Echinometra mathaei

Mathas sea urchin | Echinometra mathae | Echinometra oblonga
Echinometra mathaei
Echinometra mathaei, Photo: Rick Stuart-Smith
Echinometra mathaei
Echinometra mathaei, Ha'apai Is, Tonga, Photo: Andrew Green
Echinometra mathaei
Echinometra mathaei, Lord Howe is, NSW, Photo: Andrew Green
Echinometra mathaei
Echinometra mathaei, NSW, Australia, Photo: Ian Shaw
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Echinometra mathaei
Echinometra mathaei
Echinometra mathaei
Echinometra mathaei


Temperate Australasia, Tropical Indo-Pacific


This species has a different shape to other local sea urchins, with short fat primary spines which often have a white circle around the base. Because it can bore into limestone rock, it forms large aggregations on calcareous reefs in the zone of greatest wave action just below low water mark, including at Rottnest I.


Max Size: 9 cm

Sea Temperature Range: 19.1-30.7°C

Depth: 0-34m

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 (24.3% 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: Many (23 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