Orectolobus hutchinsi

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Orectolobus hutchinsi
Western Wobbegong in Coral Bay, Western Australia.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Orectolobiformes
Family: Orectolobidae
Genus: Orectolobus
Species:
O. hutchinsi
Binomial name
Orectolobus hutchinsi
Orectolobus sp A distmap.png
Range of western wobbegong (in blue)

Orectolobus hutchinsi, the western wobbegong, is a species of carpet shark in the family Orectolobidae. The western wobbegong shark is a moderate sized marine shark found off the coast of Western Australia. [2] Its scientific name is Orectolobus hutchinsi, and it was first identified in 1983 by Dr. Barry Hutchins, but was only recently classified, described, and published in 2006. [2] O. hutchinsi is found on the shallow continental shelf in Western Australia from Coral Bay to Groper Bluff. [2] This species is distinct from other wobbegong sharks because the western wobbegong shark has a yellowish brown upper body and darker brown saddles on their backs. [3] Unlike other wobbegong sharks from the same area, the western wobbegong shark does not have white rings or blotches on their backs. [3]

Contents

Morphology

Electrosensitivity

Like all wobbegong sharks, the western wobbegong shark is able to electrosense, meaning that the shark can sense the electricity of moving organisms around it. The way that electrosensitivity works is through the gel-filled pores on and surrounding the wobbegong shark's head. [4] The gel-filled canals open on the surface of the skin, where they pick up sensory information from the environment. [4] At the bottom of these gel-filled pores are the wobbegong's ampullae of Lorenzini. [4] Wobbegong sharks have "macro-ampullae", meaning that their ampullae have large pores and long gel-filled canals, which is an adaptation to the salt water's high electrical conductivity and allows the wobbegong to accurately process the information. [4]  The ampullae of Lorenzini pick up electric information from the water, and send it to the ampullary organ, which is used to process the stimuli. [4] These are located around the head, in order to provide the most useful information to the organism because of its close proximity to the wobbegong's mouth. [4] Additionally, the electrosensing pores are concentrated dorsally, which benefits the wobbegong in low light because it is able to sense prey rather than directly see it. [4] Overall, the wobbegong shark's electrosensitivity ability provides information about the shark's surrounding environment. Additionally, electrosensing may have numerous biological functions: detecting predators and prey, communicating with other organisms, detecting mates, and potentially allowing the shark to accurately navigate short distances. [4]

Body description

The western wobbegong shark has a firm, dorso-ventrally compressed body, meaning that O. hutchinsi is flattened more on their back and tail and less near their heads. [4] The colour of O. hutchinsi's back is brownish yellow with splotches that are dark brown down the shark’s back. [2] The western wobbegong shark has highly patterned skin with dark brown saddles on their backs which helps them blend into their environment and hide from predators. [2] Unlike other wobbegong species, the western wobbegong shark does not have any white spots or blotches on their bodies. [2] Additionally, the western wobbegong does not have any warty tubercles (wart-like growths) on their backs, and has relatively larger dorsal fins. [2] O. hutchinsi has four equally spaced gills on the side of its head which it uses to filter oxygen from the surrounding water in order to breathe. [2] The fins of the western wobbegong are the pectoral fins, a triangular pelvic fin, a lobe-like anal fin, a caudal fin, and triangular dorsal fins. [2] Their eyes are located on their heads, and O. hutchinsi's eyes have a duplex retina. [5]   Having a duplex retina means that the western wobbegong shark's eyes contain both rods and cones, for light sensitivity and colour resolution, respectively. [5]

Measurements

Western wobbegong males and females are around the same size, which may be an adaptation to surviving in their environment where it is essential to be the right size to fit into cracks in rock. [3] O. hutchinsi males mature to be around 111 cm long and 15 kg heavy, which is larger than other wobbegong species. [2] More data needs to be collected for female body size. When they mate, their young are born at 22–26 cm. [2]

Reproduction

O. hutchinsi tends to mate in late July, and females can store sperm for up to 6 months. [3] Although more genetic analysis is needed, it is hypothesized that this may be an evolutionary adaptation to make sure the female has a constant supply of sperm, as well as increasing genetic diversity in that females can store sperm from more than one male. [3]

