Pilumnus scabriusculus Adams & White, 1849

Ng, Peter K. L. & Clark, Paul F., 2005, The Indo­West Pacific Pilumnidae XVIII: On the taxonomy of Pilumnus scabriusculus Adams and White, 1849, and P. s l u i t e r i De Man, 1892, with a note on Cancer incanus Forskål, 1775 (Brachyura: Xanthoidea), Zootaxa 841, pp. 1-14 : 2-5

Pilumnus scabriusculus Adams & White, 1849 ( Figs. 2 A, 3A, B, 4A, 5A, B, 6A, B)

Pilumnus scabriusculus Adams and White, 1849: 44 , pl. 9 fig. 5; Miers, 1886: 155; Balss, 1933: 24 (part).

Material examined. Type. PHILIPPINES, holotype male, 26.0 x 19.4 mm, NHM 1843.6, Eastern Seas, HMS Samarang, pur. Cuming.

Non­types. PHILIPPINES: 1 male, 27.3 x 21.5 mm, NHM 1884.31, Zamboanga, Mindanao, HMS Challenger, pres. Lords of the Treasury, coll. Jan. 1875; 1 ovig. female, 39.6 x 31.1 mm (eggs 1.1–1.2 mm diameter), NHM 1892.4.18.140, Damma Island, HMS Penguin , pres. Lords of the Admiralty, coll. P. Bassett Smith.

Description. Carapace broader than long; dorsal surface prominently convex transversely and longitudinally, more so anteriorly; regions discernible; covered with small rounded granules; bases of most granules surrounded with very short setae, most granules each with a long, simple seta; setae almost obscure surface, setae on margins and below teeth longer, denser, obscuring most of surface. Frontal margin with 2 subtruncate lobes separated by shallow cleft, margin with scattered low granules; lateral lobes triangular, distinct, separated from frontal lobes by deep V­shaped cleft. Subfrontal surface with uneven transverse row of small granules. Supraorbital margin with low tooth on inner margin, margin granulated, with 2 shallow clefts on outer half. Infraorbital margin granulated, inner part with very low, broad triangular tooth. External orbital angle very low, broadly triangular, with sharp basal granule; anterolateral margin with 3 low teeth, first and second lobiform, subequal, third tooth smallest, triangular. Posterolateral margin gently concave, sharply converging towards gently convex posterior carapace margin. Suborbital and subhepatic regions with low granules; pterygostomial region rough. Posterior margin of epistome with median part triangular, lateral parts concave. Endostomial ridges strong, complete. Third maxillipeds relatively short; ischium subrectangular with shallow submedian sulcus; merus almost square with dorsal margin gently concave, submedian part concave; exopod relatively stout, distal edge reaching almost to dorsal edge of merus, with long flagellum.

Chelipeds unequal; outer surfaces of chelae with numerous conical granules of varying sizes, with numerous short setae between granules that partially obscure surface; inner surface of chelae smooth. Fingers shorter than palm, cutting edges with distinct teeth. Inner distal angle of carpus with 1 low tubercle, inner ventral angle with a low tubercle; outer surface covered with low rounded granules, with short setae between them. Merus short, with distal angle of dorsal margin rounded, subdistal part of dorsal margin expanded into projection with rounded tip; rest of dorsal margin with low granules. Dorsal margin of basis­ischium with low granules.

Ambulatory legs relatively short, margins densely lined with setae; second leg longest. Carpus with distinct dorsal sulcus, dorsal margin entire. Merus of last leg very short, stout, without subdistal dorsal angle; meri of first to third legs relatively more elongate, with distinct subdistal dorsal angle that is rounded, not spiniform; margins unarmed.

Thoracic sternum with scattered setae, surface uneven but not prominently granulated. Sternites 1 and 2 separated by granulated suture; sternites 2 and 3 separated by distinct suture; sternites 3 and 4 effectively fused, suture not discernible except for shallow furrow between them. Male abdomen narrowly triangular longitudinally with all segments freely mobile; telson acutely triangular with concave lateral margins; segments 3–6 progressively less trapezoidal, lateral margins gently concave to almost straight. G1 prominently sinuous, distal part strongly recurved, distinctly hooked, tip relatively sharp.

Figures

FIGURE 2. Frontal view of carapace. A, Pilumnus scabriusculus Adams & White, 1849, holotype male, 26.0 x 19.4 mm, NHM 1843.6; B, P. sluiteri De Man, 1892, lectotype male, 27.2 x 20.5 mm, ZMA 242226.