The Ophidiasterid Sea Stars or Asteriids, like Sea Urchins and Sea Cucumbers, are in the Phylum Echinodermata. Echinoderms have spiny skins and are characterized by a larval stage with bilateral symmetry and an adult stage with 5-rayed radial symmetry. They are unsegmented and can be cucumber, disc, sphere or star shaped. They have a water vascular system, tube feet, and a complete digestive system, but they lack a head, eyes, nervous system, or excretory system. They are found only in marine environments.

Ophidiasterids are in the Class Asteroidea, which is characterized by having a flattened, star shape. There is a central disc, surrounded by multiple (5 to 40) radiating arms (or rays). The disc contains most of the organs, with the mouth on the ventral side and the anus and madreporite (entry plate for the water vascular system) on the dorsal surface. Ophidiasteridae Sea Stars are 1 of 2 major Classes of Astereozoans. The other Class is Ophiuroidea.  Ophidiasterids are easily distinguished from Ophiuroideans by having a broad attachment point where the arms join the disc and arms that taper as they extend from the disc. Ophiuroideans have arms that are relatively the same width their entire length, giving them a narrow attachment point at the disc. All Ophidiasterids have the ability to regenerate amputated limbs.

Ophidiasterid Sea Stars are in the Order Valvatida. These starfish generally have five arms, with two rows of tube feet, with suckers, on the underside of each arm. They have conspicuous ossicles (calcareous particles that are part of the endoskeleton) along their margins. Sea Stars in the Family Ophidiasteridae are characterized by having small central discs and long arms that are round in cross section. The arms are somewhat snake-like in appearance. The Family name is based on the Greek word for “small snake”. While all Sea Stars have the ability to regrow an amputated arm, Ophidiasterids can actually grow a whole new individual from an amputated arm. Sea Stars in this Family have distinct marginal plates, tube feet with terminal discs, and granular skin. The pedicellariae, if present, may be foraminate or excavate. Ophidiasterids are generally brightly colored. They are small to medium in size, with the largest reaching a maximum of 40 cm (16 inches) in diameter.

Ophidiasterids feed on algae, carrion, detritus, coral mucous, detritus, microorganisms and sponges. In turn they are preyed upon by crabs, fish, gastropods, and shrimp. They may be found on coral or rock reefs, and over and within sand substrate. They reside from the intertidal zone to depths up to 380 m (1,250 feet).

The Ophidiasterids are found worldwide, in tropical and temperate waters. There are currently 103 known species in this family of which 7 are found along Mexico’s Pacific Coast.