Common Name
La Plata Skate
Year Described
Günther, 1880
Identification
Nuchal median thorns: none
Tail median thorns: 11-14
Disk rhomboidal and entirely smooth. Ventrum smooth. Median thorn row lacking anterior to pelvic fin. Snout short 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 thorns. Dorsal fins are rounded and separated by 2-3 interdorsal thorns. Pelvic fin strongly notched with projecting anterior lobe and broad posterior lobe. Tail is about body length and slender, with lateral folds. Caudal fin short but tall with double lobes. Male claspers long; reaching dorsal fin. Teeth are conical and sharp.
Color
Dorsum dull medium brown with indistinct pale markings or spots. A faint blotch is usually present on the base of each pectoral fin. Sides of snout paler but not as translucent as other species in genus. Ventrum pale gray with dark sensory pores.
Size
Maximum size to 91cm TL.
Habitat
A coastal species occurring over soft bottoms to a maximum depth of 320m.
Range
Southwestern Atlantic: Southern Brazil to northern Argentina.
References
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 other smooth-bodied Atlantoraja from the region (A. cyclophora) is paler brown with a obvious ocellus.