Deepwater stingray
From Wikipedia, the free encyclopedia
| Deepwater stingray | |
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| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Order: | Rajiformes |
| Family: | Plesiobatidae Nishida, 1990 |
| Genus: | Plesiobatis Nishida, 1990 |
| Species: | P. daviesi |
| Binomial name | |
| Plesiobatis daviesi (Wallace, 1967) |
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| Synonyms | |
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Urolophus marmoratus Chu, Hu & Li, 1981 |
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The deepwater stingray or giant stingaree, Plesiobatis daviesi, is a species of ray and the only species in the family Plesiobatidae. The largest and most widespread of the stingarees, it is found on continental slopes from South Africa to Japan and Australia.[2] It is most closely related to the genus Urolophus (family Urolophidae), with which it forms a monophyletic group.[3]
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[edit] Distribution and habitat
The deepwater stingray has a sporadic distribution in the Indo-West and Central Pacific. It has been reported from off Natal on the east coast of South Africa, Mozambique, southern India, the South China Sea off China, the Kyushu-Palau Ridge, the Ryukyu Islands, Shark Bay and Rowley Shoals off Western Australia, Townsville, Queensland and Wooli, New South Wales, and Hawaii.[4] This species inhabits deeper water than any of the other stingarees in the related family Urolophidae, generally found over soft substrate at depths of 275-680 m (350-680 m in Australia) on the upper continental slopes. There is a single record from 44 m on the continental shelf off Mozambique.[1]
[edit] Description
The largest of the stingarees, the deepwater stingray grows to at least 270 cm long (200 cm in Australia).[1] It is a heavy-bodied ray with a moderately short, stout tail bearing a serrated stinging spine well behind the pelvic fins. The snout is moderately elongated and broadly angular; the eyes are small and placed just forward of the spiracles. The anterior nasal flaps are fused into a nasal curtain that does not reach the mouth. The mouth is straight and broad, with small, oval-rounded teeth bearing short cusps on their crowns. There are 32-60 rows of teeth in either jaw, numbering more in adults than young. There are no dorsal fins, and the caudal fin is long, moderately large, and leaf-shaped, symmetrical above and below the tail. It is distinguished from the similar round rays in that its upper surface is covered with small, fine dermal denticles. The coloration is purplish brown or purplish grey above, sometimes with irregular dusky blotches or spots, and white below with a dusky disc margin. The tail is completely dark.[4]
[edit] Biology and ecology
The deepwater stingray feeds on fishes, penaeid prawns, crabs, lobsters, and cephalopods. Its diet includes mesopelagic species, suggesting that it migrates into the water column. Reproduction is probably viviparous but details are unknown; due to its large size and deepwater habits it likely bears small litters after a long gestation period. A 50 cm-long free-living specimen has been found with an umbilical scar. The smallest known mature male was 130 cm long; the size at maturity likely varies with geographical location.[1]
[edit] Relationship to humans
This species is taken by benthic trawls and deepset longlines, but not in considerable numbers in any part of its range. It is reported as locally common, and was thus assessed as of Least Concern by the IUCN Red list.[1] The meat is utilized, but is not highly valued.[2] When landed, this ray thrashes its powerful tail vigorously and should be treated with care, due to its long spine.[4]
[edit] References
- ^ a b c d e White, W.T., Kyne, P.M. and Holtzhausen, H. (2006). Plesiobatis daviesi. In: IUCN 2006. IUCN Red List of Threatened Species. Downloaded on November 21, 2008.
- ^ a b "Plesiobatis daviesi". FishBase. Ed. Ranier Froese and Daniel Pauly. November 2008 version. N.p.: FishBase, 2008.
- ^ Carrier, J.C., Musick, J.A. and Heithaus, M.R. (2004). Biology of Sharks and Their Relatives. CRC Press. ISBN 084931514X.
- ^ a b c Compagno, L.J.V. and Last, P.R. (1999). "Plesiobatidae: Giant stingaree". in Carpenter, K.E. and Niem, V.H.. FAO identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Rome: Food and Agricultural Organization of the United Nations. ISBN 9251043027.
