A primary insight into the molecular phylogeny of Colias complex of South America

Data on the molecular phylogeny of the Colias complex of South America, obtained via barcoding a mitochondrial part of genome (a specific 648 base-pair fragment of the cytochrome oxidase subunit I (CO I) – its 5’ region), are reported for the first time to the best of my knowledge. Barcoding was trialed employing the BOLD (‘Barcoding of Life Database’) platform, where a separate console (‘South-American COLias’ – ‘SACOL’), comprising 93 specimens of all South-American Colias sp. plus 2 outgroup specimens (C. philodice guatemalena from North America), was under study. The data obtained were then aggregated with the data of barcoding the specimens sourced from representatives of overseas (out of South America) Colias sp., available in GenBank, to get an overall pattern of the genus’ molecular phylogeny. It is shown that barcoding provides a way to address the type of Colias speciation in the region, along with guidance for its unbiased comparison with that of overseas Colias sp. It is established that all Colias sp. from South America form a single monophyletic clade, characterized by notable interspecific mutational divergences (~3.5–4.5%) and moderate intraspecific ones (0.3–0.9%). Particularly, it reveals the occurrence of three ‘well-established’ (i.e. notably diverged genetically) species (C. dimera, C. vauthierii, and C. alticola new st., the latter reraised to sp. level), plus a complex of three ‘emerging’ species (C. lesbia, C. euxanthe, and C. flaveola) which are weakly differentiated in mitochondrial part of genome, with intersecting haplotypes. Furthermore, fine details of molecular phylogeny at the lower than sp. level are provided for the rest of South-American Colias. Among these, only C. vauthierii cunninghamii and C. euxanthe stuebeli seem to be bona ssp., as both demonstrate higher distances to their nominative counterparts. Meanwhile, the presented analysis disregards – as per molecular phylogeny data – the sp. status of taxa weberbaueri, mossi, nigerrima, erika, blameyi and mendozina; hence, certain evidences are being brought in for considering all these as ssp. of a clinal type within ‘super-sp.‘ C. flaveola s. lat. Furthermore, the clade formed by South-American Colias is found to be sister to the one comprised of all the remaining Colias sp. occurring outside the region, i.e. in Eurasia, North America, and Africa (for instance, divergence of the former clade from outgroup C. philodice guatemalena exceeds 5.5%). In general, a straightforward comparison of the results obtained for South-American Colias with those for occurring worldwideColias, available in GenBank, led me to the conclusion that these two subcomplexes are largely divergent, constituting two genetically well-differentiated and autonomous, or ‘autochthonous’ (without inter-scattering between the two), parties, and that in fact, they are s. lat. subgenera of genus Colias. The first subgenus comprising all South-American Colias sp. and named herein Aucolias (‘Austral Colias’, viz. ‘of Southern hemisphere stem’) is sister to the second one (comprising all overseas Colias sp. of the Old and New Worlds), for which the name Colias (Colias) s. str. is preserved. The proposed subdivision of the genus is advocated by insight into the historical development of the subgenera concept for Colias, which reveals that the proposed subdivision schematics might delete the inconsistencies that are inherent to the preceding attempts of the higher than sp. level systematization of Colias butterflies.