![]() Close behind the eyes and slightly larger are the spiracles, which are rimmed by small papillae in some individuals. The eyes are minute and can be elevated on short stalks. The leading margin of the disc is straight to gently concave. The pectoral fins form a greatly enlarged disc about as wide as long, that is thick at the center and thin at the margins. ![]() Its body is flabby, with two large, kidney-shaped electric organs visible on both sides of the head. The unusual pear-like shape of the coffin ray distinguishes it from all other rays. Description The coffin ray can be identified by its greatly enlarged pectoral fin disc and tiny tail. The coffin ray favors habitats with sandy or muddy bottoms, including beaches, estuaries, and bays, and can also be found over seagrass as well as on and around rocky and coral reefs. In 1910, the trawler Endeavour caught several coffin rays at depths ranging from 47 to 120 fathoms (86–219 metres). This common, bottom-dwelling species is typically found close to shore, no deeper than 80 m (260 ft), though it has been recorded from as deep as 240 m (790 ft). It does not occur off Victoria or Tasmania. The western part of its range extends from Gulf St Vincent in South Australia to Broome in Western Australia, and the eastern part from Eden in New South Wales to Heron Island in Queensland. The coffin ray has a wide but disjunct distribution in tropical and warm- temperate Australian waters. On the other hand, there are also taxonomists who believe Hypnos to be distinctive enough to merit its own separate family, Hypnidae. Hence, some taxonomists classify it with Torpedo in the family Torpedinidae (in its own subfamily, Hypninae). ![]() Phylogenetic studies, based on morphology, have found that Hypnos is most closely related to the genus Torpedo. This species may also be referred to as crampfish, electric ray, numbfish, numbie, short-tail electric ray, or torpedo. The common name "coffin ray" comes from the coffin-like shape of beached specimens, which become bloated after death. However, the International Code of Zoological Nomenclature (ICZN) does not seem to require the change, and thus Hypnarce is regarded as a junior synonym. In 1902, Edgar Ravenswood Waite proposed Hypnarce as a replacement name for Hypnos, which he believed was preoccupied by the butterfly genus Hypna. 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. He named it Hypnos subnigrum the genus name is derived from ancient Greek ῠ̔́πνος (húpnos, "sleep"), for the ray's ability to induce numbness. 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. Shaw interpreted the specimen as a goosefish, calling it the "single-finned Lophius" or Lophius monopterygius in Latin. 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. ![]() 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. Not valued commercially, it is very hardy and can usually survive being captured and discarded. The coffin ray can deliver a severe, albeit non-fatal, shock to a human. The female gives birth to 4–8 pups during summer. Reproduction is aplacental viviparous, in which the developing embryos are nourished by yolk and maternally produced histotroph ("uterine milk"). On occasion, it may also consume invertebrates and even small penguins and rats. This species is a voracious predator that feeds mainly on benthic bony fishes, often tackling fish approaching or exceeding itself in size. It can produce a powerful electric shock reaching 200 volts for attack and defense. The sluggish and nocturnal coffin ray frequents sandy or muddy habitats, where it can bury itself during daytime. It is a varying shade of brown in color above, and has tiny eyes and a large, highly distensible mouth. 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. This small species typically reaches 40 cm (16 in) in length. It is the sole member of its genus Hypnos, and family Hypnidae. Hypnos monopterygius, also known as the coffin ray or Australian numbfish, is a species of electric ray endemic to Australia, where it is common in inshore waters shallower than 80 m (260 ft).
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