Spiny Sand Star, Astropecten armatus

The spiny sea star (Astropecten armatus), also known as Estrella de Arena, is a species of sea star that is classified within the Astropectinidae family. This species can be found in the Eastern Pacific Ocean along the coasts of Mexico, with a range that extends from Mexico to California. It prefers a habitat within sandy areas or areas with soft gravel and can be found at depths between 16 and 377 feet.

The spiny sea star can reach an average diameter of seven inches with a small disc shaped body and five thin arms.  The arms often curl at the tips and share a smooth texture with the body. Long, marginal plates extend across these arms, holding spines along the upper and lower sides. The tube feet of this species are pointed and do not hold suckers. It is typically grey, dull pink, or yellow-brown in color on the upper side.

The spiny sea star has a wide range of movement and is said to glide across the sea floor, using the spines that line its tube feet to move swiftly. If an individual becomes turned upside down, it can push itself back up, and if a number of individuals are stacked on top of one another, they can detach themselves quickly. Its main food source is the olive snail, but if other food types such as sand dollars or sea pansies are more abundant, the spiny sea star will readily consume them.

Image Caption: Astropecten armatus at the Birch Aquarium in San Diego, California, USA. Credit: Stickpen/Wikipedia