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 …

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 …

Dec 25, 2025 · Echinoderms are a diverse group of invertebrate marine animals that include starfish, sea urchins, sand dollars, sea cucumbers, and crinoids. The phylum contains about 7,000 living …

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 …

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 …

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 …

Echinoderms are an exclusively marine phylum with four distinctive characteristics: Echinoderms use a water vascular system for moving, feeding and respiration. They have a skeletal system made of limy …

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.

Oct 4, 2019 · An echinoderm is a member of the phylum Echinodermata which contains a number of marine organisms recognized by their pentamerous radial symmetry, calcareous endoskeleton, and …