golden decorator crab
Found in the temperate waters all along the Great Southern Reef, the Golden Decorator Crab (Naxia aurita) is a species of spider crab that uses materials from their environment as a means to hide from potential predators. This golden variety covers itself in seagrass and various curled fibers which stick to its yellow-ish brown carapace, or shell. You will see these decorator crabs rocky intertidal areas and often around and underneath jetties.
A crafty crab
The crabs’ carapace is covered with tiny hooks, known as setae, on which they are able to attach anything within their environment that will help them camouflage themselves – like Velcro. Once they find a favourable covering, they will use their nimble pincers to snip it from its location, chew it and coat the end of the object, invertebrate or plant with a special gland secretion that hardens in saltwater and stick it to its body cavity.
Friends close, anemones closer
Many will use other living organisms like sponges and anemones, which can be venomous, to both blend in with their surroundings but also to benefit from an additional level of security. This relationship is symbiotic, as the crab provides a constant supply of new water from which these hitchhikers can filter food.
Costume collector
Decorator crabs will keep their costumes for a lifetime unless they move to a new environment with new surroundings. When they molt, the decorator crabs will simply take their decorations with them and apply them to their new shell. With its camouflage, they implement cryptic behaviours like remaining still by day and freezing when a potential predator approaches. A carnivorous scavenger themselves, they will move over the reef and substrates looking for any meaty leftovers including other crustaceans, molluscs and other benthic organisms.
Hatch & seek
Once they reach sexual maturity, the eggs will be fertilised by the male, then carried and placed underneath the female. Once they hatch, the larvae free float until they choose a place to settle and grow into their adult form.
Fast Facts:
Species: Naxia aurita
Family: Oregoniidae (crabs)
Order: Decapoda (decapods)
Feeding: Carnivorous scavengers
Habitat: Rocky intertidal areas, underneath jetties
Distribution: Endemic to GSR
Super Power: Camouflage creator
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