The systematic position of the genera Basilissopsis Dautzenberg and Fischer, 1897, and Guttula Schepman, 1908, is discussed; both genera are confirmed to be members of the Seguenzioidea Verrill, 1884. A preliminary phylogenetic analysis of that superfamily, based principally on shell characters, is presented. The analysis suggests that two subfamilies (families) may be warranted: the Seguenziinae(idae) s.s., and the Guttulinae(idae) Goryachev, 1987. Three recent, major classifications of the Seguenzioidea are examined, with particular attention paid to the explicit or implicit characters on which those classifications were based. Assignment of the Seguenzioidea to the caenogastropod orders Littorinimorpha and Strombiformes is rejected. Placement of the superfamily, as a suborder, between the Vetigastropoda and Archaeotaenioglossa cannot be confirmed or rejected based on the available data. The pointed tip of the protoconch, presence of sensory micropapillae on cephalic and epipodial tentacles, and presence of a right subocular peduncle are suggested as potential synapomorphies with the Vetigastropoda. A compromise classification is proposed that would allow use of the taxa Archaeogastropoda and Vetigastropoda until more explicit statements of relationships among the included superfamilies can be made. |
