Atlantoraja castelnaui

Common Name

Spotback Skate

Year Described

Miranda Ribeiro, 1907


Nuchal median thorns: none
Tail median thorns: 15-21

Disk rhomboidal and entirely covered in rough denticles dorsally. Ventrum smooth. Median thorn row lacking anterior to pelvic fin. Snout moderate with slightly convex anterior margins. Snout with semi-translucent window between pectoral origin and snout tip (unique to Atlantoraja and Rioraja). Anterior margin of pectoral fins concave. No ocular thorns. No scapular thorns. Alar thorn patch is elongated. Eyes small. Median row of tail thorns single with no lateral rows. Dorsal fins are rounded and separated by four interdorsal thorns. Pelvic fin notched with projecting anterior lobe and broad posterior lobe. Tail is about body length and slender, with small lateral folds. Caudal fin short but tall. Male claspers long; reaching dorsal fin. Teeth are conical and sharp.


Dorsum yellowish to brown, with a heavy speckling of blackish spots covering entire body and tail. Spotting fades toward edges of disk. Sides of snout translucent. Dorsal fins unmarked. Ventrum bicolored with gray anteriorly and white posteriorly with black or white pores.


Maximum size to 145cm TL.


A coastal species found on soft bottoms up to depths of 220m.


Southwestern Atlantic: Southern Brazil to northern 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.

Other Notes

The only rough-bodied species of Atlantoraja from the region. Snout morphology and coloration distinguish this from other genera of softnose skates.