PHYLOGENY AND CLASSIFICATION OF SCAPHOPODA

Scaphopod classification has previously been based mainly on hard part morphology. Here, the phylogeny and supraspecific classification of Scaphopoda are considered in the light of recently obtained anatomical data. A hypothetical common ancestor is reconstructed using both in-group comparison and out-group comparison with Bivalvia and Rostroconchia. The Diasoma grouping is considered the most plausible hypothesis of relationships with other classes, although it cannot explain or demonstrate the transitions from rostroconchs to scaphopods, e.g. the changes in body axes. A first attempt is made at a cladistic analysis of the relationships among scaphopod families. An outline classification of the Recent Scaphopoda is presented, and in the order Gadilida two new suborders, Entalimorpha and Gadilimorpba, are introduced.