006 cnidarian diversity

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Cnidarian Diversity


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Phylum Cnidaria

Class

Anthozoa

Class

Hydrozoa

Class

Scyphozoa

Class

Cubozoa

Corals

Anemones

Hydra

Portuguese Man-Of-War

Stinging Limu

Fire Coral

True jellyfish Box jellies

Sea wasps


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Class

Anthozoa

Subclass

Hexacorallia

Order

Antipatharia

Subclass

Alyconaria

Order

Zoanthidae

Order

Actinaria

Order

Scleractinia

Zoanthids Sea anemones Stony corals Precious black coral

Wire coral

Sea fans

Sea whipsSea pens

Organ pipe coral

Precious gold coral


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General Characteristics of Cnidaria

Stinging cells

Two stages in life cycle (polyp & medusa)

Blind sack gut

Radial symmetry Diploblastic

Hydrostatic skeleton

Nerve net Many colonial, some solitary forms


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polyps and medusa stage, although polyp stage isdominant.

gut cavity of polyp is simple, lacking a pharynx and notdivided by mesenteries.

tetramerous (four-part) radial symmetry. gonads are ectodermal (found in the epidermis).

medusa stage may possess specialized balance organscalled statocysts and photosensitive organs called ocelli.

solitary or colonials; some colonial forms highlypolymorphic.

includes hydroids (stinging limu), fire coral, pink coral, andsiphonophores.

Class Hydrozoa(Gr. hydra, water serpent)


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The Cnidarian Life Cycle

The HydrozoanLife Cycle


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Hydrozoan Colony


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Hydrozoan Colonies

Stinging Limu


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Hydrozoan Medusa


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Hydrozoan Medusa


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Hydrocorals


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Fire Coral


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By-the-Wind-Sailor

A Floating Colony of Polyps


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ColonialityMan-of-War

Phylum Cnidaria


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Close Up of a

Portuguese Man-Of-War


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life cycle with both polyps and medusae, but medusae dominate

with polyp stage reduced or absent.

polyp stage (scyphistoma) goes through strobilization to produce

young medusa.

bell margin lacks a velum.

tetramerous (= four-part) radial symmetry.

gut divided into a complex system of radial canals.

some with a simple single mouth, but many with thousands of

microscopic mouths at the ends of oral arms.

gonads endodermal (found in the gastrodermis).

specialized sense organs called rhopalia with ocelli & statocysts .

includes some 200 marine species.

"true" sea jellies.

Class Scyphozoa(Gr. skyphos, cup)


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planula

scyphistomastrobila

ephyra

adult medusa

gametes

Scyphozoan Life Cycle

strobila scyphistoma


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Sea Jellies


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Moon JellyAnatomy


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polyps and medusae stages, but medusae dominatewith polyp stage reduced.

polyp stage develops directly into medusa.

bell margin with a velarium.

tetramerous (= four-part) radial symmetry; bell cube-shaped with tentacles arising from each corner.

gonads endodermal (found in the gastrodermis).

specialized sense organs called rhopalia with ocelli &statocysts .

includes some 15 marine species.

includes box jellies and sea wasps.

Class Cubozoa(Gr. kybos, a cube)


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Box Jellies

Seawasp


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Box Jelly Anatomy


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lack medusa stage entirely (polyp forms only)

mouth with a tubular pharynx that projects inwardinto the gut

large gut cavity divided by mesenteries that radiate

inwards from the body wall gonads endodermal, borne on the mesenteries

hexamerous (6-part) or octamerous (8-part) radialsymmetry or biradial (modified radial symmetry thatlimits the number of planes that can divide the bodyinto equal halves

includes sea anemones, true stony corals, seafans, sea pens, organ pipe coral, precious blackcoral, & zoanthids

(Gr. anthos, flower)

Class Anthozoa

S


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Subclass Zoantharia

Order Actinaria

Sea Anemones


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Sea Anemone Anatomy


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Subclass Hexacorallia

Order Zoanthidae

No hard skeleton

May be tough and leathery

Shallow water forms Encrusting forms

Some with zooxanthellae

Polyp stage only


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Order Antipatheria

Black Coral & Wire Coral

Wire coral

Black coral


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Order Scleractinia

True Stony Corals

Hermatypic- reef building, zooxanthellae

Common species: Acroporidae- table

Acroporidea- rice

Agariciidae- flat lobe, corrugated

Faviidae- crust, ocellated Fungiidae- humpback, mushroom

Pocilloporidae- lace, antler, cauliflower

Poritidae- finger, lobe, plate

T St C l


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True Stony Coralslobe

finger

mushroom

Pori tes rus

S b l Al i
http://www.coralreefnetwork.com/stender/corals/lobe/por-rus2.jpghttp://www.coralreefnetwork.com/stender/corals/lobe/por-rus2.jpg


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8 branched tentacles surrounding the mouth

Both hard and soft forms exist

Ahermatypic- non reef building, no

photosynthesis

Five Orders found in Hawaii:

1. Stolonifera

2. Pennatulacea (sea pens)3. Alcyonacea (soft corals)

4. Telestacae (snowflake corals)

5. Gorgonacea (sea fans)

Subclass Alyconaria

Octocorals


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Octocorals

Sea pen


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Organ pipe coral

006 cnidarian diversity

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