أشلاق (القروش و الشفانين) (sharks and rays) >
Rajiformes (Skates and rays) >
Rajidae (Skates)
Etymology: Dipturus: Greek, di = two + Greek, pteryx = fin (Ref. 45335).
Eponymy: Stewart ‘Stew’ Springer (1906–1991) was a field naturalist who dropped out of Butler College (1929) but was awarded a baccalaureate by George Washington University (1964), by which time he was world-renowned as an expert on both the taxonomy and [...] (Ref. 128868), visit book page.
Environment: milieu / climate zone / depth range / distribution range
البيئة
بحري قاعية المعيشة; نطاق العمق 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).
الحجم / وزن / العمر
Maturity: Lm ? range ? - ? cm
Max length : 192 cm TL ذكر/ مختلط الجنس; (Ref. 114953)
وصف مختصر
مفاتيح التعريف | الوصف الخارجي | قياسات المظهر الخارجي
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
النضج | التكاثر | وضع البيض | بيض | الخصوبة | 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. 130435: Version 2024-2)
استخدامات بشرية
مصائد: غير ذات اهمية
أدوات
تقارير خاصة
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مصادر علي الأنترنت
Estimates based on models
Preferred temperature (Ref.
123201): 6.4 - 12.5, mean 10.4 °C (based on 32 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00275 (0.00175 - 0.00433), b=3.20 (3.07 - 3.33), in cm total length, based on LWR estimates for this species & Genus-body shape (Ref.
93245).
مستوى غذائي (Ref.
69278): 4.3 ±0.69 se; based on food items.
المرونه (Ref.
120179): منخفض, الحد الزمني الأدني لتضاعف عدد أفراد المجتمع 4.5-14 سنة (Fec assumed to be <100).
Fishing Vulnerability (Ref.
59153): Very high vulnerability (90 of 100).
