Phyllacanthus imperialis

Slate-pencil urchin
Phyllacanthus imperialis
Phyllacanthus imperialis, Tonga, Photo: Graham Edgar
Phyllacanthus imperialis
Phyllacanthus imperialis, Raja Ampat, Indonesia, Photo: Andrew Green
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Phyllacanthus imperialis
Phyllacanthus imperialis



Test is dark purplish brown, spines are cream to light or dark brown and often banded. Fine longitutinal lines may be seen on spines. Nocturnal species which is found in crevices and holes, and is common across the tropical Indo-Pacific.


Max Size: 14 cm

Sea Temperature Range: 15.2-28.7°C

Depth: N/A

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: Infrequent (2.2% 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.