Rusted Coral Guard Crab

Trapezia rufopunctata

Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Family: Trapeziidae
Genus: Trapezia
Species: Trapezia rufopunctata

The rusted coral guard crab (Trapezia rufopunctata) is a small coral crab covered in rusty red spots that guards Pocillopora corals. Its pale, smooth carapace and large claws are densely dotted with red, making it one of the most colourful guard crabs.

It grows to around 2-3 cm across and lives in pairs among the branches of its host. It feeds on coral mucus and tissue secretions, and actively defends the coral from crown-of-thorns starfish and other predators, which helps its host survive.

Pocillopora colonies on Philippine reefs are the place to look for this crab. It tends to stay in the shadows of the branches, but often peers out at divers who approach slowly.