About Xantho poressa (Olivi, 1792)
Juveniles of Xantho poressa have cryptic coloration that helps them camouflage among epibionts growing on Posidonia leaves. Juvenile carapace color is variable: it may be yellowish, reddish, brown, or dark grey, and typically has patches of another colour, most often white. For most juvenile pereiopods, dark brown or black bands alternate with white or translucent stripes or spots. However, the fifth pereiopod is brighter in colour and often lacks any markings. Adult X. poressa are uniformly dark grey. Adults leave seagrass beds to inhabit more open, rocky substrates instead. Xantho poressa is distributed across the Black Sea and the Mediterranean Sea, and extends into the warmer regions of the northeastern Atlantic as far as the Canary Islands.
