Contribution to the Knowledge of Dicranoptychini (Diptera, Tipuloidea, Limoniidae) in China, with the First Mitochondrial Genome of the Tribe and Its Phylogenetic Implications

SIMPLE SUMMARY: Limoniidae, the most speciose family in the superfamily Tipuloidea (crane flies), consists of four subfamilies (i.e., Chioneinae, Dactylolabidinae, Limnophilinae, and Limoniinae) and more than 11,000 species. However, its four-subfamily classification system has been controversial, among which the taxonomic position of the tribe Dicranoptychini (Limoniinae) is subject to debate. In addition, the knowledge of species diversity and geographical distribution of the tribe in China is seriously insufficient. We conducted investigations on Dicranoptychini in China and examined specimens from several Chinese localities to discover new species and new records and selected suitable materials for mitochondrial (mt) genome sequencing. In this study, two new and one newly recorded species from China have been found, which increases the number of Dicranoptychini species in the Chinese Mainland from four to seven, and adds three new provincial distribution records for the tribe in China. The first key for all Chinese Dicranoptycha species based on the type and non-type specimens and literature is also presented. The mt genome of one of the new species is sequenced and annotated, representing the first mt genome of the tribe Dicranoptychini. Phylogenetic analysis supports both new and traditional arrangements. This study will improve the knowledge of Chinese Dicranoptychini and provide genomics data and new horizons for the phylogeny of Limoniidae. ABSTRACT: Dicranoptychini is a tribe in the subfamily Limoniinae (Diptera, Tipuloidea, and Limoniidae) and includes only the genus Dicranoptycha Osten Sacken, 1860. However, the species diversity of the tribe in China was seriously underestimated, and the taxonomic status of Dicranoptycha has long been controversial. In this study, types of Chinese Dicranoptycha species and specimens collected from several localities in China were examined, and the first mitochondrial (mt) genome of the tribe Dicranoptychini is presented. Two Dicranoptycha species, D. jiufengshana sp. nov. and D. shandongensis sp. nov., from China, are described and illustrated as new to science. A Palaearctic species, D. prolongata Alexander, 1938, is recorded in China for the first time. In addition, the complete mt genome of D. shandongensis sp. nov. is sequenced and annotated, indicating that it is a typical circular DNA molecule with a length of 16,157 bp and shows a similar gene order, nucleotide composition, and codon usage to mt genomes of other Tipuloidea species. The two pairs of repeat elements are found in its control region. Phylogenetic results confirm the sister-group relationship between Cylindrotomidae and Tipulidae, question the position of the genus Epiphragma Osten Sacken, 1860 in Limoniidae, and indicate that Dicranoptychini may be a basal lineage within Limoniinae.