Gymnorhamphichthys

Gymnorhamphichthys
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Gymnotiformes
Family: Rhamphichthyidae
Genus:
M. M. Ellis, 1912[1]
Type species
Gymnorhamphichthys hypostomus
M. M. Ellis, 1912[1]
Synonyms[1]

Gymnorhamphichthys is a genus of South American sand knifefishes found in the Amazon, Araguaia, Orinoco and Río de la Plata basins, as well as rivers in the Guianas. They inhabit both small streams and large rivers, but usually over a sandy bottom.[2][3] During the night they swim head-down over the sandy bottom to locate small invertebrate prey like insect larvae and during the day they rest buried under the sand.[4]

They are generally very pale (almost whitish, light silvery, light yellowish or semi-translucent), and have a pattern of dark bars/spots or a dark line along the side of the body. Their snout is relatively long, thin and tubular.[2][3] Gymnorhamphichthys are small knifefish with the largest species reaching up to about 23 cm (9 in) in total length.[4]

Species

These are the currently recognized species in this genus:[5]

  • Gymnorhamphichthys bogardusi Lundberg, 2005
  • Gymnorhamphichthys britskii T. P. Carvalho, C. S. Ramos & Albert, 2011
  • Gymnorhamphichthys hypostomus M. M. Ellis, 1912
  • Gymnorhamphichthys rondoni (A. Miranda-Ribeiro, 1920)
  • Gymnorhamphichthys rosamariae Schwassmann, 1989

References

  1. ^ a b c Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Rhamphichthyinae". Catalog of Fishes. California Academy of Sciences. Retrieved 3 June 2025.
  2. ^ a b Nijssen, H.; I.J.H. Isbrücker; J. Géry (1976). "On the species of Gymnorhamphichthys Ellis, 1912, translucent sand-dwelling Gymnotid fishes from South America (Pisces, Cypriniformes, Gymnotoidei)". Studies on Neotropical Fauna and Environment. 11 (1–2): 37–63. Bibcode:1976SNFE...11...37N. doi:10.1080/01650527609360496.
  3. ^ a b Carvalho, T.P.; C.S. Ramos; J.S. Albert (2011). "A New Species of Gymnorhamphichthys (Gymnotiformes: Rhamphichthyidae) from the Paraná–Paraguay Basin". Copeia. 2011 (3): 400–406. doi:10.1643/ci-10-154. S2CID 85019301.
  4. ^ a b Zuanon, J.; F.A. Bockmann; I. Sazima (2006). "A remarkable sand-dwelling fish assemblage from central Amazonia, with comments on the evolution of psammophily in South American freshwater fishes". Neotrop. Ichthyol. 4 (1): 107–118. doi:10.1590/S1679-62252006000100012.
  5. ^ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Gymnorhamphichthys". Catalog of Fishes. California Academy of Sciences. Retrieved 3 June 2025.