Ophidiasteridae Family of Sea Stars

Three Sea Stars of the Ophidiasteridae Family can be found in this website:

Phylogeny:  Ophidiasterid Sea Stars of the Ophidiasteridaeidae Family  are in the phylum Echinodermata, which is a large phylum that includes brittle stars, sea cucumbers, sea lilies, sea stars and sea urchins. They are in the subphylum Asterozoa and the class Asteroidea. Asteroideans are  characterized by having a flattened, star shape, with a central disk, surrounded by multiple (5 to 40) radiating arms (or rays). Ophidiasterid Sea Stars are in the subclass Ambuloasteroidea, the infraclass Neoasteroidea, the superorder Valvatacea, and the order Valvatida. The Ophidiasteridaeidae Family is one of fifteen families in this order. The Ophidiasteridaeidae Family contains twenty-two genera and one hundred one species. The name Ophidiasteridae comes from the Greek words meaning “snake star”, referring to the long flexible arms.

Morphology:  Ophidiasterid Sea Stars 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 disks and long arms that are round in cross section. The arms are somewhat snake-like in appearance. The disk 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. 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. They have a water vascular system and a complete digestive system, but they lack a head, eyes, nervous system, or excretory system.    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.

Habitat and Distribution: Ophidiasterid Sea Stars may be found attached to hard substrates such as rock, reef, and manmade structures, or on sand. They reside from the intertidal zone to depths up to 380 m (1,250 feet). Ophidiasterids are found worldwide, in tropical to temperate seas. At least eight species from this family are found in Mexican waters.

Reproduction: Ophidiasterid Sea Stars are gonochoric (male or female for life). They reproduce sexually, through broadcast spawning, with external fertilization. The fertilized eggs develop into planktonic larvae.  They can also reproduce asexually through autotomy, where a detached arm can grown a new individual.

Ecosystem Roles: Ophidiasterids feed on algae, carrion, detritus, coral mucous, detritus, microorganisms and sponges. In turn they are preyed upon by crabs, fish, gastropods, and shrimp.