The genus Meiothrips Priesner (Thysanoptera, Phlaeothripidae, Idolothripinae) with a key and a new species from China

Abstract The genus Meiothrips Priesneris reviewed, with Meiothrips fuscicrussp. n., and Meiothrips nepalensis Kudo & Ananthakrishnan recorded and described from China, and a key provided to the five known species. COI sequences of the new species and Meiothrips nepalensis are also provided.


Introduction
Meiothrips was erected as a subgenus of Idolothrips with the type-species M. annulipes Priesner (1929). This was recognized as a full genus by Bagnall (1934) as a member of the Idolothrips -Actinothrips group. Subsequently four species have been added to the genus: M. menoni Ananthakrishnan, M. nepalensis Kudo & Ananthakrishnan, M. kurosawai Okajima, and M. baishanzuensis Duan & Li. However, the last of these has recently been recognized as belonging to a different genus, and this information will be published separately. As a result of the new species described below, there are still five species recognized in the genus, of which three are recorded from China.
DNA barcoding sequences (COI) are provided here as identifying characters for M. fuscicrus sp. n., also the newly recorded species M. nepalensis. We suggest that, if possible, DNA barcoding sequences (COI or other molecular marker) should be provided when a new taxon is described in order to provide an additional method of identification.

Materials and methods
The samples of thrips were collected into 95% ethanol and stored at -20°C. Total genomic DNA was extracted from single thrips using the method of Rugman-Jones et al. (2006), Mound et al. (2010) and Chen et al. (2011). The COI was amplified using primers LCO1490 and HCO2198 (Mound et al. 2010). Sequences were assembled by Seqman II (DNAstar, Inc., Madison, WI, USA) and then aligned using Clustal W.
The remaining carcass was removed and stored in 10% KOH for several days (usually 4-6 days for the large thrips, about 8-10 mm), then mounted in Canada balsam. Descriptions and pictures are based on permanent slides of specimens using a Leica DM4000B microscope. Measurements and pictures were processed using the Leica Microsystems with Microsoft QWIN (Leica QWin plus). Thrips terminology in this paper generally follows Mound (2011) and Okajima (2006). The unit of measurements is micrometre.

Depositories and abbreviations
All specimens including types and vouchers are deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing, China. The following abbreviations are used for pronotal setae: am-anteromarginals, aa-anteroangulars, ml-midlaterals, epim-epimerals, epima-epimeral accessory, pa-posteroangulars, pm-posteromarginals.

