Two new species of Dzhanokmenia (Hymenoptera, Eulophidae) from China, with first report on a host association for the genus

Abstract Two new species of Dzhanokmenia Kostjukov (Hymenoptera: Eulophidae: Tetrastichinae), D. stefaniolae Li, Wang & Hu, sp. nov. and D. yuxuannis Li, Wang & Hu, sp. nov., are described and illustrated from Xinjiang Uyghur Autonomous Region, China. D. stefaniolae was reared from stem-galls made by Stefaniola sp. (Diptera: Cecidomyiidae) on black saxaul, Haloxylon ammodendron (Chenopodiaceae); D. yuxuannis was collected by sweeping from both black saxaul and white saxaul, H. persicum, in Beishawo Desert near Fukang. A key to females of all known species of Dzhanokmenia is provided.


Introduction
Tetrastichinae is the largest subfamily of Eulophidae (Hymenoptera: Chalcidoidea). At present, this subfamily includes about 1900 species in more than 100 genera throughout the world (Noyes 2020). Kostjukov (1977) regarded Tetrastichus (Dzhanokmenia Kostjukov), with typespecies Tetrastichus bibikovae Dzhanokmen, as one of the 17 subgenera of the genus Tetrastichus Haliday (sensu lato). Graham (1991) revised the European Tetrastichinae, recognizing 28 valid genera including Dzhanokmenia, which he upgraded to genus level. The reasons why it was given a generic rank were discussed in Li et al. (2016).  and Kosheleva (2014, 2015) described three species of Dzhanokmenia. Li et al. (2016) described three more species of the genus during an expedition to study insect biodiversity of the Junggar Basin in northern Xinjiang Uyghur Autonomous Region (hereafter Xinjiang), China. Up to now, 13 valid species of Dzhanokmenia have been described from arid and semi-arid areas of southern Russia and Central Asia; however, their hosts remained unknown.
Here we describe two new species of Dzhanokmenia from rearings and collections, and provide a key to females of all known species of the genus.

Parasitoid wasp collection and rearing
Our research group (Hong-Ying Hu, Qin Li, Wan Yin, Ya-Jie Zhu, Feng Li) collected many insects in 2015 by sweeping with a net and searching for galls on black saxaul, Haloxylon ammodendron, and white saxaul, H. persicum (Chenopodiaceae), in Beishawo Desert,near Fukang (44°22'29"N to 44°22'49"N,87°52'57"E to 87°52'58"E,. These galls were reared by Qin Li in the laboratory at room temperature (20-32 °C) and 22-60% relative humidity, with natural and fluorescent lighting of approximately 13:11 L:D, at the College of Life Science and Technology, Xinjiang University, Urumqi. The emerged insects were preserved in 100% ethanol after dying naturally, without any food or water for 2-3 days usually.

Taxonomy
All the specimens were examined under a Nikon SMZ 745T stereomicroscope. The images were taken with a Nikon DS-Fi3 connected to a Nikon SMZ 25 stereomicroscope. All images were stacked with NIS-Elements software and arranged in plates using Adobe Photoshop.
Description of each new species is based on its holotype, with variation of some key morphological features in the paratypes summarized separately. Morphology and terminology follows Gibson (1997) except for the metasoma. Gibson (1997) used petiole + gaster for the metasoma. In the case of Dzhanokmenia, the petiole is sessile and metasoma is equal to gaster, the metasomal terga I-VII are synonym with gastral terga I-VII. Abbreviations of morphological terms used are: C3, claval segment 3; CC, length of costal cell; CL, length of clava; CW, width of clava; EH, height of eye; EL, length of eye; F1-F3, funicle segments 1-3; FWL, length of fore wing; FWW, width of fore wing; GL, length of metasoma; GW, width of metasoma; HL, head length; HW, head width; HWL, length of hind wing; HWW, width of hind wing; MFL, length of metafemur; MFW, width of metafemur; ML, length of mesosoma; MLL, length of midlobe of mesoscutum; MLW, width of midlobe of mesoscutum; MSP, malar space; MV, length of marginal vein; MW, width of mesosoma; OOL, distance between eye and posterior ocellus; PMV, length of postmarginal vein; POL, distance between posterior ocelli; PSV, length of parastigma; SL, length of scape; SMV, length of submarginal vein of fore wing; STL, length of scutellum; STV, length of stigmal vein; STW, width of scutellum; SW, width of scape.
An acronym for the depository of parasitoids is: ICXU, Insect Collection of College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China. All the parasitoids were identified by the first and second authors. Stefaniola sp. was identified to genus by Ke-Long Jiao (Department of Plant Protection, College of Horticulture and Landscape, Tianjin Agricultural University, Tianjin, China), in whose collection some of the voucher specimens of this gall-maker are deposited; the remainder are in ICXU.
The key is an update of that in Li et al. (2016).

