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coffin ray
''Hypnos monopterygius'' also known as the Coffin ray is a species of electric ray endemic to Australia, where it is common in inshore waters shallower than . It is the sole member of its family Hypnidae. This small species typically reaches in length. Greatly enlarged pectoral fins and an extremely short tail, coupled with diminutive dorsal and caudal fins all concentrated towards the rear, give the coffin ray a distinctive pear-like shape. It is a varying shade of brown in color above, and has tiny eyes and a large, highly distensible mouth.
The sluggish and nocturnal coffin ray frequents sandy or muddy habitats, where it can bury itself during daytime. It can produce a powerful electric shock reaching 200 volts for attack and defense. This species is a voracious predator that feeds mainly on benthic bony fishes, often tackling fish approaching or exceeding itself in size. On occasion, it may also consume invertebrates and even small penguins and rats. Reproduction is aplacental viviparous, in which the developing embryos are nourished by yolk and maternally produced histotroph ("uterine milk"). The female gives birth to 4–8 pups during summer. The coffin ray can deliver a severe, albeit non-fatal, shock to a human. Not valued commercially, it is very hardy and can usually survive being captured and discarded. The International Union for Conservation of Nature (IUCN) has listed this species under Least Concern, as its population does not seem threatened by human activity.
==Taxonomy and phylogeny==
The first scientific reference to the coffin ray was written by English zoologist and botanist George Shaw to accompany Frederick Polydore Nodder's illustrations of a beached fish, published in their 1795 work ''The Naturalist's Miscellany''. Shaw interpreted the specimen as a goosefish, calling it the "single-finned Lophius" or ''Lophius monopterygius'' in Latin.〔 Independently, French zoologist Auguste Duméril described a new electric ray in an 1852 volume of the journal ''Revue et Magasin de Zoologie'', based on two specimens collected off New South Wales. He named it ''Hypnos subnigrum''; the genus name is derived from the Greek word for "sleep", referring to the ray's ability to induce numbness.〔 Eventually, Gilbert Percy Whitley recognized that Nodder had illustrated the same species that Duméril had described, and thus the proper binomial name became ''Hypnos monopterygius''. In 1902, Edgar Ravenswood Waite proposed ''Hypnarce'' as a replacement name for ''Hypnos'', which he believed was preoccupied by the butterfly genus ''Hypna''. However, the International Code of Zoological Nomenclature (ICZN) does not seem to require the change, and thus ''Hypnarce'' is regarded as a junior synonym.〔
The common name "coffin ray" comes from the coffin-like shape of beached specimens, which become bloated after death.〔 This species may also be referred to as crampfish, electric ray, numbfish, numbie, short-tail electric ray, or torpedo.〔 Phylogenetic studies, based on morphology, have found that ''Hypnos'' is most closely related to the genus ''Torpedo''. Hence, some taxonomists classify it with ''Torpedo'' in the family Torpedinidae (in its own subfamily, Hypninae). On the other hand, there are also taxonomists who believe ''Hypnos'' to be distinctive enough to merit its own separate family, Hypnidae.〔〔
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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