Luidia Columbia Sea Star, Luidia columbia

Luidia Columbia Sea Star, Luidia columbia. One arm and central disk of a badly damaged individual. Sea star courtesy of the commercial fishermen in the greater Los Cabos area of Baja California Sur, July 2009. Size: 42 cm (16.5 inches). Identification courtesy of Dr. Richard Brusca, Tucson, Arizona.

Phylogeny:  The Luidia Columbia Sea Star, Luidia columbia (Gray, 1840), is a member of the Luidiidae Family of Sea Stars. The Luidia genus is the only genus in the Luidiidae Family. There are forty-nine species in the Luidia genus. They are known in Mexico as  Estrella de Mar Luidia Columbia. The family and genus names are in honor of the Welsh naturalist and botanist Edward Lhuyd, who Latinized his name to Luidius.

Morphology: The Luidia Columbia Sea Star is a large sea star that is characterized by a uniform dark gray to black color. This species has 4 to 5 arms. The arms are several times longer than the diameter of the disc. The arms taper to a sharply rounded tip. Their tube feet are pointed and lack suckers. They use these tube feet, along with their spines to borrow under the surface of the soft sediments in which they live. Their pedicellariae are sessile. The dorsal surface is covered with paxillae (umbrella-shaped ossicles). The marginal spines are slender and needle-like. Luidia Columbia Sea Stars have a maximum diameter of 51 cm (20 inches).

Habitat and Distribution:  Luidia Columbia Sea Stars are found on, and within, sand and mud bottoms. They are normally buried under a few centimeters of the substrate in the lower intertidal region, and  to depths up to 220 m (722 feet). Luidia Columbia Sea Stars are an Eastern Pacific Species that are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from the west coast of the Baja Peninsula.

Diet: Luidia Columbia Sea Stars are a poorly studied and understood species. Documentation of their diet is limited to the genus level. Other species in the Luidia genus prey on carrion and detritus or feed as predators of bivalves, crustaceans, gastropods, polychaetes, sea cucumbers, other sea stars and sea urchins. They are unable to extrude their stomachs and have to swallow their prey whole.

Predators: Luidia Columbia Sea Stars are a poorly studied and understood species. Documentation of their predators is limited to the genus level. Other species in the Luidia genus are consumed by shore birds, crabs, fish and other sea stars.

Reproduction: Luidia Columbia Sea Stars are gonochoric (male or female for life). Reproduction can be asexual, through regeneration or cloning, or sexual. Sexual reproduction is accomplished through broadcast spawning, with external fertilization. The fertilized eggs hatch into planktonic larvae, which later settle to the bottom and metamorphose into pentamorous juveniles. These juveniles develop into young sea stars with stubby arms.

Ecosystem Interactions: Luidia Columbia Sea Stars are a poorly studied and understood species and their is no formal documentation of their involvement in any form of commensal, parasitic, or symbiotic relationships.

Human Interactions: While there are no fisheries targeting Luidia Columbia Sea Stars, they are a common by-catch in otter trawls of shrimp boats. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

Synonyms:  Luidia brevispina, Luidia marginata, and Petalaster columbia.