AsteroideaStarfish or sea stars are star-shaped Echinoderms that belong to the class Asteroidea. There are About 1,500 species of starfish and they can be found on the seabed in all of the world's oceans. From the tropics to frigid polar waters, they are found from the intertidal zone down to abyssal depths, 20,000 ft below the surface.
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Skeletal Structure
Starfish are marine invertebrates usually known to have a central disc and five arms, although some species have a larger number of arms. The aboral or upper surface may be smooth, pointy, or covered with overlapping plates. Many species are brightly colored in vibrant shades of red, blue or orange, while others are dull with colors like grey or brown. Starfish have tube feet and a mouth at the center of their body. They are opportunistic feeders and are mostly predators to other invertebrates. They have the body parts needed so they can reproduce both sexually and asexually. Most Asteroidea can regenerate damaged parts of their body's including lost arms and they can shed them as a type of defense.
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