Sawshark

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The sawsharks or saw sharks are an order (Pristiophoriformes) of sharks bearing long blade-like snouts edged with teeth, which they use to slash and disable their prey. There are five species known, in a single family Pristiophoridae of two genera. Most occur in waters from South Africa to Australia and Japan, at depths of 40 m and below; in 1960 the Bahamas sawshark was discovered in the deeper waters (640 m to 915 m) of the northwestern Caribbean.

Sawsharks also have a pair of long barbels about halfway along the snout. They have two dorsal fins, but lack anal fins, and range up to 170 cm in length. Genus Pliotrema has six gill slits, and Pristiophorus the more usual five. The teeth of the saw typically alternate between large and small.

The sharks typically feed on bony fish, shrimp, squids, and crustaceans, depending on species. They cruise the bottom, using the barbels and ampullae of Lorenzini on the saw to detect prey in mud or sand, then hit victims with side-to-side swipes of the saw, crippling them.

Most of the species are fished commercially, and their meat is considered to be of excellent quality. Japanese sawshark is used to make kamaboko, a traditional type of fishcake.

Although they are similar in appearance, sawsharks are distinct from sawfish. Sawfish have a much larger maximum size, lack barbels, have evenly sized rather than alternating sawteeth, and have gill slits on their undersurface rather than on the side of the head.

[edit] Genera and species

• Genus Pliotrema
  • Sixgill sawshark, Pliotrema warreni Regan, 1906 170 cm [1]
• Genus Pristiophorus
  • Longnose sawshark, Pristiophorus cirratus (Latham, 1794) 137 cm [2]
  • Japanese sawshark, Pristiophorus japonicus Günther, 1870 136 cm [3]
  • Shortnose sawshark, Pristiophorus nudipinnis Günther, 1870 122 cm [4]
  • Bahamas sawshark, Pristiophorus schroederi Springer & Bullis, 1960 80 cm [5]
  • Eastern Australian sawshark, Pristiophorus sp. A
  • Tropical Australian sawshark, Pristiophorus sp. B
  • Philippine sawshark, Pristiophorus sp. C
  • Dwarf sawshark, Pristiophorus sp. D

[edit] See also

• List of sharks

[edit] External links

• FishBase info for Pristiophoridae
• Reefquest page
• http://www.elasmo-research.org/education/topics/d_checklist.htm
• NOVA Online photo of longnose sawshark