''Bryconops'' is a genus of freshwater fish in the family
Iguanodectidae from
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 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 ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
or
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 ...
. 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 , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...
,
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 20 ...
,
Negro
In the English language, ''negro'' is a term historically used to denote persons considered to be of Black African heritage. The word ''negro'' means the color black in both Spanish and in Portuguese, where English took it from. The term can be ...
, and
Madeira
)
, anthem = ( en, "Anthem of the Autonomous Region of Madeira")
, song_type = Regional anthem
, image_map=EU-Portugal_with_Madeira_circled.svg
, map_alt=Location of Madeira
, map_caption=Location of Madeira
, subdivision_type=Sovereign st ...
.
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
Anthropogenic hazards are hazards caused by human action or inaction. They are contrasted with natural hazards. Anthropogenic hazards may adversely affect humans, other organisms, biomes, and ecosystems. They can even cause an omnicide. The f ...
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, a ...
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. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
. Nonetheless, several species are found in areas of protected forest, which decreases some of the survival pressure.
Description
![Bryconops_giacopinii](https://upload.wikimedia.org/wikipedia/commons/2/2a/Bryconops_giacopinii.png)
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
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
,
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 rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve ...
, 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 epithelial ...
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 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 ...
''
incertae sedis
' () or ''problematica'' is a term used for a 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 (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
evidence, and prompted taxonomists to move ''Bryconops'' to a different family,
Iguanodectidae. 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
''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 ...
'' 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 subfamily botanical names with "-oideae", and zoologi ...
,
Iguanodectinae
Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. I ...
; 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 ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited with identifyin ...
, a prolific German-American ichthyologist.
''Bryconops'' has two
subgenera
In biology, a subgenus (plural: 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 t ...
: ''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
The maxilla (plural: ''maxillae'' ) in vertebrates 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 t ...
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 the ...
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'').
In alphabetical order, the species are:
* ''
Bryconops affinis
The orangefin tetra (''Bryconops affinis'') is a small species of freshwater fish from South America that belongs to the family Iguanodectidae. Though common in its native range, it seems to prefer fast-flowing and shallow creeks. It is an active ...
''
( Günther, 1864) (Orangefin tetra)
* ''
Bryconops alburnoides
''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 ...
''
( 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 the ...
& F. R. V. Ribeiro, 2019)
* ''
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 ...
''
( Günther, 1864) (Tailspot tetra)
* ''
Bryconops chernoffi''
( Oliveira, Lima
Lima ( ; ), originally founded as Ciudad de Los Reyes (City of The Kings) is the capital and the largest city of Peru. It is located in the valleys of the Chillón River, Chillón, Rímac River, Rímac and Lurín Rivers, in the desert zone of t ...
, & Bogotá-Gregory, 2018)
* ''
Bryconops colanegra
''Bryconops colanegra'' is a small, slender-bodied species of freshwater fish from South America, about 3.5 in (8.8 cm) long. It has a black tail fin that bears hints of red, and its scales are dark along the back, transitioning to a silver bell ...
''
( Chernoff & Machado-Allison, 1999)
* ''
Bryconops colaroja
''Bryconops colaroja'' is a small species of fish from the fresh waters of South America. 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 ...
''
( Chernoff & Machado-Allison, 1999)
* ''
Bryconops collettei
''Bryconops collettei'' is a small freshwater fish from the rivers of South America. 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 ...
''
( Chernoff & Machado-Allison, 2005)
* ''
Bryconops cyrtogaster
''Bryconops cyrtogaster'' is a midsize species of freshwater fish found in the rivers of South America. 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 ...
''
(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 10th and 11th centuries
** People or things connected with the Norm ...
, 1926)
* ''
Bryconops disruptus
''Bryconops disruptus'' is a small freshwater fish of the family Iguanodectidae. It is only found in the Rio Negro in South America. Like the rest of the genus ''Bryconops'', ''B. disruptus'' is silvery in color, with a relatively deep chest and ...
''
( Machado-Allison & Chernoff, 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''. Like all members of Iguanodectidae, it inha ...
''
( C. H. Eigenmann, 1908)
* ''
Bryconops florenceae''
( Oliveira, Ota, Sabaj, & Py-Daniel, 2021)
* ''
Bryconops giacopinii
''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 large ...
''
( Fernández-Yépez, 1950)
* ''
Bryconops gracilis
''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 ...
