Calcinus gaimardii (H. Milne Edwards, 1848)

(Fig. 1C)

Pagurus gaimardii H. Milne Edwards, 1848: 68 (Ambon, Indonesia, type locality).

Calcinus gaimardii – Morgan, 1991: 876–878 (in part, form I), Fig. 13.

Calcinus gaimardii – Rahayu & Forest, 1999: 463–465, Figs. 1A, 2A, B, E, F, I; Asakura, 2002: 48–52, Figs. 1 A–C, 1H–N, 12–14; McLaughlin et al., 2007: 157–158, 2 unlabelled figures; Malay & Paulay, 2010, Appendix S1.

Material examined. 1 male SL 7.0 mm (ZRC), stn M1, Alona Beach, Panglao I., 9°32.9′N, 123°46.6′E, 0–1 m, v.2004 to vii.2004; 2 males SL 5.7–7.0 mm (ZRC), 1 indiv. sex unknown SL 5.4 mm (ZRC), stn M2, west end of Alona Beach, Panglao I., 9°32.8′N, 123°45.9′E, 0–2 m, 30.v.2004 ; 1 female SL 5.5 mm, 1 male SL 5.5 mm (ZRC), stn M3, Danao, Panglao I., 9°32.5′/33.1′N, 123°44.7′/45.5′E, 0–2.5 m, 31.v.2004 ; 2 males SL 5.2–5.8 mm (ZRC), stn M8, Doljo, north coast, Panglao I., 9°35.4′N, 123°44.3′E, 0–1 m, 2.vi.2004 ; 1 female SL 6.6 mm (ZRC), stn M19, Pamilacan I., 9°30.0′N, 123°55.3′E, 0–2 m, 11.vi.2004 ; 1 male SL 5.2 mm (ZRC), stn M20, Pamilacan I., 9°29.3′N, 123°55.1′E, 0–2 m, 13.vi.2004 ; 3 ovig. females SL 3.5–7.5 mm, 1 female SL 5.0 mm, 2 males SL 6.5–7.5 mm (ZRC), stn M22, Napaling, Panglao I., 9°37.2′N, 123°46.4′E, 0–3 m, 15.vi.2004 ; 5 males SL 3.7–6.3 mm (ZRC), stn R1, Balicasag I., 9°31.2′N, 123°41.3′E, 5–7 m, 30.v.2004 ; 1 male SL 6.0 mm (ZRC), stn R11, Biking, Panglao I., 9°35.2′N, 123°50.5′E, 4 m, 2.vi.2004 ; 1 female SL 5.6 mm (ZRC), stn R14, Baclayon, Bohol I., 9°37.4′N, 123°54.5′E, 6–8 m, 3.vi.2004 ; 1 female SL 5.4 mm, 1 male SL 6.6 mm (ZRC), stn R14, Baclayon, Bohol I., 9°37.4′N, 123°54.5′E, 6–8 m, 3.vi.2004 ; 2 males SL 3.0– 5.1 mm (ZRC), stn R17, Black Forest, Panglao I., 9°31.1′N, 123°41.3′E, 3–15 m, 4.vi.2004 ; 1 male SL 6.2 mm (ZRC), stn R21, Rico’s Wall, Panglao I., 9°31.0′N, 123°40.8′E, 2–50 m, 5.vi.2004 ; 1 male SL 6.0 mm (ZRC), stn R23, lagoon off Poblacion, Panglao I., 9°33.5′/34.8′N, 123°42.7′/46.3′E, 1–5 m, 5, 6, & 21.vi.2004 ; 1 ovig. female SL 4.1 mm (ZRC), stn R24, Bingag, Panglao I., 9°37.5′N, 123°46.8′E, 0–2 m, 6.vi.2004 ; 2 ovig. females SL 3.5–4.2 mm, 2 males SL 5.8–6.1 mm (ZRC), stn R24, Bingag, Panglao I., 9°37.5′N, 123°46.8′E,, 0–2 m, 6.vi.2004 ; 3 ovig. females SL 4.4–5.4 mm, 1 female SL 3.0 mm, 1 male SL 6.8 mm, 1 indiv. in shell (ZRC), stn R27, Napaling, Panglao I., 9°37.0′N, 123°46.3′E, 2–20 m, 7.vi.2004 ; 1 male SL 6.0 mm (ZRC), stn R36, Pamilacan I., 9°30.2′N, 123°55.3′E, 3–32 m, 9.vi.2004 ; 1 ovig. female SL 6.2 mm, 4 males SL 5.4–6.8 mm, 3 indivs. in shell (ZRC), stn R38, Pamilacan I., 9°29.4′N, 123°56.0′E, 6–37 m, 11.vi.2004 ; 1 female SL 5.8 mm (ZRC), stn R40, Pamilacan I., 9°29.2′N, 123°55.1′E, 8–33 m, 12.vi.2004 ; 1 male SL 6.6 mm (ZRC), stn R42, Baclayon Takot, Bohol I., 9°37.1′N, 123°52.6′E, 8–22 m, 12.vi.2004 ; 3 males SL 4.8–6.5 mm (ZRC), stn R43, Cortes Takot, Bohol I., 9°41.3′N, 123°49.5′E, 3–41 m, 13.vi.2004 ; 1 female SL 4.5 mm (ZRC), stn R70, Pamilacan I., 9°30.1′N, 123°55.5′E, 20 m, 1.vii.2004 ; 1 ovig. female SL 4.4 mm, 6 males SL 3.6–6.0 mm (ZRC), stn R73, Balicasag I., 9°30.9′N, 123°40.8′E, 2–30 m, 2.vii.2004 ; 1 ovig. female SL 5.7 mm (ZRC), stn S12, Pamilacan I., 9°29.4′N, 123°56.0′E, 6–8 m, 14.vi.2004 .

Habitat. Intertidal to subtidal, 0–12 m deep, intertidal reef flats, seagrass beds, and reef slopes, on rocky, coralline, sandy, and mixed substrates. This species is typically found in areas sheltered from strong wave action.

Remarks. Calcinus gaimardii closely resembles C. morgani Rahayu & Forest, 1999, in morphology and colour pattern. Examination of live colour patterns is the most reliable way to separate these two species: the ocular peduncles of C. gaimardii have a narrow blue band distally; proximally the peduncle is orange coloured with a longitudinal tapering dark brown stripe running down the dorsal surface of the peduncle. In C. morgani the distal blue band on the ocular peduncle is broader, and the proximal portion of the ocular peduncle lacks orange colouration. In C. gaimardii dark brown pigmentation covers the shield (either the anterior half or the entire shield is dark coloured), while in C. morgani the entire shield is light-coloured (gray-white to cream). Also, the ambulatory legs and distal portions of the chelae are typically dark brown (light brown to white with brown spots in juvenile) in C. morgani, while the colouration of these areas in C. gaimardii tends towards orange-brown or reddish-brown.

While the two species are sympatric, the geographic range of C. gaimardii (eastern Indian Ocean to Fiji) is more restricted than that of C. morgani (east Africa to Tuamotu; see Malay & Paulay, 2010; Fig. 8). In addition, C. gaimardii prefers more wave-sheltered habitats than C. morgani (Asakura, 2002) .