Order Gymnosomata Blainville 1824 (sea angel)
Parent taxon: Opisthobranchia according to P. L. Beesley 1998
Sister taxa: Acanthotrophia, Acochlidea, Akeridae, Buscotypus, Canepina, Cephalaspida, Cephalaspidea, Cylindrobullinoidea, Floribella, Heteroptygmatis, Heterostrophia, Lutima, Mariottia, Mistostigma, Nicosiaella, Notaspidea, Paronaella, Pseudofusia, Reticulacella, Rhodopemorpha, Scorbinidola, Tectibranchia, Thecosomata, Umbraculomorpha
Subtaxa: Gymnoptera
Ecology: epifaunal
Distribution: found only at Cabanes reef, Saint-Paul-les-Dax, Adour Valley, Landes (Miocene of France)