Breynia australasiae

Australasian heart urchin
Breynia australasiae
Breynia australasiae, Photo: Graham Edgar


Temperate Australasia


Very large heart urchin with a plume of long spines projecting from the upper test. This species is extremely common within the lagoon at Lord Howe I, although rarely sighted by divers along the New South Wales mainland.


Max Size: 12 cm

Sea Temperature Range: 19.1-24.9°C

Depth: 0-10m

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: Common (25.0% 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: Few (2 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