Discoplax

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 : 400

Key to the long-legged Discoplax species

1a. Meso– and metagastric regions of carapace punctate to almost smooth (cf. Ng & Guinot 2001: fig. 9A, B); outer surface of adult ambulatory meri gently granular, gently rugose to punctate (cf. Ng & Guinot 2001: figs. 9A, 12B); ambulatory legs conspicuously long, 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 (cf. Ng & Guinot 2001: figs. 9A, 12B); Philippines.......................................................................................... D. gracilipes Ng & Guinot, 2001

1b. Meso– and metagastric regions of carapace gently to prominently granulated (e.g., Fig. 1 F); outer surface of adult ambulatory meri prominently granular to distinctly rugose (e.g., Fig. 10 A) ambulatory legs long, ratios of maximum length to maximum width of second to fourth ambulatory legs (dactylus + propodus + merus) 13.9–16.0, 13.5–15.0, 11.1–12.1, respectively (e.g., Fig. 10 A–D, G–J); other parts of West Pacific.............................................................. 2

2a. Adult G1 strongly curved, appearing almost C-shaped when viewed from ventral perspective ( Figs. 11 A, B, 12, 13, 14A–D, 15A, B, 16A, B); Loyalty Islands to French Polynesia........................... D. longipes A. Milne-Edwards, 1867

2b. Adult G1 gently curved to almost straight when viewed from ventral perspective ( Figs. 14 E–H, 15C–H, 16C, D); Guam........................................................................................... D. michalis n. sp.

Figures

FIGURE 1. Discoplax longipes A. Milne-Edwards, 1867, holotype male (54.6 × 48.5 mm) (MNHN – B 3763 S), “ New Caledonia ”. A, E, overall habitus; B, frontal view of cephalothorax; C, buccal cavity and third maxillipeds; D, G, anterior thoracic sternum and abdomen; F, carapace. A – D after A. Milne-Edwards (1873: pl. 15).

FIGURE 10. Discoplax species, ambulatory legs. A – F, right second ambulatory legs; G – L, left fourth ambulatory legs. A, G, D. longipes A. Milne-Edwards, 1867, male (68.2 × 57.4 mm) (ZRC 2002.0050), Loyalty Islands; B, H, D. longipes A. Milne- Edwards, 1867, male (43.3 × 37.7 mm) (ZRC 2001.1150), Loyalty Islands; C, I, D. longipes A. Milne-Edwards, 1867, male (65.0 × 55.7 mm) (SMF 5849), Makatea, French Polynesia; D, J, D. longipes A. Milne-Edwards, 1867, male (54.0 × 47.0 mm) (SMF 6680), Niue (laterally transposed to facilitate comparisons); E, K, D. michalis n. sp., paratype male (68.3 × 60.0 mm) (ZRC 2000.0571), Guam; F, L, D. michalis n. sp., paratype male (41.8 × 36.0 mm) (ZRC 2001.0701), Guam.

FIGURE 11. Discoplax longipes A. Milne-Edwards, 1867. A, anterior thoracic sternums, sternoabdominal cavities and G 1 s, male (58.9 × 51.1 mm) (MNHN – B 28463), Loyalty Islands; B, sternoabdominal cavity and G 1 s, male (71.9 × 61.7 mm) (MNHN – B 20150), Loyalty Islands; C, D, left G 1 (basal part broken off), holotype male (54.6 × 48.5 mm) (MNHN – B 3763 S), “ New Caledonia ”. C, ventral view; D, dorsal view.

FIGURE 14. Discoplax species, left G 1 s. A – D, D. longipes A. Milne-Edwards, 1867, male (68.2 × 57.4 mm) (ZRC 2002.0050), Loyalty Islands; E – H, D. michalis n. sp., paratype male (68.3 × 60.0 mm) (ZRC 2000.0571), Guam. A, C, E, G, ventral views; B, D, F, H, dorsal views; C, D, G, H, distal parts (denuded).