Phylogenetic position of African punctoid snails (Stylommatophora, Punctoidea, Trachycystinae)

Abstract

The punctoid land snail family Charopidae, as currently defined, is a paraphyletic assemblage of taxa with Gondwanan distribution. It is represented in Africa largely by the pinwheels (genus Trachycystis and allies) and afrodontas (genus Afrodonta and allies), as well as a few additional genera, such as Reticulapex, Pilula, and Helenoconcha. Herein, a Bayesian inference phylogenetic analysis (using four molecular markers) is conducted to test whether these taxa belong to the Charopidae and, if so, what their position is in the phylogenetic tree. It is concluded that Reticulapex and Pilula do not belong to the Punctoidea and are thus transferred to the Acavidae and Helicarionoidea, respectively. The pinwheels and afrodontas form a monophyletic group, the most basal branch of “Charopidae”, here classified as the subfamily Trachycystinae. It possibly represents an old southern African lineage potentially dating back to the split of Gondwana, while the remaining “Charopidae” and Punctidae can be found in Zealandia and Australia, and later, in the Americas and Europe. If further studies support the present findings, the elevation of Trachycystinae to the family level might be warranted. Finally, Flammoconchinae is also identified as a New Zealand subfamily of “Charopidae”.