Carpilius convexus, commonly known as the marbled stone crab,[1] is a species of crab found in the Indo-Pacific, from Hawaii to the Red Sea and South Africa.[2] It was first described by Peter Forsskål in 1775 as "Cancer convexus", and has sometimes been treated as a variety of the larger species Carpilius maculatus.[2] The biology of the genus Carpilius is poorly known.[2] The coloration of Carpilius convexus is a yellow-brown or red, with patches that are mainly brown, growing up to 25 cm. Despite us knowing their size, coloration, and habitat, little else is known about their biology.