Fionidae: Fiona pinnata (Eschscholtz, 1831) (‘pinnate sea-slug’)

Synonym(s): pinnata Eschscholtz, 1831 longicauda Quoy & Gaimard, 1832 nobilis Alder & Hancock, 1851 atlantica Bergh, 1857 marina Eliot, 1910 elegantissima Costa, 1867.

Typical body-length 20 mm. Lives afloat on ocean surface. Native. Occurs all around Australia (QLD, NSW, TAS, VIC, SA, WA and NT); also widespread in warmer oceanic waters worldwide.