SHELL STRUCTURES OF THE RECENT VETIGASTROPODA

A cladistic analysis of the shell microstructures of Recent Vetigastro poda demonstrates, it is more parsimonious to assume crossed lamellar shell structures, rather than nacreous, are plesiomorphic. The clade V etigastropoda is characterized by having intersected crossed platy she ll structure. The analysis suggests resolution of the internal phyloge ny of the Vetigastropoda, particularly separation of a crown group wit h nacreous shells, composed of Haliotidae, Pleurotomariidae, Seguenzii dae, Stomatellidae, Trochidae, and Turbinidae, separated from an unres olved grade with cross lamellar structures, Fissurellidae, Osteopeltid ae, and Pseudococculinidae. It is also suggested, that Phasianellidae is neither part of nor sister taxon to Turbinidae.