A new species of whiptail stingray of the genus Dasyatis Rafinesque, 1810 from the Southwestern Atlantic Ocean (Chondrichthyes: Myliobatiformes: Dasyatidae)

Abstract

The new species is compared both with other Dasyatis species of the southwestern Atlantic and with similarly shaped species of Dasyatis from other areas of the world. The holotype was collected in Maraj Bay; near Colares Island, district of Colares, Bel m, Par State, Brazil. It differs from known Dasyatis species by the combination of the following characters: a diamond-shaped (rhomboid) disc; an elongate snout (preorbital distance ranges from 35.7 to 37.7 % in disc width); a dark, well defined band or dark blotches outlining the lower lips; a row of small tubercles along midline of disc from shoulder region to base of tail, presenting a widespread and random arrangement; posterior margins of pectoral fins uniformly rounded; triangular-shaped pelvic fins with posterior margin almost straight or slightly sinuous and tips exceeding the limits of the posterior margin of disc; dorsal caudal keel absent in the holotype, but vestigial in both paratypes.