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Echinoderms of Zihuatanejo

PHYLUM ECHINODERMATA

-Animals (Kingdom Animalia)

-Echinoderms (Phylum Echinodermata)

-Sea Stars and Brittle Stars (Subphylum Asterozoa)

-Sea Stars Class Asteroidea

-Valvatacean Sea Stars (Superorder Valvatacea)

-Valvatidan Sea Stars (Order Valvatida)

-Family Ophidiasteridae

-Genus Pharia

-Pyramid Sea Star (Pharia pyramidata)


The Pyramid Sea Star — scientifically Pharia pyramidata is a species of sea star (starfish) found in the tropical Eastern Pacific, including waters off Mexico (e.g., Baja California, Gulf of California), the Galápagos Islands and Central America. Base coloration ranges from tan, brown, gray to lavender, with distinctive yellow-green spots that often form lines or rows down each arm, giving a somewhat “speckled” or pyramidal look from above. Where it lives: Found from the low intertidal zone down to depths of around 130–140 m (about 430 ft), mainly on and under rocks, coral rubble, or other hard substrates on reef slopes and coastal bottoms.

Diet

  • Omnivorous sea star that feeds primarily on small molluscs and other small benthic invertebrates.

  • It also consumes algae and detrital material, with its diet varying with the available food on the reef.

Range

  • Tropical eastern Pacific, ranging from the Gulf of California and the Pacific coast of Mexico south through Central America to Colombia, Ecuador, Peru and the Galápagos Islands.

  • It occurs in the Zihuatanejo area and was recorded among the sea stars associated with reef formations around Zihuatanejo and Acapulco.

Habitat

  • Primarily associated with rocky and coral reefs in shallow coastal waters.

  • Found from the intertidal zone to at least 50 metres.

  • In the Zihuatanejo region it occurs on reef formations and rocky substrates, where it moves across the exposed surface in search of food.

Description

  • Large sea star with five long, slender, cylindrical arms arising from a relatively small central disc.

  • Adults can reach approximately 25–30 cm across.

  • Colour is variable, commonly brown, tan, yellowish or reddish, with numerous yellow-green spots along the arms.

  • The spots form distinctive longitudinal patterns while leaving a relatively clear line along the centre of each arm.

  • The upper surface is covered with small granules and low, flattened spines; the arms have a single prominent row of spines along each side.

Pyramid Sea Star

Pharia pyramidata

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