Daisy stingray

Lore & Background

British zoologist Albert Günther originally described the daisy stingray as Trygon margarita in his 1870 Catalogue of the Fishes in the British Museum; subsequent authors synonymized the genus Trygon with Dasyatis. This species resembles, and is likely closely related to, the pearl stingray and the Niger stingray (D. garouaensis), both also native to West Africa. Numerous scientific accounts have been confounded by confusion with the pearl stingray, dating back to the two West African specimens referenced in Günther's original description. In 1984, Leonard Compagno and Tyson Roberts identified one of them as a pearl stingray and designated the other as the lectotype for this species. The specific epithet margarita is derived from the Latin for 'pearl,' referring to the large tubercle on its back.

The pectoral fin disc of the daisy stingray is moderately thin and rounded, measuring about as wide as long. The tail is longer than the disc and usually bears a single long, thin stinging spine on the upper surface. Young rays are smooth-skinned, while older rays over 20 cm (7.9 in) across gain a wide band of small, flattened, circular dermal denticles covering the median third of the back. This ray is a plain grayish brown above, and whitish below. Apart from being much larger, the daisy stingray can be distinguished from the pearl stingray in having a relatively larger, round pearl spine, fewer tooth rows, and more pectoral fin radials (129–136 versus 113–127).

The known range of the daisy stingray extends from Senegal to the Democratic Republic of the Congo; records of it occurring as far as Mauritania and Angola may have been mistakenly based on the pearl stingray. This bottom-dwelling species is found in marine and brackish waters with a salinity of 20–40 ppt, favoring sandy habitats in shallow coastal waters to a depth of 60 m (200 ft), though most are found between 11 and 20 m (36 and 66 ft). This ray also reportedly frequents lagoons and estuaries; however, this also requires confirmation due to confusion with the pearl stingray.

Reader's Guide

The daisy stingray is a little-known species that has suffered from taxonomic confusion with the pearl stingray, complicating scientific understanding of its distribution and ecology. It feeds mainly on shrimp, crabs, bivalves, and annelid worms; off Nigeria, some three-quarters of its diet consists of the shrimp Farfantepenaeus duorarum. Like other stingrays, this species is aplacental viviparous, with females bearing litters of 1–4 pups. Coastal lagoons and estuaries serve as a breeding ground, with reproductive activity peaking during the rainy season from April to September, likely to correspond to high abundances of prey species.

The tail spine of the daisy stingray is reportedly highly venomous and potentially injurious to humans. It is caught by intensive artisanal and small-scale commercial fisheries occurring off the coasts of Senegal, Ghana, and Côte d'Ivoire, and sold fresh, smoked, or dried and salted for human consumption. A wide variety of fishing gear is used, including longlines, bottom trawls, trammel nets, gillnets, traps, beach seines, and hook-and-line. Habitat degradation from agricultural runoff and industrial development may also threaten its population. Once common, catches of this slow-reproducing ray have become scarce in recent years, leading the IUCN to assess it as Vulnerable. The daisy stingray has not yet been the target of any specific conservation schemes.

Did You Know?

• The daisy stingray's pearl spine is a greatly enlarged, nacreous denticle in the middle of its back.
• It can reach a maximum disc width of 1 m (3.3 ft) and weight of 17 kg (37 lb).
• The species was originally described by British zoologist Albert Günther in 1870 as Trygon margarita.