Gymnosomata, commonly known as sea angels, are a group of marine heterobranch gastropod molluscs traditionally classified among the pteropods. They are specialised for life in the open ocean and are recognised by their delicate, often transparent bodies and wing-like extensions of the foot, called parapodia, which they use to swim. Unlike their close relatives, the sea butterflies (Thecosomata), adult gymnosomes lack an external shell. Their streamlined bodies and active swimming movements make them particularly distinctive among pelagic gastropods.<\/p>\n