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Cyclodius ungulatus
H. Milne Edwards, 1834

Hoof-Clawed Reef Crab

Joshua Gaschk (2014)


Fact Sheet



Physical Description


Life History & Behaviour

Anatomy & Physiology

Evolution & Systematics

Biogeographic Distribution

Conservation & Threats

References & Links


Cyclodius ungulates, commonly referred to as the Hoof-clawed reef crab, is a worldly distributed species of Xanthidae. It can survive and reproduce in many habitats including coral reefs, rubble flats, intertidal zones and within fouling communities. Both the common and scientific name refer to the hoof –like claw that C. ungulatus uses to scrub algae of various surfaces including rocks and coral. Reaching sizes of around 30mm carapace width, expressing dark camouflage to blend within crevices or rocky substrate, C. ungulatus also bears bright orange bands around its joints to warn predators of a toxic composition. The mutualistic behaviours and large possibilities with respect to dispersal (i.e. larvae and anthropogenic migration with fouling communities) this creature will probably be gracing our oceans for many years to come.