Results
Two new species of Dzhanokmenia Kostjukov are described and illustrated here.  Figs 1-6). Body length 2.1 mm; Head with metallic tinge, vertex with small yellow area outside of each posterior ocellus, and with a triangular yellow T-shaped area in front of anterior ocellus; eye red; ocelli dark red; antenna with scape, pedicel and flagellum yellow; mandible dark brown. Mesosoma green with strong metallic tinge. Legs yellow except all coxae mostly dark green with metallic luster, as on mesosoma, and apical tarsomeres brown (Fig. 2). Metasoma with tergum I yellow except for metallic tinge in a triangular anteromedial area; terga II-IV entirely yellow; tergum V medially with a round green or orange metallic pattern; tergum VI mostly with green metallic tinge, laterally with small yellow part round like, yellow part not large than metallic tinge area; tergum VII fully dark green with metallic tinge. Ovipositor black with green metallic tinge; hypopygium fully black with green metallic tinge; outer plate of ovipositor mostly black. Head (Fig. 3) 1.1× as wide as high, 1.5× as wide as midlobe of mesoscutum. Ocellar triangle surrounded by shallow grooves (vertex collapses along these lines in airdried specimens). POL 3.8× OOL. Torulus at lower margin of eye. Malar space about 0.4× eye height. Malar sulcus strongly curved.
Antenna (Fig. 4) with scape 4.0× as long as wide, not reaching anterior ocellus; pedicel 1.6×, F1 1.6×, F2 1.5×, F3 1.0×, and clava 1.9× as long as wide; C3 short with rounded apex, without a terminal spine. Mesosoma 1.7× as long as wide, convex. Pronotum in dorsal view medially very short. Mesoscutum with midlobe about 1.2× as long as wide, with median line very weak, and with a single row of 3 or 4 adnotaular setae. Scutellum 1.2× as long as wide, with anterior pair of setae in posterior half, and submedian and sublateral grooves strong and parallel to each other. Propodeum medially as long as dorsellum, with a median carina but without paraspiracular carinae; callus with 4 or 5 setae; with a groove extending from spiracle to posterior margin of propodeum. Fore wing (Fig. 5) hyaline, 1.9× as long as wide. Speculum large, extending from parastigma to stigmal vein. Discal setae short. CC 1.6× as long as MV; MV thick, 6.0× as long as wide; MV 2.4× as long as STV, with 7 marginal setae (about 0.5× as long as STV); STV rather thick; PSV not thicker than MV, short, stub-like. Hind wing rounded apically, 4.5× as long as wide.
Variation (paratypes, Figs 7-12). Body length 1.9-2.1 mm. Metasomal tergum V with metallic area small to large size which occupying most of the tergum (Figs 7, 9, 11); tergum VI with metallic pattern area large to very large, relatively, with yellow part laterally from middle size to small (Figs 8, 10, 12); hypopygium from dark brown to black; outer plate of ovipositor mostly black to entirely black with metallic reflections (Figs 8, 10, 12). Pedicel 1.6-1.7×, F1 1.6-1.7×, F2 1.5-1.6×, F3 0.9-1.0×, clava 1.8-1.9× as long as wide. POL 3.8-4.0× OOL. EL 1.9-2.4× MSP. ML 1.6-1.7× MW. STL 1. Host. An unidentified species of Stefaniola Kieffer (Cecidomyiidae). The larval, pupal and adult stages of Stefaniola sp., are shown in Figs 13-17. The emergence hole of adult D. stefaniolae is shown in Fig. 18 Description. Female (holotype,. Body length 1.9 mm. Head with metallic tinge, eye red; ocelli dark red; antenna with scape, pedicel and flagellum yellow; mandible dark brown. Mesosoma with strong metallic tinge. Legs yellow except metacoxa mostly with metallic luster, as on mesosoma, and apical tarsomeres dark. Tergum I yellow except for metallic tinge in a triangular anteromedial area; terga II-IV entirely yellow; tergum V mostly yellow except medially with a faint pale brown round with faint metallic tinge; tergum VI mostly yellow, with brown stripe from anterior to posterior margins with green metallic tinge, with anterior margin brown; tergum VII with anterior triangular-shaped area dark brown with green metallic tinge, with yellow part laterally which is larger than the metallic area (Fig. 20). Ovipositor dark brown with metallic tinge; hypopygium laterally with a yellow oval area surrounded by brown to black part; upper outer plate of ovipositor with two dark brown stripe areas with metallic reflections on either side of ovipositor, and lower outer plate of ovipositor with yellow stripe-like part between dark brown stripe and ovipositor, which is linked with tergum VII. Head (Fig. 21) 1.2× as wide as high, 1.6× as wide as midlobe of mesoscutum. Ocellar triangle surrounded by shallow grooves. POL 5.0× OOL. Malar space about 0.4× eye height. Torulus at lower margin of eye. Malar sulcus strongly curved.
Mesosoma 1.8× as long as wide, convex. Pronotum in dorsal view medially very short. Mesoscutum with midlobe about 1.1× as long as wide, with median line very weak, and with a single row of 3 or 4 adnotaular setae. Scutellum 1.15× as long as wide, with anterior pair of setae in its posterior half, submedian and sublateral grooves strong and parallel to each other. Propodeum medially as long as dorsellum, with a median carina but without paraspiracular carinae; callus with 4 or 5 setae; with a groove extending from spiracle to posterior margin of propodeum.
Legs. Metafemur 3.3× as long as wide.  Metasoma 1.2× as long as mesosoma, 2.0× as long as wide; hypopygium extending to about half length of metasoma; cercal setae subequal in length; ovipositor sheath slightly protruding.
Variation (paratypes,. Body length 1.9-2.0 mm. Metasomal tergum V with pale brown round from nearly invisible to visible (Figs 20,23,25); tergum VI with brown stripe small to large, anterior margin pale brown to brown; tergum VII with anterior triangular-shaped to crescent-shaped area dark brown with green metallic tinge, laterally with yellow part occupying mostly area of tergum VII. Ovipositor brown to dark brown with faint green or orange metallic tinge; hypopygium with oval shaped yellow area middle size to large, which is surrounded by brown to black part with metallic tinge; upper outer plate of ovipositor with dark brown stripes narrow to wide, relatively, lower outer plate of ovipositor with yellow stripe-like part from wide to narrow (Figs 24,26 Table 1.

