2. Phylum Echinodermata

3. End show End show Jenna Hellack Fall 2000 Echinodermata l Bilateral larvaeradial adults l Bilateral larvae, radial adults. five symmetrical radiating areas l Body surface with five symmetrical radiating areas (ambulacra). l Water-vascular system l Water-vascular system. pedicellariaTiedemanns l Often with pedicellaria and Tiedemanns bodies. calcareous plates l Endoskeleton of calcareous plates. Mutable” connective tissue l “Mutable” connective tissue. Connective tissue can rapidly polymerize from stiff and hard to soft gel and vise versa. l Systems Systems l Taxonomy Taxonomy

4. End show End show Jenna Hellack Fall 2000 Systems l Integumentary l Integumentary - thin epidermis l Skeletal l Skeletal - Mesodermal endoskeleton of calcareous plates (movable or fixed) l Water vascular system- l Water vascular system- derived from coelomic pouches. l Nervous net l Nervous - a diffused net typically of three rings centered on mouth region with radiating branches. l Excretory l Excretory - isotonic, some use of amoebocytes from Tiedemann bodies.

5. End show End show Jenna Hellack Fall 2000 Systems continue l Respiratory l Respiratory - skin gills (dermal branchiae or papulae from coelom) cloacal respiratory trees in Holothuroidea. l Digestive complete l Digestive - usually complete with anus on aboral surface. Some (Echinoidea) with mouth parts. Most use water vascular system to procure food. l Circulatory- l Circulatory- in general no special system, use the water vascular system and the coelom. l Reproductive l Reproductive - Sexes usually separate, no dimorphism. Fertilization usually in the sea. Larva bilateral and usually free swimming. Many readily regenerate body parts.

6. End show End show Jenna Hellack Fall 2000 Echinodermata Taxonomy Crinoidea Crinoidea l Class: CrinoideaCrinoidea Holothuroidea Holothuroidea l Class: HolothuroideaHolothuroidea Echinoidea Echinoidea l Class: EchinoideaEchinoidea Ophiuroidea Ophiuroidea l Class: OphiuroideaOphiuroidea Asteroidea Asteroidea l Class: AsteroideaAsteroidea  Asterias dissection Asterias dissection Asterias dissection

7. End show End show Jenna Hellack Fall 2000 Class Crinoidea l Sea lilies and feather stars  Arms branched attached by a stalk or free-moving. The mouth and anus on oral surface. No spines, madreporite or pedicellariae. fossils Return to Taxonomy Return to Taxonomy

8. End show End show Jenna Hellack Fall 2000 Class Holothuroidea l Sea cucumbers  Elongated body with no arms, spines, or pedicellariae. Skeleton only of microscopic plates mouth ringed by retractile tentacles(modified tube feet). Pedicellariae absent, madreporite internal. Return to Taxonomy Return to Taxonomy

9. End show End show Jenna Hellack Fall 2000 Class Echinoidea l Sea urchins and sand dollars  Skeleton rigid (plates fused), mouth parts present, pedicellariae with 3-jaws. Spines movable. Ambulacral grooves closed. Return to Taxonomy Return to Taxonomy aboral surface oral surface endoskeleton Aristotle’s lantern Sea urchin Sand dollar Sea biscuit aboral oral Mouth parts

10. End show End show Jenna Hellack Fall 2000 Class Ophiuroidea l Brittle stars and basket stars  Arms distinct from central disc. Ambulacral grooves closed, tube fee without suckers (not used in locomotion). Pedicellariae and anus absent. Return to Taxonomy Return to Taxonomy Basket star Aboral surface Oral surface

11. End show End show Jenna Hellack Fall 2000 Class Asteroidea l Sea stars and starfish  Arms are not sharply distinct from central disc. Ambulacral grooves open, tube feet with suckers, pedicellariae present. Return to Taxonomy Return to TaxonomyAsteriasdissection Aboral surface Oral surface Aboral surface

12. End show End show Jenna Hellack Fall 2000 Asterias dissection 1 Oral surface Aboral surface Return to Taxonomy Return to Taxonomy

13. End show End show Jenna Hellack Fall 2000 Asterias dissection 2 l Aboral surface removed. Return to Taxonomy Return to Taxonomy

14. End show End show Jenna Hellack Fall 2000 Asterias dissection 3 l Aboral surface removed. Return to Taxonomy Return to Taxonomy

15. End show End show Jenna Hellack Fall 2000 Asterias dissection 4 l Aboral surface, stomachs and some pyloric caeca removed Return to Taxonomy Return to Taxonomy

16. End show End show Jenna Hellack Fall 2000 Asterias dissection 5 l Aboral surface, stomachs and some pyloric caeca removed End of dissection Return to Taxonomy Return to Taxonomy