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Ocellated electric ray
The ocellated electric ray or bullseye electric ray (''Diplobatis ommata'') is a species of electric ray in the family Narcinidae, native to the shallow inshore waters of the eastern central Pacific from the Gulf of California to Ecuador. Reaching in length, this species has a rounded pectoral fin disc and pelvic fins with convex margins. Its short and thick tail bears two dorsal fins and terminates in a triangular caudal fin. The ocellated electric ray is named for the distinctive large eyespot on the middle of its disc, consisting of a black or yellow center surrounded by concentric rings. Its dorsal coloration is otherwise highly variable, ranging from plain to ornately patterned on a light to dark brown background. The front part of its disc is darker brown.
Solitary and nocturnal in nature, the ocellated electric ray is a bottom-dweller found in sandy and rocky habitats. It moves along the bottom by "hopping" on its pelvic fins, and feeds on small crustaceans and polychaete worms. For defense, it can generate an electrical discharge from its electric organs. This species probably bears live young that are sustained by yolk and later histotroph ("uterine milk") during gestation. The International Union for Conservation of Nature (IUCN) has listed the ocellated electric ray as Vulnerable, as it is susceptible to the heavy trawling activity within its limited range.
==Taxonomy==
American ichthyologists David Starr Jordan and Charles Henry Gilbert described the ocellated electric ray in an 1890 article for the scientific journal ''Proceedings of the United States National Museum''. Their account was based on a female specimen caught by the United States Fish Commission steamer USS ''Albatross'' in 1888. The female was collected off the Pacific coast of Colombia at a depth of . Gilbert had previously obtained a specimen from Panama in 1882, but it had been destroyed in a fire before it could be studied. Jordan and Gilbert named the new species ''ommata'' (Greek for "eyed") in reference to the distinctive spot on its back, and assigned it to the genus ''Discopyge''.〔〔 In 1948, Henry Bryant Bigelow and William Charles Schroeder created the new genus ''Diplobatis'' for this species based on then-unique subdivision of its nostrils.〔 Three other species of ''Diplobatis'' have since been described from the Atlantic. The Atlantic species more closely resemble each other in morphology than they do the ocellated electric ray, though as a whole all four ''Diplobatis'' species are extremely similar.〔 Another common name for this species is "target ray".〔
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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