6. Phylum Ctenophora
What are the 6 synapomorphies of Ctenophora?
1. 8 comb rows of fused cilia 2. Pair of tentacles 3. Colloblast cells on tentacles 4. Biradial symmetry with oral-aboral axis 5. Well- developed mesenchyme 6. Third class of Hox genes
What arises from the pit?
8 meridional comb rows
What defines the order platyctenida? 4
Benthic Most adults lack comb rows Cydippid larva Some reproduce asexually via fragmentation
What special organisms swallows other ctenophores whole?
Beroe
How do Beroe capture their prey?
Cells of mouth edge produce adhesive mucus and toxins
What carries food and mucus to mouth?
Cilia
What defines the order cestida? 4
Compresses, elongated, ribbon-like body 4 comb rows 2 small tentacles Undulatory swimming
What phylum are comb jellies?
Ctenophora
What defines the Order Cydippida? 3
Cydippud larva 2 tentacles with deep sheaths polyphyletic
What defines the order lobata? 3
Flattened body 2 large ciliated oral lobes 2 short non-rectile tentacles
What defines the order Beroida? 5
Flattened thimble-like sac Lacks tentacles Large mouth and pharynx Feed on other Ctenophores Meridional canals highly branched
What is protandric hermaphrodites?
Male when young and then female when older
What is a general description of Ctenophora?
Marine Delicate & gelatinous medusa-like coastal and oceanic
What is the basic structure of ctenophora?
Mouth at oral pole, leads into GVC (complex branching canal system) Anal pore at aboral pole releases both gametes and waste
What is the apical organ?
Pit at aboral pole containing statocyst
How do all of them feed?
Predatory Long tentacle wiped across mouth to remove prey
What is 2 things is special about Ctenophore reproduction?
Protandric hermaphrodites Cydippid larva
What defines the order Thalassocalycida?
Single deep-water medusa-like species
What is special about the cilia on the comb rows?
They are iridescent
What is mesenchyme?
Thick gelatinous mass with fibers, ameboid cells, and network of muscle cells
What are colloblasts?
adhesive club-shaped cells
What can only be used once during feeding?
colloblast cells
What is a statocyst?
how an organism knows its orientation pebble in a fluid
What are lobates?
mucus sheets that trap prey on lobes
What are colloblasts anchored to?
tentacle mesenchyme
What is a cydippid larva?
the larva form looks like the adult form
What is special about the planktonic form?
they bioluminescent
Where do the retractile tentacles arise from?
two deep ciliated sheaths
How do they move?
waves of ciliary beating at aboral end
