A molecular phylogeny of the Cephalaspidea<i>sensu lato</i>(Gastropoda: Euthyneura): Architectibranchia redefined and Runcinacea reinstated

Abstract

The monophyly and phylogenetic relationships of the Cephalaspidea sensu lato ( sensu Burn and Thompson 1998 ) have been investigated by means of Bayesian, parsimony and distance analyses of nuclear (18S rRNA and 28S rRNA) and mitochondrial cytochrome oxidase I (COI) genes. Results revealed the presence of three monophyletic groups among the Cephalaspidea s. l. (i) Architectibranchia ( sensu Haszprunar 1985 , in part: including Acteonidae and Aplustridae, but excluding Diaphanidae), (ii) Cephalaspidea including Diaphanidae but not Runcinidae (both previously of uncertain systematic affinity), and (iii) Runcinacea. The monophyly of the architectibranch families Acteonidae (represented by Acteon and Pupa ) and Aplustridae ( Hydatina and Micromelo ); of the runcinacean family Runcinidae ( Runcina ); and of the cephalaspidean families Aglajidae ( Chelidonura , Aglaja , Odontoglaja , Navanax and Philinopsis ), Bullidae ( Bulla ), Gastropteridae ( Siphopteron and Sagaminopteron ), Haminoeidae ( Atys , Haminoea , Phanerophthalmus and Smaragdinella, but not Ventomnestia ), and Retusidae ( Retusa and Pyrunculus , but not Volvulella ) is suggested. The families Scaphandridae ( Scaphander ) and Rhizoridae ( Volvulella ) are reinstated as valid. A new phylogenetic classification of the Cephalaspidea is proposed.