Carpet shark

Carpet sharks
Temporal range: Late Jurassic–Recent[1]
Whale shark (Rhincodon typus) at the Georgia Aquarium
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Orectolobiformes
Applegate, 1972
Families

See text

Carpet sharks are sharks classified in the order Orectolobiformes. Sometimes the common name "carpet shark" (named so because many species resemble ornately patterned carpets) is used interchangeably with "wobbegong," which is the common name of sharks in the family Orectolobidae. Carpet sharks have five gill slits, two spineless dorsal fins, and a small mouth that does not extend past the eyes. Many species have barbels.

Characteristics

The carpet sharks are a diverse group of sharks with differing sizes, appearances, diets and habits. They first appeared in the fossil record in the late Jurassic.[2] All species have two dorsal fins and a relatively short transverse mouth that does not extend behind the eyes. Besides the nostrils are barbels, tactile sensory organs, and grooves known as nasoral grooves connect the nostrils to the mouth. There are five short gill slits just in front of the origin of the pectoral fin and the fifth slit tends to overlap the fourth one.[2] There is a spiracle beneath each eye which is used in respiration. The only exception to this rule is the whale shark, the spiracles of which are situated just behind the eyes.[3] Carpet sharks derive their common name from the fact that many species have a mottled appearance with intricate patterns reminiscent of carpet designs. The patterning provides camouflage when the fish is lying on the seabed.[4] The largest carpet shark is the whale shark (Rhincodon typus) which can grow to a length of 14 metres (46 ft). It is the largest species of fish but despite its size is not dangerous, as it is a filter feeder, drawing in water through its wide mouth and sifting out the plankton. The smallest carpet shark, at up to about 30 centimetres (12 in) long, is the barbelthroat carpet shark, (Cirrhoscyllium expolitum).[3] Some of the most spectacularly coloured members of the order are the necklace carpet shark (Parascyllium variolatum), the zebra shark (Stegostoma fasciatum) and the ornate wobbegong (Orectolobus ornatus). Nurse sharks and whale sharks have a fringe of barbels on their snout, and barbelthroat carpet sharks (Cirrhoscyllium expolitum) have barbels dangling from the throat region.[4]

Behaviour

Most carpet sharks feed on the seabed in shallow to medium-depth waters, detecting and picking up molluscs and crustaceans and other small creatures.[3] The wobbegongs tend to be ambush predators, lying hidden on the seabed until prey approaches. One has been observed swallowing a bamboo shark whole.[5]

The methods of reproduction of carpet sharks varies. Some species are oviparous and lay eggs which may be liberated direct into the water or may be enclosed in horny egg cases. Some female sharks have been observed to push egg cases into crevices and this would be an added protection for the developing embryos. Other species are ovoviviparous and the fertilised eggs are retained in the mother's oviduct. There the developing embryos, which are usually few in number, feed on their yolk sacs at first and later hatch out and feed on nutrients secreted by the walls of the oviduct. The young are born in an advanced state, ready to live independent lives.[3]

Distribution

Carpet sharks are found in all the oceans of the world but predominantly in tropical and temperate waters. They are most common in the western Indo-Pacific region and are usually found in relatively deep water.[3]

Classification

The order is small, with seven families in thirteen genera and with a total of around forty three species:

Family Image Common name Genera Species Description
Brachaeluridae Blind sharks 1 2 Blind sharks are found in shallow coastal waters up to 110 metres (360 ft) deep off the eastern coast of Australia.[1] They are distinguished by the presence of long barbels, large spiracles, and groove around the nostrils. They have two dorsal fins, placed close together on the back, and a relatively short tail. Blind sharks feed on small fish, cuttlefish, sea anemones, and crustaceans. The female retains the eggs in her body until they hatch (ovoviviparity), during which time the embryos feed solely on the egg yolk.[1] Blind sharks are not blind; the name came because it closes its eyes when taken out of water.[1] There are only two species.
Ginglymostomatidae Nurse sharks 3 4 Nurse sharks have long tails and distinctive mouths which are far ahead of the eyes and before the snout (sub-terminal), an indication of the bottom-dwelling (benthic) nature of these sharks. Also present on the lower jaw are two fleshy barbels, chemosensory organs which help the nurse sharks find prey hidden in the sediments. Common in shallow, tropical and subtropical waters, these sharks are sluggish and docile bottom-dwellers. Nurse sharks typically attack humans only if directly threatened. The largest species can reach a length of 4.3 metres (14 ft).[6]
Hemiscylliidae Bamboo sharks 2 extant 4 extinct 16 extant 6 extinct Bamboo sharks, sometimes called longtail carpet sharks, are distinguished by a relatively long snout with subterminal nostrils.[7] They are relatively small sharks, with the largest species reaching only 121 cm (48 in) in length. They have elongated, cylindrical bodies, with short barbels and large spiracles. As their common name suggests, they have unusually long tails, exceeding the length of the rest of the body. They are found in shallow waters of the tropical Indo-Pacific. They are sluggish fish, feeding off bottom dwelling invertebrates and smaller fish.[1]
Orectolobidae Wobbegong sharks 3 extant 1 extinct 12 extant 1 extinct Wobbegong sharks are well camouflaged with symmetric bold patterns resembling a carpet. The camouflage is improved by the presence of small weed like whiskers lobes surrounding the jaw, which help to camouflage it and act as sensory barbs.[8] Wobbegongs are bottom-dwelling and spend much time resting on the sea floor. They are found in shallow temperate and tropical waters of the western Pacific Ocean and eastern Indian Ocean, chiefly around Australia and Indonesia. Most species have a maximum length of 1.25 metres (4.1 ft) or less, and the largest reach about 3 metres (9.8 ft) in length. Wobbegongs are generally not dangerous to humans unless provoked.[9]
Parascylliidae Collared carpet sharks 2 8 Collared carpet sharks have elongated, slender, bodies, cat-like eyes, and barbels behind the chin. They are found only in the shallow waters of the western Pacific. They are relatively small sharks, with the largest species reaching no more than 91 centimetres (2.99 ft) in adult length.[10]
Rhincodontidae Whale sharks 1 1 The whale shark is the largest extant fish species, growing over 12 meters (40 ft) long and weighing over 20 tonnes (45,000 lb). It is a slow-moving filter feeder with a very large mouth, feeding mainly, though not exclusively, on plankton. The whale shark is a pelagic species, living in the open sea in tropical and warm oceans with a lifespan of about 70 years.[2] The IUCN has assessed it as vulnerable.[11]
Stegostomatidae Zebra sharks 1 1 Zebra sharks are distinctive in appearance, with five longitudinal ridges on a cylindrical body, a low caudal fin comprising nearly half the total length, and a pattern of dark spots on a pale background. They grow to a length of 2.5 m (8.2 ft), and are found throughout the tropical Indo-Pacific, frequenting coral reefs and sandy flats to a depth of 62 m (210 ft). They are nocturnal and spend most of the day resting motionless on the sea floor. They are innocuous to humans. The IUCN has assessed them as vulnerable and there is evidence that their numbers are dwindling.[12]

