Fire Urchin

Asthenosoma varium is a sea urchin (an echinoderm, a member of the phylum that also includes star fish).

Description

Growing up to 22 cm (8.7 in) in diameter. It has an uniform arrangement of tightly packed spine clusters, variable in color and length on red spherical body, venom-tipped spines with globular swellings below the tip, long thin yellow spines on the lower skirt. Locomotion is assisted by non-venomous spines on the underside of its test.

Its venom tipped spines, with distinctive globular swellings below the tip, can inflict a painful sting if handled; the pain lasts as long as several hours. This capacity, perhaps coupled with its reddish brown color, has given it the common name Fire Urchin.

Distribution and habitat

It lives on sand and rubble sea bottoms in the Indo-Pacific, from the Red Sea to Australia and Southern Japan. It feeds on algae, seaweed, detritus and small invertebrates.

It plays host to the commensal shrimp Periclemenes colemani and the zebra crab, Zebrida adamsii.