Seaweed Crab

Naxia aries

Systematics Brachyura Family Majidae

Distinguishing Characters:
The carapace is pear shaped, up to 30 mm wide with 5 strong spines protruding from each side. Two slender, outwardly curving spines protrude from the head. When not camouflaged with seaweed, the carapace can be seen to be covered with bumps. The legs are long, spindly and slightly flattened.

Habitat and Distribution:
The seaweed crab hides on rock platforms and in sandy environments rich in algae, sponges or seagrass in south-eastern Australia.

General Biology:
The family Majidae includes spider crabs and decorator crabs such as this seaweed crab. The decorator crabs have small hooked hairs on their carapace to which they attach bits of seaweed, sponge or bryozoan. This camouflage, and moving very slowly, makes them hard to see in their natural habitat. The photo above is of a 'naked' crab with seaweed removed. To see it 'dressed-up' click on the subheading "General biology".

Feedback and queries should be sent to the Discovery Centre at Museum Victoria.
Please note, the Discovery Centre can help you only with questions about crustaceans from southeastern Australia. It can not advise on the care of pet hermit crabs or on crustaceans from other regions.