Acanthaster is a bitypic genus of large and venomous starfish placed in its own family, Acanthasteridae. Its two members are known as crown-of-thorns starfish. Acanthaster are native to coral reefs in Indo-Pacific region. The species in this genus are a contributor to coral reef degradation because they prey on a large amount of live coral at high density.

Species

These species are listed in the World Register of Marine Species: Some sources add Acanthaster ellisi, (Gray, 1840) but it is now considered as a subspecies of A. planci in the eastern Pacific. Recent molecular work has suggested that Acanthaster planci is a species complex of up to 4 different species that have yet to be separately described (Vogler et al., 2008). Haszprunar, Vogler & Wörheide (2017) suggest to split "A. planci" in :