Author: Hemprich and Ehrenberg, 1899
Field Marks:
A unspotted, large Mustelus with a short head and snout, broad internarial space, large eyes, narrow interorbital space, upper labial furrows about equal to lowers, low-crowned teeth with weak cusps, buccopharyngeal denticles covering anterior half or entire buccal cavity, lateral trunk denticles usually lanceolate and with complete ridges, unfringed dorsal fins, a semifalcate ventral caudal lobe, 59 to 81 precaudal centra, and heavily hypercalcified head and other cartilages. This is the only species of Mustelus in most areas where it occurs.
Diagnostic Features:
Body fairly slender. Head short, prepectoral length 17 to 22% of total length; snout moderately long and bluntly angular in lateral view, tip rather expanded and bulbous in adults with hypercalcified rostral mass, preoral snout 5.5 to 6.6% of total length, preorbital snout 6.3 to 7.3% of total length; internarial space broad, 2.4 to 2.9% of total length; eyes fairly large, eye length 2.1 to 3 times in preorbital snout and 2.5 to 3.3% of total length; interorbital space 2.4 to 2.9% of total length; mouth moderately long, greater than eye length, its length 2.7 to 3.8% of total length; upper labial furrows about equal to lowers and 1.3 to 2% of total length; teeth molariform and asymmetric, with cusp reduced to a low point, cusplets absent except in very young sharks; buccopharyngeal denticles covering anterior half of palate and mouth floor or entire palate and floor. Interdorsal space 20 to 23% of total length; trailing edges of dorsal fins denticulate, without bare ceratotrichia; first dorsal somewhat falcate, with posterior margin nearly vertical from apex, its midbase closer to pectoralbases than to pelvics; pectoral fins moderate-sized, length of anterior margin: 13 to 15% of total length, width of posterior margin 9.8 to 13% of total length; pelvic fins small, anterior margin length 6.5 to 7.9% of total length; anal height 2.9 to 4.7% of total length; anal caudal space greater or subequal to second dorsal height, and 7.1 to 9.1% of total length; ventral caudal lobe more or less falcate in adults. Crowns of lateral trunk denticles lanceolate or tricuspidate, with longitudinal ridges extending their entire length. Rostral node of cranium, hyomandibulae, scapulocoracoid tips, sometimes supraorbital crests and rostral shafts of cranium, extrabranchial cartilages, and radials of second dorsal, pectoral, pelvic, and caudal fin radials hypercalcified in adults; palatoquadrates not subdivided; monospondylous precaudal centra 25 to 39, diplospondylous precaudal centra 34 to 48, precaudal centra 59 to 81. Colour uniform grey or grey-brown, above, light below, no white or dark spots or dark bars; South African examples generally have white-tipped first dorsal and black-tipped second dorsal and caudal. Development viviparous. Size large, adults 63 to 150 cm.
Geographical Distribution:
Western Indian Ocean: Red Sea and the "Gulf" to India, Pakistan and Sri Lanka; Natal, South Africa (P.C. Heemstra, pers. comm.).
Habitat and Biology:
A common bottom-dwelling shark of continental waters, found inshore and offshore, some on coral reefs. Viviparous, number of young 6 to 10 per litter. Eats small bottom fish, molluscs, and crustaceans. Readily lives in captivity.
Size:
Maximum 150 cm, males maturing between 63 and 67 cm and reaching 106 cm, adult female 82 cm.
Interest to Fisheries:
Apparently regularly fished off Pakistan and India and used for human food.
Remarks:
This species was included in synonymy of M. punctulatus by Fowler (1941) and generally confused with M. manazo or M. mustelus by various writers until Heemstra (19733 examined its type and concluded that it was a valid species. The heavy hypercalcification of the skeleton of adults of this species is unique in its genus and family, although other carcharhinoids have hypercalcified skeletons (see Compagno, 1979). With present evidence (Heemstra, 1973, pers. comm.), there seem to be isolated populations of this species off Natal, South Africa (the Mustelus species of Bass, D'Aubrey and Kistnasamy, 1975a, which Dr P.C. Heemstra identifies as M. mosis and which the writer has examined and skeletonized) in the Red Sea, and in the "Gulf" and Arabian Sea to southern India and Sri Lanka, though this may be an illusion of inadequate collecting. The writer examined a specimen labelled M. manazo in the Zoological Survey of India, illustrated by Day (1878), and found it to be M. mosis. A. Baranes of the Hebrew University of Jerusalem has done a study of the ecology and behaviour of this species in the Red Sea off Elat, Israel. In Israeli waters off Elat it is called the Moses smooth-hound and off South Africa, the hardnose smooth-hound.
Type material:
Holotype: Zoologisches Museum, Humboldt Universitat, Berlin, ZMB 4501, stuffed specimen. Type Locality: Red Sea.