Holopneustes porosissimusShort-spined urchin
Common sea urchin that is rarely observed, because of its habit of living wrapped in macroalgal fronds, particularly those of Sargassum sp. and Cystophora sp. While the primary spines are a vivid red at the tips (khaki at the base) and the tube feet are purple, this brilliant colouration rarely stands out against the host alga because of the lack of red light at depth.
Max Size: 7 cm
Sea Temperature Range: 12.5-23.3°C
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 (21.5% 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