Six complete mitochondrial genomes of mayflies from three genera of Ephemerellidae (Insecta: Ephemeroptera) with inversion and translocation oftrnIrearrangement and their phylogenetic relationships

Abstract

As a small order of Pterygota (Insecta), Ephemeroptera has almost 3,500 species around the world. Ephemerellidae is a widely distributed common group of Ephemeroptera. However, the relationship among Ephemerellidae, Vietnamellidae and Teloganellidae is still in dispute. In this study, we sequenced six complete mitogenomes of three genera from Ephemerellidae (Insecta: Ephemeroptera):Ephemerellasp. Yunnan-2018,Serratella zapekinae,Serratellasp. Yunnan-2018,Serratellasp. Liaoning-2019,Torleya grandipennisandT. tumiforceps. These mitogenomes were employed to reveal controversial phylogenetic relationships among the Ephemeroptera, with emphasis on the phylogenetic relationships among Ephemerellidae. The lengths of the six mayfly mitogenomes ranged from 15,134 bp to 15,703 bp. Four mitogenomes ofEphemerellasp. Yunnan-2018,Serratella zapekinae,Serratellasp. Yunnan-2018 andSerratellasp. Liaoning-2019 had 22 tRNAs including an inversion and translocation oftrnI. By contrast, the mitogenomes ofT. tumiforcepsandT. grandipennishad 24 tRNAs due to an extra two copies of inversion and translocation oftrnI. Within the family Ephemerellidae, disparate gene rearrangement occurred in the mitogenomes of different genera: one copy of inversion and translocationtrnIin the generaEphemerellaandSerratella, and three repeat copies of inversion and translocation oftrnIin the genusTorleya. A large non-coding region (≥200 bp) betweentrnS1(AGN) andtrnEwas detected inT. grandipennisandT. tumiforceps. Among the phylogenetic relationship of the Ephemeroptera, the monophyly of almost all families except Siphlonuridae was supported by BI and ML analyses. The phylogenetic results indicated that Ephemerellidae was the sister clade to Vietnamellidae whereas Teloganellidae was not a sister clade of Ephemerellidae and Vietnamellidae.