Much better known by the name Spondylus princeps Broderip, 1833 which was recently synonymised with the current name, the showy « Pacific Thorny Oyster » gains its vernacular name from its distribution range in the Pacific Americas, from Baja California to Peru. Being rather variable in spine development and colouration it has a couple further synonyms including S. basilicus Reeve, 1856 which refers to an orange form, and S. dubius Broderip, 1833. Spondylus leucacanthus Broderip, 1833 with more sparce spines which are usually white was traditionally considered to be a form of this species but currently separated out as a valid species on its own right. A filter-feeding sessile bivalve like all spondylids, it lives attached to hard substrates around moderate depths of -10~50m. Typical shell length including spines around 100mm., very large specimens are known to exceed 170mm. Although a locally comm.on species, specimens of fine quality are uncomm.on on the international shell trade market.