In wobbegong sharks, ovulation is hypothesized to occur in a biennial or triennial cycle, meaning it happens 2-3 times per year. [3] The gestation period for O. hutchinsi is 9–11 months, [3] and O. hutchinsi females have litters of about 23 pups. [6] Compared to other wobbegong species, O. hutchinsi can carry a larger litter to term because they are not physiologically constrained by uterus structure or size. [3]

Evolutionary history

Wobbegong sharks are a species located under the elasmobranch subclass of Chondrichthyes, meaning the wobbegongs are cartilaginous fish with 4-7 gill slits. Elasmobranch fish have survived four mass-extinctions, and it is speculated that members of the elasmobranch lineage (including western wobbegong sharks) are related to ancestors from the Mesozoic period. [7] The orectolobidae genus of sharks likely diversified from their other ancestors in the Miocene age, which may explain the high distribution of wobbegongs within the Inso-Australian region. [7] It is suspected that there was a rapid spreading of wobbegong sharks within the last 2 million years, despite there being a lack of an extensive fossil record. [7] This rapid spreading and diversification of wobbegongs was likely caused by two distinct events: major tectonic plate movement in the region causing geological changes, and glacial cycles causing changes in oceanography, coastal geology, and geographic barriers. [7] These two potential changes may have occurred simultaneously or sequentially, but both were likely factors in influencing the present day wobbegong distribution. Genetically, studies have been conducted to analyze the western wobbegong's mitochondrial DNA to determine their relation to other wobbegong species, which found that O. hutchinsi was one of the more recent species to diverge and has a sister species to Orectolobus parvimaculatus. [7]

Habitat

O. hutchinsi are mainly benthic organisms, meaning they spend most of their lives on the seafloor. [4] Wobbegongs as a genus are usually found in temperate and tropical continental water in the western Pacific and eastern Indian Ocean, but the western wobbegong is part of the recent diversification in Australian waters. [7] O. hutchinsi is one of the 7 wobbegong species to be recorded in Australian waters, out of the 8 total wobbegong species recognized as valid. [8] O. hutchinsi has been found in waters from 0.1 to 106 m, showing that they prefer to live in the shallow water of the continental shelf. [2] They live in rocky reefs or seagrass habitats, [4] and use their high patterned skin to camouflage to their surroundings and await prey. [3]

Feeding

The wobbegong genus as a whole normally feeds on demersal teleost fish and smaller elasmobranchs, but O. hutchinsi additionally preys on cephalopods, which are squids, nautilus or octopus. [4] The western wobbegong shark uses its electrosensing capabilities to sense and capture prey. [4] Their electrosensitivity is highly accurate behind their heads, which allows the wobbegong to accurately strike and capture prey even when the prey is not visible. [4] Because wobbegong sharks wait for prey on the seafloor, their electrosensing capabilities are essential in detecting prey swimming near them. [4] The western wobbegong shark employs a "sit-and-wait" feeding strategy, meaning that they wait for prey to swim by and then strike quickly and accurately with the help of their electrosensing abilities. [4] Their feeding strategy is unusual for sharks: wobbegongs ambush prey during the daylight, because their well-camouflaged body makes it difficult for prey to detect them when they're motionless on the seafloor. [4]

Predation

A significant threat for the western wobbegong shark is human activity. [7] Wobbegong species are used as a food source not only in Australia, where the western wobbegong shark lives, but also China, Japan, and Malaysia. [7] O. hutchinsi also may be experiencing a population decline, which may be a result of fishing practices in Australia. [7] They are frequently caught for food and are commercially targeted in some parts of Australia, as well as being caught accidentally as a byproduct of gillnet, longline, rock lobster, and recreational fisheries. [2]

See also

Related Research Articles

<span class="mw-page-title-main">Carpet shark</span> Order of sharks

Carpet sharks are sharks classified in the order Orectolobiformes. Sometimes the common name "carpet shark" 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.

