Data from: Diversity of land snail tribe Helicini (Gastropoda: Stylommatophora: Helicidae): where do we stand after 20 years of sequencing mitochondrial markers?

Sequences of mitochondrial genes revolutionized the understanding of
animal diversity and continue to be an important tool in biodiversity
research. In the tribe Helicini, a prominent group of the western
Palaearctic land snail fauna, mitochondrial data accumulating since the
2000s helped to newly delimit genera, inform species-level taxonomy, and
reconstruct past range dynamics. We combined the published data with own
unpublished sequences and provide a detailed overview of what they
revealed about the diversity of the group. The delimitation of Helix is
revised by placing Helix godetiana back in the genus and new synonymies
are suggested within the genera Codringtonia and Helix. The spatial
distribution of intraspecific mitochondrial lineages of several species is
shown for the first time. Comparisons between species reveal considerable
variation in distribution patterns of intraspecific lineages, from broad
postglacial distributions to regions with a fine-scale pattern of
allopatric lineage replacement. To provide a baseline for further research
and information for anyone re-using the data, we thoroughly discuss the
gaps in the current dataset, focusing on both taxonomic and geographic
coverage. Thanks to the wealth of data already amassed and the relative
ease with which they can be obtained, mitochondrial sequences remain an
important source of information on intraspecific diversity over large
areas and taxa.