A new species of transparent miniature cyprinid in the genus Danionella has been described from the Brahmaputra River drainage in northeastern India by ichthyologist Ralf Britz.
This tiny fish is just 16mm/0.63" long.
Publishing the description of Danionella priapus in a recent issue of the journal Zootaxa, Britz distinguishes the new species from congeners by the presence in adult males of a conical projection of the genital papilla situated between the pelvic fins, which form a funnel-like structure, by possessing 8 pectoral-fin rays and 20"21 anal"fin rays, and by the position of insertion of the last anal-fin pterygiophore.
It differs further from D. translucida and D. mirifica in details of the colour pattern, from D. dracula and D. mirifica in the number of procurrent caudal-fin rays, from D. translucida in number of vertebrae and from D. dracula in several skeletal characters.
Danionella priapus is named after the Greek god of fertility.
The name is used in reference to the conical projection of the genital papilla in males, which is reminiscent of the mammalian penis.
The January 2010 issue of Practical Fishkeeping features an in-depth interview with Dr Britz which looks at the Danionella genus.
For more information, see the paper: Britz, R (2009) Danionella priapus, a new species of miniature cyprinid fish from West Bengal, India (Teleostei: Cypriniformes: Cyprinidae). Zootaxa 2277, pp. 53"60.