﻿The genus Apterygothrips Priesner (Thysanoptera, Phlaeothripinae, Haplothripini) from China, with one new species

﻿Abstract The genus Apterygothrips Priesner is a group of mainly wingless species in the tribe Haplothripini. The genus is diagnosed here based on the three species known from China, including A.flavescens Dang & Qiao sp. nov. collected from bases of grass in Tibet. An illustrated identification key to the three species from China is provided and the CO1 barcode sequence is given for the new species.


Introduction
Species of Apterygothrips Priesner in the tribe Haplothripini are distributed worldwide and almost always wingless. Although there are now 39 species listed in this genus (ThripsWiki 2022), it has always been a weakly diagnosed group that is closely related to the huge genus Haplothrips. Species of Apterygothrips cannot be distinguished from wingless Haplothrips species, except for antennal segment IV bearing two or three sense cones and pelta trapezoidal or hemicircular. In Haplothrips species, antennal segment IV usually bears four sense cones and the pelta is triangular or with lateral lobes. Moreover, biological information about species of this genus is often unclear, with species likely to be phytophagous, fungus-feeding or predatory. Three species living on green plant tissues were described from Spain and Israel by zur Strassen (1966): A. longiceps zur Strassen on young shoots of Erica arborea, A. piceatus zur Strassen in Crataegus flowers and A. priesneri zur Strassen on leaves of Pinus halepensis. In contrast, Mound and Wells (2015) recorded A. sparsus Mound & Walker as collected together with large populations of mites, suggesting that it may be predatory. Some species of the genus from the Asian region are known from dead leaves and branches (Bhatti and Mehra 1994;Bhatti 1997;Okajima 2006) and may possibly be fungus-feeding. The genus Apterygothrips remains complicated, and thrips workers simply placed species of Haplothripini with reduced wings and antennal segment IV with 2 or 3 sense cones in this poorly-defined genus. Four species of Apterygothrips are recorded from New Zealand, but each of these is known to produce macropterae although only in very low numbers (Mound and Walker 1986). The genus needs more evidence, such as combining morphological characters with molecular data, to confirm the relationship of its members as a monophyletic group.
At least eight species of Apterygothrips are listed from Asia (ThripsWiki 2022), only two of which were recorded from China prior to this study: A. brunneicornus Han and A. haloxyli Priesner (Han et al. 1991;Han 1997). As part of ongoing research on Haplothripini from China, we focused, in this study, on the wingless species. Three such species are recognized here, including the two named above and one new species. The new species is placed in the genus Apterygothrips because of the following major structures: slender body, wings absent, antennal segment III with one outer sense cone, antennal segment IV with two outer sense cones, head longer than wide, postocular setae well developed, pronotal notopleural sutures complete, basantra broader than long, pelta hemicircular and anal setae slightly shorter than tube. Because of these characters the new species could not be considered to belong to other associated genera such as Haplothrips, Karnyothrips, Podothrips and Xylaplothrips. The new species, Apterygothrips flavescens Dang & Qiao sp. nov., is described here and illustrated, and a key to the three Apterygothrips species from China is also provided.

Materials and methods
The descriptions, photomicrograph images and drawings were produced from slidemounted specimens with an Olympus BX53 and drawing tube. The abbreviations used for the pronotal setae are as follows: am -anteromarginal, aa -anteroangular, ml -midlateral, epim -epimeral, pa -posteroangular. The unit of measurement in this study is the micrometre. The genomic DNA of Apterygothrips flavescens Dang & Qiao sp. nov. was extracted from single specimens following the standard protocol of DNeasy kit (Qiagen, Hilden, Germany). The CO1 sequence was amplified using primers LCO1490 and HCO2198 (Mound et al. 2010). Sequence was assembled by Seqman II (DNAstar, Inc., Madison, WI, USA) and then aligned using Clustal W.
All specimens studied here are deposited in the School of Bioscience and Engineering, Shaanxi University of Technology (SUT), Hanzhong, China, and in the National Zoological Museum of China (NZMC), Institute of Zoology, Chinese Academy of Sciences, Beijing, China.

Apterygothrips Priesner
Apterygothrips Priesner, 1933: 153. Type species: Apterygothrips haloxyli Priesner, 1933. Diagnosis. Micropterous or apterous (rarely macropterous). Body uniformly brown or bicolored. Head longer than wide, eyes normal or small, ocelli small or absent, postocular setae well developed, pointed or capitate at apex; stylets about one third of head width apart, maxillary bridge present. Antennae eight-segmented, antennal segment III with one or two sense cones, IV with two or three. Pronotum usually smooth, with five pairs of major setae, sometimes am or (and) ml reduced, notopleural sutures complete; basantra present; mesopresternum boat-shaped or eroded medially; metathoracic sternopleural sutures absent. Fore tarsal tooth small or absent. Pelta trapezoidal or hemicircular; tergites II-VII with or without two pairs of weak, wing-retaining setae; tube shorter than head. Apterygothrips brunneicornus Han, 1991: 337. Comments. This species was described by Han et al. (1991) from Sichuan Province and Tibet based on two females. In the present study, we checked the two type specimens. They were squashed (Fig. 1), but fortunately the major characters could be seen.

Key to Apterygothrips species from China
Apterygothrips brunneicornus is similar to A. flavescens Dang & Qiao sp. nov. in having major setae pointed (Figs 2, 3), and it comes from the same location: Tibet. It can be distinguished by having body uniformly brown (Fig. 1), antenna brown with segment III paler at base (Figs 1, 4), antennal segment IV with 1+2 sense cones, fore tarsal tooth present (Fig. 5), pronotum with five pairs of well-developed setae (Fig. 2) and by its pelta shape (Fig. 21).
Measurements (   head and pterothorax, and major setae pointed at apex. In A. bicolor from Mexico, the head, prothorax, mesothorax and apical two thirds of the tube are brown, the metathorax, abdominal segments I-IX and the basal third of the tube are pale yellow, and the major setae are expanded at the apex (from original description, Johansen 1982). In A. dempax Bhatti & Ananthakrishnan from India, the body is almost yellow except for abdominal tergites IX-X or only the tube brown, and the major setae are expanded at the apex (from original description, Bhatti and Ananthakrishnan 1978).

Apterygothrips haloxyli Priesner
Apterygothrips haloxyli Priesner, 1933: 1. Comments. This species was described by Priesner (1933) from Egypt, based on specimens collected on fallen petals of Haloxylon schweinfurthi. It was first recorded from China (Ningxia Autonomous Region) by Han (1997). Here, one female and one male identified by Han and four females and one male from Inner Mongolia were studied. Apterygothrips haloxyli can be distinguished from the other Chinese species by having major setae capitate at apex.