imitator'' (
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
& Machado-Allison, 2002)
* '' Bryconops inpai'' ( Knöppel,
Junk Junk may refer to: Arts and entertainment * ''Junk'' (film), a 2000 Japanese horror film * '' J-U-N-K'', a 1920 American film * ''Junk'' (novel), by Melvin Burgess, 1996 * ''Junk'', a novel by Christopher Largen * '' Junk: Record of the Last ...
&
Géry Géry () is a commune in the Meuse department in Grand Est in north-eastern France. See also *Communes of the Meuse department The following is a list of the 499 Communes of France, communes of the Meuse (department), Meuse Departments of ...
, 1968)
* '' Bryconops magoi'' (
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
& Machado-Allison, 2005)
* '' Bryconops marabaixo'' ( Oliveira,
Moreira Moreira may refer to: Places * Moreira (Maia), a parish in Maia Municipality, northern Portugal * , a parish in Monção Municipality, northern Portugal * , a parish in Nelas Nelas () is a municipality located in the Centro Region of continent ...
,
Lima Lima ( ; ), founded in 1535 as the Ciudad de los Reyes (, Spanish for "City of Biblical Magi, Kings"), is the capital and largest city of Peru. It is located in the valleys of the Chillón River, Chillón, Rímac River, Rímac and Lurín Rive ...
, & Py-Daniel, 2020)
* '' Bryconops melanurus'' (
Bloch Bloch is a surname of German origin. Notable people with this surname include: A *Adele Bloch-Bauer (1881–1925), Austrian entrepreneur *Albert Bloch (1882–1961), American painter *Alexandre Bloch (1857–1919), French painter *Alfred Bloch ( ...
, 1794)
* '' Bryconops munduruku'' ( C. S. de Oliveira,
Canto The canto () is a principal form of division in medieval and modern long poetry. Etymology and equivalent terms The word ''canto'' is derived from the Italian word for "song" or "singing", which comes from the Latin ''cantus'', "song", from th ...
& F. R. V. Ribeiro, 2015)
* ''
Bryconops piracolina ''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 col ...
'' ( Wingert & L. R. Malabarba, 2011) * '' Bryconops rheoruber'' ( Oliveira, Ota, Sabaj, & Py-Daniel, 2019) * '' Bryconops sapezal'' ( Wingert, Chuctaya, & Malabarba, 2018) * '' Bryconops tocantinensis'' ( Guedes, E. F. de Oliveira & P. H. F. Lucinda, 2016) * '' Bryconops transitoria'' (
Steindachner Franz Steindachner (11 November 1834 in Vienna – 10 December 1919 in Vienna) was an Austrian zoologist, ichthyologist, and herpetologist. He published over 200 papers on fishes and over 50 papers on reptiles and amphibians. Steindachner descri ...
, 1915)
* '' Bryconops vibex'' ( Machado-Allison,
Chernoff Chernoff may be either a Jewish surname, meaning "descendent of Charna" or a German-language transliteration of the Russian surname Chernov. Notable people with the surname include: * Herman Chernoff (born 1923), American applied mathematician, st ...
& Buckup, 1996)


History

Upon describing ''Bryconops alburnoides'' in 1858, Austrian ichthyologist
Rudolf Kner Rudolf Ignaz Kner (24 August 1810 – 27 October 1869) was an Austrian geologist, paleontologist, zoologist and ichthyologist. He also wrote some poems which were published by his brother-in-law K.A. Kaltenbrunner. Biography Kner was bo ...
established ''Bryconops'' as a new genus. Kner also offered a description of new congener ''B. lucidum'', which has since been synonymized with ''B. alburnoides.'' In 1910, German-American ichthyologist
Carl H. Eigenmann Carl Henry Eigenmann (March 9, 1863 – April 24, 1927) was a German-American ichthyology, ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited wit ...
designated ''Bryconops alburnoides'' the
type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
of the genus. Technically, the earliest member of the genus to be described is '' Bryconops melanurus'', which was originally classified as ''Salmo melanurus'' by German naturalist
Marcus Elieser Bloch Marcus Elieser Bloch (1723–1799) was a German physician and naturalist who is best known for his contribution to ichthyology through his multi-volume catalog of plates illustrating the fishes of the world. Brought up in a Hebrew-speaking Jewish ...
in the year 1764.


