Spiny Sand Star, Astropecten armatus

Spiny Sand Star, Astropecten armatus. Collected from a tidal pool in the greater Los Cabos area, Baja Californa Sur, November 2015. Pictured stars wingspan: 17 cm (6.7 inches).

The Spiny Sand Star, Astropecten armatus (Gray, 1840), is a member of the Astropectinidae Family of Astropectinid Starfish that is also known as the Armored Sand Star and the Comb Sand Star and in Mexico as estrella espinosa de arena. The Astropecten Genus has 102 known global species.

Spiny Sand Stars have a smooth surface and are somewhat flattened, with a moderately wide disc and 5 long tapering arms with slightly upturned tips. The margins of the disc and arms are lined with spines and obvious plates. Their tube feet are pointed and do not have suckers. The dorsal side may be brown, gray, lavender, orange, or pink in color to match the substrate. The ventral side is pale yellow or ivory. Spiny Sand Stars reach a maximum of 36 cm (14 inches) in diameter.

Spiny Sand Stars are found on, or just under, the surface of sand, mud, and fine gravel substrate. The combination of their pointy tube feet and marginal spines allow this species to move quickly over soft substrates. If turned upside down it can right itself with a flip and if several are stacked on top of each other, they will quickly disperse. They are predatory feeding on the Olive Snail, Olivella biplicata with their diets being supplemented with sand dollars, sea pansies and dead fish. They reside from the very low intertidal zone to depths up to 160 m (525 feet).

The Spiny Sand Star is a resident of all Mexican waters of the Pacific Ocean and are probably the most abundant Sea Star in sandy habitats of Western Mexico.