Dendrocerus sergii Alekseev, 1994

Wang, Xu, Li, Fang, Zhao, Wen-Jing, Huang, Yi-Xin, Xiang, Chun-Hui, Chen, Hua-Yan & Zhu, Chao-Dong, 2025, Five new species and three new country records of Megaspilidae from Xizang Autonomous Region, China (Hymenoptera, Ceraphronoidea), ZooKeys 1260, pp. 279-312 : 279-312

Dendrocerus sergii Alekseev, 1994

Figs 11 , 12

Dendrocerus sergii Alekseev, 1994: 153.

Species notes and history.

Dendrocerus sergii was first described by Alekseev in 1994, who described the male antennae, wings, head, mesosoma, and metasoma and illustrated the antennae for the first time. However, the morphological characteristics were represented by hand-made drawings, without records of the male genitalia or images of the female head, mesosoma, or metasoma. The present paper redescribes the male, adding descriptions of the male genitalia and color photographs. Furthermore, this article is the first to describe the syntergal translucent patch and S 9.

Material examined.

• 2 ♂♂ ( AHNU), China: Xizang, Jilong, Rikaze , 17 Apr. – 23 May. 2021, D. Wu leg., XZL-2 , XZL-1 ; • 1 ♂ ( AHNU), China: Xizang, Jilong, Rikaze , 10–20 May. 2021, D. Wu leg., XZKJQ-2 ; • 1 ♂ ( AHNU), China: Xizang, Jilong, Rikaze , 3 Aug. 2021, D. Wu leg., XZQ-1 .

Diagnosis.

This species can be separated from other Dendrocerus species by the following characters: harpe of male genitalia triangular in lateral view (terminally flat in lateral view; distoventral margin of harpe with projections, distodorsal margin of harpe concave in lateral view in other species), rectangular in dorsal and ventral views, gonossiculus with two setae apically. Gonostyle – volsella complex with medioventral ridge incomplete, length equal that of the gonostyle – volsella complex. Facial pit present, preoccipital furrow grooved, not reaching anterior ocellar; anterior mesopleural sulcus present; posteroventral area (part of mesopleuron) smooth; mesometapleural sulcus present, grooved, not in contact with mesopleural pit.

Description.

Male. Body length: 1.5–2.2 mm.

Coloration (Fig. 11 C ). Head, mesosoma, and metasoma black. Flagellum dark brown, scape and pedicel brown. Mouthparts brown; eyes silvery; ocelli silvery-black. Legs usually brown, sometimes darkened proximally, especially on femora and tibiae. Pterostigma and stigmal vein dark brown. Body pubescence white; marginal fringes of wings brown.

Antennae (Fig. 11 C ). Ramose with five branches; scape ~ 3 × longer than wide, pedicel small and rounded. Male scape length vs pedicel length 3.3–3.8. Scape length vs F 1 length 5.4–6.0. F 1 length vs F 2 length 0.6–1.0. F 5 longest flagellomere, F 8 shortest. A 1 length vs F 1 length 12.2–15.8. A 2 length vs F 2 length 10.7–11.8. A 3 length vs F 3 length 5.2–6.7. A 4 length vs F 4 length 2.7–3.0. A 5 short, A 5 length vs F 5 length 0.17–0.22. Setae long, reaching 2–4 × flagellomere width.

Head (Fig. 11 B, E ). Head width 1.1 × longer than mesosoma width. HH: HL = 0.8–1.6. HW: IOS = 1.7–1.8. HW: HH = 1.2–1.6. POL: OOL = 1.9–2.0. Ocellar triangle with long base, OOL: LOL = 1.3–1.4. Head circular in anterior view. Facial pit present and shallow, facial sulcus absent. Preocellar pit present, ocellar fovea present. Preoccipital lunula present. Preoccipital furrow present, grooved, not reaching posterior ocellar. Preoccipital carina present. Scrobes absent, intertorular carina absent. Head with sparse hairs.