Etymology

The genus name ''Bryconops'' originates from the genus ''
Brycon ''Brycon'' is a genus of fish in the family Bryconidae and order Characiformes found in freshwater habitats in Central and South America, ranging from southern Mexico to northern Argentina. Despite not being closely related to true trout, they a ...
'' and the Greek suffix "-ops", which means "appearance" or "resemblance". This is because Kner noted visual similarities between members of the two genera upon description. In turn, the genus name ''Brycon'' originates from the Greek "bryko", which means "to bite" or "to devour". Fish of the genus ''Brycon'' are equipped with a full set of teeth on their
maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...
ries, making for an apt name. Many of the specific names in ''Bryconops'' originate with aspects of the species' appearances. For instance, "caudomaculatus" means "tail spot", for the distinct caudal ocellus on ''B. caudomaculatus''. Other epithets originate in specific people, such as ''B. allisoni'' (
Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...
n ichthyologist
Antonio Machado-Allison Antonio is a masculine given name of Etruscan origin deriving from the root name Antonius. It is a common name among Romance language–speaking populations as well as the Balkans and Lusophone Africa. It has been among the top 400 most popular m ...
), ''B. chernoffi'' (
American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...
ichthyologist
Barry Chernoff Barry may refer to: People and fictional characters * Barry (name), including lists of people with the given name, nickname or surname, as well as fictional characters with the given name * Dancing Barry, stage name of Barry Richards (born c. 195 ...
), and ''B. magoi'' (
Francisco Mago-Leccia Francisco Mago Leccia (“Mago”; May 21, 1931, in Tumeremo, Bolívar (state), Bolívar State, Venezuela – February 27, 2004, in Puerto La Cruz, Anzoátegui State, Venezuela),Schaefer, Provenzano, Pinna & Baskin (2005) - ''New and Noteworthy V ...
, considered the pioneer of Venezuelan ichthyology). A few species are named after specific locations, such as ''B. tocantinensis'', which earned its specific epithet from its likely restriction to the upper
Tocantins basin The Tocantins basin, or Araguaia-Tocantins basin, is a Brazilian river basin, almost entirely located between the 2ºS and 18ºS parallels and the 46ºW and 56ºW meridians. The main rivers in the basin are Tocantins and Araguaia. The basin exten ...
. Another example is ''B. sapezal'', from its type locale of the Sapezal municipality in
Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
. Some species names take after cultural or historical significance from the type locality, like ''B. munduruku'', after an indigenous tribe, or ''B. marabaixo'', after a religious and historical festival of the same name.


