Discoplax gracilipes Ng & Guinot, 2001

Ng, Peter K. L. & Shih, Hsi-Te, 2015, The land crabs of the Discoplax longipes A. Milne-Edwards, 1867 species group, with description of a new species from Guam (Crustacea: Decapoda: Brachyura: Gecarcinidae), Zootaxa 3980 (3), pp. 379-405 : 392-396

Discoplax gracilipes Ng & Guinot, 2001

Discoplax aff. longipes — Takeda 2000: 62, fig. 1B (Bohol, Philippines).

Discoplax gracilipes Ng & Guinot, 2001: 324 , figs. 9–11, 12B, 14–16 (Bohol, Philippines); Ng et al. 2008: 214 (list); Husana et al. 2010: 55 (Samar, Philippines); Bucol & Alcala 2013: 64, fig. 4 (Siquijor, Philippines); Shih 2013: 26, fig. 6 (no new locality).

Material examined. Holotype: male (53.1 × 45.9 mm) (USC), Virata Cave, Libaong, Panglao, Panglao Island, Bohol, Philippines, coll. local villagers, 18 December 2000. Paratypes: Philippines: 3 males (26.0–50.5 × 22.6– 43.3 mm), 1 female (44.3 × 52.0 mm) ( ZRC 2001.317), 2 males (35.6 × 30.9 mm, 46.9 × 40.6 mm) ( MNHN – B27771), same data as holotype; 1 male (17.7 × 15.5 mm), 1 female (20.2 × 17.4 mm) ( ZRC 2001.318), 1 male (29.6 × 26.3 mm), 1 female (22.7 × 19.9 mm) ( MNHN –B27770), Tawala Cave, in pools near entrance, Tawala, Panglao, Panglao Island, Bohol, coll. L. Liao et al., 17 December 2000; 1 male (17.7 × 15.5 mm) ( MNHN – B26951), station 85–067, Calingoob Cave, Panglao Island, Bohol, 1 m depth, bottom rocks, with dip net, coll. T.M. Iliffe, 6 April 1985; 1 male (18.0 × 15.8 mm) ( MNHN –B26952), station 85–077, Underpass Cave, Panglao Island, Bohol, 1 m depth, salinity 8 ppt, coll. T.M. Iliffe, 8 April 1985; 1 female (25.7 × 22.1 mm) ( MNHN –B26950), station 85–062, Tuala (= Tawala) Cave, Panglao Island, Bohol, 0–1 m depth, mud bottom, in dark section, salinity 4 ppt, with dip net, coll. T.M. Iliffe, 3 April 1985; 7 males (40.2–53.5 × 36.0– 47.3 mm), 2 females (46.3 × 42.0 mm, 47.2 × 42.4 mm) (USC), Virata Cave, Libaong, Panglao, Panglao Island, Bohol, coll. A. Porpetcho et al., April–May 2001; 5 males (40.6–57.8 × 35.8–50.6 mm), 3 females (38.1–62.0 × 33.3–54.4 mm) ( ZRC 2001.2301), Virata and Tawala Caves, Libaong, Panglao, Panglao Island, Bohol, coll. Manong et al., 29 November 2001; 5 males (35.2–59.2 × 30.9–52.9 mm), 9 females (39.6–58.1 × 35.0– 50.8 mm) ( ZRC 2001.2302), Baloc-Baloc Cave, near Virata Cave, Libaong, Panglao, Panglao Island, Bohol, coll. Manong et al., 30 November 2001; 1 juvenile male ( ZRC), Hinagdanan Cave, northern part of Panglao Island, Bohol, coll. P.K.L. Ng, 29 November 2001; 7 males (48.3–62.8 × 43.2–53.5 mm), 1 female (55.3 × 48.6 mm) ( ZRC 2001.2303), caves near Hinagdanan Cave, northern part of Panglao Island, Bohol, coll. Gary et al., 30 November 2001; 1 male (32.2 × 28.6 mm), 2 females (21.8 × 18.9 mm, 22.2 × 19.5 mm) ( NSMT –Cr 12990), Alona Cave, Balicasag Island, Panglao, Bohol, coll. T. Kase, February 1999; 1 male (57.2 × 48.6 mm), 4 females (51.0 × 44.8 mm, 39.0 × 32.6 mm, 36.2 × 30.4 mm, 28.8 × 24.8 mm) ( NSMT), river mouth, close to Hinagdanan Cave, Panglao Islands, Bohol, coll. T. Kase et al., 2000. Others— 1 female ( ZRC 2011.0659), Panglao Island, Bohol, coll. P.K.L. Ng, July 2002; 3 males ( ZRC 2003.0389), Panglao Island, Bohol, coll. P.K.L. Ng, 30 July 2003; 2 males (46.4 × 39.9 mm, 22.1 × 19.2 mm), 2 females (26.3 × 23.6 mm, 22.2 × 19.2 mm) ( TMCD), Tawala Cave, Tawala, Panglao, Panglao Island, Bohol, coll. H.-C. Liu, 30 November 2001; 3 males ( ZRC 2003.0393), Tawala Cave, Panglao Island, Bohol, coll. P.K.L. Ng, 25–30 July 2003; 1 male ( ZRC 2001.2305), Baloc-Baloc Cave, near Virata cave, Panglao Island, Bohol, coll. Manong et al., 30 November 2001; 1 female ( ZRC 2003.0377), Hinagdanan Cave, northern part of Panglao Island, Bohol, coll. P.K.L. Ng, 31 July 2003; 3 males, 4 females ( ZRC 2002.0589), Hinagdanan Cave, northern part of Panglao Island, Bohol, local collectors, June 2002; 1 female ( ZRC 2004.0461), cave inside Panglao Island Nature Resort, Panglao Island, Bohol, coll. P.K.L. Ng, 3 March 2004; 14 males, 7 females ( ZRC 2004.0461), cave inside Panglao Island Nature Resort, Panglao Island, Bohol, coll. P.K.L. Ng, 3 March 2004; 7 males ( ZRC 2012.0435), cave inside Panglao Island Nature Resort, Panglao Island, Bohol, coll. P.K.L. Ng & P. Y.C. Ng, December 2010.

