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Porcupine ray
The porcupine ray (''Urogymnus asperrimus'') is a rare species of stingray in the family Dasyatidae and the only member of its genus. This bottom-dweller is found throughout the tropical Indo-Pacific, as well as off West Africa. It favors sand, coral rubble, and seagrass habitats in inshore waters to a depth of . A large and heavy-bodied species reaching in width, the porcupine ray has a nearly circular, plain-colored pectoral fin disc and a thin tail without any fin folds. Uniquely within its family, it lacks a venomous stinging spine. However, an adult ray can still defend itself ably with the many large, sharp thorns found over its disc and tail.
The diet of the porcupine ray consists mainly of benthic invertebrates and bony fishes, which it digs up from the sea floor. It is aplacental viviparous, in which the developing embryos are nourished by histotroph ("uterine milk") produced by the mother. The porcupine ray has long been valued for its rough and durable skin, which was made into a shagreen leather once used for various utilitarian and ornamental purposes, such as to cover sword hilts and shields. It is caught incidentally by coastal fisheries. Because it must be handled carefully due to its thorns, its commercial significance is limited. Unregulated fishing has led to this species declining in many parts of its range, and thus has been listed as Vulnerable by the International Union for Conservation of Nature (IUCN).
==Taxonomy==
German naturalists Marcus Elieser Bloch and Johann Gottlob Schneider described the porcupine ray in their 1801 work ''Systema Ichthyologiae'', based on a partial dried skin obtained from Mumbai, India. They placed it in the genus ''Raja'' and named it ''asperrima'', meaning "roughest" in Latin. In the same work, they also described a West African form, ''Raja africana''.〔 Later authors have regarded the two as synonymous. However, since the two names were published simultaneously, there is uncertainty about which name has priority. Some works give the ray's specific epithet as ''asperrimus'', and others as ''africanus''.〔〔
In 1837, Johannes Peter Müller and Friedrich Gustav Jakob Henle placed the porcupine ray in a new genus, ''Gymnura''. As the name ''Gymnura'' was already in use, referring to the butterfly rays, later that year Müller and Henle replaced it with ''Urogymnus''.〔 Both names are derived from the Ancient Greek ''oura'' ("tail") and ''gymnos'' ("naked" or "unarmed"), referring to the lack of a tail sting.〔 Other common names for this species include black spotted ray, rough-skinned ray, roughback stingaree, Solander's ray, and thorny ray.〔 There may be more than one species of porcupine ray, as is currently recognized.〔
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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