Habitat and distribution

All members of ''Bryconops'' are restricted to the northern half of
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
, where they occupy various river basins and tributaries of major rivers. Their distribution is quite wide as a genus, though individual species display some endemism (such as the cases of ''B. piracolina'', restricted to the creek of its namesake, and ''B. chernoffi'', to the Rio Ipixuna). Specific rivers known to host various species of ''Bryconops'' include the
Tapajós The Tapajós ( ) is a river in Brazil. It runs through the Amazon Rainforest and is a major tributary of the Amazon River. When combined with the Juruena River, the Tapajós is approximately long. Prior to a drastic increase in illegal gold mi ...
,
Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...
,
Negro In the English language, the term ''negro'' (or sometimes ''negress'' for a female) is a term historically used to refer to people of Black people, Black African heritage. The term ''negro'' means the color black in Spanish and Portuguese (from ...
, Casiquiare, and
Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...
. Members of ''Bryconops'' have varying preferences when it comes to specific environments, though they generally fall into one of two categories - those that inhabit blackwater, and those that inhabit fast-moving clearwater. Examples of the former include ''B. disruptus'', ''B. humeralis'', and ''B. colaroja''. Examples of the latter include ''B. rheoruber'', ''B. sapezal'', and ''B. florenceae''. Several members are found in both environments despite the contrast, such as ''B. collettei'' and ''B. caudomaculatus''. The lattermost species, ''B. caudomaculatus'', demonstrates varying body composition based upon where it lives (a fast-moving creek versus a still lagoon). Examination based upon physical aspects can correctly classify at least 75% of any given specimens' habitats. More of the body weight is shifted backwards for tailspot tetras that live in lagoon habitats, and the mouth is slightly more upturned for channel-dwelling tetras.Langerhans, Brian & Layman, Craig & LANGERHANS, AIMEE & Dewitt, Thomas. (2003)
Habitat-associated morphological divergens in two Neotropical fish species
Biological Journal of the Linnean Society. 80. 689 - 698. 10.1111/j.1095-8312.2003.00266.x.
It is unknown if similar morphology changes affect other members of the genus.


Ecology and diet

Species of ''Bryconops'' are known to live peacefully amongst other species of fish, as well as syntopically with other members of Bryconops. They frequently form schools midstream regardless of species. The exception to this may be ''B. caudomaculatus'', which has a reputation for being "quarrelsome", though it does spawn in schools. Not only are members of ''Bryconops'' a food source for larger fish, but they are also notably preyed upon by
parasites Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...
. In 2011, ''B. caudomaculatus'' was discovered to be the host for a new species of
trematode Trematoda is a Class (biology), class of flatworms known as trematodes, and commonly as flukes. They are obligate parasite, obligate Endoparasites, internal parasites with a complex biological life cycle, life cycle requiring at least two Host ( ...
(parasitic flatworm), ''Auriculostoma foliaceum'' (which is currently accepted as ''Creptotrema foliaceum''). ''B. affinis'' is frequently subject to infestation by gill parasites of the genus ''Jainus'' (not to be confused with the sawfly genus ''
Janus In ancient Roman religion and myth, Janus ( ; ) is the god of beginnings, gates, transitions, time, duality, doorways, passages, frames, and endings. He is usually depicted as having two faces. The month of January is named for Janus (''Ianu ...
'').


Reproduction

Little is known of general reproduction habits for ''Bryconops'', but there is limited research on species-specific behaviors. For instance, ''B. caudomaculatus'' is known to spawn in schools during
monsoon season The wet season (sometimes called the rainy season or monsoon season) is the time of year when most of a region's average annual rainfall occurs. Generally, the season lasts at least one month. The term ''green season'' is also sometimes used a ...
. ''B. affinis'' is a batch spawner, releasing batches of eggs in a gradual manner as opposed to all at once, and the eggs are adhesive, though this is not the result of an additional substance secreted alongside them; a layer of the outer membrane of the egg, called the zona pediculla, displays specialized microscopic structural aspects during formation that play a role. It prefers to spawn in schools, hidden between plants.


Diet

Many members of ''Bryconops'' are
invertivore Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγε ...
s, largely with a preference for terrestrial insects. For instance, ''B. inpai'' and ''B. magoi'' both live in areas with dense
riparian vegetation A riparian zone or riparian area is the interface between land and a river or stream. In some regions, the terms riparian woodland, riparian forest, riparian buffer zone, riparian corridor, and riparian strip are used to characterize a ripari ...
, which means that insects frequently fall into the water from above, generating a consistent food source. ''B. alburnoides'' picks insects from the riverbanks, though it does take advantage of wind or rain that sweep food into the water. ''B. caudomaculatus'' eats the aquatic larval forms of its prey, but will also actively leap from the water to target flying insects, especially during twilight hours. Though largely invertivores, several members of ''Bryconops'' are omnivores that take supplemental plant material, like ''B. inpai'' and ''B. affinis''. ''B. caudomaculatus'' is known to eat plants as well, and includes smaller fish in its diet. ''B. collettei'' is thought to be an herbivore.


