Raja hyperborea

Author: Collett, 1879

Raja (Amblyraja) hyperborea Collett, 1879

Status in World Register of Marine Species:
Accepted name: Amblyraja hyperborea (Collett, 1879) (updated 2009-06-25)

Diagnosis: body thick and somewhat flabby, tail relatively short. Tooth rows 35-48. Upper surface rough, with more or less loosely scattered prickles and mainly thornlets, adults with almost bare areas on centres of pectoral fins and along sides of back. Thorns with their bases ribbed and with the margin stellate (as also the thornlets). Orbital thorns separate; aregular row of 25-32 thorns from nape to first dorsal fin, 0-2 thorns between the close-set dorsal fins; underside smooth. Colour: upper surface dark grey or brown, sometimes with indistinct light or dark spots; under- side predominantly white in juveniles only, dark speckling increasing with age until predominantly dark. Size: to about 85 cm TL.

Habitat: benthic at about 300-1,500 m (single records down to about 2,500 m) in arctic and boreal latitudes, where restricted to waters of 1.0 to +1.5 °C; moderately common. Food: all kinds of bottom animals. Reproduction: oviparous; egg-cases 81-125 by 54-77 mm (excluding horns).

Distribution: northern Atlantic, from Spitsbergen southward to the Greenland - lceland - Faroe Shetland Ridge and across to northern Norwegian coasts. Elsewhere, Davis Strait.

Note: Raja (Amblyraja) spec. of Clofnam suppl. 21.1.9a resembles R. hyperborea but has more tooth rows (50 68), is generally lighter in colour (plain white above and below in extreme cases) and larger (a female to 115 cm TL). Several specimens from mainly very deep polar water in the Denmark Strait (south of the ridge) and near Flemish Cape in the north-western Atlantic are being studied by Stehman.

Complementary iconography. Clark, 1930, in Faune ichthyol. Atl. N., fiche 45 | Bigelow and Schroeder, 1953: fig. 43-44.
Eggs, embryonic and young stages. Jensen, 1914: fig. 6-7 (egg-capsules) | Thielemann, 1922: fig. 3 (egg-capsule) | Clark, 1930, Faune ichthyol. Atl. N. (egg-capsule), fiche 45.