Theoxapus buchanani (Monod, 1956) Rahayu & Ng, 2014

Rahayu, Dwi Listyo & Ng, Peter K. L., 2014, New genera and new species of Hexapodidae (Crustacea, Brachyura) from the Indo-West Pacific and east Atlantic, Raffles Bulletin of Zoology 62, pp. 396-483 : 481

Theoxapus buchanani , new combination

( Figs. 67 , 68E–I )

Hexapus buchanani Monod, 1956: 372 , figs. 497–501. Hexapinus buchanani – Manning & Holthuis, 1982: 169, Fig. 31 ;

Ng et al., 2008: 86; Hendrickx, 2013: fig. 3A.

Material examined. Holotype: male (7.0 × 4.9 mm) ( NHM 1957.12.4.20), station 57-29-1-53, Gold Coast, West Africa , 7 m, coll. J. B. Buchanan.

Diagnosis. Carapace subquadrate ( Figs. 67A , 68E ), about 1.4 times as broad as long, dorsal surface granulated, convex; regions indistinct, distinct median H-shaped depression. Anterolateral margin rounded; crenulated, lateral margin parallel, straight, posterior margin straight. Front slightly deflexed ( Fig. 67C ), slightly divided into 2 lobes, projecting beyond edge of orbits. Orbit distinct, transverse; eye movable, corneas subglobular, pigmented ( Fig. 67C ). Third maxillipeds broad ( Figs. 67B , 68G ), covering buccal cavity, without gap when closed; ischium notably broader, longer than merus, mesial margin slightly convex, crenulated; merus relatively ovoid, crenulated on mesial and lateral margins; carpus, propodus and dactylus cylindrical, dactylus longer than propodus; exopod narrow, 0.3 width of ischium, slightly sinuous, margins crenulated, flagellum well developed. Chelipeds subequal ( Fig. 67D ); major chela with slight gap when fingers closed; with large teeth at cutting edge of dactylus and fixed finger; outer surface of dactylus and palm granulated; palm longer than wide; minor chela with wider gap when fingers closed; ornamentation similar to that of major chela. P2–P4 relatively long, granulated and setose ( Figs. 67A , 68E ); P3 longest; P2 most slender; dactylus sligtly upcurved; P3 longer than P2; dactylus straight; P4 shorter than P3, merus about 3 times as long as broad. Male thoracic sternum broad ( Fig. 67B ), surface granulated; sternites 1 and 2 fused, separated from sternite 3 by distinct ridge; sternite 3 not separated from sternite 4, sternites 4–7 well developed, separated by distinct sutures; sternoabdominal cavity reaching middle of sternite 4, no thoracic sternal groove. Male abdomen relatively narrow ( Fig. 68F ); somites 1 and 2 free, somites 3–5 fused, lateral margin sinuous; somite 6 long, lateral margin slightly expanded subproximally; telson rounded, slightly shorter than somite 6. G1 ( Fig. 68H, I ) concealed under abdomen, slightly sinuous, dense stiff setae subdistally, covering tapered, pointed tip.

Colour. Not known.

Remarks. See discussion for genus.

Type locality. Gold Coast, West Africa .

Distribution. West Africa.

Figures

Fig. 67. Theoxapus buchanani (Monod, 1956), holotype male (7.0 × 4.9 mm) (NHM 1957.12.4.29). A, overall view of carapace, chelipeds and P2–P4; B, ventral view of cephalothorax; C, frontal view of cephalothorax; D, chelae.

Fig. 68. A–D, Parahexapus africanus (Balss, 1922); E–I, Theoxapus buchanani (Monod, 1956).A, E, overall views of carapaces, chelipeds and P2–P4; C, G, left third maxillipeds; B, F, male abdomen and telsons; D, H, G1s; I, distal part of G1. A, C, after Monod, 1956: figs. 494, 496; B, D, after Crosnier, 1967: figs. 30, 33; E–I, after Monod, 1956: figs. 497–500.

Fig. 31. Mariaplax daviei, new species. A–I, holotype male (6.0 × 4.5 mm) (WAM C23270); J, paratype female (6.2 × 4.9 mm) (WAM C23270). A, dorso-lateral margin of carapace; B, thoracic sternites 1–5, showing sternoabdominal cavity and thoracic sternal groove; C, thoracic sternites 1–5, showing thoracic sternal groove and telson; D, right third maxilliped; E, male abdomen and telson, F, major chela; G, minor chela; H, I, G1; J, female abdomen and telson. Scale bars = 1.0 mm.