Fiona pinnata (Eschscholtz, 1831)
This nudibranch about 6 cm long, is only slightly adapted to pelagic life and resembles in habitus the benthic members of the group. It is a naked slug beset with papillae of variable colour and lives in the tropical pleuston of in all oceans (Fiona pinnata).
Thick, elongated body with long tail, white to yellow coloured with a pink tinge. The papillae [or ceras] are variable in colour depending on the foot, they project from the sides of the dorsal surface. Each ceras bears an immobile, undulating membrane along the line of the mesial surface. The sail-shaped cerata are unique. The head is rounded with one pair of long oral tentacles and a pair of long rhinophores. The flattened foot has slightly extended margins. The liver lobes are brownish. The anus is latero-dorsal, slightly anterior to the middle of the body. The median teeth are unicuspoid, with central cusp bordered by 6-10 smaller cusps.
Body length up to 60 mm.
A special description is not available.
This species is hermaphroditic.
This species lives in the pleuston and is carnivorous, feeding on Velella and attacks Lepas anserifera. Cannibalism is also found.
This species lives in the tropical and subtropical waters of all oceans, see the Fiona pinnata map.