Halicarcinus ovatus

Three-pronged flat spider crab
Halicarcinus ovatus
Halicarcinus ovatus


Temperate Australasia


Three short spines of equal size on the front margin between the eyes. It has an almost rounded carapace, which bends at a blunt point on the front of each side, and is extremely variable in colour pattern.


Max Size: 2 cm

Sea Temperature Range: 10.5-18.8°C

Depth: 0-85m

Habitat Generalization Index: N/A

Also referred to as the SGI (Species Generalisation Index), this describes the habitat niche breadth of the species. Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most hard substrates within their range (generalists). Learn more here.

Conservation and Rarity

IUCN Status: Not Evaluated

Occurrence: Widespread (100% of sites)

Occurrence describes how often the species is found on surveys within its distribution. It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed

Abundance: Solitary (1 per transect)

Abundance is calculated as the average number of individuals recorded per RLS transect, where present.

Edit by: GJ Edgar. 2008. Australian Marine Life. New Holland, Sydney