ECHINODERMATA

Was auf diesem Rad steht (24 Optionen)

• Presence of calcareous endoskeleton
• Deuterostomes with modified radial symmetry
• Cephalization mostly absent –no anterior or posterior part, Parts are designated as oral (area where the mouth is) or aboral (area away from mouth)
• Typically with five arms arranged around a central disk
• Presence of five (or multiple of 5) arms originating from a central disc
• The madreporite is located near one of the jaw plate
• Multigene inversion of the mitochondrial DNA
• Spherical (regular urchins) or disk shaped (irregular urchins) body covered in test made from overlapping ossicles (skeletal plates)
• The central disk is sharply marked off from the arms
• Podia passes through the ambulacral plates
• With pedicellaria
• Includes the sea stars (formerly class Asteroidea)and brittle stars (formerly class Ophioroidea)
• Stalked species is composed of the stem, calyx and arms
• Presence of shields protective calcareous plate made of single calcite crystal
• Presence of Aristotle’s Lantern –a system of ossicles and muscles which protrude from the mouth for feeding
• Gonads and part of the digestive system extends into the arms (pyloric caeca)
• Can be attached to substrate by a stalk(Sea lilies –with columnalsor calcareous disc in the stalk) or unstalked forms (Feather stars –with cirri or grasping claws)
• Predatory on bivalves and other echinoderms
• Defense mechanism includes Cuvierian tubules (sticky or toxic structures) or by completeevisceration= ejecting its internal organs
• Cucumber-shaped
• No arms
• With U shaped gut where the anus is located near the mouth
• With respiratory trees highly branched muscular respiratory structures
• With eversible stomach