Phylogenetic relationships and distribution of the enigmatic semislug Aillya (Gastropoda: Aillyidae)

Abstract

Aillya is an enigmatic African semislug, which was originally classified into the American Amphibuliminae (Orthalicoidea) by Odhner. Later, Baker established a separate family for this group and placed it together with the Succineidae and Athoracophoridae in the suborder Heterurethra. Minichev & Slavoshevskaja subdivided the Heterurethra even into three separate orders and introduced the name Aillyida for the Aillyidae. In contrast, Pilsbry, Solem, Tillier and van Mol supposed that Aillya is most closely related to some limacoid groups, i.e. Helicarionidae or Urocyclidae. We investigated the phylogenetic relationships of Aillya based on ITS2 and partial 5.8S and 28S rDNA sequences. Furthermore, we examined the morphology of type specimens and newly collected material to clarify the taxonomy and distribution