Mollusks research

1. MOLLUSKS
Matteo Peretti e Marco Samorì

2. Scientif Classification
• DOMAIN Eukarya
• KINGDOM Animalia
• PHYLUM Mollusca
• SUPERPHYLUM Lophotrochozoa
• CLASSES 1)Bivalvia
2)Cephalopod
3)Gastropoda
4)Rostroconchia

3. Generals Characteristics
• Bilateral symmetry;
• Specialized respiratory organs (gills and lungs);
• Open circulatory system (except incephalopods);
• Foot-muscle.
• Mouthparts-equipped by radule.
• Many have the trocofora-larva (common ancestor with
the annelids).
• Ciliated epithelial surface and provided withmucous glands
and sensory nerve endings.
• Digestive system complex with anus that usually opens into the
mantle cavity.
• Nervous system consists of pairs of cerebral ganglia connected
by nerve cord.
• Embryogenesis typically protostomale.

4. Summary Diagram
SYMMETRY DIGESTIVE SYSTEM METAMERISM
MOLLUSK BILATERAL TWO OPENINGS NO
Nuclear Mitochondrions Chloroplasts Cell wall Multicellularity
membrane
Cells of Present Presents Absents Absent Present
mollusks

5. Bivalvia
Anatomy:
1: posterior adductor, 2: anterior adductor, 3: outer gill
demibranch, 4: inner gill demibranch, 5: excurrent
siphon, 6: incurrent siphon, 7: foot, 8: teeth, 9: hinge, 10:
mantle, 11: umbo.
The shell of a bivalve is composed
by calcium carbonate and consists of two
halves called valves…

6. Cephalopod
This exclusively marine animals have a bilateral
body symmetry, a prominent head and a set of arms
or tentacles modified from the primitive molluscan
foot.
A peculiarity of some cephalopoda is that their
penis elongation may result in a penis that is as long
as the mantle, head and arms combined.

7. Gastropod
There are many kinds of gastropods with sizes from
microscopic to quite large. A peculiarity of gastropods
is that most land gastropods are hermaphrodite that is
an organism having normally both the male and female
organs of generation.

8. Rostroconchia
They have a single shell in their larval stage, and
the adult typically has a single, pseudo-
bivalved shell enclosing the mantle and
muscular foot.