Rajella

Weigmann, Simon, Stehmann, Matthias F. W. & Thiel, Ralf, 2014, Rajella paucispinosa n. sp., a new deep-water skate (Elasmobranchii, Rajidae) from the western Indian Ocean off South Mozambique, and a revised generic diagnosis, Zootaxa 3847 (3), pp. 359-387 : 383-384

Key to the species of Rajella in the southeastern Atlantic and western Indian Oceans

1 Dorsal surface of body with only two thorns on each orbit and few individual thorns on nape-shoulder region, tail with only one median row of thorns, maximal total length about 50 cm, predominantly white dorsally and ventrally.................................................................................... R. paucispinosa n. sp. (off Mozambique)

- Dorsal surface of body with numerous thorns including half rings of thorns on orbital rims and a triangle of many thorns on the nuchal and scapular region, at least three rows of tail thorns, maximal total length ≥ 65 cm, coloration darker............. 2

2 Maximal total length about 95 cm, 50–70 tooth rows in upper jaw, 31–32 trunk vertebral centra, dorsal surface of disc largely smooth in large males and tail thorns in the median row not reduced in size.................................................................................. R. leoparda (from off eastern and western South Africa to off Mauritania)

- Maximal total length between 65 and 82 cm, fewer than 50, often fewer than 40 tooth rows in upper jaw, 27–31 trunk vertebral centra, dorsal surface of disc largely spinulose or largely smooth, but if largely smooth, tail thorns in the median row reduced in size at least posteriorly.............................................................................. 3

3 Snout short and obtusely angled, preorbital snout length 7–12.5% of TL, snout angle 100–130°, disc inverse heart-shaped, tail thorns in the median row reduced in size posteriorly but median row on trunk and tail never absent.................... 4

- Snout rather long and acutely angled, preorbital snout length 13–15% of TL, snout angle 85–100°, disc nearly rhombic at least in large specimens, thorns in median row on trunk and tail totally reduced with growth.............................. 5

4 Snout angle 100–120°, tail about as long as body, conspicuous large white thorns on upper surface including snout, dorsal surface of disc nearly completely and very densely set with fine spinules, upper side without dark spots................................................................. R. barnardi (from off eastern and western South Africa to Mauritania)

- Snout angle 125–130°, tail clearly longer than body, no thorns on snout, dorsal surface of disc largely smooth, upper side often with dark spots................................. R. caudaspinosa (off eastern and western South Africa and Namibia)

5 Tail clearly longer than body, dorsal surface of disc largely smooth in large males, a few small thorns usually on snout tip, underside of disc white with a broad dark margin at outer corners and posterior edges...................................................................... R. dissimilis (from off eastern and western South Africa to off Western Sahara)

- Tail about as long as body, dorsal surface of disc largely covered with spinules, no thorns or thornlets on snout tip, underside of disc white to pale ochre with outer margins only slightly darker...................................................................................................... R. ravidula (from off western South Africa to off Morocco)