EchinodermsEchinoderms

““Spiny Skinned Animals”Spiny Skinned Animals”

Spiny skinned because of the Spiny skinned because of the calcium carbonate internal calcium carbonate internal skeletonskeleton

Echinoderm CharacteristicsEchinoderm Characteristics• Radial Symmetry (aboral and oral Radial Symmetry (aboral and oral

sides)sides)• All marineAll marine• Most pentamerousMost pentamerous• No heart, gills, lungs, brain, or eyesNo heart, gills, lungs, brain, or eyes• Nutrients and gases transported in Nutrients and gases transported in

fluid that fills body cavityfluid that fills body cavity• Water vascular systemWater vascular system• Calcium carbonate internal skeletonCalcium carbonate internal skeleton• Nervous system is simple nerve netNervous system is simple nerve net

Sides of the Sides of the EchinodermEchinoderm

Oral Side: Oral Side:

• mouthmouth• ampullae- ampullae- store store

waterwater

• ambulacral grooveambulacral groove

• tube-feettube-feet

Aboral Side:Aboral Side:• pedicellariae-pedicellariae-

pincherspinchers

• anusanus• Madreporite-Madreporite-water water

openingopening

Oral SideOral Side

Ampullae

Tube Feet

Aboral Aboral SideSide

Pedicellariae(all over surface)

Pedicellariae: tiny pinchers Pedicellariae: tiny pinchers amongst the spines to help amongst the spines to help keep off parasites & catch bits keep off parasites & catch bits of foodof food

Water Vascular System Water Vascular System (WVS)(WVS)• Hydraulic system containing Tube Hydraulic system containing Tube

Feet, attached to appullae which Feet, attached to appullae which store water for the WVS.store water for the WVS.

• Used for:Used for:

locomotionlocomotion

attachmentattachment

sensationsensation

feedingfeeding

gas exchangegas exchange

Water Vascular SystemWater Vascular System

Madreporite

Ring Canal

Radial CanalWith Ampullae

Water Vascular SystemWater Vascular System

Water Vascular System Water Vascular System Tube FeetTube Feet

Tube feet and ampullaTube feet and ampulla

FeedingFeeding• Some carnivorous (sea stars)Some carnivorous (sea stars)

• Some detritus foragers ( urchins & sea Some detritus foragers ( urchins & sea cucumbers)cucumbers)

• Some planktonic feeders (feather stars Some planktonic feeders (feather stars and basket stars)and basket stars)

• Many have mouth on oral surface and Many have mouth on oral surface and anus on aboral surface. Sea stars can anus on aboral surface. Sea stars can extend stomach out of mouth and extend stomach out of mouth and engulf and digest preyengulf and digest prey

• Sea cucumbers can eviscerate gutSea cucumbers can eviscerate gut

Sea Star feeding on clamSea Star feeding on clam

ReproductiReproductionon

• The sexes are separate in mostThe sexes are separate in most

• Many release sperm and egg into waterMany release sperm and egg into water

• Most form pelagic bilaterally symmetrical Most form pelagic bilaterally symmetrical larvaelarvae

• Asexual reproduction and RegenerationAsexual reproduction and Regeneration

Sexual ReproductionSexual Reproduction Fertilization produces pelagic planktonic Fertilization produces pelagic planktonic larvaelarvae

Brittle Star Larvae

Sea Urchin Larvae

Sea Star Larvae

Asexual Reproduction by Asexual Reproduction by regeneration-all you need is regeneration-all you need is one arm & part of the one arm & part of the central disk!central disk!