Order Orectolobiformes

See also

References

  1. 1 2 3 4 5 Froese, Rainer, and Daniel Pauly, eds. (2011). "Orectolobiformes" in FishBase. February 2011 version.
  2. 1 2 3 Nelson, J. S. (1994). "Order Summary for Orectolobiformes". Fishbase. Retrieved 2013-10-12.
  3. 1 2 3 4 5 Du Plessis, Amelia. "Orectolobiformes". Sharks. Retrieved 2013-10-11.
  4. 1 2 "Carpet shark". Encyclopædia Britannica online. Retrieved 2013-10-13.
  5. ↑ Scales, Helen (2012-02-13). "Pictures: Shark Swallows Another Shark Whole". National Geographic: Daily News. Retrieved 2013-10-13.
  6. ↑ Froese, Rainer, and Daniel Pauly, eds. (2011). "Ginglymostomatidae" in FishBase. February 2011 version.
  7. ↑ Compagno, Leonard J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food and Agricultural Organization. ISBN 92-5-101384-5.
  8. ↑ "Wobbegongs - five species encountered in Queensland". Queensland Primary Industries and Fisheries. 2009-03-02. Retrieved 2009-06-14.
  9. ↑ Kuiter, Rudie (1999). Guide to Sea Fishes of Australia (amended ed.). New Holland Publishers (Aust.) Pty Ltd. p. 12. ISBN 1-86436-091-7.
  10. ↑ Froese, Rainer, and Daniel Pauly, eds. (2011). "Parascylliidae" in FishBase. February 2011 version.
  11. ↑ Norman, B. (2005). "Rhincodon typus". IUCN Red List of Threatened Species. Version 2011.1. International Union for Conservation of Nature. Retrieved 18 August 2011.
  12. ↑ Pillans, R.; Simpfendorfer, C (2003-04-30). "Stegostoma fasciatum". IUCN Red List of Threatened Species. Version 2013.1. Retrieved 2013-10-15.
  13. ↑ Moral-Flores, L.F.D., Ramírez-Antonio, E., Angulo, A. & Pérez-Ponce de León, G. (2015). "Ginglymostoma unami sp. nov. (Chondrichthyes: Orectolobiformes: Ginglymostomatidae): a new species of nurse shark from the Tropical Eastern Pacific". Revista Mexicana de Biodiversidad 86: 48–58. doi:10.7550/rmb.46192.
  14. 1 2 Allen & Erdmann (2008). "Two new species of bamboo sharks (Orectolobiformes: Hemiscylliidae) from Western New Guinea". Aqua (Miradolo Terme) 13 (3-4): 93–108.
  15. ↑ Allen, G.R., Erdmann, M.V. & Dudgeon, C.L. (2013): Hemiscyllium halmahera, a new species of Bamboo Shark (Hemiscylliidae) from Indonesia. aqua, International Journal of Ichthyology, 19 (3): 123-136.
  16. ↑ Allen & Dudgeon (2010). "Hemiscyllium michaeli, a new species of Bamboo Shark (Hemiscyllidae) from Papua New Guinea". Aqua International Journal of Ichthyology 16 (1): 19–30.
  17. ↑ Huveneers (2006). "Redescription of two species of wobbegongs (Chondrichthyes: Orectolobidae) with elevation of Orectolobus halei Whitley 1940 to species level" (PDF). Zootaxa 1284: 29–51.
  18. ↑ Last, Chidlow & Compagno (2006). "A new wobbegong shark, Orectolobus hutchinsi n. sp. (Orectolobiformes: Orectolobidae) from southwestern Australia" (PDF). Zootaxa 1239: 35–48.

Further reading

External links

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