Pilumnus sluiteri De Man, 1892

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 : 5-9

Pilumnus sluiteri De Man, 1892 ( Figs. 1 C, 2B, 3C, D, 4B, 5C, 6C, D)

Pilumnus forskalii De Man, 1888: 295 , pl. 12 fig. 1 (not H. Milne Edwards, 1834).

Pilumnus sluiteri De Man, 1892: 283 , pl. 15 fig. 2; 1929: 1; Alcock, 1898: 195.

Pilumnus scabriusculus Lanchester, 1901: 541 ; Balss, 1933: 24 (part); 1938: 56; Sakai, 1939: 533, pl. 100 fig. 5; 1976: 486, text figure 259; Takeda & Miyake, 1968: 24, Fig. 10c, d; Takeda, 1982: 187 (with figure); Miyake, 1983: 137, pl. 46 fig. 2; Nagai & Nomura, 1988: 189; Naiyanetr, 1998: 86; Ng et al., 2001: 30; Minemizu, 2000: 281; Ng & Davie, 2002: 377.

Material examined. Types. INDONESIA, lectotype male (here designated), 27.2 x 20.5 mm, ZMA 242226, Enkhuizen Island, near Batavia (= Jakarta), Java, Indonesia, coll. M. Weber, 18881889. Paralectotype female, 26.1 x 19.8 mm, ZMA 242209, off Bay of Batavia (= Jakarta Bay), Java, coll. Sluiter.

Non­types. INDONESIA: 2 males, 32.2 x 24.3 mm, 26.3 x 19.4 mm, ZMA 242221, Pulau Berhala, coll. van der Meer, 1928. MALAYSIA: 1 male, 37.5 x 27.8 mm, ZRC 1987.35, Kuala Menggatal, Kota Kinabalu, Sabah, coll. N. Lee, 5 Nov. 1986; 1 male, 35.8 x 26.5 mm, ZRC 1987.854, Kuala Menggatal, Kota Kinabalu, Sabah, coll. N. Lee, 5 Nov. 1986; 1 male, 18.6 x 13.4 mm, ZRC 1987.855, Kuala Menggatal, Kota Kinabalu, Sabah, coll. N. Lee, 5 Dec. 1986; 1 male, 32.8 x 23.5 mm, ZRC 1987.1193, Pulau Tiga, Sabah, coll. N. Lee, 22 Apr. 1987. SINGAPORE: 1 female, 26.9 x 20.3 mm, ZRC 1965.9.9.49, Pulau Pawai, southern Singapore, coll. M.W.F. Tweedie, Nov. 1933; 2 males, 45.0 x 34.3 mm, 21.4 x 16.3 mm, ZRC 1965.9.9.4647, Sultan Shoal, southern Singapore, coll. M.W.F. Tweedie, Dec. 1933; 1 ovig. female, 26.3 x 18.9 mm, ZRC 1970.1.5.12, Raffles Lighthouse, southern Singapore, coll. A. Monteiro, Jul. 1937; 1 female, 29.6 x 23.9 mm, ZRC 1965.9.9.48, Horsburg Lighthouse, South China Sea, coll. A. Monteiro, Apr. 1938. PHIL­ IPPINES: 1 male, 21.4 x 15.8 mm, ZRC, Alona Beach, Panglao, Bohol, coll. P.K.L. Ng, Jul. 2003; 1 ex­ovig. female, 26.8 x 18.8 mm, ZRC 2003.281, Alona Beach, Panglao, Bohol, coll. P.K.L. Ng & P.F. Clark, Jul. 2003. THAILAND: 1 male, 26.5 x 19.8 mm, 1 ovig. female, 31.6 x 23.7 mm, ZRC 1999.519, southern Phuket, western Thailand, coll. P.K.L. Ng, Dec. 1998; 1 male, 29.5 x 22.1 mm, 1 female, 28.8 x 21.2 mm, NHM 2001.194041, Cape Sai Yok, Phuket, western Thailand, coll. P. Clark et al., 36 May 2000.

Description. Carapace broader than long; dorsal surface convex transversely and longitudinally, more so anteriorly; regions discernible; surface covered with small rounded granules, relatively denser anteriorly; bases of most granules surrounded with very short setae, most granules on anterior half of carapace with a long, simple seta each, those on posterior surface mostly without the long seta; setae do not obscure surface, setae on margins and below teeth longer, denser, obscuring surface. Frontal margin with 2 truncate lobes separated by deep cleft, margin with granular; 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 triangular tooth. External orbital angle low, broadly triangular, with sharp basal granule; anterolateral margin with 3 triangular teeth, all spine­or tubercle­tipped, third tooth smallest. Posterolateral margin gently convex to almost straight, sharply converging towards gently convex posterior carapace margin. Suborbital, subhepatic and pterygostomial regions with low granules. Posterior margin of epistome with median part acutely triangular, lateral parts prominently concave. Endostomial ridges strong, complete. Third maxillipeds relatively longer; ischium subrectangular with shallow submedian sulcus; merus almost square with dorsal margin gently concave, submedian part concave; exopod relatively stout, distal edge not reaching dorsal edge of merus, with long flagellum.

Chelipeds unequal; outer surfaces of chelae with numerous conical granules of varying sizes, those medially relatively lower, in larger specimens, median granules not discernible; with short setae between distinct granules that do not obscure surface; inner surface if 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, with low granule between them; outer surface covered with low rounded granules amongst short setae. Merus short, with distal angle of dorsal margin spiniform, subdistal part of dorsal margin expanded into projection with spiniform tip; remainder of dorsal margin granulated. 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 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 but sternites separated by deep furrow. Male abdomen narrowly triangular longitudinally with all segments freely mobile; telson triangular with gently concave lateral margins; segments 3–6 progressively less trapezoidal, lateral margins slightly sinuous to almost straight. G1 prominently sinuous, distal part gently curved; tip relatively sharp.

Figures

FIGURE 1. Overall dorsal view. A, Pilumnus scabriusculus Adams & White, 1849, holotype male, 26.0 x 19.4 mm, NHM 1843.6; B, P. scabriusculus Adams & White, 1849, male, 27.3 x 21.5 mm, NHM 1884.31; C, P. s l u i t e r i De Man, 1892, lectotype male, 27.2 x 20.5 mm, ZMA 242226.