Дженкинс Кнут
| Дженкинс Кнут | |
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Научная классификация 
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| Домен: | Эукариота |
| Королевство: | Животное |
| Филум: | Chordata |
| Сорт: | Хондрихти |
| Subclass: | Elasmobranchii |
| Superorder: | Batoidea |
| Order: | Myliobatiformes |
| Family: | Dasyatidae |
| Genus: | Pateobatis |
| Species: | P. jenkinsii
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| Binomial name | |
| Pateobatis jenkinsii (Annandale, 1909)
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| Range of the Jenkins' whipray | |
| Synonyms | |
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Хилрей Дженкинса ( Pateobatis Jenkinsii ) является видом скаты до в семействе Dasyatidae , с широким распространением в Индо-Тихоокеанском регионе от Южной Африки малайского архипелаго до северной Австралии . Этот большой вид растет до 1,5 м (4,9 фута) в поперечнике и имеет широкий диск грудного плавника в форме алмаза и хвост, похожий на кнут без плавных складок. Он имеет полосу душераздирающих кожных зубьев, проходящих от глаз до хвоста на верхней поверхности, наряду с характерным рядом больших копья, похожих на копья вдоль средней линии. Это равномерное желтовато -коричневое выше, становясь сероватым на хвосте мимо жениха позвоночника, и белым внизу; По -видимому, есть пятнистый вариант цвета , который ранее был описан как другой вид, драконский скат ( H. draco ).
Проведя в основном на мелких костяных рыбах и ракообразных , брюк Дженкинса обычно встречается в прибрежной , песчаной или иловой среде обитания , более 50 м (160 футов). Это Aplacental Viviparors , когда женщины питают их развивающихся молодых гистотрофом (« молоко матки »). Этот вид регулярно ловит прибрежный рыболовство на большей части своего ассортимента, особенно в Арафуре -море ; Его кожа высоко ценится за большие шипы, в то время как мясо и хрящ также могут быть проданы. Международный союз сохранения природы хлыст Дженкинса (МСОП) перечислил уязвимый , отметив, что он сталкивается с минимальными угрозами сохранения у Северной Австралии , которая охватывает большую часть его диапазона. наблюдается интенсивное давление на рыбалку Тем не менее, в Юго -Восточной Азии и привело к значительному снижению населения.
Taxonomy
[edit]
The first known specimens of the Jenkins' whipray were two 1.0 m (3.3 ft) wide adult males collected near Ganjam, India by the steamer Golden Crown, and described by Scottish zoologist Nelson Annandale in a 1909 issue of Memoirs of the Indian Museum. He named the new species Trygon jenkinsii, in honor of Dr. J. Travis Jenkins, the Scientific Advisor on Fisheries to the Government of Bengal, who assisted the Golden Crown expedition.[2] Other common names for this ray include brown stingray, golden whip ray, pointed-nose stingray, rough-back stingray, and sharpnose stingray.[3]
The Jenkins' whipray is easily confused for the pink whipray (H. fai), and has likely been misrepresented as that species in various publications.[1] In 2004, Mabel Manjaji grouped it with H. fai, H. gerrardi, H. leoparda, H. toshi, H. uarnak, and H. undulata in the 'uarnak' species complex.[4] The dragon stingray (H. draco), described from South Africa in 1984, closely resembles the Jenkins' whipray but has dark spots along the posterior margin of the disc. Similarly spotted rays have since been documented from the Arafura Sea, Sulu Sea, Sumatra, and western Sri Lanka, leading taxonomists to tentatively re-classify H. draco as a color morph of H. jenkinsii.[1]
Description
[edit]
The pectoral fin disc of the Jenkins' whipray is diamond-shaped and rather thick in the center, measuring 1.1–1.2 times wider than long; the outer corners of the disc are broadly rounded. The anterior margins of the disc are nearly straight and converge at a very obtuse angle on the snout, which has a barely protruding tip. The eyes are medium-sized and closely followed by larger spiracles. A short, broad curtain of skin with a finely fringed posterior margin is present between the long, thin nostrils. The mouth is wide and gently arched, and contains four papillae (nipple-shaped structures) on the floor, the inner pair of which is shorter than the outer.[5][6]
The pelvic fins are small and narrow. The cylindrical, tapering tail lacks fin folds and measures slightly longer than the disc width. One to three serrated, stinging spines are located atop the tail, approximately one-quarter of the total tail length back from the base. The upper surface of the disc has a granular texture and bears a broad central band of closely spaced, flattened heart-shaped dermal denticles, beginning between the eyes, becoming widest at the "shoulders", and extending to entirely cover the tail. One or more rows of large, spear-like thorns also run along the dorsal midline from the center of the disc to the base of the sting. Barring the possible spotted variant, this species is a uniform yellowish brown above, with the disc margin and underside white, and the tail gray past the sting. It can grow up to 1.5 m (4.9 ft) across and 3.0 m (9.8 ft) long.[5]
