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.[1][2] 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.[3]
| Gymnorhamphichthys | |
|---|---|
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Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Gymnotiformes |
| Family: | Rhamphichthyidae |
| Genus: | Gymnorhamphichthys M. M. Ellis, 1912 |
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.[1][2] Gymnorhamphichthys are small knifefish with the largest species reaching up to about 23 cm (9 in) in total length.[3]
Species
editThere are currently six recognized species in this genus:[4]
- Gymnorhamphichthys bogardusi Lundberg, 2005
- Gymnorhamphichthys britskii T. P. Carvalho, C. S. Ramos & Albert, 2011
- Gymnorhamphichthys hypostomus M. M. Ellis, 1912
- Gymnorhamphichthys petiti Géry & T. T. Vu, 1964
- Gymnorhamphichthys rondoni (A. Miranda-Ribeiro, 1920)
- Gymnorhamphichthys rosamariae Schwassmann, 1989
References
edit- ^ 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. doi:10.1080/01650527609360496.
- ^ 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.
- ^ 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.
- ^ Froese, Rainer; Pauly, Daniel (eds.). "Species in genus Gymnorhamphichthys". FishBase. December 2017 version.
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