Calcinus guamensis Wooster, 1984
Illustrations. - Female shield length 4.2 mm, Marquesas. Ocular peduncles, color pattern. Left third pereopod, color pattern.
References. - Calcinus guamensis Wooster, 1984: 141 (type locality, Mariana).
Calcinus guamensis - Haig & McLaughlin, 1983: 110 (Hawaii). - Haig & Ball, 1988: 159 (Indonesia). - Morgan, 1991: 879 (Western Australia). - Asakura, 1992: 37 (Japan); 1995: 356 (Japan). - Shih & Yu, 1995: 242 (Taiwan). - Poupin, 1997: 694 (Marquesas, French Polynesia). - Hoover, 1998: 254 (Hawaii). - Shih, 1998: 88 (Taiwan). - Kawamoto & Okuno, 2003: 75 (Okinawa, Japan).
Calcinus vachoni - Forest, 1958: 285 (pro parte, only 1 male 6.0 mm; Vietnam). - Lewinsohn, 1982: 624 (Somalia; cf. Gherardi & McLaughlin, 1994: 624) [Not C. vachoni Forest, 1958].
Shield and cephalic appendages. - Ocular scale with several terminal spines (35 spines).
Chelipeds (P1). - Upper margin of right chela tuberculated or spinous. Outer face of left palm regularly convex.
Ambulatory legs (P2-P3). - Dactyl of P3 distinctly shorter than propodus (only 0.50.7 time as long as propodus). Distal pilosity of P3 weak, similar to distal P2.
Armament of telson. - Left lobe of telson with several spines disposed on posterior and lateral margins (1014 spines in total). Right lobe with several spines (69).
Coloration. - Shield white or cream. Ocular peduncle multicolored without narrow ring close to cornea. Detailed coloration of ocular peduncle: cream, with large black patch or ring (black median ring of variable extension). Distal antennular peduncle black (basal segments of peduncle also black; flagella black-blue). Distal antennal peduncle black (basal segments of peduncle cream; flagellum orange). Chela uniformly colored, often grading to paler distally (green turning to cream, tip of tubercles white; carpus of cheliped black with white tubercles). Ambulatory legs (P2 & P3) with ring(s) (a single black ring at base of dactyls, on a cream background).
Habitat. - Facultative associates of corals (e.g. Pocillopora, Acropora), shallow-waters (subtidal and up to 30 m).
Geographic distribution. - Eastern Africa (Somalia); Indian Ocean (Christmas & Cocos Islands, North-western Australia); Indonesia; Vietnam; Japan, Mariana, Hawaii, French Polynesia (Marquesas). Indo-West Pacific.
Remarks. - Calcinus guamensis is remarkable by the large median black ring that is disposed on the ocular peduncles and the black coloration of antennular peduncles, distal segments of antennal peduncles and carpi of chelipeds. In C. vachoni, a black mark is also present on the ocular peduncles and the two species have sometimes been confused.