''Acestrorhynchus lacustris'' is a

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 ...

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 family

Acestrorhynchidae ''Acestrorhynchus'' ("needle jaw" ) is a genus of 14 species of characiform fish found only in fresh water in South America, the sole genus in the family Acestrorhynchidae. Their greatest diversity is in the Orinoco and Amazon basin The Ama ...

. It was described by

Christian Frederik Lütken Christian Frederik Lütken (; 7 October 1827, in Sorø – 6 February 1901), was a Denmark, Danish zoologist and naturalist. In 1852, he resigned his commission as a lieutenant with the Danish army, and earned his master's degree in sciences the ...

in 1875, originally under the genus '' Xiphorhamphus''. It inhabits the São Francisco and

Paraná River The Paraná River ( es, Río Paraná, links=no , pt, Rio Paraná, gn, Ysyry Parana) is a river in south-central South America, running through Brazil, Paraguay, and Argentina for some ."Parana River". Encyclopædia Britannica. Encyclopædia Br ...

. It reaches a maximum

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 ...

of . ''A. lacustris'' spawns between July–March.Spawning for ''Acestrorhynchus lacustris''
at www.fishbase.org.

References

Acestrorhynchidae Taxa named by Christian Frederik Lütken Fish described in 1875 {{Characiformes-stub