''Hyphessobrycon'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

freshwater fish Freshwater fish are those that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 1.05%. These environments differ from marine conditions in many ways, especially the difference in levels of s ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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 ...

. These

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

are among the fishes known as tetras. The genus is distributed in the

Neotropical realm The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

from southern

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

to Río de la Plata in

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. Many of these species are native to

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 ...

; about six species are from

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

and a single species, '' H. compressus'' is from southern Mexico. All small fishes, the ''Hyphessobrycon'' tetras reach maximum overall lengths of about . Great anatomical diversity exists in this genus.Lucena, C.A.S.d. (2003)
New characid fish, ''Hyphessobrycon scutulatus'', from the rio Teles Pires drainage, upper rio Tapajós system (Ostariophysi: Characiformes: Characidae).
''Neotropical Ichthyology, 1 (2): 93–96.'' They are generally of typical characin shape, but vary greatly in coloration and body form, many species having distinctive black, red, or yellow markings on their bodies and fins. These species are generally omnivorous, feeding predominantly on small

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecol ...

worms, and

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. When spawning, they scatter their eggs and guard neither eggs nor young.

Taxonomy

This large genus of characins includes over 150 species. The systematics of ''Hyphessobrycon'' are still largely unresolved.Lima, F.C.T. & Moreira, C.R. (2003)
Three new species of ''Hyphessobrycon'' (Characiformes: Characidae) from the upper rio Araguaia basin in Brazil.
''Neotropical Ichthyology, 1 (1): 21–33.'' Six groups within this genus have been recognized based on color patterns alone.Bertaco, V.A. & Malabarba, L.R. (2005)
A new species of ''Hyphessobrycon'' (Teleostei: Characidae) from the upper Rio Tocantins drainage, with bony hooks on fins.
''Neotropical Ichthyology, 3 (1): 83–88.'' With no

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 ...

analysis of this genus, species are placed into this genus as anatomically defined by

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 ...

in 1917. By this definition, ''Hyphessobrycon'' is identified by the presence of an adipose fin, incomplete

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 ...

, two tooth series in the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

, with the teeth of the external series continuous in a single series, teeth not strictly conical, preventral scales arranged in more than one row and lack of scales in the

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

. The characteristic of extension of scales onto the caudal fin that differentiates this genus from ''

Hemigrammus ''Hemigrammus'' is a genus of freshwater fish in the family Characidae native to South America (including Trinidad) and commonly seen in the aquarium trade. These are medium-small tetras where the largest species reach up to around . Species Th ...

'' is not satisfactory, as it occurs in intermediate conditions. This genus is not

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

. A monophyletic group within ''Hyphessobrycon'' has been hypothesized, termed the rosy tetra

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, ...

; this group is based upon coloration pattern and the shape of dorsal and

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

s of males. Recognition of monophyletic groups among ''Hyphessobrycon'' species is complicated by the difficulty in finding characters useful for hypothesis of relationships among the species. Traditional characters used to identify ''Hyphessobrycon'' are phylogenetically unreliable.

Etymology

The

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name, ''Hyphessobrycon'', is of slightly uncertain origin. The second part derives from the Greek βρύκω (to bite); the first, derives from an ostensible Greek ''hyphesson'', which may be an error for υπελάσσων (slightly smaller).

Relationship to humans

None of the roughly 100 fishes in the genus has been rated 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 ...

, but many species have small distributions and at least one, ''

Hyphessobrycon flammeus The flame tetra (''Hyphessobrycon flammeus''), also known as the red tetra or Rio tetra, is a small freshwater fish of the characin family Characidae. This tetra was first introduced as aquarium fish in 1920 by C. Bruening, Hamburg, Germany, and ...

'', is believed to be highly

threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensat ...

. This species only occurs in a few rivers and streams in coastal

Rio de Janeiro State Rio de Janeiro () is one of the 27 federative units of Brazil. It has the second largest economy of Brazil, with the largest being that of the state of São Paulo. The state, which has 8.2% of the Brazilian population, is responsible for 9.2% of ...

and in

São Paulo State SAO or Sao may refer to: Places * Sao civilisation, in Middle Africa from 6th century BC to 16th century AD * Sao, a town in Boussé Department, Burkina Faso * Saco Transportation Center (station code SAO), a train station in Saco, Maine, U.S ...

. Three other species are recognized as threatened in Brazil: ''H. coelestinus'', ''H. duragenys'', and ''H. taurocephalus''. ICMBio (Ministry of the Environment, Brazil)
Portaria MMA nº 445, de 17 de dezembro de 2014
. Lista de Especies Ameaçadas - Saiba Mais. Retrieved 1 December 2018. Many ''Hyphessobrycon'' species are popular

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

fish, and some, including ''H. flammeus'', are bred in large numbers in captivity.''Hyphessobrycon flammeus'' Myers, 1924 Flame Tetra.
Seriously Fish. Retrieved 21 March 2017.Korotev, K. (2017)
Breeding ''Hyphessobrycon flammeus''.
AquaInfo. Retrieved 21 March 2017.

Species

The 156 currently recognized species in this genus are:

References

{{Taxonbar, from=Q132810 Characidae Taxa named by Marion Durbin Ellis Fish of South America Freshwater fish genera Tetras