Glaucostegus obtusus (Müller & Henle, 1841)
Widenose guitarfish
photo by Osmany, H.B.

Family:  Glaucostegidae (Giant guitarfishes)
Max. size:  93 cm TL (male/unsexed)
Environment:  demersal; marine; depth range - 60 m
Distribution:  Northern Indian Ocean: Pakistan to Thailand, with eastern limits unclear (Ref. 114953). South African records refer to Rhinobatos blochii and Rhinobatos leucospilus (Compagno pers. comm.).
Diagnosis:  This species is distinguished by the following: colour uniform greyish to brownish body and shovel-shaped disc; short snout broadly triangular, broad oblique nostrils with an oval anterior opening; disc flattened centrally, its length ca 1.2 times its width, anterior margin largely convex, outer corner broadly rounded to abruptly angular; snout relatively obtuse, ca. 80° angle, tip broadly rounded and not extended forward as a lobe, very small orbit its length ca 6.5 time preorbital length, 2.5-2.7 in interorbital space; rostral ridges are well separated, margin of cranium sharply demarcated before eyes; one small spiracular fold; nostrils much shorter than mouth, subequal to internasal width, ca. 50-52 nasal lamellae; anterior nasal flaps barely penetrating into internasal space, the interspace equal to 2.4-2.5 times length of posterior nasal aperture; rough skin covered with small denticles, enlarged slightly and more granular on dorsal surface than ventrally; along midline of the body in young are thorns in irregular row, irregular in shape, often obscure in adults; no obvious patch on each shoulder or greatly enlarged thorns in snout tip and around orbits; long tail, 1.4-1.6 times disc length; short dorsal fins, apices rounded, close together, interspace exceeding twice base length of first dorsal fin, well separated from pelvic fins (Ref. 114953).
Biology:  Found inshore and offshore (Ref. 9909). Ovoviviparous (Ref. 50449). Biology little known (Ref. 9909); but males are known to be mature ca. 48 cm TL (Ref. 114953). Probably utilized where it occurs, but details lacking (Ref. 9909).
IUCN Red List Status: Critically Endangered (CR); Date assessed: 03 December 2018 (A2bd) Ref. (130435)
Threat to humans:  harmless


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