The first definitive echinoderms appeared near the start of the Cambrian. Echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the …

Echinoderm, any of a variety of invertebrate marine animals belonging to the phylum Echinodermata, characterized by a hard, spiny covering or skin. Living species include sea lilies, sea urchins, sea …

Echinoderms possess an unusual suite of appendages on their skeletons, which are used for movement, interaction, and defense. In addition to spines, urchins and sea stars both possess …

Jun 30, 2025 · Echinoderms are spiny-skinned invertebrates of the phylum Echinodermata, specifically recognized by the pentamerous body (five-pointed) symmetry in adults. The phylum derives its name …

Echinoderms include several familiar organisms such as starfish (or sea stars), sea urchins, sand dollars, sea cucumbers, and brittle stars. These animals are found in oceans worldwide, from shallow …

Whereas five major groups of echinoderms are living today (starfish, brittle stars, sea urchins, sea cucumbers, and sea lilies), more than 20 other, equally distinctive extinct echinoderms groups lived …

Aug 4, 2025 · Echinoderms are a group of marine invertebrates found across all the world’s oceans, from shallow coastal waters to the deepest abyssal plains. These organisms contribute significantly …

Feb 6, 2024 · Echinoderms are a group of animals that include starfish, sea urchins, sea cucumbers, brittle stars, sea lilies and feather stars. On this page is a complete guide to echinoderms, with …

Aug 26, 2010 · Perhaps the best-known echinoderms are members of the class Asteroidea, or sea stars. They come in a large variety of shapes, colors, and sizes, with more than 1,800 species known.

Echinoderm - Radial Symmetry, Tube Feet, Spines: Echinoderms have a skeleton composed of calcium carbonate (calcite). Living echinoderms have a conspicuous five-rayed, radial symmetry that masks …