Q: What are Pteropods?
A: Pteropods are free-swimming pelagic sea snails and sea slugs. They are marine opisthobranch gastropods.
Q: Are they considered a natural group?
A: The monophyly of Pteropoda is the subject of debate.
Q: Is Pteropoda monophyletic according to molecular studies?
A: Yes, by molecular studies, the group is monophyletic.
Q: How many clades does Pteropoda have and what are they called?
A: Pteropoda has two clades: Thecosomata, the sea butterflies, and Gymnosomata, the sea angels.
Q: Do the two clades of Pteropoda have shells?
A: The Thecosomata have a shell, while the Gymnosomata ("naked body") do not.
Q: Are the two clades of Pteropoda sister taxa?
A: The two clades may or may not be sister taxa. If not, their similarity may reflect adaptation to their particular lifestyle.
Q: How do Pteropods swim, and what is their size and appearance?
A: Pteropods are pelagic, small, and transparent, and they swim using wing-like flaps (parapodia) which protrude from their bodies.