''Danionella priapus'' is a species of ''

Danionella ''Danionella'' is a genus of danionin fish found in freshwater habitats in Myanmar and West Bengal, India. It includes some of the smallest fishes. Distribution Four out of five described species of ''Danionella'' are found in Myanmar. ''D. tr ...

'' endemic to

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

. It is

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

and, like other species in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

, possesses a skeleton with fewer bones than the closely related

zebrafish The zebrafish (''Danio rerio'') is a species of freshwater ray-finned fish belonging to the family Danionidae of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (an ...

. However, it has a number of distinguishing features which differentiate it from others in the genus, with the most notable example being the conically projecting genital papilla between the funnel-shaped

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s of males.Britz, Ralf. “''Danionella Priapus'', a New Species of Miniature Cyprinid Fish from West Bengal, India (Teleostei: Cypriniformes: Cyprinidae).” ''Zootaxa'', vol. 2277, no. 2277, Magnolia Press, 2009, pp. 53–60, https://doi.org/10.11646/zootaxa.2277.1.4.

References

priapus In Greek mythology, Priapus (; ) is a minor rustic fertility god, protector of livestock, fruit plants, gardens, and male genitalia. Priapus is marked by his oversized, permanent erection, which gave rise to the medical term priapism. He becam ...

Cyprinid fish of Asia Taxa named by Ralf Britz Fish described in 2009 {{Danioninae-stub