Studies on the genus Psephenothrips Reyes from China (Thysanoptera, Phlaeothripinae), with one new species.

Species from China of the Asian genus Psephenothrips are reviewed, with P. eriobotryae sp. nov. collected from the leaves of Eriobotrya japonica in Sichuan Province. A key to the five species known from China is provided and the COI sequence of the new species is also given. Li-Hong Dang, Lin-Peng Zhao, Yan-Qiao Li, Ge-Xia Qiao.

Introduction

, the larger of the two subfamilies of , is generally accepted as including three groups, , -lineage and -lineage, with the last one considered to be complex and polyphyletic (Buckman et al. 2013). Of the other two, reasonably well-defined major groups, has been given a formal tribal name (Minaei and Mound 2008), but the -lineage of leaf-feeding species remains confused and difficult to interpret. The major reason is that about half of the genera are monobasic, with many poorly-defined genera and no clear suprageneric classification (Stannard 1957; Mound and Marullo 1996; Buckman et al. 2013; Dang et al. 2014). There is a lack of identification systems worldwide to members of the -lineage and, for China, a serious lack of field studies of species and genera of the -lineage. Dang et al. (2014) provided a key to 100 genera from southeast Asia and China, including 34 genera associated with . More recently, Wang and Lin (2020) published keys to 11 genera and 28 species of -lineage from Taiwan. However, there is a lack of information about the fauna of mainland China and preparation of suitable identification systems will require a great deal of work studying slide-mounted specimens and establishing host associations through extensive field work.

As part of attempted studies on the -lineage from China, the Asian genus is reviewed here. This is one of the poorly-defined genera associated with , with which it shares the following characteristics: antennal segment III with one outer sense cone, segment IV with 1+2 sense cones and prosternal basantra absent. However, species of this genus differ in having the maxillary stylets long and close together in the middle of the head, the fore tarsal tooth absent in both sexes and the male sternite VIII without a pore plate (Okajima 2006; Tyagi and Kumar 2012). Worldwide, there are seven species listed in this genus (ThripsWiki 2021), of which the type species was described from Philippines, , and from Japan and from India (Reyes 1994; Okajima 2006; Tyagi and Kumar 2012). Recently, Wang and Lin (2020) reported four species in this genus from Taiwan, of which and were new species. Presumably, these species all feed on green leaves, although and were collected from dead branches and wood. The new species sp.nov. is described here from Sichuan Province and from Yunnan Province is newly recorded from the Chinese mainland. A key to five species from China is provided and the COI sequence of the new species is also given.

Methods

The descriptions, photomicrograph images and drawings were produced from slide-mounted specimens using an Olympus BX53 microscope with a drawing tube. The abbreviations used for the pronotal setae are as follows: am – anteromarginal, aa – anteroangular, ml – mid-lateral, epim – epimeral, pa – posteroangular. The unit of measurements is the micrometre. All specimens studied here are deposited in the School of Bioscience and Engineering, Shaanxi University of Technology (), Hanzhong, China, with some specimens in the National Zoological Museum of China (), Institute of Zoology, Chinese Academy of Sciences, Beijing, China.

Taxonomy

Reyes

83E85954-EAF1-59B5-9838-6387848C3872

Reyes, 1994: 478. Type species:

Diagnosis.

Head as long as broad or longer than broad; postocular setae well developed, shorter or as long as eyes. Antenna eight-segmented, segment III with 0+1 sense cone, IV with 1+2 sense cones. Maxillary stylets long, reaching eyes and close together in the middle of head and maxillary bridge absent. Prothorax usually with five pairs of setae, sometimes am minute; notopleural sutures complete; basantra absent. Mesopresternum boat-shaped or divided into two parts; metathoracic sternopleural sutures present or absent. Fore tarsus without tooth in both sexes. Fore wing parallel-sided, with numerous duplicated cilia. Pelta broadly triangular; abdominal tergites II–VII with two pairs of sigmoid wing-retaining setae; tergite IX with S1 and S2 setae shorter or as long as tube. Male without a pore plate on abdominal sternite VIII.

Comments.

The species of are similar to , but they are distinguished by the long maxillary stylets that are close together in the middle of the head and abdominal segment VIII without a pore plate in the male. This genus is also closely related to in body shape as well most characters including those above (Mound 1968). In this study, these two genera could not be separated from each other. However, according to the generic diagnosis (Mound 1968; Dang et al. 2014), can be distinguished from only by having no stout maxillary bridge and that is the reason this new species, sp.nov., is considered to be a species of . They both are poorly-defined genera in the -lineage and the relationship between them is extremely confused and requires further considerable study.

