Descriptions and Barcoding of Five New Chinese Deuterophlebia Species Revealing This Genus in Both Holarctic and Oriental Realms (Diptera: Deuterophlebiidae) †

SIMPLE SUMMARY: The insects of the dipteran family Deuterophlebiidae have remarkedly specialized morphology and biology. Larvae of them prefer to live in the rapid current of monte streams. Their adults, with extremely elongated antennae and enlarged thorax covering their head, were recorded having few hours lifespan. The research on this group of peculiar insects began one century ago and 14 species have been reported from Asian Palearctic and Nearctic realms. However, the species of vast China have not been collected or studied systematically so far, only one species was known while the molecular work did not appear. Here, with specific sampling widely in China and careful classification, we provide the first species diversity data of this country, the first interspecific genetic distance, and the first Oriental record of the family. As a result, five new species are added to the previous eight Asian known ones, distribution and biology of this genus are updated correspondingly. ABSTRACT: The monotypic family Deuterophlebiidae of China was recorded twice previously from far northwest upon adults, the most parts of this country have not been investigated, leaving a huge blank of knowledge on their morphology, diversity, biology, or distribution. After deliberated collecting and rearing in recent years, we obtained more than one thousand specimens of Deuterophlebiidae, they are classified into five new species herein: Deuterophlebia sinensis sp. nov., D. yunnanensis sp. nov., D. wuyiensis sp. nov., D. acutirhina sp. nov. and D. alata sp. nov. Detailed descriptions and photographs of gathered life stages are given for these new species. Adults of them can be identified by chaetotaxy and length ratio of flagellomeres and legs, microtrichia on postgena and shape of their clypeus, pupae can be recognized by thoracic spines and abdominal chitin bands, and larvae can be separated by setae on thorax and abdomen. Genetic distances between species are 0.086–0.175 based on their COI genes. This contribution represents the first database of the enigmatic Deuterophlebiidae from China and shows a new distribution pattern of Deuterophlebia. In addition, the discovery throws some light on the origin and biogeography of the genus and family.