Sawshark: Difference between revisions
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==Comparison with sawfish== |
==Comparison with sawfish== |
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Sawsharks and [[sawfish]] are [[cartilaginous fish]] possessing large saws. Although they are similar in appearances, sawsharks are distinct from [[sawfish]]. Sawfish are not sharks, but a type of [[Batoidea|ray]]. The gill slits of the sawfishes are positioned on the underside like a ray, but the gill slits of the sawshark are positioned on the side like a shark. Sawfish can have a much larger size, lack barbels, and have evenly sized teeth rather than alternating sawteeth of the sawshark. clear difference is that a sawfish has no barbels and a sawshark has a prominent pair halfway along the saw. The sawshark uses these like other bottom fish, as a kind of antennae, feeling the way along the ocean bottom until it finds some prey of interest. |
Sawsharks and [[sawfish]] are [[cartilaginous fish]] possessing large saws. Although they are similar in appearances, sawsharks are distinct from [[sawfish]]. Sawfish are not sharks, but a type of [[Batoidea|ray]]. The gill slits of the sawfishes are positioned on the underside like a ray, but the gill slits of the sawshark are positioned on the side like a shark. Sawfish can have a much larger size, lack barbels, and have evenly sized teeth rather than alternating sawteeth of the sawshark. clear difference is that a sawfish has no barbels and a sawshark has a prominent pair halfway along the saw. The sawshark uses these like other bottom fish, as a kind of antennae, feeling the way along the ocean bottom until it finds some prey of interest. |
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Revision as of 17:01, 7 December 2017
| Sawsharks Temporal range:
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| Shortnose sawshark, Pristiophorus nudipinnis | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Division: | Selachii |
| Superorder: | Squalomorphi |
| Order: | Pristiophoriformes L. S. Berg, 1958 |
| Family: | Pristiophoridae Bleeker, 1859 |
| Genera[2] | |
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The sawshark or saw shark is an order (Pristiophoriformes) of sharks bearing a unique long, saw-like rostrum (snout or bill) edged with sharp teeth, which they use to slash and disable their prey. There are 6 species within the prisiophoriformes family including Longnose Sawshark-Pristiophorus cirratus, Japanese Sawshark-Pristiophorus japonicus, Southern Sawshark-Pristiophorus nudipinnis, Bahamas Sawshark-Pristiophorus schroederi, Sixgill Sawshark-Pliotrema warreni, and the Tropical Sawshark-Pristiophorus delicatus <ref[1]</ref>.
The sawshark is found in many areas around the world, but is most commonly found in waters from the Indian Ocean to the Southern Pacific Ocean. They are normally found depths around 40-100m, but can be found at much lower depths in tropical regions. The Bahamas Sawshark was discovered in deeper waters (640 m to 915 m) of the northwestern Caribbean.
Description and Life Cycle
Sawsharks have a pair of long barbels about halfway along the rostrum. They have two dorsal fins, but lack anal fins, and range up to 170cm in length.[3] Genus Pliotrema has six gill slits, and Pristiophorus the more usual five. The teeth of the saw typically alternate between large and small.
These sharks typically feed on small fish, squid, and crustaceans, depending on species. They navigate the ocean floor using the barbels and ampullae of Lorenzini on the saw to detect prey in mud or sand, then hit prey with side-to-side swipes of the saw, crippling them. The saw can also be utilized against other predators in defense.
Sawsharks have a relatively slow life history. They have liters of 3-22 pups every 1-2 years. After 12 months of gestation, the pups are born at 30cm long. It is interesting to note that while in the mother, pups teeth are inverted into their mouth to avoid harm. Sawsharks typically live more than 15 years Cite error: The <ref> tag has too many names (see the help page).
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| Barbels
| Single pair of barbels on saw
| No barbels
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|-
| Saw teeth
| Alternate between large and small
| Equal size
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| Habitat
| Deep offshore waters
| Shallow coastal waters
| style="text-align:center"|[4]
|-
| Size
| Relatively small, reaching only 5 ft
| Relatively large, reaching 23 ft
| style="text-align:center"|[4]
|}
_Saw_shark_-_William_Buelow_Gould,_c1832.jpg)
See also
References
- ^ Froese, Rainer; Pauly, Daniel (eds.). "Order Pristiophoriformes". FishBase. January 2009 version.
- ^ Froese, Rainer; Pauly, Daniel (eds.). "Family Pristiophoridae". FishBase. October 2013 version.
- ^ FishBase
- ^ a b Cite error: The named reference
uflwas invoked but never defined (see the help page).
