Four new species of Closterocerus Westwood (Hymenoptera, Eulophidae) from China, with a key to Chinese species

Ming-Rui Li; Cheng-De Li

doi:10.3897/zookeys.1017.62256

Abstract

Four new species of Closterocerus Westwood, C. rectisulcus sp. nov., C. shaanxiensis sp. nov., C. separatus sp. nov. and C. unifasciatus sp. nov. are described from China, each with a distinct pattern on the fore wings, and belonging to subgenus Closterocerus. A key to all species of the genus Closterocerus in China is provided.

Keywords

Chalcidoidea, Entedoninae, natural enemy, parasitoid wasp, taxonomy

Introduction

Closterocerus Westwood (Hymenoptera, Eulophidae, Entedoninae), contains 74 valid species worldwide, but only four species have been recorded from China (Noyes 2020). Hansson (1994) divided the Nearctic species into two subgenera, Achrysocharis Girault and Closterocerus Westwood according to whether the pedicel was compressed or not. Species of subgenus Closterocerus, with a more or less compressed pedicel provided with dorsal and ventral edges, include one Holarctic species (C. trifasciatus Westwood), seven Nearctic species (C. brachyphagus Hansson, C. cincinnatus Girault, C. cinctipennis Ashmead, C. nitidus Hansson, C. ruforum (Krausse), C. tau Girault, C. utahensis Crawford) and one Palearctic species (C. lyonetiae (Ferrière)). Additional species from other parts of the world possibly belong to the subgenus Closterocerus, but the descriptions lack the character Hansson (1994) used to characterize the subgenus.

In the present paper, we describe four new species of the subgenus Closterocerus s. str. from China, each with a distinct pattern on the fore wing, and a key to all species of the genus Closterocerus distributed in China is provided.

Material and methods

Specimens were collected by sweeping, and were dissected and mounted in Canada Balsam on slides following the method of Noyes (1982), or mounted on a card. Photos were taken with a digital CCD camera attached to an Olympus BX51 compound microscope or Aosvi AO-HK830-5870T digital microscope. Measurements were made using an eye-piece reticle, or using the ruler tool in Adobe Photoshop 2020.

Terminology follows the Hymenoptera Anatomy Consortium (2020), and the following abbreviations are used:

F1–5 flagellomeres 1–5;

HE height of eye;

MS malar space;

MV marginal vein;

OOL minimum distance between a posterior ocellus and corresponding eye margin;

PMV postmarginal vein;

POL minimum distance between posterior ocelli;

SMV submarginal vein;

STV stigmal vein;

WM width of mouth opening.

All type material is deposited in the insect collections at Northeast Forestry University (NEFU), Harbin, China.

Taxonomy

Key to Chinese species of genus Closterocerus (females)

