New insights into the phylogeny of the Pyramidellidae (Gastropoda)

The phylogeny of the marine ectoparasitic gastropod family Pyramidellidae and its systematic placement have been a matter of debate for over a century. We employed nuclear (18S rDNA þ 28S rDNA) and mitochondrial (16S rDNA þ COI) gene fragments from 53 gastropod species (including 9 Pyramidellidae – 3 Turbonillinae and 6 Odostomiinae) in order to infer a phylogenetic hypothesis for Pyramidellidae. A Bayesian analysis of the combined data set of the four genes revealed monophyletic Pyramidellidae. The pyramidellid subgroups Turbonillinae and Odostomiinae were also recovered monophyletic. Tree reconstruction revealed Pyramidellidae deeply nested within Pulmonata implying a pulmonate origin of these ectoparasitic marine snails. However, the sister group of Pyramidellidae could not unambiguously be inferred due to lacking statistical support.