Geothelphusa makatao Shih & Shy, 2009, sp. nov.

Geothelphusa makatao sp. nov.

(Figs. 1, 2)

Material examined. Holotype: 1 male (39.3 x 29.3 mm) (NMNS-5915-001), Longcyuan Temple, Chaishan, Kaohsiung City, Taiwan, coll. Jung-Hsiang Lee, 31 May 2002. Paratypes: 2 males, CW 32.5, 35.4 mm (NCHUZOOL 13033), same data as holotype; 1 male, CW 35.4 mm, 1 female, CW 43.0 mm (NCHUZOOL 13238), Chaishan, Kaohsiung City, Taiwan, coll. J.-H. Lee, 25 May, 2002; 4 ovigerous females, CW 37.1~ 42.6 mm (NCHUZOOL 13032, 13240, 13241), 22 May 2002, Longcyuan Temple, Chaishan, Kaohsiung City, Taiwan, coll. Hsi-Te Shih; 1 male, CW 25.3 mm (NCHUZOOL 13239), Cueiheng Dormitory, National Sun Yat-sen University, Kaohsiung City, Taiwan, coll. H.- T. Shih, 9 Aug. 2000; 1 male, CW 36.6 mm (NTOU F10708), Cueiheng Dormitory, National Sun Yat-sen University, Kaohsiung City, Taiwan, coll. H.- T. Shih, 22 May 2002.

Comparative material examined. see Table 2 for the holotypes of G. albogilva, G. ancylophallus, G. pingtung, and G. shernshan.

Diagnosis. Carapace swollen longitudinally, transversely; dorsal surface smooth, glabrous, with fine pits. Carapace length, width 1.5-, 1.9-times carapace height, respectively. Frontal margin straight, without tooth. Postorbital cristae distinct, supraorbital margin smooth, without granules; infraorbital margin smooth to almost smooth, lined with very low granules. External orbital angle stout, external orbital region concave. Anterolateral margin faint, smooth, without epibranchial tooth. Postorbital crista faint, smooth. Gastric, cardiac, intestinal regions smooth. H-shaped groove distinct. Tip of medium lobe of epistome slightly stout. Distance between tip of closed male abdomen, anterior margin of thoracic sternite 4 about 2.4 times length of thoracic sternites 1-3. Chelipeds of adult male unequal, fingers of larger chela forming large gape when closed. Ambulatory legs smooth, dorsal, ventral margins of dactyli with 2 rows of small spines. Second leg about 1.8 carapace length. Telson of male abdomen bell-shaped, moderately short, width about 1.4 carapace length. Subterminal segment of G1 (Fig. 1 a-c) slightly curving outwards, outer proximal margin with blunt tooth, inner proximal margin moderately dilated; terminal segment straight or slightly curving inwards; total length of G1 4.9 terminal segment; length of synovial membrane about 6.1 maximum width. Outer proximal margin of basal segment of G2 (Fig. 1d) dilated, showing a single lobe; distal segment short, about 0.14 total length.

Etymology. The species is named for the aboriginal Makatao Tribe, one of the Pingpu Tribes, which once lived in the Chaishan area. The name is used as a noun in apposition.

Coloration. Body, including legs, of most adults is yellow (Fig. 2d). Some young individuals range from pale yellow, orange (Fig. 2f, g), or greenish (Fig. 2e), to brown.

Ecological notes. The maximum elevation of type locality, Chaishan, is only 330 m and no permanent surface running water is present in this uplifted coral reef mountain system. Aquatic habitats rely on the presence of small ephemeral springs and periodic rainfall. Specimens were collected under rocks (Fig. 2h) or as they moved around on a road after a rain. Some individuals were observed near a burrow entrance. Ovigerous females were observed and collected in May (Fig. 2g).

Distribution. This species is found only in the Chaishan area, Kaohsiung City, southwestern Taiwan.

Remarks. Based on Shih et al. (2004, 2007b), G. makatao sp. nov. (as “ G. albogilva ” in Shih et al. 2007b), G. shernshan, G. neipu, and G. pingtung belong to the G. pingtung clade, but G. neipu was formally synonymized under G. pingtung recently (Ng et al. 2008). Morphologically, this new species is close to G. pingtung and G. shernshan, but they can be separated by several characters including carapace height and G1 morphology (Table 2). In particular, the new species differs from G. shernshan by the relatively taller and higher carapace (Table 2; Fig 2A, B in Chen et al. 2005). The external morphology of G.makatao sp. nov. and G. albogilva, both of which inhabit the uplifted coral reef mountain and are yellow in color, is also superficially similar. However, the distance between the tip of the closed male abdomen and the anterior margin of thoracic sternite 4, and the relative lengths of the second leg and terminal segment of the G1 of G. makatao sp. nov. are clearly greater than those of G. albogilva (Table 2; Fig. 4 in Shy et al. 1994).

Geothelphusa ancylophallus is also close to this new species, with the body height of both species being greater than most other species of Geothelphusa. The G1 of the former, however, is strongly curved outwards, while that of the latter is only slightly curved (Table 2; Fig. 2 in Shy et al. 1994).