Echinoderms : Five ClassesEchinoderms : Five Classes

• Feather Stars, sea Lillies (Crinoidea)Feather Stars, sea Lillies (Crinoidea)

• Sea Stars (Astroidea)Sea Stars (Astroidea)

• Brittle Stars, Basket Stars Brittle Stars, Basket Stars (Ophiuroidea)(Ophiuroidea)

• Sea Urchins, heart urchins, sand Sea Urchins, heart urchins, sand dollars (Echinoidea)dollars (Echinoidea)

• Sea Cucumbers (Holothuroidea)Sea Cucumbers (Holothuroidea)

Feather Stars and Sea Lilies Feather Stars and Sea Lilies (Crinoidea)(Crinoidea)

• 600 species600 species

• CrinoidsCrinoids

• Most ancient classMost ancient class

• Mouth open up instead of downMouth open up instead of down

• 5 arms radiate from pentagon 5 arms radiate from pentagon shaped body- arms branch into 10 or shaped body- arms branch into 10 or more armsmore arms

• Tube feet used for filter feedingTube feet used for filter feeding

• Sea lilies found in deeper waterSea lilies found in deeper water

Golden Chrinoid CR-269/355 found on coral Golden Chrinoid CR-269/355 found on coral reefsreefs

Feather StarFeather Star

CR-269/355 here the arms are closed (rolled up) notice the claw-like appendages attaching it to rock

Sea Stars (Asteroidea)Sea Stars (Asteroidea)

• 1500 living species1500 living species

• Usually 5 rays radiating from central Usually 5 rays radiating from central diskdisk

• Many are active carnivoresMany are active carnivores

• Excessive numbers can harm marine Excessive numbers can harm marine ecosystemsecosystems

• Ability to regenerate entire body from Ability to regenerate entire body from one arm and portion of central diskone arm and portion of central disk

West Indian Sea Stars Juvenile and Adult CR-271 / West Indian Sea Stars Juvenile and Adult CR-271 / 367367Shallow sea grass beds and sandy flatsShallow sea grass beds and sandy flats

West Indian Cushion Star in a West Indian Cushion Star in a Turtle Grass bedTurtle Grass bed

West Indian Cushion Star Four Rays OnlyWest Indian Cushion Star Four Rays Only

Cushion star Oral viewCushion star Oral view

West Indian Cushion Star Six RaysWest Indian Cushion Star Six Rays

Seven Ray Cushion StarSeven Ray Cushion Star

Common Comet Stars CR-275/361 found on reef Common Comet Stars CR-275/361 found on reef - notice the different numbers of rays- why the - notice the different numbers of rays- why the name Comet?name Comet?

Two-Spined Sea Star Oral View CR-277/363Two-Spined Sea Star Oral View CR-277/363Notice the ambulacral groove on reach rayNotice the ambulacral groove on reach ray

Two-Spined Sea Star Aboral View most often Two-Spined Sea Star Aboral View most often found on sandy bottoms in shallow waters- often found on sandy bottoms in shallow waters- often burrow into sandburrow into sand

Thorny Sea Stars CR-277/365 found on rock Thorny Sea Stars CR-277/365 found on rock rubble and mangrove roots (same genus as Orange-rubble and mangrove roots (same genus as Orange-ridged sea star)ridged sea star)

Thorny Sea Star often found hiding under rocksThorny Sea Star often found hiding under rocks

Brittle Stars, Basket Stars, Brittle Stars, Basket Stars, Serpent Stars (Ophiuroidea)Serpent Stars (Ophiuroidea)

• Brittle stars are most numerous (2000 Brittle stars are most numerous (2000 species)!!!species)!!!

• Most active echinoderm with swift snake-like Most active echinoderm with swift snake-like movementsmovements

• Under rocks during day & feed on detritus at Under rocks during day & feed on detritus at nightnight

• Usually 5 thin, flexible arms radiate from Usually 5 thin, flexible arms radiate from central diskcentral disk

• Basket stars have complex branched arms used Basket stars have complex branched arms used to catch planktonto catch plankton

Blunt Spined Brittle Star CR-283/373Blunt Spined Brittle Star CR-283/373

Blunt-Spined Brittle StarBlunt-Spined Brittle Star

• CR-283CR-283

Red Brittle Star Red Brittle Star

Banded-Arm Brittle Star CR-285/375Banded-Arm Brittle Star CR-285/375

Sponge Brittle Star (CR 281/371)Sponge Brittle Star (CR 281/371)

