(كوسه ها و سپرماهيان) (sharks and rays) >
Rajiformes (Skates and rays) >
Rajidae (Skates)
Etymology: Dipturus: Greek, di = two + Greek, pteryx = fin (Ref. 45335).
More on author: Smith.
محیط زیست: محیط زیست / منطقه آب و هوایی / تغييرات عمق / محدوده توزیع
بوم شناسي
دريايي نزديك كف زي; تغييرات عمق 50 - 457 m (Ref. 5578). Subtropical; 26°S - 36°S, 12°E - 29°E (Ref. 114953)
Southeast Atlantic: known only from Lüderitz, Namibia to Port Alfred, Eastern Cape (South Africa)
اندازه / وزن / سن
بلوغ: Lm ? range ? - ? cm
Max length : 130 cm TL جنس نر / بدون خواص جنسي; (Ref. 114953)
توصيف مختصر
كليدهاي شناسايي | ريخت شناسي | ريخت ستجي بوسيله انداره گيري
A striking two-toned longnose skate, medium brown above and abruptly dark grey below, with a large, conspicuous, dark brown blotch on the upper base of each pectoral fin (Ref. 5578). Snout moderately elongated and bluntly triangular, and tail stout, not conspicuously swollen and about equal to body length; pectoral disc with broadly rounded corners and smooth underside without denticles; thorns at nape and along midline of back and tail to 1st dorsal fin, nape spine enormous in young (Ref. 5578). Hatchlings and juveniles with wide-spaced black spots on upper disc, inconspicuous or lost in adolescents and adults; adults sometimes with numerous small white spots (Ref. 5578). Underside with numerous black pores (Ref. 5578).
Body shape (shape guide): other.
Found on soft bottoms of the outer shelf and upper slope (Ref. 5578). Feeds on bony fish, crabs, shrimp, mysids, mantis shrimp, euphausiids, bivalves and cuttlefish (Ref. 5578). Oviparous (Ref. 50449). Eggs have horn-like projections on the shell (Ref. 205). Males reaches maturity at 88-96 cm TL, females possibly slightly larger off Western than Southern coast of South Africa; hatching size at ca. 19 cm TL (Ref. 114953). Commonly taken by hake trawlers (Ref. 5578). Extremely slippery when caught (Ref. 5578).
چرخه زندگی و رفتار جفتگیری
بلوغ | تولید مثل | تخم ریزی | تخم ها | باروری | توزاد ( لارو)
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)
وضعيت در فهرست قرمز IUCN (Ref. 130435: Version 2025-2 (Global))
خطر برای انسان ها
Harmless
استفاده انسانی
ماهي گيري – شيلات: از بی علاقه گی
ابزارها
گزارش های ويژه
بارگيری XML
منابع اينترنتي
تخمینها بر اساس مدلها
دمای ترجیحی (مرجع
123201): 9.2 - 16.7, mean 11 °C (based on 41 cells).
شاخص تنوع فیلوژنتیکی (مرجع
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00380 (0.00255 - 0.00567), b=3.19 (3.07 - 3.31), in cm total length, based on LWR estimates for this species & Genus-body shape (Ref.
93245).
سطح تروفیک (مرجع
69278): 4.1 ±0.69 se; based on food items.
Generation time: 22.0 ( na - na) years. Estimated as median ln(3)/K based on 2
growth studies.
جهندگی (مرجع
120179): پايين ، كم, كمينه زمان لازم براي دو برابر شدن جمعيت 5/4 – 14 سال (Fec assumed to be <100).
آسیبپذیری ماهیگیری (Ref.
59153): Very high vulnerability (75 of 100).
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