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Echinodermata Gr : spine skin 6500 spp all marine except for few estuarine, none freshwater 1) pentamerous radial (adults) *larvae bilateral symmetrical 2) spines

3) mesodermally-derived

ossicles plates

up to 95% CaCO3, up to 15% MgCO3, salts, trace metals, small amount of organic materials

4) (WVS) 5) (podia)

Unicellular (acellular) Multicellular (metazoa)

protozoan

Poorly defined Diploblastic tissue layers Triploblastic Porifera

Uncertain Acoelomate Coelomate Pseudocoelomate

Priapulida Rotifera Platyhelminthes Nematoda Gastrotricha Rhynchocoela () Gnathostomulida

Protostomes Uncertain (misfits) Annelida Echinodermata Brachiopoda Hemichordata Arthropoda Phoronida Chordata Pogonophora

1 Chapter 14: Echinodermata

Classes: 1) Asteroidea (Gr: characterized by star-like) 1600 spp 2) Ophiuroidea (Gr: snake-tail-like) 2100 spp 3) Echinoidea (Gr: -form) 1000 spp

4) Holothuroidea (Gr: -like) 1200 spp

5) Crinoidea (Gr: lily-like) stalked – 100 spp nonstalked, motile comatulid (feather stars)- 600 spp

Asteroidea sea stars/

arms not sharply marked off from central star shaped disc

spines fixed

pedicellariae

ambulacral groove open

tube feet with suckers on oral side

/ aboral

2 Figure 22.01

Pincushion star, navaeguineae, preys on polyps, small organisms &

Choriaster granulatus scavenges dead on shallow Pacific reefs

Crown-of-thorns star, planci On the Great Barrier , Tosia queenslandensis forages on browses encrusting organisms

0116.jpg

3 0117.jpg

Figure 22.02a

4 Figure 22.02b

Figure 22.03a

5 Figure 22.03b

Figure 22.03c

6 Figure 22.04

Pedicellaria

Pedicellariae

Figure 22.06

pyloric

this lower stomach everted out during

7 Figure 22.05

Orthasterias koehleri eating a clam Sun star, Pycnopodia helianthoides (with 20-24 arms) eating

Pacific sea star, luzonicus:

8 Ophiuroidea /

arms separate from star shaped central disc spines on arms tube feet without suckers not used for locomotion used for feeding brittle star, Ophiura lutkeni no pedicellariae no anus ambulacral groove closed & covered by ossicles

basket star, muricatum

Figure 22.11

9 Figure 22.12

Figure 22.13

Brittle star, aculeata Basket star, Gorgoncephalus eucnemis Note swollen bursae & regenerating arms Note pentamerous radial symmetry

10 Echinoidea sea urchins, sea biscuits & sand dollars globular/disc shape endoskeletal ossicles fused no arms

movable spines (ball & socket) pedicellariae (3 jawed)

Sea urchin, purpuratus tube feet with suckers

ambulacral groove closed & covered by ossicles

Sand dollar, Encope

11 Figure 22.18

Figure 22.19

12 Figure 22.17

Heart urchin, Meoma (irregular)

13 sand dollars petuloid burrowing

aboral

oral

Figure 22.15

Ten-lined pencil urchin, Slate-pencil urchin, Colobocentrotus atraus metularia from mammilatus the Red Sea (retain ancestral characters from

Diadema antillarum from magnifica West Indies & Florida

14 Holothuroidea sea cucumber shaped (bilateral symmetrical) endoskeletal ossicles dispersed no arms no spines

no pedicellariae tube feet with suckers ambulacral groove closed & covered by ossicles Parastichopus californicus ossicles

Figure 22.22

15 16 0135.jpg

17 0136.jpg

18 Crinoidea sea lilies/feather stars aboral attachment stalk of dermal ossicles no spines five branching arms with side branches (pinnules)

no pedicellariae

ciliated ambulacral groove on oral surface

tube feet -like on oral surface for food collecting

anus on oral surface

Figure 22.24

19 feather stars

Class: Concentricycloidea sea daisies: only 2 spp 1 cm diameter 1000 m deep

20 Figure 22.28

Echinoderm Larvae

21 Figure 22.09

early sea star (Asteroidea) late sea star (Asteroidea) brittle star (Ophiuroidea)

sea urchin/ (Echinoidea) (Holothuroidea) Sea lily (Crinoidea)

Importance of I. Developmental sea urchin / à elucidate the jelly membrane surrounding a recently fertilized egg II. keystone

Intermediate Disturbance Hypothesis y t i s r e v i D Forest/ bed Communities

Disturbance sea stars/sea urchins

22 Figure 22.34

23