Shell structures of the recent Vetigastropoda

A cladistic analysis of the shell microstructures of Recent Vetigastropoda demonstrates, it is more parsimonious to assume crossed lamellar shell structures, rather than nacreous, are plesiomorphic. The clade Vetigastropoda is characterized by having intersected crossed platy shell structure. The analysis suggests resolution of the internal phylogeny of the Vetigastropoda, particularly separation of a crown group with nacreous shells, composed of Haliotidae, Pleurotomariidae, Seguenziidae, Stomatellidae, Trochidae, and Turbinidae, separated from an unresolved grade with cross lamellar structures, Fissurellidae, Osteopeltidae, and Pseudococculinidae. It is also suggested, that Phasianellidae is neither part of nor sister taxon to Turbinidae.