Pteromalus steppensis Li & Hu, 2025

Li, Qin, Liu, Ya-Lin, Yan, Guo-Hua, Zhang, Tong-You, Xiao, Hui & Hu, Hong-ying, 2025, Description of two new species of the genus Pteromalus Swederus (Hymenoptera, Pteromalidae, Pteromalinae) from Xinjiang, China, ZooKeys 1234, pp. 221-237 : 221-237

Pteromalus steppensis Li & Hu sp. nov.

Fig. 1 A – K

Type material.

Holotype. • 1 ♀ ( ICXU 20240801 ), Xinjiang, China, swept by Qin Li research group from Ulmus pumila L. ( Ulmaceae ) in People’s park of Changji City; 44°01'33.38"N, 87°18'42.67"E; 567 m; 24 May 2022 and deposited in ICXU . Paratypes: • 26 ♀ ( ICXU 20240802–20240827), and 68 ♂ (ICXU 20240828–20240895), same collection site as holotype; China, Xinjiang, Urumqi, campus of Xinjiang University , Qin Li reared from the larva and pupa of Orchestes steppensis Korotyaev, 2016 : • 5 ♀ ( ICXU 20240896 –20240900) 2 ♂ ( ICXU 20240901 –20240902), 30 May 2014; • 1 ♂ ( ICXU 20240903 ), 31 May 2015; • 2 ♀ ( ICXU 20240904 –20240905), 2 Jun 2015; • 1 ♀ ( ICXU 20240906 ), 3 Jun 2015; • 1 ♂ ( ICXU 20240907 ), 4 Jun 2015; • 2 ♀ ( ICXU 20240908 –20240909), 7 Jun 2015; • 26 ♀ ( ICXU 20240910 –20240935), 8 Jun 2015; • 9 ♀ ( ICXU 20240936 –20240944), 9 Jun 2015; • 8 ♀ ( ICXU 20240945 –20240952), 12 Jun 2015; • 1 ♀ ( ICXU 20240953 ), 15 Jun 2015; • 18 ♀ ( ICXU 20240954 –20240971) 14 ♂ ( ICXU 20240972 –20240985), 29. V. 2016; • 5 ♀ ( ICXU 20240986 –20240990) 13 ♂ ( ICXU 20240991 –20241003), 31 May 2016; • 2 ♀ ( ICXU 20241004 –20241005) 2 ♂ ( ICXU 20241006 –20241007), 3 Jun 2016; • 2 ♀ ( ICXU 20241008 –20241009), 8 Jun 2016; • 3 ♀ ( ICXU 20241010 –20241012) 1 ♂ ( ICXU 20241013 ), 13 Jun 2016; • 2 ♀ ( ICXU 20241014 –20241015) 2 ♂ ( ICXU 20241016 –20241017), 23 Jun 2016 .

Description.

Female. Body (Fig. 1 A ) length 2.5–3.2 mm (n = 24). Head and mesosoma dark green, propodeum with bluish-green metallic reflections, metasoma dark green with shine, hind margin of Gt 1, Gt 5 and Gt 6, mid-part of Gt 2, Gt 3 and Gt 4 black. Antenna with yellowish-brown scape; dorsal side of pedicel and flagellum dark chocolate-brown; ventral side yellowish brown. Mandibles brown, with dark-brown teeth. Legs with all coxae dark, metallic green; femora dark-chocolate-brown, tibiae and tarsi yellowish brown except last segment black-brown. Wings hyaline, forewing with venation brown.

Head in frontal view (Fig. 1 B ) 1.26–1.35 × as broad as high, face with metallic reflections and regular raised-reticulation; clypeus (Fig. 1 B ) with longitudinal striations; lower margin moderately emarginate, without teeth; both mandibles (Fig. 1 C ) 4 - toothed. Antennae (Fig. 1 B, D ) inserted at centre of face, higher than the lower margin of eyes; distance between upper margin of antennal toruli and lower margin of median ocellus 1.00–1.42 × as long as distance between lower margin of antennal toruli and lower margin of clypeus; antennae with scape reaching lower margin of anterior ocellus, 7.25–7.63 × as long as broad; pedicel 1.33–1.67 × as long as broad in dorsal view, 1.71–1.98 × as long as fu 1; two anelli annular; funicular segments connected tightly to each other and each with one row of sensilla; fu 1 and fu 2 1.00–1.20 × as long as broad each, fu 3 quadrate, fu 4 and fu 5 0.79–0.87 as long as broad each, fu 6 0.64–0.69 × as long as broad; clava 2.13–2.67 × as long as broad; pedicle and flagellum combined 0.73–0.84 × head width. Head in lateral view as in Fig. 1 E ; eye height 1.24–1.46 × eye width; malar sulcus linear and complete; malar space 0.35–0.50 × eye height. Head in dorsal view (Fig. 1 F ) about 2.13–2.45 × as broad as long; POL 1.10–1.14 × OOL (Fig. 1 F ).

Mesosoma in dorsal view 0.84–0.87 × head width; pronotum collar margined with carina, 0.71–0.85 × as wide as mesoscutum, medially 1 / 9–1 / 7 × as long as mesoscutum; mesoscutum 0.51–0.63 × as long as broad; scutellum 0.90–1.00 × as long as width, frenal line absent. Propodeum (Fig. 1 G ) 0.50–0.55 × as long as scutellum, with medial area smooth; median carina and plica complete and sharp; nucha with fine transverse striations. Mesosoma in lateral view with prepectus smooth, 0.75–0.86 × as long as tegula; entire thoracic pleura regularly reticulate, except upper mesepimeron smooth and shiny-metallic. Forewing (Fig. 1 I ) with apex exceeding apex of gaster, 2.01–2.24 × as long as broad; upper surface of costal cell bare, lower surface of costal cell with 2–3 rows of setae interrupted medially; basal setal line incomplete and basal cell bare; speculum large and open posteriorly. Marginal vein length 0.96–1.00 × postmarginal vein length and 1.43–1.68 × stigmal vein length; postmarginal vein length 1.50–1.71 × stigmal vein length. Metacoxa in dorsal view bare, with several long setaes (Fig. 1 H ), metafeumur 4.29–4.71 × as long as broad.

