Elasmobranchii (sharks and rays) > Rajiformes
(Skates and rays) > Rajidae
Etymology: Dipturus: Greek, di = two + Greek, pteryx = fin (Ref. 45335).
Environment: milieu / climate zone / depth range / distribution range
Marine; bathydemersal; depth range 88 - 740 m (Ref. 11284), usually 400 - 500 m (Ref. 5578). Deep-water; 21°N - 37°S, 11°E - 77°E (Ref. 114953)
Southeast Atlantic and Western Indian Ocean: in scattered localities from Lüderitz, Namibia round the Cape (South Africa) to central Mozambique; also off Madagascar and Kenya; also found off India and Oman (Ref. 114953).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 192 cm TL male/unsexed; (Ref. 114953)
Morphology | Morphometrics
An all-dark longnose skate with its underside uniformly roughened by small denticles; snout acutely pointed and greatly elongated, and tail moderately stout and not conspicuously swollen; pectoral disc angular and broader than in other longnose skates in the area; no nape thorn (Ref. 5578). Dark grey to blackish above and below, ventral mucous pores black (Ref. 5578).
Inhabits the outer shelf and upper slope (Ref. 5578). Rarely caught, probably inhabits hard bottoms that are seldom trawled (Ref. 114953). Feeds on bony fish, crabs and squid (Ref. 5578, Ref. 114953). Oviparous (Ref. 50449). Eggs have horn-like projections on the shell (Ref. 205). Males reaches maturity at 125-135 cm TL, females at 170-190 cm TL. Smallest known specimen at 27 cm TL (Ref. 114953) Probably caught by hake trawlers (Ref. 5578).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449). Eggs have horn-like projections on the shell (Ref. 205).
McEachran, J.D. and K.A. Dunn, 1998. Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs (Chondrichthyes: Rajidae). Copeia 1998(2):271-290. (Ref. 27314)
IUCN Red List Status (Ref. 123251)
CITES (Ref. 118484)
Threat to humans
Fisheries: of no interest
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates based on models
Preferred temperature (Ref. 115969
): 6.4 - 12.5, mean 10.4 °C (based on 32 cells).
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00316 (0.00147 - 0.00681), b=3.22 (3.04 - 3.40), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 4.3 ±0.69 se; based on food items.
Resilience (Ref. 120179
): Low, minimum population doubling time 4.5 - 14 years (Fec assumed to be <100).
Vulnerability (Ref. 59153
): Very high vulnerability (85 of 100) .