Frilled shark: Difference between revisions

Frilled shark
Conservation status
	Near Threatened
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Order:	Hexanchiformes
Family:	Chlamydoselachidae; Garman, 1884
Genus:	Chlamydoselachus
Species:	C. anguineus
Binomial name
	Chlamydoselachus anguineus; Garman, 1884

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The frilled shark, Chlamydoselachus anguineus, is a primitive shark species, of the family Chlamydoselachidae in the order Hexanchiformes. The Southern African frilled shark is a proposed new species from the Southern African range. These two species are very different from the other hexanchiform sharks, and it has been recently proposed that the two frilled sharks should be given their own order: Chlamydoselachiformes. Additional extinct types are known from fossil teeth; thought to be extinct itself, it was only discovered in Japanese waters in the 19th century.^[1] On January 21, 2007 a specimen was found alive off the coast of Japan near the Awashima Marine Park in Shizuoka, southwest of Tokyo. The shark was captured but died shortly afterwards.^[2] Because of the rarity of alive sightings of these sharks, and their resemblance to earlier fossils, these sharks have been called "living fossils" by some.

Appearance

Superficially the frilled shark resembles a dark brown or grey eel, but the six gill slits identify it as a shark. The tissue of the gill slits protrudes somewhat, thus inspiring the common name. Its dorsal fin is small, anal fin large, and the caudal fin (tail fin) is highly asymmetric, the dorsal part almost unnoticeable. Its teeth are small, tricuspid, and very sharp. It has been recorded at up to 2 m in length.

Distribution

Distribution is worldwide, but they are very rarely found in shallow water. The sharks are usually found at depths of between 50 m and 1,500 m. They typically eat squid, other sharks, and deepwater bony fish.^[3]

Reproduction

Reproduction is not well understood, but like many other sharks they bear live young (ovoviviparous), with litter sizes of 2 to 12 pups. Compagno states "They are pregnant for a long time, probably one to two years".

Sightings

Frilled sharks appear regularly in the catches from bottom trawling, and when caught are used as food or for fishmeal.^[3]

On January 21 2007, staff at Awashima Marine Park in Shizuoka, southwest of Tokyo, were alerted by fishermen to a 'strange eel-like fish with razor sharp teeth'. The fish was identified as a female 1.6 m frilled shark and was captured by park staff who were concerned that the shark appeared to be unhealthy. They took it out of the water and put it into a salt water tank where they filmed it and took pictures of it. The shark died a few hours after capture. This rare surface appearance of a frilled shark has been attributed to the animal being unwell and possibly disoriented.^[4]

References

^ Allen, Thomas B. (1999). The Shark Almanac. New York: The Lyons Press. p. 48. ISBN 1-55821-582-4.
^ CBS news story. Accessed 2007-01-25
^ ^a ^b Compagno (1984). Sharks of the World: An annotated and illustrated catalogue of shark species known to date. Food and Agriculture Organization of the United Nations. pp. 14–15.
^ "Rare shark captured on film". CNN. Retrieved 2007-01-24.

Template:IUCN2006 Database entry includes justification for why this species is near threatened
"Chlamydoselachus anguineus". Integrated Taxonomic Information System. 23 January. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help)
Compagno, Dando, & Fowler, Sharks, Collins Gem, HarperCollins, London 2006) ISBN 0-00-721986-5
Compagno, Dando, & Fowler, Sharks of the World, Princeton University Press, New Jersey 2005 ISBN 0-691-12072-2

External links

[allen48-1] Allen, Thomas B. (1999). The Shark Almanac. New York: The Lyons Press. p. 48. ISBN 1-55821-582-4.

[2] CBS news story. Accessed 2007-01-25

[FAO-3] Compagno (1984). Sharks of the World: An annotated and illustrated catalogue of shark species known to date. Food and Agriculture Organization of the United Nations. pp. 14–15.

[4] "Rare shark captured on film". CNN. Retrieved 2007-01-24.

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 ==Distribution==
-Distribution is worldwide, but they are very rarely found in shallow water.  The sharks are usually found at depths of  between 350&nbsp;m and 2030&nbsp;m.  They typically eat [[squid]], other sharks, and deepwater [[bony fish]].<ref name="FAO">{{cite book|author= [[Leonard Compagno|Compagno]]| title=Sharks of the World: An annotated and illustrated catalogue of shark species known to date|publisher=Food and Agriculture Organization of the United Nations|date=1984|pages=14-15}}</ref>
+Distribution is worldwide, but they are very rarely found in shallow water.  The sharks are usually found at depths of  between 50&nbsp;m and 1,500&nbsp;m.  They typically eat [[squid]], other sharks, and deepwater [[bony fish]].<ref name="FAO">{{cite book|author= [[Leonard Compagno|Compagno]]| title=Sharks of the World: An annotated and illustrated catalogue of shark species known to date|publisher=Food and Agriculture Organization of the United Nations|date=1984|pages=14-15}}</ref>
 ==Reproduction==