Stelleroidea refers to a taxonomical group within the animal kingdom that includes a diverse range of organisms commonly known as starfish or sea stars. They belong to the phylum Echinodermata, which also comprises other marine animals such as sea urchins, sand dollars, and sea cucumbers. Stelleroidea is distinguished by its characteristic radial symmetry, with a central body disc and multiple arms extending from it.
Starfish typically exhibit a five-pointed symmetry, but some species may have more arms, ranging from five to over fifty, depending on the species. The arms, also referred to as rays, are typically flexible and contain an intricate network of hydraulic canals that help with movement, feeding, and respiration. These animals are found in various marine habitats, including rocky shores, tide pools, coral reefs, and even deep oceanic environments.
Stelleroidea species have a unique water vascular system, which is responsible for their movement and feeding. Within this system, seawater is circulated through a series of tubes called the tube feet, using hydraulic pressure. This enables starfish to move and grip onto surfaces, as well as capture their prey, which mainly consists of mollusks and crustaceans.
Starfish possess a regenerative ability, allowing them to regrow lost arms or damaged body parts. Moreover, some species are capable of asexual reproduction, where a detached arm or part of the central disc can regenerate into a complete individual.
Overall, Stelleroidea is a diverse group of marine organisms known for their striking star-like appearance, radial symmetry, and unique water vascular system. They play significant roles in marine ecosystems as predators, recyclers, and contributors to biodiversity.