Key to species from China

*from descriptions; Okajima 2006; Wang and Lin 2020.

Wang & Lin

7A484A35-9F99-595D-96EF-6E1B2078B3BB

Wang & Lin, 2020: 371.

Described recently from Taiwan, this species was based on three females collected from dead wood. However, as it shares the characteristics of the -lineage, it presumably feeds on green leaves. In this study, no specimen was examined, but antennal segments VI–VIII were described as uniformly dark brown and this distinguishes the species within the genus .

Wang & Lin

896D4F76-431B-5014-A001-58D28AB007AE

Wang & Lin, 2020: 371.

As with , this species was described from Taiwan and was based on six females and three males from . We did not see any specimens of and the original description “mid tibiae greyish brown and fore wings pale brown” is not strong evidence for distinguishing the species from and other species. The mesopresternum, divided into two parts that may be narrowly connected, could be an obvious distinguishing characteristic, but its form needs to be verified in further study.

Dang & Qiao sp.nov.

A4F88D62-2F48-5727-BB9B-97A3EEF970A1

http://zoobank.org/7DCC1A9C-8306-4E14-9ACA-0918D510C950

Figs 1–7 , 8–15

Figures 1–7.

sp. nov. 1 head, pronotum and fore legs 2 tergites I, female 3 pelta 4 base of forewing 5 mesopresternum 6 tergites IX–X, male 7 antenna.

Figures 8–15.

sp. nov. 8 adult, female 9 adult, male 10 prosternum and mesopresternum 11 meso-, metanotum and pelta 12 head and pronotum 13 antenna 14 tergites IX–X, male 15 tergites IX–X, female. Scale bars: 100 μm.

Material examined.

♀ (SUT), China, Sichuan Province, Guangyuan City, Fenghuangshan Park, on the leaves of loquat tree ( (Thunb.) Lindl, 07.viii.2018, L.H. Dang, Y. Hu & D.L. Xie. 3♂, with the same data as holotype.

Body uniform brown (Fig. 8); head as long as wide (Figs 1, 8), postocular setae shorter than eyes, very weakly expanded at apex (Fig. 1); maxillary stylets retracted into eyes, little wide apart (Figs 1, 8); pronotal am minute, other four pairs of major setae well-developed, weakly expanded at apex (Fig. 1); mesopresternum boat-shaped with a protrusion (Figs 5, 10); metathoracic sternopleural sutures absent; fore wing sub-basal setae S1 about as long as S2, expanded at apex, S3 small, pointed (Fig. 4); female abdominal tergite IX setae S1 and S2 shorter than tube (Figs 2, 15); male abdominal sternite without a pore plate, S2 setae of tergite IX short and stout (Figs 6, 14).

Description.

Body brown (Fig. 8). Antennal segments I–II and VII–VIII brown, III yellow, IV–V yellow, but apically brownish, VI brown with basal part yellow (Fig. 13); fore tibiae yellowish-brown with brown at basal 1/3, all tarsi yellow, rest of legs brown (Fig. 8). All major setae yellowish-brown.

Head as long as wide (Figs 1, 8); dorsal surface weakly sculptured with transverse striae, ocellar region smooth; postocular setae shorter than eyes, very weakly expanded at apex (Fig. 1); cheeks gradually narrowed towards base, with a few stout setae; mouth-cone rounded, maxillary stylets retracted into eyes, little wide apart (Figs 1, 8). Antennae 8-segmented, VIII weakly constricted at base, slightly shorter than VII, sense cones stout, III with 0+1, VI with 1+2, V–VI with 1+1, respectively (Fig. 7).

Pronotum almost smooth, notopleural sutures complete (Figs 1, 12), am minute, other four pairs of major setae well-developed, weakly expanded at apex, epim about as long as pa (Fig. 1); metanotum weakly sculptured with reticulation, with pointed setae (Fig. 11); mesopresternum boat shaped with a protruding (Figs 5, 10), metathoracic sternopleural sutures absent. All legs normal, without fore tarsal tooth (Fig. 1); fore wing parallel sided (Fig. 8), with 8–14 duplicated cilia, sub-basal wing setae arranged in a triangle, S1 about as long as S2, expanded at apex, S3 small, pointed (Fig. 4).

