Pastinachus gracilicaudus Last & Manjaji-Matsumoto, 2010
Narrowtail stingray
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Family:  Dasyatidae (Stingrays), subfamily: Hypolophinae
Max. size:  74.7 cm WD (male/unsexed); 83 cm WD (female)
Environment:  benthopelagic; depth range - 60 m
Distribution:  Western Pacific: This species is reasonably common but patchily distributed in both Malaysian and Indonesian Borneo, including Sabah, Sarawak, and western and northeastern Kalimantan. Possibly more widespread in the Indo-Malay Archipelago, east to at least the Wallace Line and the the identity of a specimen collected off Beruwala (Sri Lanka) needs confirmation.
Diagnosis:  This medium-sized species (attaining about 75 cm DW) is distinguished by the following set of characters: snout rounded, not produced, angle more than 115°, apex largely naked and lacking enlarged denticles; disc length 83-89% DW; head length 38-41% DW; preoral length 15-17% DW; distance between nostrils 7-8% DW; distance between first gill slits 18-20% DW; tail compressed above mid-base of ventral cutaneous fold, its width 0.5-0.8 times its height; ventral fold low and slender, length 0.7-1.0 times DW, 17-22 times its depth below its mid-base, depth 2.0-3.6 times tail height at its mid-base; distance from anterior cloaca to sting 0.8-1 in precloacal length; two large, midscapular pearl thorns, usually preceded by a smaller irregular thorn; 120-122 pectoral-fin radials; monospondylous vertebral centra (exc. synarcual) 37-40 (Ref. 84288).
Biology:  The depth occupied by this species is unknown as most material were collected in fish markets, but probably mainly coastal. A 69.5 cm DW adult male weighed ca 12 kg. Size at birth apparently variable; 83.0 cm DW female delivered a full term embryo with small umbilical scar; however, other retained specimens, 26.1 cm DW still had a substantial yolk sac, while in another 19.3 cm DW specimen the umbilical scar was barely visible. All these young specimens have large mid-scapular tubercles and well-developed denticles over most of the dorsal disc; a small embryo with yolk sac (16.5 cm DW) had prominent mid-scapular tubercles, but other denticles are just starting to form on the disc (Ref. 84288).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (120744)
Threat to humans:  harmless
Country info:   

Entered by: Capuli, Estelita Emily - 03.06.10
Modified by: Capuli, Estelita Emily - 07.10.19

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