1	Pedicel and flagellum not compressed, and all flagellomeres longer than wide (fig. 1A in Yang and Luo 1994); fore wing without distinct infuscate transverse band, only with a brown spot around STV (fig. 1C in Yang and Luo 1994)	C. litchii (Yang & Luo, 1994)
–	Pedicel and flagellum compressed, and at least 1–2 flagellomeres wider than long or quadrate (e.g. Figs 5, 31); fore wing with 1–3 distinct infuscate bands (Figs 7, 25, 33) (Closterocerus s. str.)	2
2	Scape slightly compressed, widest in middle part; F3 wider than F2 (Fig. 31)	C. unifasciatus Li & Li, sp. nov.
–	Scape strongly compressed, widest at apex; F3 at most as wide as F2, usually narrower (Fig. 5)	3
3	Frontal sulcus V-shaped (Figs 20, 22); infuscate transverse band at apex of fore wing not V-shaped	4
–	Frontal sulcus straight (Figs 2, 4); infuscate transverse band at apex of fore wing V-shaped (Fig. 7)	7
4	Mesoscutellum distinctly convex, metascutellum small, predominantly hidden under mesoscutellum	C. cincinnatus Girault, 1916
–	Mesoscutellum distinctly flat, metascutellum larger, not hidden under mesoscutellum (Figs 21, 32)	5
5	Fore wing, between cubital setal line and hind margin of wing with a longitudinal infuscation (Fig. 25); head in frontal view about 1.4 times as wide as high, nearly oval (Fig. 20)	C. separatus Li & Li, sp. nov.
–	Fore wing, between cubital setal line and hind margin of wing hyaline, without the longitudinal infuscation; head in frontal view about 1.65 times as wide as high, nearly triangular (Fig. 2)	6
6	F2 distinctly wider and longer than F1; median part of midlobe of mesoscutum usually differently colored from lateral parts of midlobe; median part of mesoscutellum usually with a differently colored longitudinal band	C. trifasciatus Westwood, 1833
–	F2 similar to F1; mesoscutum and mesoscutellum always unicolorous	C. eutrifasciatus Liao, 1987
7	Propodeal plica absent, spiracular sulcus present (Fig. 6); transverse V-shaped band at apex of fore wing dark and distinct (Fig. 7)	C. rectisulcus Li & Li, sp. nov.
–	Propodeal plica present, spiracular sulcus absent; transverse V-shaped band at apex of fore wing much paler and obscure (Fig. 14)	C. shaanxiensis Li & Li, sp. nov.

Closterocerus rectisulcus Li & Li, sp. nov.

http://zoobank.org/9DD5A3E2-25AF-4EBD-BB29-56AFDC94F088

Figs 1–3, 4–9

Type material

Holotype : ♀ [NEFU; on slide], China, Heilongjiang Province, Shangzhi City, Maoershan, 04.VIII. 2016, Si-Zhu Liu, Ye Chen and Hai-Yan Wang, sweeping. Paratypes: 4♀ [1 on slide, 3 in alcohol], same data as holotype; 2♀ [in alcohol], China, Liaoning Province, Anshan City, Mountain Qian Shan, 23.VI.2015, Hui Geng, Si-Zhu Liu, Zhi-Guang Wu and Yan Gao, sweeping; 1♀ [in alcohol], China, Shaanxi Province, Ankang City, Ningshan County, Guanghuojie Town, 03.VIII.2015, Ye Chen and Chao Zhang, sweeping; 2♀ [1 on card, 1 in alcohol], China, Shaanxi Province, Ankang City, Ningshan County, Chengguan Town, Huoditang Forestry Station, 11.VIII.2015, Ye Chen and Chao Zhang, sweeping.

Figures 1–3.

Closterocerus rectisulcus Li & Li, sp. nov., paratypes, females 1 habitus in dorsal view, on card 2 head, frontal view, before slide-mounting 3 mesosoma and petiole, before slide-mounting. Scale bars: 100 μm.

Diagnosis

Frontal sulcus straight, reaching eye margins; fore wing with three infuscate transverse bands (Fig. 7): band I V-shaped, with upper arm longer and more distinct than lower arm; band II obscure medially or nearly interrupted; band III V-shaped, with upper arm slightly longer than lower arm; the three bands are nearly connected in the middle; stigmal hairline absent, radial cell setose; below base of cubital setal line with five setae in a row; propodeum with a short median carina delimited by a transverse carina posteriorly; propodeal plica absent; spiracular sulcus present.

Figures 4–9.

Closterocerus rectisulcus Li & Li, sp. nov., holotype, female, on slide: 4 head, frontal view 5 antenna 6 mesosoma and petiole 7 fore and hind wings 8 metasoma without petiole 9 legs, from left to right: fore, mid and hind leg. Scale bars: 100 μm.