Gaster (Fig. 1 J ) long-oval, 1.98–2.38 × as long as broad, 1.43–1.88 × as long as mesosoma, 1.13–1.21 × as long as head plus mesosoma; Gt 1 0.20–0.25 × as long as gaster and sides of Gt 1 with some sparse long setaes; Gt 7 0.62–0.73 × as long as broad; ovipositor sheaths slightly exserted; hypopygium extending about 0.38–0.45 × the length of gaster.

Male (Fig. 1 K ). Body length: 3.0– 3.2 mm. Body color: head, mesosoma, and metasoma the same color as the female; antenna yellowish brown; legs yellow, except all coxae dark green with metallic reflections and apical tarsi black-brown. Wings hyaline, forewing with venation brown.

Head in frontal view 1.25–1.35 × as broad as high; distance between upper margin of antennal toruli and lower margin of median ocellus 0.92–1.16 × as long as distance between lower margin of antennal toruli and lower margin of clypeus; pedice and flagellum combined 0.89–0.96 × head width. Head in dorsal view 2.08–2.29 × as broad as long; POL 1.19–1.29 × OOL.

Mesosoma in dorsal view 0.79–0.81 × as head width; pronotum 0.81–0.85 × as wide as mesoscutum; mesoscutum 0.66–0.67 × as long as broad. Propodeum 0.49–0.54 × as long as scutellum. Forewing with marginal vein length 1.03–1.19 × postmarginal vein length and 1.48–1.88 × stigmal vein length; postmarginal vein length 1.44–1.60 × stigmal vein length.

Gaster long-oval, 1.89–2.18 × as long as broad, 0.77–0.84 × as long as head plus mesosoma; Gt 1 about 0.35–0.39 × as long as gaster.

Etymology.

The species is named after its host species Orchestes steppensis Korotyaev, 2016 (Coloptera, Curculionidae ) (used as a noun in apposition).

Biology.

This species was reared as a primary, solitary ectoparasitoid of the larval and pupal stage of O. steppensis Korotyaev, 2016 . Figures of the development and its damage on the host are provided in Figs 3 , 4 .

Distribution.

Changji and Urumqi, Xinjiang, China.

Comments.

This species is similar to P. procerus . In females of that species: both mandibles with four teeth; anterior margin of clypeus shallowly emarginate, hardly impressed in the middle; clypeus strigose, the striae hardly extending on to the face and genae; pronotal collar distinctly less wide than the mesoscutum, shorter medially than at the sides, medially from slightly more than 1 / 8–1 / 7 as long as the mesoscutum, finely reticulate with a narrow shiny strip along its hind edge, slightly to distinctly margined anteriorly; propodeum somewhat more than half as long as the mesoscutellum ( Graham 1969: fig. 389); gaster lanceolate or sublanceolate, usually as long as or slightly longer than the head plus thorax, occasionally slightly shorter, 1.8–2.3 times as long as broad. However, the new species can be distinguished from P. procerus by the following: POL 1.10–1.14 × OOL; distance between upper margin of antennal toruli and lower margin of median ocellus 1.00–1.42 × as long as distance between lower margin of antennal toruli and lower margin of clypeus; antennae with scape reaching lower margin of anterior ocellus; combined length of pedicellus and flagellum shorter than breadth of head (0.73–0.84 ×); medial area of propodeum smooth and shiny. In P. procerus : POL 1.20–1.25 × OOL; toruli about equidistant from the median ocellus and the lower margin of clypeus; antennae with scape reaching to level of vertex or slightly above it; combined length of pedicellus and flagellum almost equal to breadth of head; propodeum panels almost uniformly reticulate and not shiny.

In males of P. steppensis Li & Hu , sp. nov. (Fig. 1 K ): antenna yellowish brown; legs yellow, except all coxae dark green with metallic reflections, and apical tarsi black-brown; propodeum smooth and shiny, 0.49–0.54 × as long as scutellum. In contrast, in P. procerus (Fig. 2 A – D ): antenna dark brown to black; pale parts of the legs yellowish, hind femora lightly infuscate at the base only and the fore and mid femora yellowish; propodeum reticulated, about 2 / 3 × as long as scutellum.

Figures

Figure 1. P. steppensis Li & Hu, sp. nov. A – J female A habitus, dorsal view B head, frontal view C mandible D antenna E head, lateral view F head, dorsal view G propodeum, dorsal view H hind coxa I forewing J metasoma, dorsal view K male, lateral view.

Figure 2. P. procerus Graham, 1969 A – C male A body, lateral view B mesosoma and metasoma, dorsal view C head, frontal view D paratype information.

Figure 3. Development stages of P. steppensis Li & Hu, sp. nov. and their emergence holes, A – H. A, B the parasitoid larva feeding on the third larva of the host C prepupa D – F pupa G, H emergence holes.

Figure 4. Damage on Ulmus pumila leaves made by the adults as well as the larvae of O. steppensis Korotyaev, 2016 A – D. A, B holes on U. pumila leaves made by the adults C, D U. pumila leaves.