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Jenkins' whipray
The Jenkins' whipray (''Himantura jenkinsii'') is a species of stingray in the family Dasyatidae, with a wide distribution in the Indo-Pacific region from South Africa to the Malay Archipelago to northern Australia. This large species grows to across and has a broad, diamond-shaped pectoral fin disc and a whip-like tail without fin folds. It has a band of heart-shaped dermal denticles running from between the eyes to the tail on its upper surface, along with a characteristic row of large spear-like thorns along the midline. It is uniform yellowish brown above, becoming grayish on the tail past the stinging spine, and white below; there is apparently a spotted color variant that had previously been described as a different species, the dragon stingray (''H. draco'').
Preying mainly on small bony fishes and crustaceans, the Jenkins' whipray is commonly found in inshore, sandy or silty habitats shallower than . It is aplacental viviparous, with the females nourishing their developing young with histotroph ("uterine milk"). This species is regularly caught by coastal fisheries across much of its range, particularly in the Arafura Sea; its skin is highly valued for the large thorns, while the meat and cartilage may also be marketed. The International Union for Conservation of Nature (IUCN) has listed the Jenkins' whipray under Least Concern, noting that it faces minimal conservation threats off northern Australia, which encompasses a large portion of its range. However, the IUCN has assessed this species as Vulnerable in Southeast Asia, where intense fishing pressure has likely lead to significant population declines.
==Taxonomy==
The first known specimens of the Jenkins' whipray were two 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. Other common names for this ray include brown stingray, golden whip ray, pointed-nose stingray, rough-back stingray, and sharpnose stingray.
The Jenkins' whipray is easily confused for the pink whipray (''H. fai''), and has likely been misrepresented as that species in various publications.〔 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.〔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.〕 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''.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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