Genus Pastinachus Rueppell, 1829 ^ZBK

Pastinachus ^ZBK (subgenus of Trigon) Rüppell, 1829:51. Type Raja sephen Forsskal 1775 ^ZBK, by subsequent designation.

Hypolophus Mueller and Henle, 1837 ^ZBK:117. Type Raja sephen Forsskal 1775 ^ZBK, by subsequent designation.

Definition. Dasyatid rays with the following combination of characters: robust, strongly rhomboidal disc; moderately elongate, broad-based tail; ventral cutaneous fold well developed, slender to very deep, length interspecifcally variable, its base 80-130% of disc width; dorsal cutaneous fold absent; dorsal surface uniform greyish, greyish brown or black, lacking a structured colour pattern; 1-3 enlarged thorns in nuchal area, no enlarged thorns anywhere else on disc or tail; broad, well-developed denticle band on mid-disc, developing before or soon after birth; denticles in band dense, typically broad based, stellate or irregular, with flat crowns; claspers pointed distally; internasal flap elongate, lobe-like distally; jaws strongly asymmetric, with symphysial and medial arches in the upper jaw and a subtriangular, plate-like lower jaw.

Remarks. A good summary of the nomenclature is provided by Eschmeyer’s (2005) Online Catalog of Fishes (http://www.calacademy.org/research/ichthyology/catalog/ fishcatsearch.html, as at 10 July 2005).