Animal Species:Semaphore Crab
The Semaphore Crab is the most abundant crab found in mangroves and estuaries, and usually lives among the mangrove roots.
Semaphore Crab on sand
Dr Isobel Bennett
© Australian Museum
Identification
The Semaphore Crab is easily identified by its mottled purple carapace and eyes on the end of long stalks. Juveniles have orange claws while the claws of adults are purple.
Size range
25 cm
Distribution
The Semaphore Crab is found from Brisbane in Queensland, New South Wales to Port Philip Bay in Victoria, and eastern Tasmania.
Habitat
The Semaphore Crab lives in intertidal mangroves.
Other behaviours and adaptations
The word 'semaphore' means a type of signalling apparatus with moving arms or flags, and refers to the males' habit of standing by their burrows and signalling to other crabs by waving their claws up and down. Exactly what they are signalling is unclear. Perhaps they are trying to grab the attention of females by showing off their large claws, or they may be warning other males to stay out of their territory.
Classification
- Species:
- cordiformis
- Genus:
- Heloecius
- Subfamily:
- Heloecinae
- Family:
- Ocypodidae
- Infraorder:
- Brachyura
- Suborder:
- Pleocyemata
- Order:
- Decapoda
- Superorder:
- Eucarida
- Class:
- Malacostraca
- Subphylum:
- Crustacea
- Phylum:
- Arthopoda
- Kingdom:
- Animalia
Last Updated:
Tags crabs, crustaceans, arthropods, invertebrates, wildlife of sydney, identification,