Animal Species:Decorator Crab

The Decorator Crab looks like seaweed on the move.

Decorator Crab hiding with shells

Dr Isobel Bennett © Australian Museum

Standard Common Name

Decorator Crab

Alternative Name/s

Seaweed Crab

Identification

The Decorator Crab's carapace is covered with hooks to attach algae, seaweed or anything in the environment that will assist in camouflage.

Size range

4 cm

Distribution

The Decorator Crab is found in the temperate waters of Australia in New South Wales, Victoria, Tasmania and Western Australia.

Habitat

The Decorator Crab lives on intertidal rocky shores.

Other behaviours and adaptations

Once a suitable covering is found, the Decorator Crab snips it off with its pincers, coats the end with a special gland secretion that hardens in seawater, and deliberately places it onto its carapace. The crab continues the process until it is sufficiently covered. The algae continue to grow once attached, helping the concealment.

This and other decorator crabs belong to the 'spider crab' family, Majidae. This group includes the largest crab in the world - the Giant Japanese Spider Crab (Macrocheira kaempferi) with a leg span of over 2 m.

Classification

Species:
tumida
Genus:
Naxia
Subfamily:
Majinae
Family:
Majidae
Infraorder:
Brachyura
Suborder:
Pleocyemata
Order:
Decapoda
Class:
Malacostraca
Subphylum:
Crustacea
Phylum:
Arthopoda
Kingdom:
Animalia

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Tags crustaceans, crabs, invertebrates, arthropods, wildlife of sydney, identification,