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Reticulate whipray
The reticulate whipray or honeycomb stingray (''Himantura uarnak'') is a species of stingray in the family Dasyatidae. It inhabits coastal and brackish waters across the Indo-Pacific region from South Africa to Taiwan to Australia, favoring sandy habitats. A large species reaching in width, the reticulate whipray has a diamond-shaped pectoral fin disc and an extremely long tail without fin folds. Both its common and scientific names refer to its ornate dorsal color pattern of many small, close-set dark spots or reticulations on a lighter background. However, the reticulate whipray is only one of several large spotted stingrays in the Indo-Pacific which, coupled with the variability of its coloration with age and locality, has resulted in a great deal of taxonomic confusion.
Often encountered resting on the bottom during daytime, the reticulate whipray is a predator of bottom-dwelling invertebrates and bony fishes. Like other stingrays, it is aplacental viviparous, with the developing embryos nourished at first by yolk and later by histotroph ("uterine milk"). Females bear litters of up to five pups in summer, following a gestation period of a year. The reticulate whipray is fished in Southeast Asia and parts of the Indian Ocean for meat, skin, cartilage, and other purposes. It is highly susceptible to population depletion because of its large size, inshore habits, and low reproductive rate, and is additionally threatened by extensive habitat degradation. Consequently, the International Union for Conservation of Nature (IUCN) has assessed this species as Vulnerable.
==Taxonomy and phylogeny==
In 1775, Carsten Niebuhr published ''Descriptiones animalium – avium, amphibiorum, piscium, insectorum, vermium: quæ in itinere orientali observavit'', the work of his late friend, the Swedish naturalist Peter Forsskål. Within Forsskål had described ''Raja sephen'', now commonly known as the cowtail stingray, with a spotted variant he called ''uarnak'', derived from an Arabic word that describes the color pattern. No type specimen was designated.〔 Forsskål's account formed the basis for two subsequent writings that named the spotted ray as a distinct species: Pierre Joseph Bonnaterre's ''Raia scherit'' in 1788, and Johann Friedrich Gmelin's ''Raja uarnak'' in 1789. Although Bonnaterre's name was published first and thus would have had precedence, later authorities have regarded Forsskål's ''uarnak'' as the earliest available name even though it was not initially part of a binomial. Consequently, modern sources give ''uarnak'' as the valid specific epithet and either Gmelin or Forsskål as the species authority.〔〔 In 1837, Johannes Peter Müller and Friedrich Gustav Jakob Henle included the reticulate whipray in the newly created genus ''Himantura''; David Starr Jordan and Barton Warren Evermann made it the type species in 1896.〔
The reticulate whipray is closely related to ''H. undulata'' and ''H. leoparda'', which share much of its range. All three species are very similar in size, shape, and color pattern, resulting in a long history of taxonomic confusion that only recently is starting to be untangled. In 2004, Mabel Manjaji described the 'uarnak' species complex, containing ''H. fai'', ''H. gerrardi'', ''H. jenkinsii'', ''H. leoparda'', ''H. toshi'', ''H. uarnak'', and ''H. undulata'', plus three more undescribed species.〔 The reticulate whipray itself varies in appearance throughout its range, and further taxonomic comparisons are required to determine whether its spotted and reticulated color morphs in fact represent different species.〔 Alternate common names for this ray include coachwhip ray, leopard stingray, longtail stingray, and marbled stingray; some of these names are shared by other, similar species.〔
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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