The phylogenetic position of Synprosphyma A.J. Wagner, 1920 within Clausiliidae: biogeographic and taxonomic implications

Molecular phylogenetic studies have provided new insights into the relationships within the highly speciose clausiliid subfamily Phaedusinae, but they have also triggered new questions about the position of Synprosphyma A.J. Wagner 1920 within that subfamily. This study shows that Synprosphyma constitutes a c. 37.3 million-year-old lineage within Clausiliidae, which is neither closely connected with the remaining Phaedusinae nor with any other clausiliid taxon. Synprosphyma is therefore placed in a separate subfamily, Synprosphyminae. It constitutes a third eastern Eurasian lineage of Clausiliidae, next to Garnieriinae and the redefined Phaedusinae. Our phylogeographic analysis points to a larger role of eastern Eurasia in the biogeographic history of Clausiliidae than previously assumed; however, it is not yet resolved whether this was as part of a wide ancestral Eurasian range of Clausiliidae or as an area that was repeatedly colonized from western Eurasia. The distributional pattern of Phaedusinae, Synprosphyminae, and Garnieriinae in Eurasia is similar to that of relict floras, which suggests similar climatic preferences coupled with a comparable role of historical range contractions and/or passive dispersal.