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OSTRACODA
By Catherine, Brandon, & Nicole
A.Characteristics
-
Class of Crustacea
Known as seed or mussel shrimp
Generally small (0.1 - 32 mm in length)
Approximately 8,000 living species
Very numerous in both marine and
freshwater environments
- Date back to the Cambrian period
- Reveal detailed information on the
history of our planet like climatic
changes etc
B. Difference from Regular Athropods
Arthropod
- exoskeleton
- segmented body
- jointed appendages
Ostracod
- laterally compressed
bodies
- undifferentiated head
- molt carapace so
lacking growth lines
C. Body Plan
-
Shrimp-like organisms, encased in a bean
shaped, bivalved shell (carapace)
Typically have eight pairs of appendages
- 5 head and 3 body
the 2 valves are articulated by a dorsal ligament
and closed by a single adductor muscle
-
carapace can be:
be transparent (usually young)
or opaque
- elliptical, round, or rectangular
1. Sea Firefly (Vargula hilgendorfii)
- only member of genus Vargula to
inhabit Japanese waters
- known in Japan as humi-hoturu
- it is nocturnal and lives in the sand
at the bottom of shallow water
- at night, it feeds actively
- known for its bioluminescence
- predation defense or mating
2. Darwinula stevensoni
-
considered to be ancient asexuals, males are
unknown
wide geographical and ecological distribution
- In Japan they are from lakes, ponds, rice
fields, and spring run off.
Female right lateral
view shows the brood
chamber towards the
rear with three eggs.
The right valve is larger than the left,
and overlaps the left along the ventral
margin when the carapace is closed.
Most other genera have an opposite
overlap.
3. Terrestricythere elisabethae
- Can walk over dry surface by
- taking a small supply of water with them, in and
around their shells
- special hairs on the shells help to retain the water
and drag it along with them
- if unable to replenish water before it evaporates they
perish
4. Potamocypris humilis
- eggs are tiny and can survive
complete drying
- The eggs and adults can hitch a
lift on the feet of birds
the long migrations of Arctic
Terns explain the distribution
of one species found in
Northern Europe and South
Africa
5. Cypridopsis vidua
- Fish eat ostracods,
sometimes in great numbers
- Experiments show that 26% of
specimens eaten by small
bluegill sunfish came out the
other end alive/unharmed
- By tightly closing their shells
and waiting they survived
passage through the gut of
the fish
"Whoa! That was a journey I don't want to
repeat!”