It was long accepted that the crown-of-thorns found throughout the Indo-Pacific and Eastern Pacific were all A. planci but recent genetic and morphological studies indicate there are different species. The Eastern Pacific version is often referred to as A. cf ellisi since it is thought to need more taxonomic attention. It eats living coral, feeding by crawling over its prey, opening its mouth wide and extruding its stomach over the coral, as shown in the first photo below. The coral tissue is digested in place and sucked into the star, leaving a completely white and empty coral skeleton that quickly gets covered by algae. The spines covering these stars are pointed and sharp, easily puncturing a diver's skin and delivering a venom that causes relatively intense pain. The venom also appears to have anticoagulant properties, causing puncture wounds from the star to bleed for quite a long time. The one below appeared to be eating a gorgonian.
Created 7 February 2021
Updated 11 February 2024