Mitochondrial DNA-based phylogeography of the large ringlet Erebia euryale (Esper, 1805) suggests recurrent Alpine-Carpathian disjunctions during Pleistocene (Nymphalidae, Satyrinae)

Most species of the butterfly genus Erebia are high altitude specialists, in which territorial fragmentation is associated with distinct genetic patterns. This is also true for the large ringlet, Erebia euryale (Esper, 1805), a species widespread across European mountain systems. Previous molecular studies revealed four lineages: two in the Alps, coinciding with the ssp. adyte and isarica, one in the Pyrenees and Cantabria (ssp. pyraenaeicola), and one in the Carpathians and the Balkans (ssp. syrmia). Two morphological subspecies inhabiting delimited ranges in the southern Alps (ssp. pseudoadyte and kunzi) were not included in these studies. To further our understanding of the relationships between populations, both the Alpine and the extra Alpine ones, we sequenced 1,496 bp of the COI gene in 16 Alpine and Jurassian populations and analysed them in combination with published Pyrenean and Carpathian sequences. The resulting haplotype network shows five lineages, congruent with the morphologic delineation of subspecies. Based on the current distribution ranges and genetic affinities, we reconstructed a pre-Würm phylogeographic scenario. This suggests an initial split resulting in an Alpine and a Carpathian clade, probably of Carpathian origin. Within the Alps, three subspecies subsequently differentiated, probably during several glacial cycles, generating ssp. adyte, pseudoadyte and kunzi. In parallel, the Carpathian clade underwent a second Alpine–Carpathian disjunction and differentiated into ssp. euryale and syrmia in the Carpathians, and ssp. ocellaris and isarica in the eastern Alps, revealing a heterogeneous origin of the E. euryale subspecies across the Alps. The Pyrenean and Jurassian populations are a relatively young divergence in the western part of the species’ range