Chocolate Chip Sea Star, Nidorellia armata
Chocolate Chip Sea Star, Nidorellia armata. Sea star courtesy of the commercial fishermen of the greater Los Cabos area, Baja California Sur, July 2009. Wingspan: 12.5 cm (4.9 inches).
Chocolate Chip Sea Star, Nidorellia armata. Underwater photographs taken within Zihuatanejo Bay, Guerrero, March 2018. Photographs courtesy of Ron Woheau, Zihuatanejo.
Chocolate Chip Sea Star, Nidorellia armata. Underwater photograph taken in coastal waters in the greater Los Cabos area, Baja California Sur, October 2019. Photograph courtesy of Bob Hillis, Ivins, Utah.
Chocolate Chip Sea Star, Nidorellia armata. Underwater photograph taken in coastal waters off Isle Coronado, Baja California Sur, May 2023. Photograph courtesy of Dr. Tom Bartol, Carlsbad, California.
Phylogeny: The Chocolate Chip Sea Star, Nidorellia armata (Gray, 1840), is a member of the Oreasteridae Family of Sea Stars. The Nidorellia Genus is one of eighteen genera in the large Oreasteridae Family. The Nidorellia Genus is monospecific cointaining only one species. They are known in Mexico as Estrella de Chispas de Chocolate.
Morphology: The Chocolate Chip Sea Star has a thick and inflated disc, with very short, thick arms that almost appear to be webbed. The aboral surface may be cream, gray, greenish, or tan. They have dark brown, conical spines (resembling chocolate chips) scattered around the disc, and a row of these spines along the center of each arm. Ambulacral grooves with suckered tube feet are visible on the ventral side of the arms. The disc margin may be dark brown, orange brown, or reddish brown. The Chocolate Chip Sea Stars reach a maximum of 15 cm (5.9 inches) in diameter. This species is sometimes confused with the Horned Sea Star, Protoreaster nodosus, which is also referred to as the Chocolate Chip Sea Star. P. nodosus tends to have a red or brown aboral surface with large horns covering the central disk. In comparison, the spikes of Nidorellia armata are of more uniform size across the body.
Habitat and Distribution: The Chocolate Chip Sea Star is found on cobbles, rocky reefs, and occasionally on sand. They live in the lower intertidal zone, and to a depth of 73 m (240 feet). Chocolate Chip Sea Stars are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the excepton that they are absent from north of Magdalena Bay, Baja California Sur, along the central and northwest coasts of the Baja Peninsula.
Diet: The Chocolate Chip Sea Star feeds on both benthic algae and sessile invertebrates.
Predators: Chocolate Chip Sea Stars are preyed upon by crabs and other sea stars.
Ecosystem Interactions: The commensal Sea Star Shrimp, Periclimenes soror, is often found in association with the Chocolate Chip Sea Star. It is found on the ventral side and feeding on the mucus secreted by the sea star.
Human Interactions: The Chocolate Chip Sea Star is utilized by the aquarium trade on a limited basis. Otherwise, they have no very little impact on human activities. 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: Goniodiscus armata, Goniodiscus conifer, Goniodiscus michelini, Goniodiscus stella, Nidorellia michelini, Oreaster armatus and Pentaceros armatus.