Acteonimorpha

Belongs within: Heterobranchia.Contains: Acteonidae. The Acteonimorpha are a clade of marine gastropods supported by molecular data. The clade unites the Rissoellidae, minute gastropods with transparent, conical shells, with the Acteonoidea, which have fusiform shells with an elongate aperture and a well-developed head-shield. <==ActeonimorphaBR17 |–Rissoellidae [Heterophrosynidae, Jeffresiidae, Jeffreysiidae, Rissoelloidea]BR17 | |–CithnaC64 | | |–C. albida Carpenter… Continue reading Acteonimorpha

Acteonidae

Belongs within: Acteonimorpha.Contains: Pupa. The Acteonidae are a group of marine gastropods of uncertain affinities. Though anatomically similar to opisthobranchs, they possess certain plesiomorphic features such as the presence of an operculum to close the shell aperture. The shell is well calcified with a distinct spire and an elongate aperture. The radula usually lacks a… Continue reading Acteonidae