Sponge Brittle Star on zoanthid CR-281/371Sponge Brittle Star on zoanthid CR-281/371

Ruby Brittle Star CR-283/373Ruby Brittle Star CR-283/373

Giant Basket Star (closed) CR-287/377Giant Basket Star (closed) CR-287/377

Giant Basket Star (open) open mostly at Giant Basket Star (open) open mostly at night filtering planktonic animalsnight filtering planktonic animals

Sea Urchins, Heart Urchins, Sea Urchins, Heart Urchins, and Sand Dollars (Echinoidea)and Sand Dollars (Echinoidea)

• ““without arms”without arms”• Test: Calcareous plates fused into shell Test: Calcareous plates fused into shell • Often covered with spines- spines often Often covered with spines- spines often

used for locomotion instead of tube feetused for locomotion instead of tube feet• Most hide during day and are more active Most hide during day and are more active

at nightat night• Sand dollars and heart urchins burrow Sand dollars and heart urchins burrow

under the sand during dayunder the sand during day• Most feed on detritus or algaeMost feed on detritus or algae

Diadema Long Spined Sea Urchin CR-287/379Diadema Long Spined Sea Urchin CR-287/379

Rock Boring sea Urchin CR-289/380 Rock Boring sea Urchin CR-289/380 Aboral View - shorter spines- shallow rocky Aboral View - shorter spines- shallow rocky tidal areatidal area

Rock Boring Sea Urchin Oral ViewRock Boring Sea Urchin Oral View

Diadema Rock BoringDiadema Rock Boring

Slate Pencil Sea Urchin CR= 291/385 Slate Pencil Sea Urchin CR= 291/385 found on sea grass beds and reef rublefound on sea grass beds and reef ruble

West Indian Sea Egg CR-293/385 found in West Indian Sea Egg CR-293/385 found in sea grass beds and shallow reefs sea grass beds and shallow reefs

West Indian Sea Egg oral viewWest Indian Sea Egg oral view

Variegated Urchin CR-291/383Variegated Urchin CR-291/383

Red Heart Urchin CR-293/387 hide under Red Heart Urchin CR-293/387 hide under sand during day – when discovered, will sand during day – when discovered, will “jump” out“jump” out

Six-Keyhole Sand Dollar CR-295/389 Six-Keyhole Sand Dollar CR-295/389 covered with short spine “fuzz”covered with short spine “fuzz”

Sea Cucumbers Sea Cucumbers (Holothuroidea)(Holothuroidea)• Elongated soft body – no spinesElongated soft body – no spines• Bilateral symmetryBilateral symmetry• Skeletal plates are very small and Skeletal plates are very small and

buried under leathery body wallburied under leathery body wall• Some have tentacle-like tube feet Some have tentacle-like tube feet

around moutharound mouth• Mouth in front and anus at rearMouth in front and anus at rear• Defense mechanismsDefense mechanisms

Three Rowed Sea Cucumber (CR-297/392)Three Rowed Sea Cucumber (CR-297/392)

Agassiz Sea CucumberAgassiz Sea Cucumber

Florida Sea Cucumber CR-397 found in Florida Sea Cucumber CR-397 found in shallow sand flats and sea grass bedsshallow sand flats and sea grass beds

Donkey Dung Sea Cucumber CR-297/395 Donkey Dung Sea Cucumber CR-297/395 inhabit sandy areas around reefs and sea inhabit sandy areas around reefs and sea grass bedsgrass beds

Behavior

Sea CucumberExpelling CuvierianThreadsDefense Mechanism (actually Part of the animal’s gut

These threads are toxicAnd can be quicklyRegenerated.

Sea Cucumber PoopSea Cucumber Poop

Pearlfish and Sea Cucumbers Pearlfish and Sea Cucumbers have an INTERESTING have an INTERESTING RELATIONSHIPRELATIONSHIP