Phylogeny and evolutionary timescales of the tribes Tagiadini and Celaenorrhinini (Hesperiidae, Pyrginae) inferred from mitochondrial genome and nuclear genes

Tagiadini and Celaenorrhinini, two closely related groups of skippers in the subfamily Pyrginae, are mainly distributed across the Oriental, Palaearctic and African regions. While some efforts have been made to explore the phylogenetic relationships within Tagiadini and Celaenorrhinini, several unresolved issues still persist. In this study, we sequenced 13 complete mitochondrial genomes from Tagiadini and Celaenorrhinini. Additionally, we extracted nuclear genes CAD, EF-1 alpha, IDH, MDH, RPS5 and Wingless from the public database. Through comparative analysis, we gained insights into the structure of these newly sequenced mitogenomes. Furthermore, we constructed a comprehensive phylogenetic tree for Tagiadini and Celaenorrhinini, integrating the newly obtained mitochondrial genomes and nuclear genes with previously published mitogenomes and data from the sequence read archive (SRA). The total length of the mitochondrial genomes of the 13 skipper species ranged from 15,228 bp (Seseria sambara indosinica) to 15,431 bp (Pseudocoladenia festa). The newly sequenced genomes featured the standard set of 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs) and a non-coding A + T-rich region implicated in replication initiation. The phylogenetic analysis encompassing all mitochondrial and nuclear gene data consistently upheld the monophyly of genera within the tribes Tagiadini and Celaenorrhinini. Most of the intergeneric relationships identified in our study agreed with recent genomic discoveries, showing enhanced nodal support values in some cases. Lastly, we estimated the divergence of the Tagiadini + Celaenorrhinini branch at approximately 44.06 million years ago (Ma) during the middle Eocene epoch. The crown ages of Tagiadini and Celaenorrhinini were estimated at approximately 41.69 Ma and 38.49 Ma, respectively.