Class Cubozoa - jan.ucc.nau.edu

Class Cubozoa
Cnidarian
Phylogeny:
Continued
Class Cubozoa
Seem Intermediate
between Hydrozoa
and Scyphozoa:
Chironex fleckeri –
the sea wasp
Class Cubozoa
Class Cubozoa
Similar to
Hydromedusae:
1. Small medusae,
simple bell margin
2. 4 tentacles or
tentacle clusters
3. Velum like structure
- velarium - fast
swimmers
Class Cubozoa
Similar to
Scyphomedusae:
Unique
Characteristics:
1. Gastric septa,
filaments.
1. cubic shape - hence
the name.
2. Marginal nervous
tissue.
2. lenses on rhopalia.
3. Gonads in
gastrodermis.
a. appear to have acute
sensitivity to light
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Class Cubozoa
Class Cubozoa
Reproductive cycle
Unique
Characteristics:
a. no strobila - instead
polyplanulation
b. are active
swimmers and
predators.
b. sea wasps copulate
c. How do they
copulate?
c. extremely
toxic venom in
nematocysts.
Very carefully!
Class Anthozoa
1.Over 6,000
species, 3
subclasses.
Anthozoan Apomorphies
1. (10) loss of
medusoid life
stages
2. Extremely
successful – in
biomass and in
numbers of
species.
Anthozoan Apomorphies
2. (11)
development
of complex
symmetry.
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Class Anthozoa
2. (11) development of
complex symmetry.
a.Hexaradial multiple of 6.
b. Octoradial multiples of 8.
Class Anthozoa
Anthozoan Apomorphies
3. (12)
Evolution of
actinopharynx
(stomadaeum)
4. (13)
Evolution of
syphonoglyph.
Anthozoan Apomorphies
5. (14)
Mesentarial
filaments.
Class Anthozoa
5. (14) Mesentarial
filaments.
Class Anthozoa
5. The context for
evolution of
actinopharynx,
siphonoglyph and
mesenteries:
Allows
exploitation of
larger food items.
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Anthozoan Apomorphies
Class Anthozoa
6. (15-18)
Modifications of
cnidae.
6. (15-18)
Modifications
of cnidae.
Class Anthozoa
General
Characteristics:
7. internal or external
skeletons
8. All cnidaria are
carnivores
a. some have
photosynthetic
symbionts
Anthozoa: Body Form
Complexity of
GVC:
1. Great increase in
internal surface area.
a. Increased
absorptive capacity.
b. Exploitation of
larger prey; larger
size.
2. Nematocysts in
septa (acontia) assist
this.
Spirocysts are adhesive
in nature.
Ptychocysts occurr only
in the Ceriantharia;
their function is to
entangle bits of mud to
form the tube of these
burrowing animals.
Anthozoa: Body Form
Structure typical of
Metridium:
a. Extensive nerve net
- capable of
coordinated
movement, preception.
1. Despite the fact that
CNS is absent.
a. Evasive behavior
b. Preferrence for
certain substrates
c. aggressive
behavior.
Anthozoa: Body Form
Complexity of GVC:
3. A trade off:
Osmoregulation is
difficult; perhaps
explanation for
exclusive marine
existence.
a. Siphonoglyph circulates water into
and out of GVC.
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Anthozoa: Reproduction
Also polyp extrusion,
Particularly in massive Scleractinia.
Similar to Hydra:
1. Egg+sperm ->
planula -> polyp.
2. Some species
brood.
3. Most (all)
capable of asexual
reproduction –
fission.
Anthozoa: Important Groups
Subclass
Zoantharia
(hexacorals)
1. sea anemones,
tube anemones,
stony corals and
black corals.
2. tentacles in
multiples of 6.
3. exoskeletons if
present.
Subclass Zoantharia
Order
Actinaria –
a. larger
solitary
anemones.
b. Two
siphonoglyphs,
hexamerous.
c. Metridium.
Anthozoa: Reproduction
Subclass Zoantharia
Order Zoanthidia a. small, one
siphonoglyph
b. Zoanthus
c. Palythoa
Subclass Zoantharia
Order
Scleractinia
a. stony corals,
colonial,
hexamerous
tentacles
b. Fungia,
Porites,
Acropora,
c. Hexagonaria
(Petoskey stone)
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