This sea star is an echinoderm, a marine invertebrate characterized by a rigid, internal skeleton (typically spines), a water-vascular system, adhesive tube feet and radial symmetry. The species typically has five arms with spines covering its body.
Considered a predatory carnivore, purple sea stars feed by using their tube feet to pry open prey like snails, clams, mussels and barnacles. Once open, the sea star extends its stomach into the shell to consume its meal.
This species lacks a brain and has a very simple nervous system. A nerve ring surrounding the mouth connects with nerves which extend the length of each arm. The nerve ring relays signals to one arm and the subsequent arms follow. Neuro-sensory cells across the body relay optical, chemical and mechanical messages.