''Distocyclus conirostris'' is a species of glass knifefishes found in the deep waters (3.8-28.3 m) of the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...

, lower portions of the Potaro River and in major parts of the Rio Orinoco. They are typically relegated to flood basins, flooded forests and main river channels. They have been found often when gathering in small groups around vegetation, indicating a social nature. The fish has semi-translucent, glass-like pectoral and anal fins. The main body is a ground-like color with a lighter head. The largest currently recorded specimen is 34.5 cm (9.65 inches).

Ecology

''Distocyclus conirostris'' has a tapering, conical snout with the top and bottom jaws being equal in length. The mouth is located terminally. The eyes are located on either side of a bilaterally compressed, elongated body and are covered by a

nictitating membrane The nictitating membrane (from Latin '' nictare'', to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye from the medial canthus to protect and moisten it while maintaining vision. All ...

. The snout contains a uniquely small nasal capsule for the family Sternopygidae. The mouth of ''Distocyclus conirostris'' contains a single row of teeth located on the anterior area of the dentary bone, a trait also unique to this species in comparison to the other members of the Sternopygidae.Dutra, G.M.; de Santana, C.D.; Vari, R.P. & Wosiacki, W.B. (2014). "The South American Electric Glass Knifefish Genus Distocyclus (Gymnotiformes: Sternopygidae): Redefinition and Revision". Copeia. 2014 (2): 345–354. doi:10.1643/ci-13-066. S2CID 83494276Albert, J. S., and W. L. Fink. 1996. Sternopygus xingu, a newspecies of electric fish from Brazil (Teleostei: Gymnotoi-dei), with comments on the phylogenetic position ofSternopygus. Copeia 1996:85–102 The fish is covered in

cycloid scales A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as we ...

and typically has 4 to 5 gills with 4 to 11 small gill rakers. The body lacks any dark bands running laterally down the body, something present in ''

Japigny kirschbaum ''Japigny kirschbaum'' is a species of glass knifefish described in 2011 from the Approuague, Mana and Maroni rivers in French Guiana. It is the only member of its genus. It reaches up to in total length and is brownish-dusky with a pattern ...

'', another species of the Sternopygidae. The fish also typically has 13-14 precaudal vertebrae, differing significantly from the 20-26 precaudal vertebrae present in the Sternopygus genus. ''

Distocyclus goajira ''Eigenmannia goajira'' is a species of glass knifefish found in the Lake Maracaibo basin in Colombia and Venezuela.Dutra, G.M., Santana, C.D.d., Vari, R.P. & Wosiacki, W.B. (2014): The South American Electric Glass Knifefish Genus ''Distocyclus ...

'', a potential sister fish of ''Distocyclus conirostris'', is currently a subject of debate in regards to its phylogenetic position and relationship within either the '' Distocyclus'' genus or the Sternopygidae family.

Behavior

''Distocyclus conirostris'' are social fishes who communicate through the use of chirps and modulation of said chirps. These chirps are created by the fish's electric organ, which releases chirps of varying frequencies dependent on social context. It is currently unknown whether or not Jamming Avoidance Response ( JAR) is utilized when encountering other weakly electric knifefish in order to decrease interference between their electrolocation accuracy and their electrocommunication usage.Petzold JM, Alves-Gomes JA, Smith GT. Chirping and asymmetric jamming avoidance responses in the electric fish Distocyclus conirostris. J Exp Biol. 2018;221(Pt 17):jeb178913. Published 2018 Sep 10. doi:10.1242/jeb.178913 It is unknown whether these chirps are sexually dimorphic or whether they vary individually.

Reproduction

There is little information on specific reproduction of ''Distocyclus conirostris'' currently and it is unknown if their use of chirping for communicative purposes is uniquely modulated during spawning season or to reproductive means.

Conservation

''Distocyclus conirostris'' is considered to be of Least Concern by an IUCN 3.1 assessment conducted in 2009.Reis, R & Lima, F. 2009. ''Distocyclus conirostris''. ''The IUCN Red List of Threatened Species'' 2009: e.T167737A6374880. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T167737A6374880.en. Accessed on 18 April 2022.

References

{{Taxonbar, from=Q5754330 Sternopygidae Fish of Brazil Endemic fauna of Brazil Taxa named by Carl H. Eigenmann Taxa named by William Ray Allen Fish described in 1942 Wikipedia Student Program