Cycliophora

Question 1

characteristics (5)

Answer 1

Tiny, sessile (attached) marine invertebrates found exclusively on the
mouthparts of lobsters.
-
Have a ciliated feeding structure called a buccal funnel used for filter feeding.
-
Exhibits extreme reproductive specialization, with both asexual and sexual
cycles.
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Complex life cycle involving multiple larval forms.
-
Lacks a circulatory and respiratory system, relying on diffusion.

Question 2

body form for adults

Answer 2

Size: Very small (~300–500 µm in diameter).

Question 3

body wall and support

Answer 3

Body Wall: Soft-bodied, covered with a thin cuticle.

Support: No rigid skeleton; maintains shape through body tissues.

Question 4

locomotion (2) and body cavity

Answer 4

Locomotion:
-Sessile; attaches to lobster mouthparts via an adhesive disc.
-Some larval forms are motile, searching for a new host.

Body Cavities: Acoelomate (lacks a true body cavity).

Question 5

feeding/digestion and circulation

Answer 5

Nutrition (Feeding/Digestion):
-Filter feeders, using cilia to sweep food particles into the buccal funnel.
-Digestion occurs in a simple U-shaped gut.

Circulation: No circulatory system; nutrients are distributed by diffusion.

Question 6

excretion and respiration

Answer 6

Excretion (Osmoregulation):
Waste is excreted through diffusion across the body surface.

Gas Exchange (Respiration): Oxygen diffuses through the body wall.

Question 7

nervous system (2)

Answer 7

Simple nerve net with a small brain-like ganglion.

Some larval forms have sensory structures for detecting their
environment

Question 8

reproduction and development (4)

Answer 8

Alternates between asexual budding and sexual reproduction.
●
During asexual reproduction, new feeding individuals (clones) grow
inside the adult’s body.
●
Sexual reproduction produces male dwarf individuals that fertilize
females.
●
The fertilized female produces a free-swimming larva, which settles on a
new lobster host.

Question 9

habitat (3)

Answer 9

Found exclusively on the mouthparts of lobsters (e.g., Nephrops and Homarus
species).
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Live in marine environments, typically in cold or temperate waters.
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Each species of Cycliophoran is highly host-specific.

Question 10

when were they discovered?

Answer 10

Discovered in 1995, making Cycliophora one of the most recently recognized
animal phyla.

Question 11

what are they compared to?

Answer 11

Often compared to rotifers and entoprocts, but they are evolutionarily distinct.