Description

Female. Length 0.9–1.3 mm. Scape and pedicel dark brown to black. Flagellum dark brown to pale brown, becoming gradually paler distad. Eyes red, ocelli pale brown. Vertex and frons above frontal sulcus golden-green to golden-blue. Frons below frontal sulcus golden-yellow to golden-green. Mandibles pale brown. Pronotal collar, mesoscutum, mesoscutellum and axillae golden-green in dorsal view, golden-blue in lateral view. Metascutellum and propodeum dark bronze. Fore wing (Fig. 7) with three infuscate transverse bands: band I (below the middle of MV) V-shaped, with upper arm longer and more distinct than lower arm; band II (below STV), obscure medially or nearly interrupted; band III (at apical margin of fore wing) V-shaped, with upper arm slightly longer than lower arm; the three bands are nearly connected in middle. All coxae, femora and tarsal claws dark brown (metacoxae darker, nearly black); trochanters pale brown; protibiae and mesotibiae mainly pale yellow, slightly pale brown basally; metatibiae dark brown; pro- and mesotarsi pale yellow with last tarsomere pale brown; metatarsi pale yellow with last tarsomere dark brown. Metasoma dark brown with weak metallic bluish-green to bronze reflections.

Head (Figs 2, 4), in frontal view 1.4 times as wide as high. Sculpture on vertex and frons above frontal sulcus nearly with the same sized meshes. POL : OOL = 7 : 5. Frontal sulcus straight, reaching eye margins; inner eye margins slightly concave in lower part. Antennal scrobes join on frontal sulcus. Malar sulcus absent, but with a curved transverse carina near clypeus, extending to lower eye margins. Clypeus not delimited. HE : MS : WM about 4.8 : 1.0 : 3.3. Antenna (Fig. 5) inserted slightly above level of lower margin of eyes. Scape reticulate, extremely compressed, and expanded from base to apex, about 2.1 times as long as wide. Pedicel moderately compressed compared to the extremely compressed scape, slightly shorter than wide (ca 4 : 5). Flagellum extremely compressed; F1–3 wider than long, F2 longer and wider than F1 and F3; F4 quadrate; F5 small, tapering distad, with terminal spine shorter than the segment.

Mesosoma (Figs 3, 6). Pronotum, mesoscutum, mesoscutellum, axillae and posterior part of propodeum with reticulate sculpture, meshes nearly of same size (but wider on mesoscutellum). Metascutellum with irregular rugae. Pronotum transverse, invisible in dorsal view. Median area of mesoscutum with two pairs of setae. Notauli curved in anterior part, and indicated posteriorly by depression. Mesoscutellum 0.97 times as long as wide. Axillae slightly advanced forwards in front of level of anterior margin of mesoscutellum. Mesoscutum and mesoscutellum slightly convex. Metascutellum about 1/3 as long as median length of propodeum. Propodeum with a short median carina delimited by a transverse carina posteriorly. Propodeal plica absent, spiracular sulcus present. Fore wing (Fig. 7) about twice as long as wide, without stigmal hairline, radial cell setose. Speculum closed below. Ratio length of: SMV : MV : PMV : STV about 3 : 6 : 1 : 1. Cubital setal line straight and completely extending to base of MV. Below base of cubital setal line with five setae in a row. Hind wing (Fig. 7) about 4.5 times as long as wide. Legs (Fig. 9) with all coxae reticulate on outer surface; ventral margin of pro- and metafemur with six and ten long setae respectively; mesotibial spur about 0.9 times as long as corresponding basitarsus.

Metasoma (Fig. 8) ovate; petiole short, pyriform; ovipositor exserted beyond apex of metasoma.

Male. Unknown.

Host

Unknown.

Etymology

The name refers to the straight frontal sulcus in this species (rectus is Latin for straight).

Distribution

China (Heilongjiang, Liaoning, Shaanxi provinces).

Remarks

Closterocerus rectisulcus sp. nov. is similar to C. orientalis Yefremova & Kriskovich, 1996 because they share a similar pattern of the fore wing according to the description. The new species differs as follows: pedicel slightly shorter than, or at most as long as wide (longer than wide in C. orientalis); mesoscutellum approx. as long as wide (three times as long as wide in C. orientalis); mesotibial spur 0.9 times as long as corresponding basitarsus (1.7 times as long as corresponding basitarsus in C. orientalis).