Spinulosida
Spinulosida is an order of sea stars within the class Asteroidea. It consists of around 1,000 species in 25 families, making it the most diverse order of starfish. They are found in a wide variety of marine environments, from shallow intertidal zones to the deep sea. Spinulosida is a relatively modern order, with the first species being described in the 19th century.
Common Names
The order Spinulosida has no common name, but the species within the order are often referred to as spiny sea stars or spiny starfish due to their characteristic spiny skin.
Characteristics
Members of Spinulosida are characterized by a variety of features, including:
- Spiny skin: As the name suggests, these sea stars have a spiny, often rough, skin. These spines can be small and inconspicuous, or large and prominent, depending on the species.
- Variable body shape: The body shape of Spinulosida is highly variable, ranging from the typical five-armed star to species with more elongated arms or even disc-shaped bodies.
- Pedicellariae: Spinulosida possess pedicellariae, small pincer-like structures on the surface of their bodies. These structures serve to help the sea star defend itself and keep its body clean.
- Variety of feeding mechanisms: Spinulosida includes species that are carnivorous, omnivorous, or even suspension feeders.
Environments
Spinulosida are found in a wide range of marine environments, including:
- Intertidal zones: These are the areas along the coast that are exposed to the air during low tide and submerged during high tide.
- Subtidal zones: These are the areas of the ocean that are always submerged.
- Deep sea: Some species of Spinulosida are found in the deep sea, where they live in environments with high pressure and low light.
References
For more information on Spinulosida, you can refer to these reliable resources: