Prior to being described by Leonard Compagno and Tyson Roberts, in a 1984 paper for the Proceedings of the California Academy of Sciences, the pearl stingray was generally lumped together with the daisy stingray in scientific literature, though its existence had been recognized since at least 1965. The specific epithetmargaritella comes from the diminutive of the Latin word margarita, meaning "pearl", in reference to the smaller body and pearl spine sizes of this ray compared to the daisy stingray. The type specimen is a male across, from Mbode, Cameroon. In appearance, the pearl stingray resembles the daisy stingray and the Niger stingray, both also native to West Africa, suggesting that the three species are closely related. Lisa Rosenberger's 2001 phylogenetic analysis, based on morphology, found that the pearl stingray is the sister species of the sharpnose stingray, and that the two form a clade with the pale-edged stingray and the smooth butterfly ray. These results support the growing consensus that neither Dasyatis nor Himantura are monophyletic. The daisy and Niger stingrays were not included in the study.
The pearl stingray has a moderately thin, oval-shaped pectoral fin disc about as long as wide. The narrow snout tapers to a point that protrudes somewhat from the disc. The eyes are immediately followed by the spiracles, which are of approximately equal size. There is a flap of skin between the nares with a weakly curved or lobed, fringed posterior margin; a pair of grooves run between this flap and the corners of the gently bow-shaped mouth. There are five papillae in a row across the floor of the mouth. There are 24-41 upper tooth rows and 34-50 lower tooth rows. The blunt, ridged teeth are arranged into pavements with a quincunx pattern; those of adult males are longer than those of females, but are not pointed. The pelvic fins are short and triangular with their tips projecting slightly beyond the disc margin. The tail is broad and flattened at the base and becomes thin and whip-like past the single, slender stinging spine on the upper surface. Past the spine, there is a low dorsal keel and a well-developed ventral fin fold. There is a medium-sized oval pearl spine in the middle of the back; rays over across also gain a band of small, heart-shaped or flattened circular dermal denticles covering the median third of the disc, from between the eyes to the base of the tail. The tail is covered by small prickles behind the spine. It is a plain grayish brown above, and completely white below. The smallest West African stingray, this species grows to across and a weight of. The pearl stingray differs from the daisy stingray in being much smaller, and having a relatively smaller, oval pearl spine, more tooth rows, and fewer pectoral fin radials.
Biology and ecology
Little is known of the natural history of the pearl stingray. Like other stingrays, it is aplacental viviparous with females likely bearing litters of 1-3 pups. Sexual maturation occurs at a disc width of around.
Human interactions
Despite its small size, the pearl stingray is probably taken by "catch-all" commercial fisheries operating in coastal waters off Senegal, Ghana, Côte d'Ivoire, and elsewhere, using longlines, bottom trawls, and trammel nets. However, no specific utilization data is available as it was and continues to be combined with the daisy stingray in catch records. As a result, the International Union for Conservation of Nature has listed this species as Data Deficient. Given that the pearl stingray was once much more abundant than the daisy stingray, it likely comprised a majority of historically reported "daisy stingray" catches.