Pelta round triangled and reticulate (Figs 3, 11); abdominal tergites II–VII with two pairs of wing-retaining setae; tergite IX setae S1 and S2 shorter than tube, nearly pointed or narrowly blunt at apex (Figs 2, 15); tube about 2.0 times as long as basal width, anal setae slightly shorter than tube.

(holotype female in microns). Body length 2545. Head length 215, width across eyes 215; eye length 83, width 65; postocular setae length 38. Antennae length 450, segments I–VIII lengths 46, 58, 65, 60, 55, 55, 44 and 41. Pronotum length 163, width 315, length of pronotal setae, am 5, aa 30, ml 25, epim 65, pa 65. Fore wing length 895, wing sub-basal S1–S3, 40, 35 and 15. Pelta length 110, width 200; tergite IX posteromarginal setae S1–S3, 105, 85 and 102; tube length 165, basal width 88, width in the middle 68, at apex 38; anal setae length 160.

Very similar to female (Fig. 9), fore legs without fore tarsal tooth (Fig. 9); abdominal sternite without a pore plate, S2 setae of tergite IX short and stout (Figs 6, 14).

(paratype male in microns). Body length 2190. Head length 195, width across eyes 203; eye length 75, width 65; postocular setae length 60. Antennae length 460, segments I–VIII length 42, 60, 65, 62, 57, 57, 55 and 45. Pronotum length 150, width 370, length of pronotal setae, am 10, aa 38, ml 40, epim 75, pa 56. Fore wing length 860, wing sub-basal S1–S3, 38, 30 and 20. Pelta length 95, width 175; tergite IX posteromarginal setae S1–S3, 120, 45 and 155; tube length 185, basal width 90, width in the middle 65, at apex 38; anal setae length 155.

COI sequence.

It includes 1492 bp with the GenBank number MW567215.

Etymology.

This species name is composed of one Latin word, , based on its host plant.

Comments. This new species can be distinguished from the other members of by having pronotal am minute. It is similar to in body shape and colour, but differs in having postocular setae shorter than eyes (Figs 1, 8), sub-basal setae S3 small and pointed at apex (Fig. 4), and posteromarginal setae of tergite IX much shorter than tube (Figs 2, 15). In , the postocular setae are about as long as eyes (Fig. 16), sub-basal setae S3 are as long as S2 and expanded at apex (Fig. 21), and posteromarginal setae of tergite IX are slightly shorter than tube (Fig. 19).

Figures 16–25.

16 head, pronotum and fore leg 17 mesopresternum 18 meso- and metanotum 19 tergites IX–X, female 20 antenna 21 base of forewing 22 tergites V–VI 23 pelta 24 metathoracic sternopleural suture, left 25 tergites IX–X, male.

Okajima

2B384F65-C5A3-5485-BABD-E573A0416E39

Figs 16–25

Okajima, 2006: 554.

Described from Japan on dead branches, this species was recorded from Taiwan on by Wang and Lin (2020). It is here recorded from the Chinese mainland in Yunnan Province for the first time, based on five females and one male from a mango tree. Although the original description stated this species was collected from dead branches, it could be feeding on green leaves.

(Moulton)

DAA9109B-9CD1-55E6-83A1-7329759024FF

Moulton, 1928: 313.

Described from Taiwan by Moulton (1928), this species was transferred by Okajima (2006) to the genus after checking the types and many specimens from Japan. Subsequently, Ananthakrishnan and Varadarasan (1978) from India was synonymised with by Tyagi and Kumar (2012), based on all paratypes and three females. These specimens were all collected from leaves of sp., but no specimen was examined in the present study. According to the re-description by Okajima (2006), this species is similar to sp.nov., but can be distinguished by the well-developed pronotal am setae and sub-basal wing setae S3 developed and expanded at the apex. Moreover, they feed on different plants.

1	Four pronotal major setae well-developed, am setae minute	eriobotryae sp.nov.
–	Five pronotal major setae well-developed including am setae	2
2	Metathoracic sternopleural sutures absent or vestigial	3
–	Metathoracic sternopleural sutures distinct	4
3	Antennal segment VIII about as long as VII	leptocerus
–	Antennal segment VIII shorter than VII	machili *
4	Mesopresternum boat-shaped with a sharp median protruding	baiheensis *
–	Mesopresternum narrowly connected or separated into 2 parts	cymbidas *