Sawshark

Taxobox
name = Sawsharks

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image_caption =
height = 7-8 meters
regnum = Animalia
phylum = Chordata
classis = Chondrichthyes
subclassis = Elasmobranchii
ordo = Pristiophoriformes
ordo_authority = Berg, 1958
familia = Pristiophoridae
familia_authority = Bleeker, 1859
genus = "Pristiophorus"
genus2 = "Pliotrema"
subdivision_ranks = Species
subdivision = See text.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 described (and four undescribed) 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 convert|170|cm|ft in length. [http://www.fishbase.org/Summary/SpeciesSummary.php?id=720] 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.

Genera and species

* Genus "Pliotrema"
** Sixgill sawshark, "Pliotrema warreni" Regan, 1906 170 cm [http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=720&genusname=Pliotrema&speciesname=warreni]
* Genus "Pristiophorus"
** Longnose sawshark, "Pristiophorus cirratus" (Latham, 1794) 137 cm [http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=721&genusname=Pristiophorus&speciesname=cirratus]
** Japanese sawshark, "Pristiophorus japonicus" Günther, 1870 136 cm [http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=722&genusname=Pristiophorus&speciesname=japonicus]
** Shortnose sawshark, "Pristiophorus nudipinnis" Günther, 1870 122 cm [http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=723&genusname=Pristiophorus&speciesname=nudipinnis]
** Bahamas sawshark, "Pristiophorus schroederi" Springer & Bullis, 1960 80 cm [http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=724&genusname=Pristiophorus&speciesname=schroederi]
** Eastern Australian sawshark, Pristiophorus sp. A
** Tropical Australian sawshark, "Pristiophorus delicatus"
** Philippine sawshark, Pristiophorus sp. C
** Dwarf sawshark, Pristiophorus sp. D

ee also

* List of sharks

External links

* [http://www.fishbase.org/Summary/FamilySummary.cfm?ID=14 FishBase info for Pristiophoridae]
* [http://www.elasmo-research.org/education/shark_profiles/pristiophoriformes.htm Reefquest page]
* [http://www.elasmo-research.org/education/topics/d_checklist.htm Checklist of Living Sharks]
* [http://www.pbs.org/wgbh/nova/sharks/world/thlongnose.html NOVA Online photo of longnose sawshark]