Mesosoma (Fig. 11 A, D ). Mesosoma slightly narrow, 1.6 × longer than wide, length / width / height = 770 / 490 / 590 µm; densely pubescent, alutaceous in sculpture; mesoscutum length / mesoscutum width = 400 / 490 µm, mesoscutum 1.2 × wider than long, Ascw / Pscw = 400 / 370 µm; notauli and median mesoscutal sulcus very distinct, notauli groove, median with continuous fovea, fovea deep, equal to or longer than width; shallow sulcus on the mesoscutum lying lateral to the notaulus and parallel to median mesoscutal sulcus, 1 / 2 length of mesoscutum. Scutellum length / scutellum width = 300 / 340 µm, scutellum width almost equal to length; scutoscutellar sulcus foveolate; fovea (part of scutoscutellar sulcus) length shorter than width, continuous with interaxillar sulcus. Axilla width slightly longer than length. Posterior of scutellum foveolate. Pronotum triangular, anterior mesopleural area present; anterior mesopleural sulcus present; posteroventral area (part of mesopleuron) smooth; mesometapleural sulcus present, groove, not contact with mesopleural pit, mesopleural pit expansion; ventral division of metapleuron densely pubescent; pleural carina with long bristles. Anteromedian projection of the metanoto-propodeo-metapecto-mesopectal complex absent.

Wings (Fig. 11 F ). Forewing length 1.9 mm, with pterostigma, radius, and some transparent veins. Hyaline, densely pubescent, and marginal fringes numerous. Stigma length / width = 270 / 100 µm, 2.7 × as long as wide, semicircular. Stigmal vein 440 µm, slightly curved in the latter section and 1.6 × longer than pterostigma.

Metasoma (Fig. 11 G ). Metasoma 2.5 × longer than wide, length / width / height = 950 / 380 / 390 µm. Syntergum smooth, reaching 1 / 2 of metasomal length. Syntergum with six distinct gastral carinae, reaching 1 / 4 of syntergum length. Syntergal translucent patch present, orbicular.

Male genitalia (Fig. 12 ). Genitalic cupula present, proximodorsal notch of cupula blunt or straight, with a darker brown coloration near the central region; distodorsal margin of cupula straight. Cupula length vs gonostyle – volsella complex length: cupula short, only 1 / 4 the length of gonostyle – volsella complex in lateral view. Proximoventral median projection of cupula present. Harpe triangular in lateral view, with a flat terminus, a distoventral margin bearing projections, and a concave distodorsal margin; rectangular in dorsal view; length shorter than gonostipes in lateral view, reaching 1 / 2 of gonostipes. Proximal end of dorsomedian conjunctiva of the gonostyle – volsella complex acute. Gonostipes longer than width; parossiculus separated from gonostipes. Gonostyle – volsella complex with medioventral ridge incomplete, its length equal that of the gonostyle – volsella complex. Parossiculus with one seta apically. Gonossiculus rectangular in ventral view, with two setae apically. Penisvalva straight. S 9 circular, with irregular row of setae and more than 13 setae; submedial projections on proximal margin of S 9 absent; distal margin of male S 9 flat; proximolateral corner of male S 9 with projections, not acute; proximal margin of S 9 without projections. Medial projections on proximal margin of S 9 present, length of projections 1 / 3 length of S 9 shield.

Distribution.

China ( Xizang) – new record for China, Vietnam.

Figures

Figure 11. Dendrocerus sergii Alekseev, 1994, male. A. Head and mesosoma, dorsal view; B. Metasoma, dorsal view; C. Lateral habitus; D. Head and mesosoma, lateral view; E. Head, anterior view; F. Wings; G. Metasoma, lateral view.

Figure 12. Dendrocerus sergii Alekseev, 1994, male, genitalia. A. Dorsal view; B. Ventral view; C. Lateral view; D. S 9.