The blind electric ray (''Typhlonarke aysoni'') is a little-known

species In biology, a species is the basic unit of 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 the appropriate s ...

of sleeper ray in the

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

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. Th ...

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 elsew ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. It is found on the bottom, typically at a depth of . Reaching in length, this species has a thin, nearly circular

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

disc without visible eyes, and a short tail with a single

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 conv ...

. Its

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s are divided in two, with the anterior portion forming a limb-like appendage; in males the

claspers In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's ...

do not extend past the disc margin. A weak swimmer, the blind electric ray likely pushes itself along using its pelvic fins. It is known to feed 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 mad ...

s, and can defend itself with an

electric shock Electrical injury is a physiological reaction caused by electric current passing through the body. The injury depends on the density of the current, tissue resistance and duration of contact. Very small currents may be imperceptible or produce ...

. Reproduction is

aplacental viviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

(IUCN) does not have enough information to assess the conservation status of this species.

Taxonomy

The

trawl Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different speci ...

er ''Doto'' collected the first known specimen of the blind electric ray from the

Foveaux Strait The Foveaux Strait, (, or , ) separates Stewart Island, New Zealand's third largest island, from the South Island. The strait is about 130 km long (from Ruapuke Island to Little Solander Island), and it widens (from 14 km at Ruapuk ...

, during a research cruise in early 1900. The head of the expedition Lake F. Ayson gave the specimen to

Augustus Hamilton Augustus Hamilton (1 March 1853 – 12 October 1913) was a New Zealand ethnologist, biologist and museum director. He was born in Poole, Dorset, England on 1 March 1853. He wrote on the fishing and seafoods of the ancient Māori people. He also w ...

of the

Dominion Museum The Museum of New Zealand Te Papa Tongarewa is New Zealand's national museum and is located in Wellington. ''Te Papa Tongarewa'' translates literally to "container of treasures" or in full "container of treasured things and people that spring fr ...

, who named it ''Astrape aysoni'' in his honor. Hamilton published his account of the species in a 1902 volume of the

scientific journal In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. Content Articles in scientific journals are mostly written by active scientists such as s ...

''Transactions and Proceedings of the New Zealand Institute''. In 1909, Edgar R. Waite created the new genus ''Typhlonarke'' for this species. The blind electric ray may also be referred to as the blind legged torpedo or the round electric ray.

Distribution and habitat

The exact range of the blind electric ray is uncertain owing to confusion with the oval electric ray. The two species are found off the eastern coast of New Zealand, from the

East Cape East Cape is the easternmost point of the main islands of New Zealand. It is located at the northern end of the Gisborne District of New Zealand's North Island. It can also refer to the broader Gisborne cape. East Cape was originally named "C ...

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

to the Snares Shelf south of

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

, including the

Cook Cook or The Cook may refer to: Food preparation * Cooking, the preparation of food * Cook (domestic worker), a household staff member who prepares food * Cook (professional), an individual who prepares food for consumption in the food industry * ...

and Foveaux Straits and the Stewart and

Chatham Islands The Chatham Islands ( ) (Moriori: ''Rēkohu'', 'Misty Sun'; mi, Wharekauri) are an archipelago in the Pacific Ocean about east of New Zealand's South Island. They are administered as part of New Zealand. The archipelago consists of about te ...

. This bottom-dwelling species typically occurs at a depth of , but has been reported from between deep.

Description

The blind electric ray has a nearly circular

disc measuring about 70% of the total length, with rather thin margins. The tiny eyes are not visible externally, being located beneath the surface of the skin; their positions are indicated by small white patches. Following the eyes are oval

spiracle Spiracle or spiraculum may refer to: * Spiracle (arthropods), opening in the exoskeletons of some arthropods * Spiracle (vertebrates), openings on the surface of some vertebrates * Spiraculum, a genus of land snails in family Cyclophoridae Cycl ...

s with raised, smooth rims. The nostrils are closely spaced, with their outer margins curled to form near-complete tubes, and their inner margins enlarged and fused together into a fleshy, skirt-shaped curtain that almost reaches the mouth. The mouth is small and deeply recessed. The teeth are arranged with a

quincunx A quincunx () is a geometric pattern consisting of five points arranged in a cross, with four of them forming a square or rectangle and a fifth at its center. The same pattern has other names, including "in saltire" or "in cross" in heraldry (dep ...

pattern to form narrow plates limited to the front of the jaws. There are 10–12 tooth rows in either jaw; the innermost teeth have a sharp cusp, while the outermost teeth are worn down and flattened. The five pairs of

gill slit Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In con ...

s are short and curved. The anterior portion of each

is modified into a wide, paddle-like appendage. The posterior portion of the pelvic fins merge smoothly with the pectoral fins to form part of the disc; there is a notch where their margins meet the tail. Adult males have relatively small, slightly flattened

whose tips do not extend past the disc margin. The single

is rectangular in shape with a rounded trailing margin, and originates over the rear of the pelvic fin bases. The short, thick tail bears faint lateral skin folds along either side and terminates in a nearly circular

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

slightly longer than tall. The skin is entirely devoid of

dermal denticle A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as we ...

s. This species is uniformly brown above, becoming darker towards the tail, and beige below. The undersides of the pelvic fin appendages are nearly white. Most blind electric rays do not exceed in length. However, there is an old report of a specimen that may have been over long.

Biology and ecology

With flabby musculature and a reduced tail, the blind electric ray seems to have very limited swimming capability. Instead, it is inferred to "walk" along the bottom on its mobile pelvic fin appendages. A blind

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

that probably feeds via suction, this species is known to consume

s. Like other electric rays, it has a pair of kidney-shaped

electric organ An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has since developed ...

s located beside its head, that allow it to generate an

for defense. Each electric organ is made of 180–200 relatively large, fluid-filled hexagonal columns, which essentially act as

batteries Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...

connected in parallel. A known

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

of this species is the

tapeworm Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestodar ...

''Pentaloculum macrocephalum''. The blind electric ray is

, with females bearing litters of up to 11. The newborns measure long.

Human interactions

The blind electric ray is caught in

bottom trawl Bottom trawling is trawling (towing a trawl, which is a fishing net) along the seafloor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towing ...

s and may be threatened by

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

within its range. However, specific data is lacking and the

(IUCN) has listed it under

Data Deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...

. In June 2018 the New Zealand

Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment ...

classified the blind electric ray as "Not Threatened" with the qualifier "Data Poor" under the

New Zealand Threat Classification System The New Zealand Threat Classification System is used by the Department of Conservation to assess conservation priorities of species in New Zealand. The system was developed because the IUCN Red List, a similar conservation status system, had some ...

References

{{Taxonbar, from=Q2489603

blind electric ray The blind electric ray (''Typhlonarke aysoni'') is a little-known species of sleeper ray in the family Narkidae, endemic to New Zealand. It is found on the bottom, typically at a depth of . Reaching in length, this species has a thin, nearly ci ...

Endemic marine fish of New Zealand

Strongly electric fish