Conservation status

Though not all members have been evaluated, members of ''Bryconops'' are largely thought to be of least concern or near threatened by the
IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
. Almost all threats come in the form of environmental
anthropogenic hazard A hazard is a potential source of harm. Substances, events, or circumstances can constitute hazards when their nature would potentially allow them to cause damage to health, life, property, or any other interest of value. The probability of that ...
s, including farmland settlement, illegal mining, dam construction, and riparian zone destruction. Species in the
Rio Tapajós Rio or Río is the Portuguese and Spanish word for "river". The word also exists in Italian, but is largely obsolete and used in a poetical or literary context to mean "stream". Rio, RIO or Río may also refer to: Places United States * Rio, Flo ...
in particular are under greater survival pressure due to environmental disturbance as a result of
illegal mining Illegal mining is mining activity that is undertaken without state permission. Illegal mining is the extraction of precious metals/rocks without following the proper procedures to participate in legal mining activity. These procedures include pe ...
. The illegal mining sector is enormous in Latin America as a whole, despite its risks to both participants and the environment, and can have disastrous results, such as
mercury poisoning Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashe ...
affecting the people and wildlife involved. At one point, there was such heavy sediment disturbance and deposition that entire portions of the Tapajós turned entirely brown. The Tapajós is also often targeted for infrastructure development, though considerations have been taken in recent times in the context of environmental preservation. Species from the
Tocantins basin The Tocantins basin, or Araguaia-Tocantins basin, is a Brazilian river basin, almost entirely located between the 2ºS and 18ºS parallels and the 46ºW and 56ºW meridians. The main rivers in the basin are Tocantins and Araguaia. The basin exten ...
are largely pressured by the construction of
hydroelectric dams Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other renewable sources combined and also ...
, which greatly alter the flow of water and present new environmental hazards. This is also the case for species native to the Xingu, which is home to the world's third-largest hydroelectric dam, the
Belo Monte dam The Belo Monte Dam (''formerly known as'' Kararaô) is a hydroelectric dam complex on the northern part of the Xingu River in the state of Pará, Brazil. After its completion, with the installation of its 18th turbine, in November 2019, the in ...
. Some species are adaptable, and can survive in the subsequent altered environments. Destruction and disturbance of the
riparian zone A riparian zone or riparian area is the interface between land and a river or stream. In some regions, the terms riparian woodland, riparian forest, riparian buffer zone, riparian corridor, and riparian strip are used to characterize a ripari ...
(the interface between water and land) is another factor that could trouble various species of ''Bryconops''.
Deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
and
logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucks Settlement of the surrounding land for use in
farm A farm (also called an agricultural holding) is an area of land that is devoted primarily to agricultural processes with the primary objective of producing food and other crops; it is the basic facility in food production. The name is used fo ...
s causes a marked decrease in water quality, including factors like pesticide use and fecal contamination.


Presence in aquaria

Data is limited, as species of ''Bryconops'' are not in particularly high demand from aquarists, but several species have a presence in the fish-keeping community, and are known to be deported from their native habitats for use therein. * ''B. colanegra'' and ''B. colaroja'' are taken from the wild, though not in numbers great enough to be concerning. * ''B. melanurus'' is exported from
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
and has a presence in hobbyist communities. Still, it tends to fare poorly in tank settings. * ''B. cyrtogaster'' is likely taken from the wild for use in the aquarium industry. Details are sparse. * ''B. caudomaculatus'' is taken from the wild in multiple countries, and remains common in many areas thanks to its hardy nature. * ''B. affinis'' is of definite interest to hobbyists, but extensive research has not been done regarding its popularity or export.


References

{{Taxonbar, from=Q147193 Bryconops Characiformes genera Taxa named by Rudolf Kner Taxa described in 1858