<span class="mw-page-title-main">Wobbegong</span> Family of sharks

Wobbegong is the common name given to the 12 species of carpet sharks in the family Orectolobidae. They are found in shallow temperate and tropical waters of the western Pacific Ocean and eastern Indian Ocean, chiefly around Australia and Indonesia, although one species occurs as far north as Japan. The word wobbegong is believed to come from an Australian Aboriginal language, meaning "shaggy beard", referring to the growths around the mouth of the shark of the western Pacific.

<span class="mw-page-title-main">Ampullae of Lorenzini</span> Sensory organs in some fish that detect electrical fields

Ampullae of Lorenzini are electroreceptors, sense organs able to detect electric fields. They form a network of mucus-filled pores in the skin of cartilaginous fish and of basal bony fishes such as reedfish, sturgeon, and lungfish. They are associated with and evolved from the mechanosensory lateral line organs of early vertebrates. Most bony fishes and terrestrial vertebrates have lost their ampullae of Lorenzini.

<span class="mw-page-title-main">Nervous shark</span> Species of shark

The nervous shark is a species of requiem shark, and part of the family Carcharhinidae, so named because of its timid behavior in regard to humans. It is common in shallow, coastal waters off northern Australia, Papua New Guinea, and the Solomon Islands. A small brownish or grayish shark typically measuring 1.0–1.3 m (3.3–4.3 ft) long, this species has a short, blunt snout, oval eyes, and a relatively large second dorsal fin. The leading margins of most fins are finely edged with black, and the lower caudal fin lobe is black-tipped.

<span class="mw-page-title-main">Cobbler wobbegong</span> Species of shark

The cobbler wobbegong, Sutorectus tentaculatus, is a carpet shark in the family Orectolobidae, the only member of the genus Sutorectus. It is found in the subtropical eastern Indian Ocean around Western Australia between latitudes 26° S and 35° S. It is frequently found in rocky and coral reef areas. Cobbler wobbegongs reach a length of 92 cm. It has unbranched dermal lobes on the head, rows of warty tubercles along the back and black spots on the body and fins.

<span class="mw-page-title-main">Tasselled wobbegong</span> Species of shark

The tasselled wobbegong is a species of carpet shark in the family Orectolobidae and the only member of its genus. It inhabits shallow coral reefs off northern Australia, New Guinea, and adjacent islands. Reaching 1.8 m (5.9 ft) in length, this species has a broad and flattened body and head. Its most distinctive trait is a fringe of branching dermal flaps around its head, which extends onto its chin. The fringe, along with its complex color pattern of small blotches and reticulations, enable it to camouflage itself against the reef environment.

<span class="mw-page-title-main">Japanese wobbegong</span> Species of shark

The Japanese wobbegong is a carpet shark in the family Orectolobidae of the wobbegong family, found in the tropical western Pacific Ocean from Japan and Korea to Vietnam and the Philippines, between latitudes 43 and 6°N. It reaches a length of 1 m. Japanese wobbegong sharks typically remain motionless during the daytime, and are not active hunters. They use camouflage and their electroreceptor pores on their dorsal area to help them sense prey nearby.

<span class="mw-page-title-main">Spotted wobbegong</span> Species of shark

The spotted wobbegong is a carpet shark in the family Orectolobidae, endemic to Australia. It is a large, robust species, typically reaching 150–180 centimetres (59–71 in) in length. Coloured green, yellow, or brown, it has distinctive O-shaped spots throughout its body. It is nocturnal, resting at day and feeding on fish and invertebrates at night. An ovoviviparous species, the spotted wobbegong gives birth in the spring, during which time males can act aggressively towards other males and females. It has been known to bite humans, sometimes unprovoked, which can produce severe wounds. The species is fished commercially in Australia, but it is not severely threatened. It is listed as a least-concern species on the IUCN Red List.

<span class="mw-page-title-main">Ornate wobbegong</span> Species of shark

The ornate wobbegong is a species of carpet shark that lives in Australia and possibly other countries in the Western Pacific Ocean. It is coloured golden brown, yellow-green and blueish-grey, and it grows to maximum 120 centimetres (3.9 ft). Described by Charles Walter De Vis in 1883, it is similar in appearance to other Australian wobbegongs and has previously been classified as the same species as the Gulf wobbegong. It is a nocturnal species, hunting at night, and it can bite humans when disturbed. The International Union for Conservation of Nature has listed it as a least-concern species.

