Molecular phylogeny, classification, and biogeographic origin of Callerebia and other related Sino-Himalayan genera (Insecta: Lepidoptera: Nymphalidae: Satyrinae)

The Sino-Himalayan subregion is a widely extended transition zone between the Oriental Region and the Palaearctic Region. A most interesting feature of this area is the unique nature of many of the animal and plant taxa characteristic of its biota. In fact, the Sino-Himalayan subregion although representing the transition zone between broadly overlapping elements from two zoogeographical regions, is also the abode of several endemic plant and animal taxa. This feature is well testified by the butterfly fauna which includes several speciose genera typical of this area. Employing DNA sequences (471 bp) of the elongation factor nuclear gene (EF-1α) as molecular marker, the present study is aimed to investigate the phylogenetic relationships of five genera of the tribe Satyrini (Satyrinae, Nymphalidae), namely Callerebia, Argestina, Hemadara, Loxerebia, (from now on this group of genera will be named “callerebias”) and Eugrumia, most of them consisting of extremely localized species. So far, these butterflies have never been included in molecular studies, since most of the species are rare and/or geographically restricted. Results from this study, although preliminary, draw attention to the need for a systematic revision of the whole tribe Satyrini. In particular, our results lead to reconsider the placement of all the “callerebias” genera that should be moved from subtribe Ypthimina to Erebiina. In addition, the “callerebias” are recognized as more related to the strictly Holarctic genus Erebia rather than to the tropical Ypthima, almost certainly of Oriental origin. Thus, it is possible to hypothesize the origin of the “callerebias” from an ancient stock of Palaearctic butterflies. Ecological specialization and adaptive radiation might have driven early speciation events of the “callerebias“ genera.