University of Tasmania, Australia

Pteropod

Blainville 1824

Taxonomy

Size

• Range in size from a few mm to 1 or 2 cm.

Distinguishing characteristics

• Planktonic opisthobranch molluscs belonging to two Orders:
  • Thecosomata (shelled bodies):
    • Thecosome pteropds have a very thin transparent calcareous shell that can be coiled or triangular.
    • The foot has two very large parapodia or wings, hence the name pteropod or wing-foot. Note that pteropod is not a formal taxonomic term.
    • The wings are used for swimming as well as suspension feeding on microplankton using cilia.
    • Both the shells and body are very delicate and easily damaged, and are rarely caught completely intact.
  • Gymnosomata (naked bodies):
    • Gymnosomes are more robust, lack a shell and the wings are much smaller, appearing as lateral lobes.
    • Gymnosome pteropods are carnivorous.

Distribution

• Very common in the open ocean.