Echinothrix
Echinothrix is a genus of sea urchins which was first described in 1853 by Wilhelm Peters, a German naturalist and explorer. Description and characteristics. The genus contains two species, "E. diadema" and "E. calamaris". These can be distinguished by the fact that "E. diadema" has fully black spines whereas "E. calamaris" has striped spines. Both of these species are found in the Indo-Pacific region, living on coral reefs. Taxonomy. According to World Register of Marine Species :