Definition of echinoderm Echinoderm

e•chi•no•derm

We found 7 definitions of echinoderm from 6 different sources.

What does echinoderm mean?

WordNet

Noun Plural: echinoderms
echinoderm - marine invertebrates with tube feet and five-part radially symmetrical bodies
		invertebrate any animal lacking a backbone or notochord; the term is not used as a scientific classification
		echinodermata, phylum echinodermata radially symmetrical marine invertebrates including e.g. starfish and sea urchins and sea cucumbers
		water vascular system system of fluid-filled tubes used by echinoderms in locomotion and feeding and respiration
		ambulacrum one of the five areas on the undersurface of an echinoderm on which the tube feet are located
		sea star, starfish echinoderms characterized by five arms extending from a central disk
		brittle-star, brittle star, serpent star an animal resembling a starfish with fragile whiplike arms radiating from a small central disc
		basket fish, basket star any starfish-like animal of the genera Euryale or Astrophyton or Gorgonocephalus having slender complexly branched interlacing arms radiating from a central disc
		sea urchin shallow-water echinoderms having soft bodies enclosed in thin spiny globular shells
		crinoid primitive echinoderms having five or more feathery arms radiating from a central disk
		holothurian, sea cucumber echinoderm having a flexible sausage-shaped body, tentacles surrounding the mouth and tube feet; free-living mud feeders

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Wiktionary

echinoderm (Noun)
Any member of the Echinodermata, a group of radially symmetric, spiny-skinned marine animals. Examples of echinoderms include seastars, sea urchin s, sea cucumber s, crinoids, and sand dollar s.

Webster DictionaryWebster's Unabridged Dictionary 📘

echinoderm (n.)
One of the Echinodermata.

OmegaWiki DictionaryOmegaWiki Dictionary Ω

echinoderm
Marine coelomate animals distinguished from all others by an internal skeleton composed of calcite plates, and a water-vascular system to serve the needs of locomotion, respiration, nutrition or perception.
echinoderm
A phylum of marine animals found at all ocean depths. The phylum appeared near the start of the Cambrian period, and contains about 7,000 living species,

Wikipedia

Echinoderms are a phylum (group) of animals that one can find at all depths of the oceans.

Extinct forms known from fossils include blastoids, edrioasteroids, and several early Cambrian animals such as "Helicoplacus", carpoids, Homalozoa, and eocrinoids such as "Gogia".

Echinodermata is the largest animal phylum which has no freshwater or terrestrial representatives. (no animals in this group live on land or in not-salty water)

Physiology.

Echinoderms evolved from (started out as) animals with bilateral symmetry; later forms were lopsided. Echinoderms' larvae (babies) are ciliated free-swimming organisms that organize in a bilaterally symmetric fashion that makes them look like embryonic chordates. Later, the left side of the body grows at the expense of the right side, which is eventually absorbed. The left side then grows in a pentaradially symmetric fashion, in which the body is arranged in five parts around a central axis (point). (This means they often look like stars.)

All echinoderms exhibit fivefold radial symmetry in portions of their body at some stage of life, even if they have secondary bilateral symmetry. They also have a mesodermal endoskeleton (bones on the outside of their body) made of tiny calcified plates and spines, that forms a rigid support contained within tissues of the organism; some groups have modified spines called pedicellariae that keep the animal free of debris (dirt).

Echinoderms possess a hydraulic water vascular system, a network of fluid-fil