Brevitrygon heterura (Bleeker, 1852)
Dwarf whipray
Brevitrygon heterura
photo by Krajangdara, T.

Family:  Dasyatidae (Stingrays), subfamily: Urogymninae
Max. size:  24 cm WD (male/unsexed)
Environment:  demersal; marine; depth range - 50 m
Distribution:  Indo-West Pacific (Indo-Malay Archipelago): western Thailand to Indonesia (Java and Borneo).
Diagnosis:  This species is distinguished by the following characters: a very small whipray, oval disc, pointed snout, adults with broad almost rectangular denticle band, no enlarged mid-shoulder denticles, tail short (with bulbous tip in adult females) with median row of enlarged spearshaped thorns, skin folds on tail absent, and dorsal surface plain coloured; disc slightly longer than wide, length ca. 1–1.1 times DW, pectoral-fin apex is broadly rounded; snout rather long, broad, with apical lobe narrowly rounded, anterior margins moderately concave; eyes small, protruding slightly, orbit length and spiracle ca. 2.9–3.1 in snout length, the interorbital space rather broad, 1.2–2.1 times orbit length; mouth is moderately arched, 2-3 well-developed oral papillae (well separated), lower jaw arched with central concavity; nasal curtain is skirtshaped, broad, posterior margin finely fringed; mid-shoulder denticle is weak, the denticle band expanded over abdomen in adults, converging forward of orbits and tail, and constricted beside spiracles, skin is smooth outside denticle band; thorns in median row on tail 4-6 and enlarged with convex crowns; tail short to moderately elongate, its length 1–1.7 times DW, depressed, stout at base but filamentous beyond caudal sting in young and adult males while bulbous with short filamentous tip in large females, with 1 or 2 caudal stings (Ref. 114953).
IUCN Red List Status: Vulnerable (VU); Date assessed: 12 May 2020 (A2d) Ref. (130435)
Threat to humans:  harmless

Source and more info: For personal, classroom, and other internal use only. Not for publication.