Torymus quernus Matsuo, 2020

Matsuo, Kazunori, 2020, A revision of Japanese Torymus Dalman (Hymenoptera: Torymidae), Zootaxa 4758 (3), pp. 401-441 : 426-427

Torymus quernus Matsuo n. sp.

Figs 3b , 6g , 17 a–d, 25b

Etymology. The specific name, quernus , is derived from the host plant of host insect.

Type material. Holotype: ♀ ( BLKU), emerged on 27 April 2010 from a gall of Dryocosmus kunugiphagus on Quercus acutissima collected by N. Wachi on 18 April 2010 from Kokonoe, Oita, Japan. Paratypes: 1 ♀, same data as the holotype ( BLKU). 3 ♀, emerged on 6 April 2017 from a gall of Dryocosmus kunugiphagus on Quercus acutissima collected by K. Matsuo on 18 March 2017 from Kokonoe, Oita, Japan ( BLKU).

Description. Female. Body length excluding ovipositor sheath 2.8–2.9 mm. Head bluish green. Scape yellowish brown but darker apically; pedicel and flagellum dark brown. Mesosoma bluish green. Fore wing hyaline. All coxae concolorous with mesosoma; all femora bluish green, basal and apical tips lighter; fore tibia and mid tibia yellowish brown; hind tibia dark green. Metasoma bluish green with bluish tint ( Fig. 3b ).

Head in dorsal view 2.0–2.2× as wide as long; temple 0.2–0.3× as long as dorsal length of eye, curved; POL 1.9× OOL; OOL 1.7× OD. Head in frontal view 1.3× as wide as high ( Fig. 17a ); eyes separated by 1.1× their height; mouth 2.5× malar space, the latter 0.3× height of eye; gena slightly curved; clypeus with apical margin not produced, straight. Antenna clavate ( Fig. 6g ); scape 0.6× as long as height of eye, not reaching anterior ocellus; combined length of pedicel and flagellum 1.1× width of head; pedicel 1.2× as long as wide; anellus transverse, 2.0–2.5 as wide as long; F1 1.0–1.2× as long as wide, slightly longer than pedicel; F2 0.9× as long as wide; F3–F4 0.8× as long as wide; F5 0.7× as long as wide; F6–F7 0.6× as long as wide; each funicular segment bearing longitudinal sensilla arranged in irregular one or two rows; C3 with a small tuft of micropilosity beneath.

Mesosoma 1.6× as long as wide; mesoscutum ( Fig. 17b ) transversely reticulate; scutellum ( Fig. 17c ) 1.3× as long as wide; frenal line absent; frenal area indicated by a difference in sculpture from the rest of scutellum, smoother and glabrous toward apex; dorsellum with a median carina; propodeum ( Fig. 17d ) with complete submedian carina; lower mesepimeron 1.5–1.8× as long as wide, rectangular. Fore wing 2.3× as long as wide ( Fig. 25b ); costal cell 9.1–9.3× as long as wide, on upper surface with a setal row in distal half, on lower surface with a setal row, with scattered setae; basal cell closed, with a row of setae below submarginal vein; cubital setal line present; basal setal line present; speculum narrowly opened below; relative lengths of marginal vein: postmarginal vein: stigmal vein=7.9: 2.3: 1.0. Hind coxa 1.8–2.0× as long as wide, with sharp dorsal carina extending half length; dorsal surface of hind coxa bare in basal half; hind femur 3.6–3.9× as long as wide; hind tibia with longer spur 1.2–1.3× as long as width of hind tibia, 0.4–0.5× length of basitarsus; shorter spur 0.6× length of longer spur.

Metasoma slightly shorter than mesosoma; posterior margin of metasomal tergum five entire; tip of hypopygium situated at 0.5 length of metasoma, with a few setae; ovipositor sheath as long as metasoma plus 1/2 mesosoma, 2.5–2.8× as long as hind tibia.

Male. Unknown.

Distribution. Japan (Kyushu).

Host information. This species is a parasitoid of Dryocosmus kunugiphagus Ide and Abe ( Hymenoptera : Cynipidae ) that induces spindle–shaped gall on the buds of Quercus acutissima Carruth (Fagaceae) (gall photo: fig. 27d, C–079 of Yukawa & Masuda 1996).

Remarks. Females of T. quernus are similar to T. koreanus Kamijo by having the following share features: temple curved; antenna clavate; scape not reaching anterior ocellus; frenal area indicated by a difference in sculpture from the rest of scutellum; propodeum with complete submedian carina; ovipositor sheath 2.5–2.8× as long as hind tibia. However, females of T. quernus can be distinguished from T. koreanus by the following characters: pedicel 1.2× as long as wide (1.4–1.5× as long as wide in T. koreanus ); longitudinal sensilla on each funicular segment arranged in irregular one or two rows (one row in T. koreanus ); hind coxa with sharp dorsal carina extending half length (with a complete dorsal carina in T. koreanus ); costal cell of fore wing on upper surface with a setal row in distal half (with a setal row which becomes double in distal half in T. koreanus ); speculum narrowly opened below (closed below in koreanus ).

Figures

FIGURE 3 a–d. ♀, lateral view. a, T. minamii; b, T. quernus; c, T. ringofushi; d, T. rugosus.

FIGURE 6 a–g. Antenna. a, T. hirtipennis ♀; b, T. hirtipennis ♂; c, T. macrops ♀; d, T. matsunagae ♀; e, T. minamii ♀; f, T. minamii ♂; g, T. quernus ♀. Scale lines 0.25 mm.

FIGURE 17 a–d. T. quernus ♀. a, head, frontal view; b, mesoscutum, dorsal view; c, scutellum, dorsal view; d, propodeum, dorsal view.

FIGURE 25 a–f. ♀ fore wing upper surface. a, T. minamii; b, T. quernus; c, T. rugosus; d, T. sasae; e, T. sawadai; f, T. wanggyui. Scale lines 0.5 mm.