About Astrostole scabra (Hutton, 1872)
Astrostole scabra (Hutton, 1872) is commonly called the seven-armed seastar. Subtidal individuals can reach up to 350mm in diameter. Their colour ranges from orange through dark red to brown, or from light blue to grey. The dorsal surface is covered in speckled plates; one or two short, stubby white specialized ossicle spines protrude from the center of each plate. These spines are blunt at the top, and become sharper, and sometimes longer, along the sides of the arms. Juveniles can have blue spines. The madreporite is not easily visible. Tube feet are a mix of off-white and bright orange. Intertidal individuals are generally smaller, and have thicker dermal plates that give them greater protection when tossed by waves. Even with this thicker protection, intertidal individuals still sustain more damage than subtidal individuals. This seastar is a common inhabitant of rocky subtidal reefs and rocky intertidal shores. Adult seven-armed seastars have been found at depths down to 150m. A. scabra has unique roaming habits: it never has a permanent home. All migratory and resident A. scabra individuals in any location are the result of random movement. In the coastal intertidal, juveniles are more adventurous than adults. They show considerable movement within intertidal and shallow sublittoral zones, and do not venture deeper than 20m.
