Torpedo mackayana


Torpedo mackayana, commonly known as the ringed torpedo, Western African torpedo, West African torpedo ray, McKay electric ray, or McKay's torpedo ray, is an electric ray species in the family Torpedinidae, which lives in shallow waters on the western coast of Africa. Characterized by rounded spiracles and white and brown spots, females grow to and males to.

Taxonomy

Torpedo mackayana was described in 1919 by Jan Metzelaar, a Dutch biologist.

Etymology

The fish was named in honor of Donald Jacob Baron Mackay, the then colonial administrator and governor in India; he was one of the promoters of the 1904-1905 expedition that collected the type specimen in the Dutch West Indies.

Description

Torpedo mackayana has a round, "fleshy" disc, which has a slightly greater width than length. It has a gray-brown or rusty-brown upperside and a white underside. It is covered with small patches of brown or white. These patches may differ significantly in size and distribution throughout its body. It has a long, strong tail and two dorsal fins. The first dorsal fin is broad, while the second is slightly smaller and more slender. Its teeth are distributed in up to 38 rows and it has visible flaps on its nostrils. It has rounded spiracles, a feature that does not appear in any other species in the genus Torpedo.
Torpedo mackayana is a small to medium-sized ray. Its growth and size was surveyed in the Coast of Senegal from 1994 to 1998, with the results having been published in 2001. This study showed that it has an average length of about and an average weight of at birth. Females typically reach sexual maturity at about and males reach it at. As an adult, females are larger than males. According to the survey, the length of adult females is and the length of adult males is. The largest female observed weighed and the largest male weighed.

Ecology

The reproductive cycle of Torpedo mackayana can take a year, and gestation can take nearly half a year. Ovulation happens in May or June, and young are born in August or September. Like other species in the genus Torpedo, the oocyte of the species is sometimes prevented from growing until birth. Females have two uteri and two ovaries. The eggs of the species, when fertilized, weigh about on average, and the oocytes weigh an average of.
Torpedo mackayana has a coastal habitat and lives in depths of. It has been found in estuaries and on sea floors of mud or sand. Its prey consists of fish and smaller invertebrates. Little else is known about its biology.

Distribution and conservation

Torpedo mackayana lives in tropical waters of the eastern Atlantic Ocean, in 16 countries on the western coast of Africa. The most northern part of its range is Senegal, and the most southern part is Angola. It is likely caught by fisheries as a bycatch. Pollution and habitat destruction, due to coastal development, are also threats in part of its range. However, nothing is known about its population size or trend. The adult population consists of more females than males, while young are more commonly male than female. No conservation actions are taking place for the species, and it is listed on the IUCN Red List as Endangered. According to the IUCN, further research is required of the species' population before planning conservation actions.