Radiate Phyla II

Chapter 7

Class Cubozoa: Sea wasps and box jellyfishAbout 3 dozen species almost all are tropical.

medusa & polyp body forms thick mesoglea

Unfrilled bell margin drawn inward to form a velum-like structure.

Cubozoan Sensory Structures

Sensory structures called rhopalia.

Cubozoan Sensory Structures

cubozoans have eyes.

The larger regions actually contain lenses, corneas, and retinas.

Nematocysts are concentrated in rings on the tentacles of cubozoans.

Predominantly two species responsible

• The Box Jelly Chironex fleckeri

• Irukandji Carukia barnesi

The Box Jelly Chironex fleckeri

The Box Jelly Chironex fleckeri

Box Jelly Chironex fleckeri

• Box jellies or sea wasps are thought to be responsible for about 65-100 deaths over the past 50 years in Australia.

• The tentacles can be up to 10 feet long.

• In Australia twice as many people die annually from box jellies as from sharks.

• The toxin of most cubomedusan jellies is more potent than cobra venom.

Irukandji Carukia barnesi

Stings have been recorded from Australia, and a similar syndrome has been described elsewhere in the Pacific.

Every summer, more than sixty people are hospitalized with this potentially fatal syndrome.

Cubozoan Life Cycle

• Similar to jellyfish.

Class Anthozoa

• polyp body form ONLY • all marine

Class Anthozoa

• some are colonial colonies are formed of individual zooids

• some are solitary

Class Anthozoa- life cycle

eggsperm

larva

Sexual reproduction

Class Anthozoa- life cycle

asexual reproduction

fission

pedal laceration

fission

Class Anthozoa

Sea anemones

Class Anthozoa

                                                 

Soft Corals

Sea pen

Sea pansy

Class Anthozoa

                                                 

                            

Stony Corals

The Corals

• Make up the largest group of Anthozoa

• Colonial

• Secrete skeleton of calcium carbonate– Cup shaped– Polyp is fixed to this

Theca

Sclerosepta

Ctenophorescomb jellies

• Solitary

• All marine

• Sexual reproduction

Ctenes of comb row

Feeding

• Feed with specialized cells called colloblasts or lasso cells.

• A few species have cnidocytes.

Colloblasts on ctenophore tentacles

colloblasts

Kleptocnidae

Ph. Ctenophora

Coeloplana sp. Cestus sp.

Cl. Nuda

Pleurobrachia sp.

Deiopea kaloktenota

ctene row

Cl. Tentaculata

Bioluminescence

• Produce light using photocytes

• Located in the walls of the digestive system

• Appears that light is coming from comb rows

• NOT all produce luminescence

Big Picture

• The radiate phyla are the first (i.e. basal) Metazoans

• Most have a dimorphic life cycle

• Specialized structures the Cnidocytes

• Some such as corals secrete a calcium carbonate base

• Ctenophores produce bioluminescence