Amblypneustes ovum

Egg urchin
Amblypneustes ovum
Amblypneustes ovum


Temperate Australasia


A species of Holopneustes have a primary spine only at the edge of every second or third ambulactral plate. Amblypneustes ovum, as originally described, has test width approximately equal to height, and the test pores through which tube feet pass are lined up in vertical series. Closely related species are Amblypneustes pachistus, a southern Australian species with the test pores not in vertical series, and Amblypneustes grandis, a large (to 85 mm diameter) southeastern Australian species with test width greater than the height (a ratio of 1.2:1). Most species of Amblypneustes are commonly associated with macroalgal fronds but also can be found on bare reef surfaces.


Max Size: 6 cm

Sea Temperature Range: 10.2-21.2°C

Depth: 0-70m

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: Frequent (16.5% 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 (3 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