Erebia (Erebia) pawloskii Ménétriés, 1859 is confirmed as a species distinct from Erebia theano (Tauscher, 1806) and Erebia stubbendorfii Ménétriés, 1847

Nuclear genome phylogeny reveals that Erebia (Erebia) theano (Tauscher, 1806) (type locality in Altai Mts.) (Fig. 3a brown), Erebia (Erebia) stubbendorfii Ménétriés, 1847 (type locality Russia: Kansk) (Fig. 3a olive), and Erebia (Erebia) pawloskii Ménétriés, 1859 (type locality in Russia: Sakha) (Fig. 3a purple, blue, magenta, green, dark blue, and cyan, with the nominate in blue), form strongly supported (100% ultrafast bootstrap (Minh et al. 2013)) clades genetically differentiated at the species level, e.g., their Fst values are: 0.36 ( E. theano and E. stubbendorfii), 0.36 ( E. theano and E. pawloskii), and 0.28 ( E. stubbendorfii and E. pawloskii). Therefore, genomic analysis supports the three distinct species hypothesis (Lukhtanov and Lukhtanov 1994; Gorbunov 2001) and suggests that the name stubbendorfii should not be applied to E. pawloskii . Curiously, mitochondrial genome phylogeny is different, and reveals two major haplotypes for these species, split by geography: the Old World haplotype (including the North Slope of Alaska, USA) and the New World haplotype (the rest of Alaska, Canada, and the US) (Fig. 3b). Similar evolutionary scenarios, likely resulting from mitochondrial introgression, are known in other butterfly groups, such as Junonia Hübner, [1819] (Gemmell and Marcus 2015), and offer a cautionary lesson against relying solely on mitochondrial data (e.g., COI barcodes) to address species delimitation.