<span class="mw-page-title-main">Northern wobbegong</span> Species of shark

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<span class="mw-page-title-main">White ghost catshark</span> Species of shark

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<span class="mw-page-title-main">Gulf wobbegong</span> Species of shark

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<i>Orectolobus</i> Genus of sharks

Orectolobus is a genus of carpet sharks in the family Orectolobidae. They are commonly known as wobbegongs, although this name also applies to the other members of the family. They are found in shallow temperate and tropical waters of the western Pacific Ocean and eastern Indian Ocean, chiefly around Australia and Indonesia, although one species occurs as far north as Japan.

<span class="mw-page-title-main">Outline of sharks</span> Overview of and topical guide to sharks

The following outline is provided as an overview of and topical guide to sharks:

<span class="mw-page-title-main">Dwarf spotted wobbegong</span> Species of shark

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<span class="mw-page-title-main">Floral banded wobbegong</span> Species of shark

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<i>Orectolobus reticulatus</i> Species of shark

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<span class="mw-page-title-main">Indonesian wobbegong</span> Species of shark

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References

  1. Huveneers, C.; McAuley, R.B. (2015). "Orectolobus hutchinsi". IUCN Red List of Threatened Species . 2015: e.T42717A68638402. doi: 10.2305/IUCN.UK.2015-4.RLTS.T42717A68638402.en . Retrieved 12 November 2021.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 LAST, PETER R.; CHIDLOW, JUSTIN A.; COMPAGNO, LEONARD J.V. (21 June 2006). "A new wobbegong shark, Orectolobus hutchinsi n. sp. (Orectolobiformes: Orectolobidae) from southwestern Australia". Zootaxa. 1239 (1): 35. doi:10.11646/zootaxa.1239.1.3. ISSN   1175-5334.
  3. 1 2 3 4 5 6 7 8 9 Huveneers, Charlie. The ecology and biology of wobbegong sharks (Genus Orectolobus) in relation to the commercial fishery in New South Wales, Australia. OCLC   225593518.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Theiss, Susan M.; Collin, Shaun P.; Hart, Nathan S. (4 December 2010). "Morphology and distribution of the ampullary electroreceptors in wobbegong sharks: implications for feeding behaviour". Marine Biology. 158 (4): 723–735. doi:10.1007/s00227-010-1595-1. ISSN   0025-3162. S2CID   85409903.
  5. 1 2 Theiss, Susan M.; Collin, Shaun P.; Hart, Nathan S. (2010). "Interspecific Visual Adaptations among Wobbegong Sharks (Orectolobidae)". Brain, Behavior and Evolution. 76 (3–4): 248–260. doi:10.1159/000321330. ISSN   0006-8977. PMID   21051877. S2CID   11454513.
  6. Huveneers, C.; Otway, N. M.; Harcourt, R. G.; Ellis, M. (6 April 2011). "Quantification of the maternal-embryonal nutritional relationship of elasmobranchs: case study of wobbegong sharks (genus Orectolobus)". Journal of Fish Biology. 78 (5): 1375–1389. doi: 10.1111/j.1095-8649.2011.02938.x . ISSN   0022-1112. PMID   21539548.
  7. 1 2 3 4 5 6 7 8 9 Corrigan, Shannon; Beheregaray, Luciano B. (July 2009). "A recent shark radiation: Molecular phylogeny, biogeography and speciation of wobbegong sharks (family: Orectolobidae)". Molecular Phylogenetics and Evolution. 52 (1): 205–216. doi:10.1016/j.ympev.2009.03.007. ISSN   1055-7903. PMID   19303452.
  8. Goto, Tomoaki (May 2008). "Revision of the wobbegong genus Orectolobus from Japan, with a redescription of Orectolobus japonicus (Elasmobranchii: Orectolobiformes)". Ichthyological Research. 55 (2): 133–140. doi:10.1007/s10228-007-0033-y. ISSN   1341-8998. S2CID   22042954.