Physical Description
C. guamensis is a relatively small hermit crab, with an average body length of 18mm and an average weight 0.09g (n=12, collected from Heron Island, Australia). C. guamensis can often be confused with other species of the Calcinus genera; C. latens being one of the most common confusions (Morgan 1991). As with all Calcinus species, C. guamensis has a distinct colouration which is used to identify it (Morgan 1991). Calcinus is a part of the family Diogenidae, which is characterised by the larger left cheliped.
Oscular acicles are trifid, meaning they have three distinct parts (Poupin & McLaughlin 1998). The cornea is black and white spotted, and the oscular peduncle is white with a broad black band located basally with minute white spots (Morgan 1991). The shield is cream with brown or pink tinges and two black spots are present sub-medially on the cervical groove (Morgan 1991). The carapace and abdomen are predominately purple sometimes with blue tinges; telson and uropod are cream. Antennular peduncles are black to dark green gradually fading to blue-green; the flagella is bright orange. Fingers of chelipeds are distally cream and fading proximally into green-grey (Morgan 1991). The carpus is black with white spots of different sizes on the tubercles (raised bumps). The merus is cream with distinct black distal bands and with white tubercles (Haig & McLaughlin 1984). The second and third pereiopods have a cream dactylus and a broad black band that is proximal and marked with white spots (Morgan 1991). The propodus, carpus and merus are cream or pale grey-green and the propodus is very pale distally. The setae are also a pale yellow colour. The telson has a row of spines on both the left and the right lobes. The most defining characteristic is the darks rings on the oscular peduncles, carpi of chelipeds, and the dactyls of the pereiopods (Poupin & McLaughlin 1998). |