Dwarf sawshark
Dwarf sawshark | ||||||||||||
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Pristiophorus nancyae | ||||||||||||
Ebert & Cailliet , 2011 |
The dwarf saw shark ( Pristiophorus nancyae ) is a shark from the family of saw sharks (Pristiophoridae). Like its relatives, the shark is characterized by a long saw-like snout. It is known from a few specimens from only a few deep-sea areas in the western Indian Ocean off the coast of Mozambique , possibly also off Somalia and the coast of Pakistan . The species was only described in July 2011 .
features
The dwarf sawshark reaches a maximum length of about 62 cm (males 45–50 cm, females 57–62 cm) and is thus the smallest known species of sawshark. The body is long, cylindrical and slim. The head is flattened and has a greatly elongated and flattened snout with a saw-like rostrum typical of saw sharks . The rostrum has a distinctive pair of barbels that are significantly closer to the mouth than to the tip of the rostrum . The bases of the large posterior teeth of the "saw" are provided with conspicuous ridges. On the underside of the rostrum there is a very distinctive double row of conspicuously large pits, four to five of which are behind the barbels.
The top of its body is a solid brown, the underside is white. On the light rostrum there are dark brown stripes on the center line and along the edges. The pectoral and dorsal fins have dark front and light rear edges.
The greenish eyes are on the side of the head, behind them the large suction holes . Like other species of the genus, the sawshark has five gill slits . Like all saw sharks, it has two dorsal fins without a thorn and no anal fin. The first dorsal fin is large and triangular. Its rear tip extends behind the middle of the base of the pelvic fin. The caudal fin consists only of a large upper lobe while the lower lobe is absent in all sawsharks.
Way of life
The dwarf sawshark is a ground shark that occurs in water depths between 286 and 500 meters. Hardly any data are available about its way of life; it probably feeds on various fish and other soil organisms in a predatory manner.
distribution
The dwarf saw shark lives in the western Indian Ocean off the coast of Mozambique. Another occurrence is in the Arabian Sea off the coast of Somalia and the coast of Pakistan. The habitat is in the area of the upper continental slope near the seabed in water depths of 286 to 500 meters. It is the only species of Pristiophorus in the western Indian Ocean . From sympatric occurring Warrens Sixgill Sawshark ( Pliotrema warreni ) can be distinguished mainly by its five gill slits.
literature
- Leonard Compagno , Marc Dando, Sarah Fowler: Sharks of the World. Princeton Field Guides, Princeton University Press , Princeton and Oxford 2005; Pp. 133-134, ISBN 978-0-691-12072-0 .
- Ebert, DA & Cailliet, GM (2011): Pristiophorus nancyae, a New Species of Sawshark (Chondrichthyes: Pristiophoridae) from Southern Africa. Bulletin of Marine Science, 87 (3): 501-512. doi : 10.5343 / bms.2010.1108
Web links
- Dwarf sawshark on Fishbase.org (English)