Author: Cadenat, 1950
Field Marks:
A large hammerhead with a moderately broad, fairly narrow-bladed head, anterior margin of head very broadly arched in adults and with a prominent median indentation, teeth with moderately broad cusps and smooth edges, moderately falcate first dorsal fin with origin over pectoral midbases and free rear tip in front of pelvic origins, low second dorsal fin with weakly concave posterior margin, long posterior margin about twice fin height, and free rear tip nearly or quite reaching upper caudal origin, non-falcate pelvic fins, a deeply notched posterior anal margin, and plain pectoral fins.
Diagnostic Features:
Expanded prebranchial head hammer- or axe-shaped and moderately wide but longitudinally moderately short, its width 21 to 25% of total length; distance from tip of snout to rear insertions of posterior margins of expanded blades half to slightly less than half of head width; anterior margin of head broadly arched with prominent medial and lateral indentations; posterior margins of head of moderate width, angled posterolaterally, and about equal or less than mouth width; well-developed prenarial grooves present anteromedial to nostrils; preoral snout between 1/5 to 1/3 of head width; rear ends of eyes about opposite to upper symphysis of mouth; mouth rather broadly arched; anterior teeth with moderately long stout cusps and smooth edoes. Dosterior teeth mostiv cuspidate and not keeled and molariform. First dorsal somewhat falcate, its origin over rear ends of pectoral bases ahead of their insertions, its free rear tip well anterior to pelvic origins; second dorsal fin low, somewhat less than anal height, with a slightly concave posterior margin; its inner margin long, about twice the fin height, and ending almost opposite upper caudal origin; pelvic fins not falcate, with straight or slightly concave posterior margins; anal fin larger than second dorsal fin and rather long, base 4.5 to 5.6% of total length, its origin well ahead of second dorsal origin, its posterior margin deeply notched. Vertebral counts unknown. A large hammerhead, to 3 m. Colour blue-grey or grey-brown above, white below, fins unmarked.
Geographical Distribution:
Eastern North Atlantic: Senegal, Ivory Coast, Guinea, Gabon, and Congo; possibly Mediterranean Sea.
Habitat and Biology:
A little-known and uncommon coastal-pelagic shark of tropical West Africa. Viviparous, with a yolk-sac placenta; number of young 24 to 28. Mainly eats fishes, especially benthic bony fishes such as eels and flatfish, also benthic and epibenthic cephalopods. Not known to attack people.
Size:
Maximum said to be about 300 cm; adult males 141 to 184 cm; adult (gravid) females from 230 to 235 cm; size at birth about or above 30 to 32 cm (full-term fetuses).
Interest to Fisheries:
Taken in West African shark fisheries, but details are lacking.
Remarks:
According to Cadenat and Blache (1981), one of the syntypes of S. tudes Valenciennes, 1822, MNHN 1049 from Nice, France (Mediterranean Sea), and the lectotype of that species as designated by Gilbert (1967), is actually based on a fetus of the present species (see remarks under S. tudes), which, apart from causing further nomenclatorial confusion, would also extend the range of this species into the Mediterranean.
Type material:
Holotype: In Museum National d'Histoire Naturelle, Paris? Type Locality: Senegal.