Molecular phylogenetics reveals Eocene origin and out‐of‐Africa dispersals of the stalk‐eyed flies (Diptera: Schizophora: Diopsidae)

The stalk-eyed flies (Diptera: Schizophora: Diopsidae) are a diverse clade of acalyptrate flies known for their remarkable eye stalks and intriguing courtship behaviours. Despite their striking appearance and significance as subjects for ecological and ethological studies, phylogenetic relationships within Diopsidae have not yet been comprehensively investigated, and the evolutionary history of the family remains inadequately resolved. We here present the first time-calibrated phylogenetic analysis of Diopsidae based on 17 genes (12S, 16S, 18S, 28S, and 13 mitochondrial protein-coding genes, 18 536 bp) from 48 taxa, including all extant subfamilies and ~76% extant genera of the family, thus clarifying a number of outstanding questions about intra-familial relationships and the evolutionary history of the stalk-eyed flies. Our results support the monophyly of Diopsidae and its three subfamilies; Centrioncinae is recovered as sister to the stalk-eyed lineage Sphyracephalinae + Diopsinae; the Teleopsis genus-group as well as several currently recognized genera are non-monophyletic and require further taxonomic review to better resolve their phylogenetic status. Molecular dating and biogeographic analyses indicate an African origin of the crown group of Diopsidae in the middle Eocene, ca. 45 Ma; its early diversification events might have been driven by climatic and ecosystem transformations during the middle Eocene to middle Miocene; available evidence suggests that factors shaping the current distribution of Diopsidae include colonization of Madagascar from Africa via the Mozambique Channel, out-of-Africa dispersals mediated by the Gomphotherium land bridge along with favourable environmental conditions, and colonization of North America via the Bering Land Bridge. This study provides a framework for future investigations into the evolutionary history of the stalk-eyed flies, as well as for ecological and morphological evolutionary research.