family Gymnuridae

Medium to large rays(disc width to4 m), the disc lozenge-shaped and broader than long; snout obtuse and littleproduced, head not elevated from disc;tail distinct from disc, very slenderbut much shorter than disc length, oneor several serrated spines at base oftail in some species, as also keel alongtop of tail, but no membranous folds.Nostrils separated from mouth, but theirfront margins greatly expanded backwardto meet across a narrow isthmus; mouthalmost stright to arched, without papillae on floor. Spiracles well developed, with or without a tentacle-likeprocess poiting back from inner margin.Pectoral fins attached to side of head,the finrays beginning at tip of snout;dorsal fin present or absent; caudal finabsent. Upper surface naked or withscattered thornlets.

Benthic on soft bottoms, generallyin shallow waters to 70 m. Rather inactive, lying partially covered with bottom substrate or swimming slowly overthe bottom by undulating the margins ofthe pectoral fins. Feeding on fishes,crustaceans and molluscs. Ovoviparous,the females containing 2-6 embryos.