Sternarchorhynchus

Of the 32 recognized species, more than are restricted to the Amazon basin (including the Tocantins system) in Bolivia, Brazil, Colombia, Ecuador and Peru, 7 species are found in river basins flowing into the Gulf of Paria in Colombia and Venezuela (mostly Orinoco system, but S. mendesi in Guanipa and San Juan), S. freemani is from the Essequibo basin in Guyana, S. galibi is from the Maroni basin in French Guiana and Suriname, and S. britskii is from the upper Paraná basin in Brazil. There are records of Sternarchorhynchus from the Oyapock on the French Guiana–Brazil border, but their validity and taxonomic position is unclear. The current conservation status of S. gnomus is unclear, as the only known locality in Venezuela's lower Caroní basin has been flooded by a dam. ==Appearance and behavior==

They have a relatively long, downwards-pointed and tube-like snout. The adult males of some species have distinct teeth on the outside of the lower jaw, likely used in confrontations with other males. Several species are only known from museum specimens and consequently their living colors are unknown. Where known, the species are generally medium to dark brownish or grayish. They are often darker on the upper part than the lower and some have a pale line on the top of the head, but otherwise they are quite uniformly colored without conspicuous patters. However, at least one species, S. cramptoni, is overall whitish-pink, similar to some other knifefish like Compsaraia and Orthosternarchus that inhabit deep, dark rivers. Very little is known about their behavior, but limited aquarium observations indicate that at least S. goeldii is nocturnal. They feed on invertebrates. ==Species==

There are currently 32 described species in this genus. Additionally, a few undescribed species are known. • Sternarchorhynchus axelrodi de Santana & Vari, 2010 (Axelrod's tube-snouted ghost knifefish) • Sternarchorhynchus britskii Campos-da-Paz, 2000 (Britski's tube-snouted ghost knifefish) • Sternarchorhynchus caboclo de Santana & Nogueira, 2006 (Cabocolo tube-snouted ghost knifefish ) • Sternarchorhynchus chaoi de Santana & Vari, 2010 (Chao's tube-snouted ghost knifefish) • Sternarchorhynchus cramptoni de Santana & Vari, 2010 (Crampton's tube-snouted ghost knifefish) • Sternarchorhynchus curumim de Santana & Crampton, 2006 (Curumim tube-snouted ghost knifefish) • Sternarchorhynchus curvirostris (Boulenger, 1887) • Sternarchorhynchus freemani de Santana & Vari, 2010 (Freeman's tube-snouted ghost knifefish) • Sternarchorhynchus galibi de Santana & Vari, 2010 (Galibi tube-snouted ghost knifefish) • Sternarchorhynchus gnomus de Santana & Taphorn, 2006 (Gnomus tube-snouted ghost knifefish) • Sternarchorhynchus goeldii de Santana & Vari, 2010 (Goeldi's tube-snouted ghost knifefish) • Sternarchorhynchus hagedornae de Santana & Vari, 2010 (Hagedorn's tube-snouted ghost knifefish) • Sternarchorhynchus higuchii de Santana & Vari, 2010 (Higuchi's tube-snouted ghost knifefish) • Sternarchorhynchus inpai de Santana & Vari, 2010 (Inpa tube-snouted ghost knifefish) • Sternarchorhynchus jaimei de Santana & Vari, 2010 (Jamei's tube-snouted ghost knifefish) • Sternarchorhynchus kokraimoro de Santana & Vari, 2010 (Kokraimoro tube-snouted ghost knifefish) • Sternarchorhynchus mareikeae de Santana & Vari, 2010 (Mareike's tube-snouted ghost knifefish) • Sternarchorhynchus marreroi de Santana & Vari, 2010 (Marrero's tube-snouted ghost knifefish) • Sternarchorhynchus mendesi de Santana & Vari, 2010 (Mendes’ tube-snouted ghost knifefish) • Sternarchorhynchus mesensis Campos-da-Paz, 2000 (Mesensis tube-snouted ghost knifefish) • Sternarchorhynchus montanus de Santana & Vari, 2010 (Montane tube-snouted ghost knifefish ) • Sternarchorhynchus mormyrus (Steindachner, 1868) • Sternarchorhynchus oxyrhynchus (J. P. Müller & Troschel, 1849) • Sternarchorhynchus retzeri de Santana & Vari, 2010 (Retzer's tube-snouted ghost knifefish) • Sternarchorhynchus roseni Mago-Leccia, 1994 (Rosen's tube-snouted ghost knifefish) • Sternarchorhynchus schwassmanni de Santana & Vari, 2010 • Sternarchorhynchus severii de Santana & Nogueira, 2006 (Severi's tube-snouted ghost knifefish) • Sternarchorhynchus starksi de Santana & Vari, 2010 (Stark's tube-snouted ghost knifefish) • Sternarchorhynchus stewarti de Santana & Vari, 2010 (Stewart's tube-snouted ghost knifefish) • Sternarchorhynchus taphorni de Santana & Vari, 2010 (Taphorn's tube-snouted ghost knifefish) • Sternarchorhynchus villasboasi de Santana & Vari, 2010 (Villasboas’ tube-snouted ghost knifefish) • Sternarchorhynchus yepezi de Santana & Vari, 2010 (Yepez’ tube-snouted ghost knifefish) ==References==