Phylum EchinodermataPhylum Echinodermata

Starfishes, sea urchins, sea Starfishes, sea urchins, sea cucumberscucumbers

Higher ClassificationHigher ClassificationEchinodermataEchinodermata

Class Asteroidea – sea starsClass Asteroidea – sea stars Class Ophiuroidea – brittle starsClass Ophiuroidea – brittle stars Class Echinoidea – sea urchinsClass Echinoidea – sea urchins Class Holothuroidea – sea cucumbersClass Holothuroidea – sea cucumbers Class Crinoidea – sea feathersClass Crinoidea – sea feathers

General CharacteristicsGeneral Characteristics

Exclusively MarineExclusively Marine Body unsegmented Body unsegmented Adults with pentamerous secondary Adults with pentamerous secondary

radial symmetryradial symmetry Larvae bilaterally symmetricalLarvae bilaterally symmetrical With unique water vascular systemWith unique water vascular system

Larval Echinoderms showing Larval Echinoderms showing bilateral symmetrybilateral symmetry

Water Vascular SystemWater Vascular System

First phylum with internal skeletonFirst phylum with internal skeleton With dermal calcareous ossiclesWith dermal calcareous ossicles Some with spines or spiculesSome with spines or spicules

Digestive system completeDigestive system complete Respiration by dermal branchae, tube feet, Respiration by dermal branchae, tube feet,

or respiratory treeor respiratory tree No kidneysNo kidneys DioeciousDioecious Locomotion by tube feet, and/or armsLocomotion by tube feet, and/or arms

General Characteristics General Characteristics cont.cont.

External AnatomyExternal Anatomy

Internal AnatomyInternal Anatomy

Brittle star anatomyBrittle star anatomy

Anatomy of a Sea UrchinAnatomy of a Sea Urchin

Aristotle’s LanternAristotle’s Lantern

Sea Urchin AnatomySea Urchin Anatomy

AsteroideaAsteroidea

OphiurodeaOphiurodea

EchinoideaEchinoidea

HolothuroideaHolothuroidea

CrinoideaCrinoidea