Pentaceraster
Pentaceraster is a genus of starfish belonging to the family Oreasteridae. They are commonly known as cushion stars and are characterized by their thick, cushion-shaped bodies and five robust arms. These starfish are found in tropical and subtropical waters around the world, inhabiting coral reefs, rocky shores, and sandy bottoms. Their diet consists primarily of algae, detritus, and small invertebrates.
Characteristics
Members of the genus Pentaceraster possess several distinctive characteristics:
- Cushion-shaped body: They have a thick, rounded, and often flattened body, resembling a cushion.
- Five robust arms: Their arms are thick and sturdy, tapering towards the tips. The arms are not distinctly separated from the central disk.
- Spines: The upper surface of their bodies is covered with numerous, short, and blunt spines, which provide protection and help in locomotion.
- Papulae: These are small, fleshy projections on the upper surface, which aid in respiration and gas exchange.
- Pedicellariae: These are tiny, pincer-like structures located on the skin, which help in defense and cleaning.
Environments
Pentaceraster starfish are predominantly found in tropical and subtropical waters, with a preference for shallow reefs, rocky shores, and sandy bottoms. They are often encountered in areas with moderate currents and abundant algae growth. Some species can tolerate varying salinity levels and may inhabit brackish water estuaries.
Diet
Pentaceraster starfish are primarily herbivorous, feeding on algae, detritus, and small invertebrates. They use their strong stomachs to digest food externally, extruding their stomachs onto their prey and absorbing the digested nutrients. Some species may also scavenge for dead animals.