Discussion
The description and illustration of the two new species from the Beishawo desert and the key to the species will contribute to our understanding of Dzhanokmenia. The 13 described species of Dzhanokmenia, show quite different colour patterns of coxae, metasomal terga and hypopygium according to Dzhanokmen (1971), Kostjukov (1977Kostjukov ( , 1978Kostjukov ( , 1984, Kosheleva (2014, 2015) and Li et al. (2016). We regard the differences as interspecific characters which allow the separation of species in Dzhanokmenia as shown in the key.
Including two new species in this paper, 15 valid species of Dzhanokmenia are known from the arid to semi-arid regions of Southern Russia and Central Asia. However, hosts remain to be discovered for any of the species. Li et al. (2016) suggested that they are most likely associated with Haloxylon and Tamarix spp., feeding on them or as parasitoids of their pests. In this study, D. stefaniolae was reared from ball-like stem-galls of Stefaniola sp. on H. ammodendron for the first time. D. yuxuannis was collected by sweeping from both H. ammodendron and H. persicum at the same collecting site. This suggests a relationship between D. yuxuannis and Haloxylon spp., but it needs further study.
Besides D. stefaniolae, from ball-like stem-galls of Stefaniola sp. on both H. ammodendron and H. persicum in the same desert localities, we also reared Mesopolobus quadrimaculatus Dzhanokmen (Pteromalidae), Aprostocetus sp. (Eulophidae), Psyllaephagus caillardiae Sugonjaev (Encyrtidae), and also some unidentified Eurytomidae and Platygastridae (Hymenoptera) (specimens in ICXU). The relationships among these species and Stefaniola sp. are not clear and need further study. Currently, the taxonomy of the Palaearctic species of Stefaniola is in flux, so unfortunately this Stefaniola sp. cannot be positively identified to species (pers. comm. by Ke-Long Jiao). All coxae mostly dark green with metallic luster, as on mesosoma.
Pro-and mesocoxae mostly yellow, metacoxa with metallic luster as on mesosoma. Tergum V Metasomal tergum V medially with a round green or orange metallic pattern from small to large size which occupying most of the tergum.
Metasomal tergum V mostly yellow except medially with a pale brown round from nearly invisible to visible with faint metallic tinge. Tergum VI Tergum VI mostly with green metallic tinge from large to very large, relatively, laterally with small yellow part round like, from middle size to small.
Tergum VI mostly yellow, with brown stripe from anterior to posterior margins with green metallic tinge small to large, with anterior margin pale brown to brown. Tergum VII Tergum VII fully dark green with metallic tinge. Tergum VII with anterior triangular-to crescent-shaped area dark brown with green metallic tinge, laterally with yellow part occupying most of tergum VII. Ovipositor Ovipositor black with green metallic tinge.
Ovipositor brown to dark brown with faint green or orange metallic tinge. Hypopygium Hypopygium dark brown to black. Hypopygium with oval shaped yellow area medium-sized to large surrounded by brown to black part with metallic tinge. Outer plate of ovipositor Outer plate of ovipositor mostly black to entirely black with metallic reflections.
Upper outer plate of ovipositor with narrow to wide dark brown stripes, lower outer plate of ovipositor with wide to narrow yellow stripe-like part.