Siderastreidae

Siderastreidae is a family of sea stars, also known as starfish, belonging to the order Valvatida. They are characterized by their unique, star-shaped body plan and are found in various marine environments, including coral reefs and rocky shores. The family includes several genera, with the most well-known being Sideraster, which is often referred to as the "sand dollar" due to its flattened, disc-like shape and the presence of tube feet that allow it to move across sandy substrates.

Members of the Siderastreidae family are typically small to medium-sized, with diameters ranging from a few centimeters to about 20 centimeters. They have a central disc surrounded by five or more arms, which can be flexible or rigid depending on the species. The tube feet, which are used for locomotion and feeding, are located on the underside of the arms and are often covered by a thin, translucent skin.

Siderastreidae sea stars are known for their ability to change color, which is thought to be a form of camouflage or communication. They are also capable of regenerating lost arms, a trait that is common among sea stars. The family is found in tropical and temperate waters around the world, with the highest diversity of species in the Indo-Pacific region.

The taxonomy of the Siderastreidae family is still a topic of ongoing research, and new species are occasionally described. The family is an important component of marine ecosystems, playing a role in nutrient cycling and serving as a food source for various marine animals. Despite their ecological significance, many species of Siderastreidae are threatened by habitat destruction and overfishing, highlighting the need for conservation efforts to protect these unique and fascinating marine organisms.