Distribution and habitat
[edit]The Jenkins' whipray is rather common, with a wide but patchy distributed in the tropical waters of the Indo-Pacific. It occurs off southeastern Africa (including Madagascar), the Socotra Islands near Yemen, South and Southeast Asia (including the Philippines), New Guinea, and northern Australia from Ningaloo Reef to the Gulf of Carpentaria.[1][5] This bottom-dwelling species is generally found close to shore in water under 50 m (160 ft) deep, though it has been recorded as far down as 100 m (330 ft) off northwestern Australia.[1] It prefers sandy or silty bottoms, often in lagoons, and has been known to enter brackish water.[3][7]
Biology and ecology
[edit]
The Jenkins' whipray may be encountered alone or in groups; there is some evidence of segregation by sex.[7][8] Small teleost fishes form a substantial portion of its diet, while crustaceans are also taken.[1][9] One individual has been observed accompanying a smalleye stingray (Dasyatis microps) off Tofo, Mozambique.[10] Known parasites of this species include the tapeworms Dollfusiella ocallaghani, Parachristianella baverstocki, P. indonesiensis, and Pterobothrium platycephalum.[11] As in other stingrays, the Jenkins' whipray is aplacental viviparous: the developing embryos are sustained at first by yolk, which is later supplanted by histotroph ("uterine milk") produced by the mother. The newborns measure 20–27 cm (7.9–10.6 in) across, and males reach sexual maturity at 75–85 cm (30–33 in) across.[1][5]
Human interactions
[edit]Because of its large thorns, the Jenkins' whipray is highly prized for its skin; the meat and cartilage may also be utilized.[1][3] It is frequently taken intentionally and incidentally across much of its range by intensive coastal fisheries, using tangle nets, bottom trawls, seine nets, and to a lesser extent longlines. Particularly large numbers are caught by an Indonesian commercial gillnet fishery targeting wedgefishes, that operates in the Arafura Sea and increasingly, illegally, in Australian waters. Although species-specific data is lacking, this fishery has caused a substantial decline in overall stingray populations. Off northern Australia, the Jenkins' whipray is relatively protected; it is thought to contribute minimally to the bycatch of the Northern Prawn Fishery (NPF) since the mandatory introduction of Turtle Excluder Devices (TERs). The International Union for Conservation of Nature (IUCN) has assessed this species as of Vulnerable globally due to the intensity and inadequate regulation of regional fishing activities in Southeast Asia.[1]
References
[edit]- ^ Jump up to: a b c d e f g h i Manjaji Matsumoto, B.M.; Fahmi.; White, W.T. (2020). "Pateobatis jenkinsii". IUCN Red List of Threatened Species. 2020: e.T161744A176850023. doi:10.2305/IUCN.UK.2020-3.RLTS.T161744A176850023.en. Retrieved 11 November 2021.
- ^ Annandale, N. (May 1909). "Report on the fishes taken by the Bengal fisheries steamer "Golden Crown." Part I, Batoidei". Memoirs of the Indian Museum. 2 (1): 1–60. doi:10.5962/bhl.title.13766.
- ^ Jump up to: a b c Froese, Rainer; Pauly, Daniel (eds.). "Himantura jenkinsii". FishBase. August 2010 version.
- ^ Manjaji, B.M. (2004). Taxonomy and phylogenetic systematics of the Indo-Pacific Whip-Tailed Stingray genus Himantura Müller & Henle 1837 (Chondrichthyes: Myliobatiformes: Dasyatidae). Unpublished PhD Thesis, University of Tasmania.
- ^ Jump up to: a b c d Last, P.R.; J.D. Stevens (2009). Sharks and Rays of Australia (second ed.). Harvard University Press. p. 445–446. ISBN 978-0-674-03411-2.
- ^ Randall, J.E.; J.P. Hoover (1995). Coastal Fishes of Oman. University of Hawaii Press. p. 45. ISBN 0-8248-1808-3.
- ^ Jump up to: a b Hennemann, R.F. (2001). Sharks & Rays: Elasmobranch Guide of the World. IKAN-Unterwasserarchiv. p. 248.
- ^ White, W. (2007). "Species and size compositions and reproductive biology of rays (Chondrichthyes, Batoidea) caught in target and non-target fisheries in eastern Indonesia". Journal of Fish Biology. 70 (6): 1809–1837. doi:10.1111/j.1095-8649.2007.01458.x.
- ^ Fahmi (March 2007). Diversity, Biology and Utilization of Chondrichthyans in West Central Indonesian Fisheries. MPhil Thesis, Centre for Marine Studies, The University of Queensland.
- ^ Pierce, S.J.; W.T. White & A.D. Marshall (2008). "New record of the smalleye stingray, Dasyatis microps (Myliobatiformes: Dasyatidae), from the western Indian Ocean". Zootaxa. 1734: 65–68. doi:10.11646/zootaxa.1734.1.5.
- ^ Кэмпбелл, Ра; I. Беверидж (май 2009 г.). « Oncomegas aetobatidis sp. Nov. (Cestoda: Trypanorhyncha), переоценка O. australiensis Toth, Campbell & Schmidt, 1992 и новые записи Trypanorhynch Cestodes из австралийских рыб Elasmobranch». Сделки Королевского общества Южной Австралии . 133 (1): 18–29. doi : 10.1080/03721426.2009.10887107 . S2CID 85869638 .
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