Calcinus nitidus Heller, 1865
Illustrations. - Male shield lenght 3.7 mm, Tahiti. Specimen from Rangiroa, Tuamotu (Photograph G. Paulay). Copyright G. Paulay.
References. - Calcinus nitidus Heller, 1865: 89 (type locality: Tahiti).
Calcinus nitidus - Forest, 1956a: 218 (Tahiti). - Poupin, 1994: 18, pro parte (French Polynesian specimens only). - Poupin, 1994: 706 (Society and Tuamotu Islands).
[Not C. nitidus - Miyake 1983: 113 (Japan). - Poupin, 1994: 18 (pro parte, only one sp. from Samoa, MNHN Pg3163) - All = C. minutus Buitendijk.].
Shield and cephalic appendages. - Ocular scale with several terminal spines (usually 2 spines, rarely 3).
Chelipeds (P1). - Upper margin of right chela tuberculated or spinous. Outer face of left palm regularly convex.
Ambulatory legs (P2-P3). - Dactyl of P3 subequal to propodus or slightly shorter (0.71.0). Distal pilosity of P3 weak, similar to distal P2.
Armament of telson. - Left lobe of telson with several spines disposed on posterior margin only (511). Right lobe with several spines (47).
Coloration. - Shield with a patch on disal half (background white, patch orange). Ocular peduncle uniformly colored. Detailed coloration of ocular peduncle: white to pale orange. Distal antennular peduncle yellow-orange (proximal half of ultimate segment and basal segments blue-black; flagella orange-brown). Distal antennal peduncle yellow-orange (flagellum orange). Chela with submedian patch or spot on outer face (background white, with a large submedian orange patch; carpus of cheliped white with dorsal median orange patch; merus with 3 similar orange patches). Ambulatory legs (P2 & P3) without ring(s) or spot(s) (uniformely orange, brighter on dactyls and propodi).
Habitat. - Facultative associates of corals (e.g. Pocillopora, Acropora), shallow-waters.
Geographic distribution. - French Polynesia: Society Islands and Tuamotu. Indo-West Pacific.
Remarks. - This is a sibling species of C. minutus. The two species are differenciated by color pattern only and are undistinguishable morphologically. For the time being C. nitidus appears to be endemic to French Polynesia. It could, however, occurs in western Australia as Morgan (1991: 895) has observed specimens of 'C. minutus' with large orange patches on chelipeds, a feature characteristic of C. nitidus.