Diagnosis. Frontal, epigastric, epibranchial, anterior part of mesobranchial regions covered with small rounded granules, those on anterior part flattened; mesogastric region punctate or with very small granules, appearing almost smooth in adults; metagastric region weakly punctate to almost smooth; posterior part of meso-, metabranchial regions with strong striae, granules epigastric regions well defined, margin sharp; postorbital cristae strong ( Ng & Guinot 2001: figs. 9, 11A, b). Surfaces of adult chelae weakly granulated, slightly rugose to punctate ( Ng & Guinot 2001: figs. 10B, C, 11C). Ambulatory legs very long, very slender; ratios of maximum length to maximum width of second to fourth ambulatory meri 4.3–4.8, 4.7–5.2, 3.5–4.1, respectively; ratios of maximum length to maximum width of second to fourth ambulatory legs (dactylus, propodus, merus) 18.0–26.2, 19.5–32.7, 15.9–29.0, respectively; surfaces covered with low granules to gently rugose; dorsal margins of merus gently granulated, not appearing serrated; lateral margins of propodus, dactylus lined with small, relatively weak setae or spines, propodus appearing almost unarmed occasionally ( Ng & Guinot 2001: figs. 9A, 12B). Male abdomen relatively broader; lateral margin of somite 6 distinctly convex ( Ng & Guinot 2001: fig. 10A). Adult G1 gently curved to almost straight when viewed from ventral perspective; tip bent at an angle of about 80° from vertical; outer margin of distal part gently sloping towards base of pectinated part, without distinct shelf or hump; base of pectinated distalmost part (outer marginal view) broad; inner surface with deep median longitudinal depression ( Ng & Guinot 2001: fig. 14). Philippines.

Remarks. Ng & Guinot (2001) discussed the differences between D. longipes and D. gracilipes at length so there is no need to repeat their treatment here. Although at the time of this paper the specimens from Guam were treated as conspecific with D. longipes (and not as a separate species), they do not affect Ng & Guinot’s (2001) discussion substantially. The major differences are (1) the meso- and metagastric regions of the carapace are punctate with scattered granules in D. gracilipes (distinctly granular in D. longipes and D. michalis n. sp.); (2) the outer surfaces of the ambulatory merus, carpus, and propodus are gently rugose in D. gracilipes (distinctly granular and/or lined with strong striae in D. longipes and D. michalis n. sp.); (3) the outer surface of the chela is punctate to granular in D. gracilipes (distinctly granular in D. longipes and D. michalis n. sp.); (4) the ambulatory legs of D. gracilipes are on average 1.3–1.5 times longer than the equivalent leg of D. longipes of a similar size; and (5) the G1 of D. gracilipes has the outer margin meets the distal part in a gentle curve, with the distal pectinated part relatively longer and directed more obliquely outwards (ca. 80° from the vertical) (the G1 outer margin joins the distal part more abruptly, forming a gentle shelf, with the distal pectinated part relatively shorter and directed ca. 90° from the vertical in D. longipes and D. michalis n. sp.).

Distribution. Bohol, Siquijor, and Samar, all in Philippines.