Author: (Valenciennes, 1839)
A small (?) grey shark with moderately long and narrowly rounded or pointed snout, fairly large eyes, oblique-cusped weakly serrated upper anterolateral teeth with strong cusplets, 14 to 15/13 to 14 rows of anteroposterior teeth, an interdorsal ridge, small pectoral fins, a fairly large first dorsal with a short rear tip and a moderately large second dorsal with a short rear tip, and black markings on the pectorals, second dorsal, dorsal and ventral caudal lobes.
A fairly stocky and possibly small species (known specimens less than 1 m). Snout moderately long and moderately pointed; internarial width 1 to 1.4 times in preoral length; eyes circular and moderately large, their length between 2 and 3% of total length; anterior nasal flaps expanded as narrow, nippleshaped lobes; upper labial furrows short and corners not conspicuously enlarged; gill slits short, the third 3.1 to 3.6% of total length and less than a third of first dorsal base; 14 to 15/13 to 14 rows of anteroposterior teeth in each jaw half; upper teeth with narrow, weakly and partially serrated, oblique, high cusps, and crown feet with strong distal cusplets; lower teeth with semierect, narrow smooth cusps and transverse roots. An interdorsal ridge present. First dorsal fin large and falcate, with pointed or narrowly rounded apex and posterior margin curving ventrally from fin apex; origin of first dorsal fin over pectoral inner margins just behind their insertions; inner margin of first dorsal moderately long, half of dorsal base or less; second dorsal fin fairly large and high, its height 2.7% of total length, its inner margin short and 1.4 to 1.6 times its height; origin of second dorsal over or slightly posterior to anal origin; pectoral fins moderately large, falcate, with narrowly rounded or pointed apices, length of anterior margins about 17 to 18% of total length; 154 total vertebral centra. Colour grey above, white below; fairly conspicuous (in fresh specimens, less so in old preserved material) black tips present on pectorals, second dorsal, and dorsal and ventral caudallobes; a conspicuous white band on flank.
Indo-West Pacific: Nominal from Oman to Viet Nam, Indonesia (Sulawesi, Java, Waigeo), New Guinea, and northern Australia, but uncertain beyond India, Pakistan and China.
Habitat and Biology:
A little-known, wide-ranging, possibly common grey shark of the continental and insular shelves of the IndoWest Pacific. This species has been reported from river mouths and fresh water up rivers, including the Hooghly River in India and the Saigon River in Viet Nam, but these old records require confirmation and might have been based on some other species. Almost nothing is known of the biology of this shark.
Maximum uncertain, probably not over 1.5 to 2 m.
A poorly known species apparently fished regularly in the waters of the Arabian Sea off Pakistan, India and possibly China.
Judging from its description and illustration in Chu et al. (1962), Hypoprion atripinna is a probable junior synonym of this species, and is tentatively placed here. This species has sometimes been confused with other species. Day (1878, pl. 184, fig. 2) illustrated it as Carcharias limbatus, but its identity as C. hemiodon was confirmed by examining the illustrated specimen in the Zoological Survey of India, Calcutta.
Holotype: Museum National d'Histoire Naturelle, Paris, MNHN 1040, 470 mm immature male. Type Locality: Pondicherry, India.