Identification Photos: Spiny Star (A), Paulia horrida: The Spiny Star (A) is an attractive and distinctive sea star and is characterized by its uniformly colored red-orange to red-brown body and webbed arms. The Spiny Star (A) has a broad flat disc with triangularly shaped arms that are covered with large, smooth, heavy, randomly spaced highly movable conical spines (as pictured below). The Spiny Star (A) has a wing span that ranges from 3 to 7 inches with large granular plates bordering the upper and lower arm margins.

The Spiny Star (A) is very similar to and can be easily confused with the more common but still very rare Spiny Star (B), Amphiaster insignis.

The Spiny Star (A) is present on sand and mud bottoms from the intertidal zone to 420 feet along the Pacific side of Baja south of Magdalena Bay, in the central and lower portions of the Sea of Cortez and along the coast of the mainland south to Guatemala. It is considered to be exceeding rare and “uncommon.”

The Spiny Star (A) is an uncommon member of the phylum Echinoderm of marine animals and is a member of the class Asteroidea and the Goniasteridae Family. The Echinoderms include Brittle Stars, Sea Cucumbers, Sea Lilies, Starfish and Urchins and are of great scientific interest because, via fossil records, they date to the Cambrian Age (over 500 million years ago) with species numbering 7,000 living and 13,000 extinct. The Starfish or Sea Stars have a unique water-vascular system that uses hydraulic power to operate a multitude of tine tube feet that are used in locomotion and food capture. Some feed via inserting the stomach out through the mouth surrounding the prey, secreting enzymes to digest the food and then retracting the stomach when finished eating. They exist from intertidal zones to depths of 30,000 feet with 1,500 species known globally. The bodies are flattened, flexible and covered with colored skin.

Spiny Star (A), Paulia horrida: Donated to Mexfish.com by the the commercial pangueros of Todos Santos, Mexico, March 2008. Size, 13.5 cm. Identification courtesy of Dr. Chris Mah, Smithsonian Institute, Washington, D.C. Description and photos courtesy of John Snow.