Circulium scandens Naruse & Ng 2020, comb. nov.

Circulium scandens (Ng and Liu, 2003), comb. nov.

Sesarma (Sesarma) rotundatum: Sakai 1939, p. 687, pl. 110, fig. 4; 1940, p. 32.

Labuanium rotundatum: Sakai 1976, p. 663, text-fig. 362; Dai et al. 1986, p. 486, pl. 68(5), fig. 273 (3, 4); Dai and Yang 1991, p. 532, fig. 273 (3, 4); Cai et al. 1994, p. 597; Liu 1999, p. 88; Ng et al. 2001, p. 42; Jeng et al. 2003, p. 228 (part).

Labuanium scandens Ng and Liu, 2003, p. 602, figs 1–4 [type locality: Hengchun, southern Taiwan]; Cuesta et al. 2006,p. 153, figs 1–3; Ng et al. 2008a,p. 221; Ng and Davie 2011, p. 35, figs 2C, 3C, 4C, 5D, 6C; Lin et al. 2011,p. 48; Ng 2012,p. 266; Li and Chiu 2013,p. 44; Nishigaki et al. 2013, p. 1, figs 1–3; Maenosono and Naruse 2017, p. 49; Ng et al. 2017, p. 103, fig. 11b.

Material examined

Holotype. TMCD 3290, holotype, male, 41.1 × 42.4 mm, Hsiang Chiao Wan, Henghun Peninsula, Pingtung, Taiwan, coll. H.-C. Liu, 24 January 2002.

Paratypes. ZRC 2002.0444, 3 males, 14.6 × 14.4–37.5 × 38.5 mm, 1 female, 21.8 × 23.2, same data as holotype.

Others. ZRC 1998.447, 1 female,39.5 × 40.0 mm, Hengchun Peninsula, Pingtung, Taiwan,coll. 20 May 1998; RUMF-ZC-2116, 1 male, 29.7 × 30.3 mm, Shiraho, Ishigaki Island, Ryukyu Islands, Japan,coll. T. Higa, 11 November 2012; RUMF-ZC-2117, 1 female, 30.7 × 32.9 mm, Funaura Bay, Iriomote Island, Ryukyu Islands, Japan,coll. S. Kobayashi, 20 July 2012; RUMF-ZC-2118, 1 female, 23.0 × 24.8 mm, Funaura Bay, Iriomote Island, Ryukyu Islands, Japan, coll. T. Naruse, 18 August 2012; RUMF-ZC-2119, 1 female, 20.3 × 20.8 mm, Funaura Bay, Iriomote Island, Ryukyu Islands, Japan, coll. T. Tanimoto, 5 November 2011; RUMF-ZC-2120, 1 female, 30.2 × 31.9 mm, Miyara, Ishigaki Island, Ryukyu Islands, Japan; RUMF-ZC-3903, 1 juvenile male, 9.8 × 10.0 mm, near Cave Sabichi, Ishigaki Island, Ryukyu Islands, Japan, coll. H. Kimura and T. Maenosono, 1 June 2007; RUMF-ZC-3065, 1 male, 28.8 × 29.1 mm, Mimikiri, Sumiyoshi, Iriomote Island, Ryukyu Islands, Japan, coll. R. Yoshida, 22 October 2015.

Diagnosis

Two pairs of postfrontal lobes present, lateral lobes exceeding mesial lobes anteriorly, anterior edge of lobes close to but never reaching frontal margin in dorsal view. Epistome posterior margin with 3 low lobes, lateral lobes terminally directed anteroventrally, median lobe terminally directed anteriorly. Chela outer surface covered with closely arranged small granules; upper surface with 1 complete longitudinally traversing row of small granules. G1 stout, relatively long, straight proximally, distally bent about 90° against main axis; distal beak-like and corneous process relatively short, narrow. Sternal vulval cover covering almost entire vulva, except for mesial slit, sternal vulval cover produced anteroventrally as earlobe-like structure.

Colouration

In life, large individuals with uniformly dark brown carapace, slightly paler ambulatory legs, dirty white chelae and purplish movable finger. Carapace and ambulatory legs of small individuals mottled with light brown to white blotches and dark specks. Eyes greenish yellow with mottled black patches. See Nishigaki et al. (2013); Ng et al. (2017, fig. 11b).

Distribution

Western Pacific: Tanshui and southern Taiwan [type locality] (Sakai 1939; Ng and Liu 2003); Ishigaki and Iriomote Islands, Ryukyu Islands, Japan (Nishigaki et al. 2013; Maenosono and Naruse 2017).

Ecological note

Circulium scandens is an arboreal species. The habitat of this species is closely associated with closed coastal forest canopy and availability of water-filled treeholes. This species has also been found on leaves of Hibiscus tiliaceus and Pandanus odoratissimus and even from a polyvinyl chloride (PVC) pipe that held water inside and was stuck on the ground near the coast. See Ng and Liu (2003) and Nishigaki et al. (2013) for details.