A new species of crown-of-thorns sea star, Acanthaster benziei sp. nov. from the Red Sea. Acanthaster taxonomy

A new species of crown-of-thorns sea star (CoTS), Acanthaster benziei, is described based on five specimens collected from Saudi Arabia’s Red Sea coast. Species delimitation from congeners in the species complex, i.e., Acanthaster planci, Acanthaster mauritiensis and Acanthaster cf. solaris, is primarily based on distinct and diagnostic mitochondrial DNA sequence regions. Species separation of Acanthaster benziei is additionally justified due to diagnostic morphological characters: fewer arms; narrower and thinner spines; fanned spine tips in primary and latero-oral spines; a wider tip or tapering shape in circumoral spines; and rhombus-shaped oral pedicellariae. The new species shares the following characteristics with the other CoTS species: convex disk and numerous arms; long, sharp spines on the aboral surface; bivalved pedicellariae; large number of madreporites; corallivorous diet with extraoral feeding; and it inhabits tropical coral reefs.