Meiothrips
Priesner http://species-id.net/wiki/Meiothrips Idolothrips (Meiothrips) Priesner, 1929: 197. Type-species: Idolothrips (Meiothrips) annulatus Priesner, now considered a synonym of Acanthinothrips annulipes Bagnall (Palmer and Mound 1978). Meiothrips Priesner: Bagnall 1934: 494;Ananthakrishnan 1964: 98;Kudo and Ananthakrishnan 1974: 385;Palmer and Mound 1978: 209. Generic diagnosis. Body large. Head much longer than width across eyes, prolonged in front of eyes, usually shorter than broad except in one species about twice as long as broad; eyes normal or obviously prolonged on ventral surface; interocellar, postocellar, postocular, mid-dorsal and posterior-dorsal setae usually well developed, sometimes small. Maxillary stylets short and far apart. Antennae 8-segmented, very slender; segment III longest, usually more than twice width across eyes; segments III and IV with 2 and 4 sense-cones. Pronotum major setae usually well developed setae, sometimes aa small and epimeral accessory always minute; notopleural sutures incomplete; basantra and ferna present. Mesopraesternum boat-shaped. Metathoracic sternopleural sutures absent. Wings usually fully developed with or without numerous duplicated cilia. All legs normal, femora with several spine-setae. Pelta always broad, lateral lobes broadly joined to median major lobe; abdominal tergites II-VII each with two pairs of sigmoid wing-retaining setae; tergites V-VIII never with lateral tubercles; tube much longer than head, surface with numerous fine setae, sometimes with 2 rows of stout tubercles and many large and small tubercles or denticles on dorsal surface; anal setae much shorter than tube. Distribution. China (Zhejiang, Yunnan, Hainan); India, Nepal, Malaysia, Thailand.
Biology. The species of Meiothrips are presumed to all feed only on fungal-spores. In the field, Meiothrips natural populations with deposited egg masses have been observed only on newly-dead dry or withered leaves hanging on branches.
Comments. This genus is close to Idolothrips and Bactrothrips. The morphological characters of the females, and the head and thorax of males, are similar in the three genera. Mound and Palmer (1983) pointed out that the species are intermediate in structure between Idolothrips and Bactrothrips, such that each could be placed in a separate genus if the traditional concepts employed in the Bactrothrips complex were accepted. M. kurosawai is particularly unusual with the eye prolonged posteriorly on the ventral surface of the head, and a long preocular projection. The systematic position and relationships of these genera require further study. Male macroptera. Body uniformly dark brown; antennal segments I-II brown, III yellow but shaded in distal and near basal part, IV-V shaded but yellow in distal pedicels 0.3-0.4, VI-VIII brown; fore wings shaded with brown longitudinal band medially in basal half; femora dark brown but about basal 2/3 and extreme distal of hind femora yellow (Figs 7, 16), tarsi, distal half and extreme bases of tibiae yellow; tube dark brown; major setae yellowish. Head 2.3 times as long as width across eyes, projecting in front of eyes, transversely striate; interocellar setae long, longer than width of one eye, one pair of postocellar setae about 1.7 times as long as diameter of posterior ocellus; eyes developed, about 0.4 of head length, postocular setae and one pair of postocular cheek setae similar with postocellar setae; mid-dorsal setae longest; cheeks with several pairs of minor setae. Maxillary stylets wide apart, retracted into head one fourth way to posterior margin of eyes (Figs 2, 13). Antennal segment III 2.2 times as long as head width across eyes (Figs 1, 13), III with 2 sensoria, IV with 4, V with 2, VI and VII each with one, these sensoria on III and IV about 2.0 times as long as apical width of segment, segments VI-VII with a short apical, ventral prolongation.
Remarks. This species is similar to M. nepalensis in that the tube of males bears about two rows of stout tubercles also many small tubercles. But the new species can be distinguished by the following characters: fore and mid-femora uniformly dark brown, only hind femora bicolored with about basal 2/3 and extreme distal parts yellow (nepalensis: fore femora uniformly dark brown, mid-and hind femora bicolored with about basal half yellow and apical half dark brown), pronotal am and aa setae about 0.3 times as long as epim setae (nepalensis: am and aa minute, much less than 0.3 times as long as epim).
COI sequences. We received two sequences of the new species, which include 674bp and 647bp with the GenBank numbers JQ411299 and JM411300, respectively. Ananthakrishnan, 1964 http://species-id.net/wiki/Meiothrips_menoni Figs 20-22 Meiothrips menoni Ananthakrishnan 1964: 99;1971: 203;1973 Comments. This species is mainly distributed in South Asia. It was described originally from India by Ananthakrishnan (1964) from only one female. The specimens in this study are very similar to the original description, but the mid-and hind tibiae are similar to specimens from Malaysia and Thailand with a dark brown sub-basal mark and a narrow paler brown subapically. Palmer and Mound (1978) discussed the differences of the specimens from India, Malaysia and Thailand. The specimens in this study with long and pale pronotal major setae and head setae are more similar to the Indian specimens than the specimens from Malaysia and Thailand with short and dark setae, although specimens from Thailand have long pronotal pa and am. Further studies are needed combining the morphological and molecular evidence.
Comments. This species is known from Nepal (Kudo and Ananthakrishnan 1974) and Thailand (Palmer and Mound 1978), and is here recorded from China for the first time. The remarkable structure of this species is that the tube of the male bears two rows of stout tubercles and numerous small and large tubercles. Idolothrips dissimilis from Australia also shows similar structures.