The biara (''Rhaphiodon vulpinus'') is a South American

piscivorous A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

in the

dogtooth characin Cynodontidae, also known as dogtooth characins or vampire tetras, are a family of predatory, characiform freshwater fishes from South America. This group is not very diverse, and includes only five genera and 14 species. Most of what is known abo ...

family. It belongs to the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus ''Rhaphiodon'', although some minor differences in

morphometrics Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...

and colour are known from across its large range.OPEFE:
Rhaphiodon.
' Retrieved 13 January 2017.SeriouslyFish:
Rhaphiodon vulpinus.
' Retrieved 13 January 2017. It is found in the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technology c ...

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 ...

, and

Río de la Plata Basin The Río de la Plata basin ( es, Cuenca del Plata, pt, Bacia do Prata), more often called the River Plate basin in scholarly writings, sometimes called the Platine basin or Platine region, is the hydrographical area in South America that drains ...

s, as well as rivers of the

Guianas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * ...

. It occurs in a wide range of freshwater habitats such as main river channels,

flooded forest Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found ...

s, lakes and reservoirs. Some populations are migratory. It reaches up to in weight. Although it reportedly can reach up to 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 ...

, the largest confirmed were . Like other dogtooth characins, the biara has very long pointed

canine teeth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened howeve ...

, but it is easily separated from its relatives by its very elongated and streamlined body shape. Like its relatives, the biara feeds almost entirely on other fish, which are speared by the long canines. In a study of the stomach content of 100 biaras, the majority were empty. The remaining had prey fish that were 30–50% of the length of the biara itself, and only a single contained another prey type, a

mayfly Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the ord ...

larvae. In a study observing the reproductive biology of the biara species in the Tocantins River of Brazil, it was found that the prime reproductive period takes place in November. The high-water conditions of the environment correlate to the increase of reproductive rate. The biara occasionally makes its way into the aquarium trade, but it requires a very large tank.

References

Cynodontidae Fish of South America Taxa named by Johann Baptist von Spix Taxa_named_by_Louis_Agassiz Fish described in 1829 {{Characiformes-stub