Parahexapus africanus Balss 1922

Parahexapus africanus Balss, 1922

Hexapus (Parahexapus) africanus.—Monod, 1956:370, figs. 494–496.—Rossignol, 1962:118.—Crosnier, 1967:337, figs. 30, 33.

Hexapus africanus.—Longhurst, 1958:88.—Gauld, 1960:71.

MATERIAL EXAMINED.—Pillsbury Material: None.

Other Material: Congo: Baie de Pointe-Noire, A. Crosnier, 2, 1 (W)

DESCRIPTION.—Monod, 1956:370.

Figures: Monod, 1956, figs. 494–496; Crosnier, 1967, figs. 30, 33.

Male pleopod: Crosnier, 1967, fig. 30 (Congo).

MEASUREMENTS.—The carapaces of our males measure 3.4 × 5.6 and 2.8 × 4.9 mm; that of the female measures 3.0 × 4.6 mm. Monod (1956) reported ovigerous females measuring 4X7 mm and 5 × 7.5 mm, and Crosnier (1967) reported males measuring 3.2 × 5 mm and 3.4 × 5.6 mm. and a female as large as 3.4 × 5.6 mm. Balss (1922) reported that the female holotype measured 4 × 7.5 mm.

BIOLOGY.—Parahexapus africanus is a sublittoral species, which has been collected in depths between 5 m and about 25 m (16–27 m; 22–25 m). Longhurst (1958) found the species off Sierra Leone in 16–27 m on shelly sand and sandy mud Crosnier (1967) found it on sandy mud in 22–25 m off the mouth of the Congo River.

Ovigerous females have been collected in February (Monod, 1956).

DISTRIBUTION.—West Africa, where it has been recorded from localities on the mainland between Sierra Leone and Cabinda, in depths between 5 m and about 25 m (16–27 m is the deepest record). Records in the literature include the following:

Sierra Leone: No specific locality, in 16–27 m (Longhurst, 1958).

Ghana: Off Accra, 5 m (Monod, 1956; Gauld, 1960).

Congo: Baie de Pointe-Noire (Rossignol, 1962; Crosnier, 1967). Off the mouth of the Congo River, 05°56′S, 12°07′E, 22–25 m (Crosnier, 1967).

Cabinda: Landana, 6 m (Balss, 1922).

Hexapus (Pseudohexapus) Monod, 1956:362, 365 [type-species:

Hexapus (Pseudohexapus) platydactylus Monod, 1956, by monotypy; gender: masculine].

DIAGNOSIS.—Eyes small, movable, cornea as broad as stalk. Third maxilliped (Figure 36e) broad, ischium short, mesial margin concave, projecting distally, carpus, propodus and dactylus slender, cylindrical, propodus longer than dactylus; exopod without flagellum. Pterygostomian region lacking oblique striae, with hairy ridge. Walking legs short, merus of longest pair (fourth) shorter than carapace. Dactyli of walking legs flattened dorsoventrally. Sternal grooves absent (?). Apices of male pleopods completely concealed by abdomen; pleopods (Figure 36f) stout, apices curved mesially, with terminal spinules and few subterminal setae. Male abdomen (Figure 36d) with 5 free somites, third to fifth fused, terminal somite elongate, rounded apically, not trilobed.

INCLUDED SPECIES