Parent taxon: Opisthobranchia according to A. G. Beu et al. 1990
Sister taxa: Acanthotrophia, Acochlidea, Anaspidea, Bullinidae, Buscotypus, Canepina, Cephalaspidea, Cylindrobullinoidea, Echininus, Floribella, Gymnosomata, Heteroptygmatis, Heterostrophia, Kotakaia, Lutima, Mariottia, Mistostigma, Nicosiaella, Notaspidea, Nudibranchia, Pseudofusia, Reticulacella, Rhodopemorpha, Sacoglossa, Scorbinidola, Tectibranchiata, Thecosomata, Umbraculomorpha
Subtaxa: Acrocolpus, Acrostemma, Actaeonellina, Actaeonidea, Adamnestia, Blancia, Bucconia, Bulimactaeon, Bullina, Ceritella, Coeloscapha, Cosmophiline, Cylichnatys, Cylichnopsis, Cylindritella, Cylindrites, Douvilleia, Eotrochactaeon, Euactaeonina, Euconactaeon, Fictoacteon, Gilbertina, Globiconcha, Goniocylindrites, Hacobjania, Hamlinia, Hermania, Kaitoa, Kleinacteon, Liloa, Limulatys, Liocarenus, Lithophysema, Maoriscaphander, Megistostoma, Mesotrochactaeon, Mexicotrochactaeon, Millosevichia, Mirascapha, Mnestocylichnella, Moniliretusa, Neocylindrites, Neotrochaetaeon, Noetca, Nucleopsis, Orthoptyxis, Ossiania, Ovulactaeon, Ovulopsis, Palaeohydatina, Palaeotrochactaeon, Parapuractaeon, Pchelincevella, Peruviella, Plicobulla, Priscaphander, Pseudavena, Pseudocassis, Pseudonerinea, Ptychocylindrites, Pyrunculus, Raincourtia, Ringiculopsis, Ringiculoptycha, Ringiculospongia, Roxaniella, Scobinodola, Semiactaeon, Sevanella, Sogdianella, Spiractaeon, Striactaeonina, Superstes, Taita, Talahabia, Trochactaeonina, Volvocylindrites, Wangacteon
Ecology: epifaunal