A taxonomic re-evaluation of the blue stingray from southern Africa (Myliobatiformes: Dasyatidae)

The taxonomic status of the southern African stingray usually referred to Dasyatis pastinaca was investigated. Morphological comparisons were made between specimens of the European Dasyatis pastinaca (Linnaeus 1758), Dasyatis marmorata (Steindachner 1892) from Senegal (Senegambia), and the blue stingray from South Africa and Namibia. The earliest name for blue stingrays is the generally overlooked Trigon chrysonotus Smith, 1828 from South Africa, which is revived, redescribed and has a neotype designated for it. The southern African blue stingray is a separate species from D. pastinaca and differs in coloration, disc length and vertebral and radial counts. However, the southern African blue stingray is considered conspecific with D. marmorata but differs slightly in snout angle and snout-to-vent length. These two are tentatively ranked as subspecies, Dasyatis chrysonota chrysonota (Smith 1828) for the blue stingray of South Africa, Namibia and Angola and D. c. marmorata (Steindachner 1892) for the Senegal blue stingray. Nominal records of blue stingrays exist from Tunisia, Spanish Sahara (Morocco) and Mauritania, tropical West Africa from Liberia to Nigeria, and off Congo, but their status is uncertain. It is uncertain if the known differences between the Senegal and southern African blue stingrays are representative of a north–south clinal gradation, or if there are two or more discrete populations of blue stingrays in the northern and southern hemispheres.