''
( C. H. Eigenmann, 1908)
* ''
Bryconops hexalepis''
( Guedes, Oliveira, & Lucinda, 2019)
* ''
Bryconops humeralis''
( Machado-Allison, Chernoff & Buckup, 1996)
* ''
Bryconops imitator''
( Chernoff & Machado-Allison, 2002)
* ''
Bryconops inpai
''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 h ...
''
( Knöppel, Junk & 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 the Meuse department of France.
The communes cooperate in the follo ...
, 1968)
* ''
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 ...
''
( Chernoff & 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 Municipality, central Portugal
People
*Moreira (name), given name ...
, Lima
Lima ( ; ), originally founded as Ciudad de Los Reyes (City of The Kings) is the capital and the largest city of Peru. It is located in the valleys of the Chillón River, Chillón, Rímac River, Rímac and Lurín Rivers, in the desert zone of t ...
, & Py-Daniel, 2020)
* ''
Bryconops melanurus''
(Bloch Bloch is a surname of German origin. Notable people with this surname include:
A–F
* (1859-1914), French rabbi
*Adele Bloch-Bauer (1881-1925), Austrian entrepreneur
*Albert Bloch (1882–1961), American painter
* (born 1972), German motor journal ...
, 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 the ...
& F. R. V. Ribeiro, 2015)
* ''
Bryconops piracolina''
( 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
''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 ...
''
(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 describ ...
, 1915)
* ''
Bryconops vibex''
( Machado-Allison, Chernoff & 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 ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited with identifyin ...
designated ''Bryconops alburnoides'' the
type species
In 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 species that contains the biological type specimen ...
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'' 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
The maxilla (plural: ''maxillae'' ) in vertebrates 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 t ...
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 ( 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 ...
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 male ...
), ''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, pe ...
ichthyologist
Barry Chernoff), and ''B. magoi'' (
Francisco Mago-Leccia, 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 exte ...
. Another example is ''B. sapezal'', from its type locale of the
Sapezal municipality in
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
. 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 relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, 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 ( pt, Rio 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. It is one of the largest clearw ...
,
Orinoco
The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...
,
Negro
In the English language, ''negro'' is a term historically used to denote persons considered to be of Black African heritage. The word ''negro'' means the color black in both Spanish and in Portuguese, where English took it from. The term can be ...
,
Casiquiare
The Casiquiare river () is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the world's largest ...
,
and
Madeira
)
, anthem = ( en, "Anthem of the Autonomous Region of Madeira")
, song_type = Regional anthem
, image_map=EU-Portugal_with_Madeira_circled.svg
, map_alt=Location of Madeira
, map_caption=Location of Madeira
, subdivision_type=Sovereign st ...
.
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
![Bryconops_alburnoides](https://upload.wikimedia.org/wikipedia/commons/e/e4/Bryconops_alburnoides.jpg)
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 Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...
. In 2011, ''B. caudomaculatus'' was discovered to be the host for a new species of
trematode
Trematoda is a class of flatworms known as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive 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 ( ; la, Ianvs ) 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 Janu ...
'').
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) is the time of year when most of a region's average annual rainfall occurs. It is the time of year where the majority of a country's or region's annual precipitation occurs. Generally, the sea ...
.
''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. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
, 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; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
. Almost all threats come in the form of environmental
anthropogenic hazard
Anthropogenic hazards are hazards caused by human action or inaction. They are contrasted with natural hazards. Anthropogenic hazards may adversely affect humans, other organisms, biomes, and ecosystems. They can even cause an omnicide. The f ...
s, including farmland settlement, illegal mining, dam construction, and riparian zone destruction.
Species in the
Rio Tapajós
Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil.
Rio or Río may also refer to:
Geography Brazil
* Rio de Janeiro
* Rio do Sul, a ...
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, in particular in absence of land rights, mining licenses, and exploration or mineral transportation permits.
Illegal mining can be a subsistence activity, as is the cas ...
. 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 exte ...
are largely pressured by the construction of
hydroelectric dams
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...
, 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 inst ...
.
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. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
(the interface between water and land) is another factor that could trouble various species of ''Bryconops''.
Deforestation
Deforestation or forest clearance is the removal 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. The most concentrated d ...
and
logging
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars.
Logging is the beginning of a supply chain ...
have a negative impact, removing food sources and shelter from the elements.
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
, image_flag = Flag of Peru.svg
, image_coat = Escudo nacional del Perú.svg
, other_symbol = Great Seal of the State
, other_symbol_type = Seal (emblem), National seal
, national_motto = "Fi ...
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
Fish of South America
Characiformes
Characiformes genera
Taxa named by Rudolf Kner
Taxa described in 1858
Freshwater animals
Freshwater fish
Freshwater fish of South America