Seven-armed starfish

With a diameter of up to 350mm in subtidal forms, the colouration of A. scabra varies from orange through dark red to brown, or light blue to grey. The dorsal surface is covered in speckled plates, from the center of which protrude one or two short, stubby white spines which are specialised ossicles. These spines are blunt on top, becoming sharper and sometimes longer on the sides of the arms. Spines can appear blue in juveniles. The madreporite is not obvious. Tube feet are a combination of off-white and bright orange. Intertidal individuals are generally smaller with thicker dermal plates, allowing them greater protection when being tossed about by waves. Despite this they are still found to be more damaged than subtidal individuals.