Discopyge castelloi

Common Name

Argentine Numbfish

Year Described

Menni, Rincón & García, 2008


Disk moderate, thickened, and heart-shaped with kidney-shaped electric organs under each pectoral fin base. Body quite flat along entire width. Snout blunt, often with a slight indentation. Mouth relatively small with well developed labial cartilage. Teeth small (~10 rows) and visible when mouth is closed. Eyes small. Spiracles about size of eye with no papillae. Nostrils very small. Pectoral fins short with concave anterior margins. Tail a little longer than disk with low fleshy ridges. Dorsal fins about equal in size and rounded. Inter-dorsal space about same as length of dorsal base. Pelvic fins moderately broad and long, without projecting anterior lobes. Pelvic fins joined at base. Caudal fin with upper lobe projecting and pointed with a straight posterior margin. Skin entirely smooth.


Dorsum and fins ochre-brown to brown without markings and a thin whitish border to sick and fins. Ventrum white.


Maximum size to 31cm TL, but males are unknown and probably larger.


Captured on the continental shelf between 35-55m but poorly collected. Likely to be taken deeper.


Known only from off Argentina.


Last, P.R., White, W.T., Carvalho, M.R. de, Séret, B., Stehmann, M.F.W & Naylor, G.J.P (Eds.). 2016. Rays of the World. CSIRO Publishing, Melbourne.

Menni, R., G. Rincón, & M. García. 2008. Discopyge castelloi sp. nov. (Torpediniformes, Narcinidae), una nueva especie de raya eléctrica del Mar Argentino. Revista del Museo Argentino de Ciencias Naturales nueva serie, 10(1), 161-171.

Other Notes

Taken alongside Discopyge tschudii in Argentinian waters, where it can be distinguished by different body shape, proportions and body coloration (Menni et al., 2008). Range and habitat almost unknown.

More data on the variability and distribution of Discopyge, and genetic data, are needed to confirm this not simply a variation of Discopyge tschudii.