The ornate sleeper-ray (''Electrolux addisoni'') is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

electric ray The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins, composing the order Torpediniformes . They are known for being capable of producing an electric discharge, ranging from 8 to 220 volts, depending ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Narkidae Members of the family Narkidae are commonly known as sleeper rays. They are restricted to the temperate and tropical Indo-West Pacific from South Africa to Japan to Indonesia, and are exclusively marine and are absent from freshwater habitats. T ...

, and the only member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

''Electrolux''. It lives on

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic processes—deposition (geology), deposition of ...

s feeding on

polychaete worm Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are ma ...

s and small

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...

s, it has only been seen by divers to feed during the daytime. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

to the coast of

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

. It was first recorded in 1984 but was not described until 2007. It was ranked as the number one newly described species of 2007 by the

International Institute for Species Exploration The International Institute for Species Exploration (IISE) is a research institute located in Syracuse, New York. Its mission is to improve taxonomical exploration and the cataloging of new species of flora and fauna. Since 2008, IISE has publi ...

. In an episode of ''

Extinct or Alive ''Extinct or Alive'' is an American wildlife documentary television programme produced for Animal Planet by Hot Snakes Media of New York City, the United States. It is hosted by conservationist and television personality Forrest Galante, who tra ...

'', an ornate-sleeper ray is caught on footage feeding.

Description

''Electrolux addisoni'' is easily distinguished from other narkids by its striking colour pattern consisting of a dark brown dorsal surface of the disc with numerous small pale yellow spots and a series of concentric stripes. It can also be distinguished by its large spiracular papillae. It and ''

Heteronarce ''Heteronarce'' is a genus of sleeper rays in the family Narkidae. This genus is found only in the western Indian Ocean along the coasts of Africa, the Arabian Peninsula and India. Species There are currently four recognized species in this g ...

'' are the only genera in the family Narkidae that have two

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

s. The conspicuous colour pattern of the species may act as a

warning signal Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...

to other animals, when closely approached the ray has been seen to make a possible threat display. The holotype pictured weighed 1.8 kg and had a

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of 515 mm. This makes it one of the largest species of Narkidae recorded, although no female specimens have been collected and measured.

Distribution

''Electrolux addisoni'' has been recorded in four locations along a 300 km strip of coastline from Coffee Bay,

Eastern Cape Province The Eastern Cape is one of the provinces of South Africa. Its capital is Bhisho, but its two largest cities are East London and Gqeberha. The second largest province in the country (at 168,966 km2) after Northern Cape, it was formed in 19 ...

, to just north of

Durban Durban ( ) ( zu, eThekwini, from meaning 'the port' also called zu, eZibubulungwini for the mountain range that terminates in the area), nicknamed ''Durbs'',Ishani ChettyCity nicknames in SA and across the worldArticle on ''news24.com'' from ...

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN and known as "the garden province") is a province of South Africa that was created in 1994 when the Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu) and Natal Province were merged. It is loca ...

in water less than 50 m deep.

Discovery

Despite being first photographed in 1984 by Peter Chrystal on Aliwal Shoal, KwaZulu-Natal the species evaded capture (and therefore

classification Classification is a process related to categorization, the process in which ideas and objects are recognized, differentiated and understood. Classification is the grouping of related facts into classes. It may also refer to: Business, organizat ...

) until 2007. Experts immediately realised that this was a new species but were unsure to which

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

it belonged. It was filmed by nature film producers Stephania and Peter Lamberti off Shelly Beach, KwaZulu-Natal in 1997 and they sent this clip to

Phil Heemstra Phillip Clarence Heemstra (9 December 1941 – 29 August 2019) was an American-South African ichthyologist. He was born in Melrose Park, Illinois, United States as the son of Clarence William Heemstra and his wife, Lydia (born Epcke). He att ...

. Heemstra sighted a live specimen in 2001 but unfortunately could not capture it. Mark Addison finally managed to capture a live specimen in September 2003 and he donated this to the South African Institute of Aquatic Biodiversity. Another specimen was collected by Mark's father, Brent Addison, and this specimen is held in the fish collection of the

South African Museum The Iziko South African Museum is a South African national museum located in Cape Town. The museum was founded in 1825, the first in the country. It has been on its present site in the Company's Garden since 1897. The museum houses important A ...

. Examination of the specimens confirmed that it was a new species and that it was also of a new genus.

Conservation

Its habitat is intensively used for recreational diving, commercial fishing and there is increasing development along the coastline which means that it may be at risk from

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

habitat degradation Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

and from being disturbed by divers. The describing authors tentatively suggest that it may possibly be critically endangered but conclude that more observations need to be made before its conservation status can be properly assessed.

Etymology

The species was named after the

Electrolux Electrolux AB () is a Swedish multinational home appliance manufacturer, headquartered in Stockholm. It is consistently ranked the world's second largest appliance maker by units sold, after Whirlpool. Electrolux products sell under a variet ...

vacuum cleaner A vacuum cleaner, also known simply as a vacuum or a hoover, is a device that causes suction in order to remove dirt from floors, upholstery, draperies, and other surfaces. It is generally electrically driven. The dirt is collected by either a ...

company. The name alludes to the well-developed

electrogenic Electroreception and electrogenesis are the closely-related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes to st ...

properties of this ray and to the "vigorous sucking action displayed on the videotape of the feeding ray that...may rival a well-known electrical device used to suck the detritus from carpets, furniture, and other dust-gathering surfaces in modern home."International Institute for Species Exploration
/ref> The species is named after Mark Addison, who collected the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

References

{{Taxonbar, from=Q2387882

ornate sleeper-ray The ornate sleeper-ray (''Electrolux addisoni'') is a species of electric ray in the family Narkidae, and the only member of the genus ''Electrolux''. It lives on reefs feeding on polychaete worms and small crustaceans, it has only been see ...

Endemic fish of South Africa Marine fish of South Africa Eastern Cape Strongly electric fish Critically endangered fish Critically endangered fauna of Africa