''Pygopristis denticulata'', also known as the lobetoothed piranha, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

piranha A piranha (, or ; ) is any of a number of freshwater fish species in the subfamily Serrasalminae, of the family Serrasalmidae, in the order Characiformes. These fish inhabit South American rivers, floodplains, lakes and reservoirs. Although ...

. It is a rare

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 ...

characiform Characiformes is an order of Actinopterygii, ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.; Buckup P.A ...

fish found in the

Orinoco River 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 ...

basin, rivers of the northern and eastern

Guiana Shield The Guiana Shield (; ; ; ) is one of the three cratons of the South American Plate. It is a 1.7 billion-year-old Precambrian geological formation in northeast South America that forms a portion of the northern coast. The higher elevations on ...

, and tributaries of the lower Amazon River. Like other piranhas, it is found in freshwater, with specimens of this species typically found in acidic clearwater or blackwater environments. Despite their ferocious reputation, many piranhas have broader diets; this species feeds on the scales of other fish as juveniles, but transitions to a broader diet of aquatic insects, small fish, and fruits as adults.

Biology

''P. denticulata'' grows to about in

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

. It has 62 chromosomes.''P. denticulata'' has pentacuspid teeth and a middle

cusp A cusp is the most pointed end of a curve. It often refers to cusp (anatomy), a pointed structure on a tooth. Cusp or CUSP may also refer to: Mathematics * Cusp (singularity), a singular point of a curve * Cusp catastrophe, a branch of bifu ...

that is usually only slightly larger than the other cusps. This is unlike other piranhas, which have tricuspid teeth with a larger middle cusp, making the teeth appear triangular.

Taxonomy

Within the family

Serrasalmidae The Serrasalmidae (serrasalmids) are a family of characiform fishes native to freshwater habitats of South America. They include more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the ...

, ''P. denticulata'' is more closely related to ''

Catoprion ''Catoprion'' is a genus of serrasalmids from tropical South America, including the basins of the Amazon, Essequibo, Orinoco and Paraguay rivers. It was believed to be a monotypic In biology, a monotypic taxon is a taxonomic group (taxon) th ...

'' than it is to the majority of species traditionally considered true piranhas.

Gallery

File:Pygopristis denticulata.jpg, Juvenile File:FMIB 52277 Dentition of Pygopristis denticulatus (Cuvier).jpeg, Dentition

References

Serrasalmidae Piranhas Monotypic fish genera Freshwater fish of Brazil Fish described in 1819 Taxa named by Georges Cuvier {{Characiformes-stub