Solasteridae
Solasteridae is a family of sea stars, also known as starfish, belonging to the order Valvatida. This family comprises about 120 species, commonly referred to as sun stars due to their distinctive star-shaped bodies with numerous arms.
Characteristics
Solasterids are characterized by their radial symmetry, with a central disc and multiple arms radiating outwards. The number of arms can vary greatly, ranging from 6 to 24, and they often have a slightly flattened, disk-shaped body. Their arms are usually slender and taper towards the tips. Their aboral surface (upper surface) can have a variety of textures and colors, often exhibiting a star-like pattern. Their oral surface (underside) is typically covered with numerous tube feet that help them move and feed.
Environments
Solasterids are found in a variety of marine environments, primarily in cold, temperate waters. They are often encountered on rocky shores, kelp forests, and soft sediment bottoms. Some species can be found at depths exceeding 1000 meters. Their distribution is largely restricted to the Northern Hemisphere, with species found in the Atlantic, Pacific, and Arctic Oceans.
Feeding
Most Solasterids are carnivorous, feeding mainly on other invertebrates such as sea urchins, mollusks, and other starfish. They use their numerous arms and tube feet to capture prey and bring it to their mouths. Some species may also be opportunistic feeders, scavenging on dead animals.
Reproduction
Solasterids reproduce sexually, releasing eggs and sperm into the water column. Fertilization occurs externally, and the resulting larvae develop into free-swimming planktonic organisms before settling on the seafloor and transforming into adult starfish.
Notable Species
- Solaster dawsoni (Dawson's sun star): Found in the northeastern Pacific Ocean.
- Solaster endeca (Eleven-armed sun star): Found in the northeastern Pacific Ocean.
- Solaster papposus (Common sun star): Found in the northeastern Atlantic Ocean.