The Shark Order Pristiophoriformes - Sawsharks
Although they are similar in appearance, saw sharks are distinct from sawfish in that they differ in several important respects. Sawfish are much larger and sawfishes are rays with gill slits located underneath the head and have evenly sized sawteeth.
Sawsharks are a small group of bottom sharks with five species in a single family. They are the order Pristiophoriformes and are true sharks with long blade-like snouts edged with teeth used to slash and disable their prey Unlike the sawfish their teeth are replaced throughout life. Saw sharks have a pair of long barbels (a slender, whisker-like tactile organ) about halfway along the snout. The rostrum of the Longnose and other sawsharks helps locate and subdue prey. The rostrum (beak like extension) is equipped with lateral line and ampullary sensors, making it sensitive to vibrations and bioelectricy. The rostrum barbels are mobile and studded with pressure and chemoreceptors which make them sensitive to touch and taste.
The sharks feed on bony fish, shrimp, squids and crustaceans, depending on the species. They cruise the bottom, using the barbels of Lorenzini (the electroecepter organ) on the saw to detect prey in mud or sand, then hit the victims with side-to-side swipes of the saw crippling them. They have two dorsal fins, but no anal fins and are 170cm or approx. 5ft. 8in. in length with the usual five gill slits.
The order Pristiophoriformes are found in tropical Australia on the Great Barrier Reef, in the Philippine off Apo Island, in subtropical water of the western Indian Ocean and Coastal waters on sand or mud waters Their habitat depends on the species. The reproduction mode is ovoviviparous and the gestation period is 12 months giving birth from 2 to 22 pups the average is 10. Within hours of birth, the long rostral teeth become erect and later the smaller rostral teeth grow in between the larger ones. Longnose saw shark pups are born during winter in shallow coastal areas. At birth the long rostral teeth of this species are folded back, possibly to make the process easier on the mother.
The Order Pristiophoriformes has one Family
Family Pristiophoridae - Sawsharks
| Species in the Family Pristiophoridae | |
|---|---|
| Pliotrema warreni | Sixgill sawshark |
| Pristiophorus cirratus | Longnose sawshark |
| Pristiophorus japonicus | Japanese sawshark |
| Pristiophorus nudipinnis | Shortnose sawshark |
| Pristiophorus schroederi | Bahamas sawshark |