Torymus achyranthii Matsuo, 2020

Matsuo, Kazunori, 2020, A revision of Japanese Torymus Dalman (Hymenoptera: Torymidae), Zootaxa 4758 (3), pp. 401-441 : 404-406

Torymus achyranthii Matsuo n. sp.

Figs 1a , 5 a–b, 8a–d, 24a

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

Type material. Holotype: ♀ ( BLKU), emerged on 25 November 2008 from a gall of Lasioptera achyranthii on Achyranthes bidentata var. japonica collected by J. Yukawa on 1 October 2008 from Mt. Tenpai, Yamaguchi, Chikushino, Fukuoka, Japan. Paratypes: 1 ♀, same data as the holotype ( BLKU); 1 ♀, emerged on 17 September 2008 from a gall of Lasioptera achyranthii on Achyranthes bidentata var. japonica collected by K. Matsuo on 16 September 2008 from Kanno, Mannou, Kagawa, Japan ( BLKU); 1 ♂, emerged under room temperature on 8 December 2008 from a gall of Lasioptera achyranthii on Achyranthes bidentata var. japonica collected by K. Matsuo on 13 October 2008 from Higashiaburayama, Fukuoka, Fukuoka, Japan ( BLKU); 1 ♂, emerged under room temperature on 3 December 2008 from a gall of Lasioptera achyranthii on Achyranthes bidentata var. japonica collected by J. Yukawa on 1 October 2008 from Mt. Tenpai, Yamaguchi, Chikushino, Fukuoka, Japan ( BLKU).

Description. Female. Body length excluding ovipositor sheath 2.5–2.7 mm. Head green. Scape yellowish brown but darker apically; pedicel and flagellum dark brown. Mesosoma green. Fore wing hyaline. Legs yellow. Lateral part of metasoma with yellowish brown area extending from base to two-thirds length of metasoma ( Fig. 1a ).

Head 2.0–2.1× as wide as long in dorsal view; temple narrow, 0.1× as long as dorsal length of eye; POL 1.8– 2.0× OOL; OOL 1.1× OD. Head 1.1–1.3× as wide as high in frontal view ( Fig. 8a ); eyes separated by their height; malar space 0.2–0.3× height of eye; mouth 2.7× malar space; clypeus with apical margin produced, truncate medially. Antenna not clearly clavate ( Fig. 5a ); scape 0.6× as long as height of eye, not reaching anterior ocellus; combined length of pedicel and flagellum as long as width of head; pedicel 1.7–2.0× as long as wide; anellus transverse, 1.2–1.5× as wide as long; F1–F5 quadrate; F6–F7 slightly transverse; each funicular segment bearing longitudinal sensilla arranged in one row.

Mesosoma 1.8–2.0× as long as wide; mesoscutum reticulate ( Fig. 8b ); notaulus shallow; scutellum ( Fig. 8c ) 1.2–1.3× as long as wide, sculptured as posterior part of mesoscutum; dorsellum with median carina though sometimes irregular; propodeum ( Fig. 8d ) with superficial reticulation; lower mesepimeron 1.3–1.6× as long as wide. Fore wing ( Fig. 24a ) 2.4–2.6× as long as wide; costal cell 8.2× as long as wide, on upper surface with a complete setal row, on lower surface with a setal row and scattered setae; basal cell closed below, and with a setal row below submarginal vein; cubital setal line present; basal setal line present; speculum narrowly open below; relative lengths of marginal vein: postmarginal vein: stigmal vein=9.5: 4.0: 1.0. Hind coxa 2.3× as long as wide, with dorsal carina basally; dorsal surface of hind coxa bare in basal half; hind femur 4.2–4.3× as long as wide; hind tibia with longer spur 1.3× as long as width of hind tibia, 0.3× length of basitarsus; shorter spur 0.6–0.7× length of longer spur.

Metasoma as long as mesosoma; posterior margin of metasomal tergum five incised; tip of hypopygium situated at 0.8 length of metasoma, with a few setae; ovipositor sheath as long as body, 3.3–3.5× as long as hind tibia.

Male. Differs from female as follows. Body length 2.6 mm. Anellus transverse, 2.0× as wide as long; F1 quadrate; F2–F5 0.8–0.9× as long as wide; F6–F7 0.7× as long as wide ( Fig. 5b ).

Distribution. Japan (Shikoku, Kyushu).

Host information. Torymus achyranthii is an ectopatasitoid of Lasioptera achyranthii Shinji ( Diptera : Cecidomyiidae ) that induces galls on Achyranthes bidentata Blume var. japonica Miq. (Amaranthaceae) (gall photo: fig. 26a, C–245 of Yukawa & Masuda 1996).

Remarks. Females of T. achyranthii are similar to T. cingulatus Nees , a Holarctic species ( Noyes 2019), because of the following shared features: OOL 1.1× OD; malar space 0.2–0.3× height of eye; scutellum wholly sculptured; propodeum with superficial reticulation; hind coxa with dorsal carina basally; dorsal surface of hind coxa bare in basal half. However, females of T. achyranthii can be distinguished from T. cingulatus by the following features: POL 1.8–2.0× OOL (POL 1.5–1.7× OOL in T. cingulatus ); scape not reaching anterior ocellus (reaching vertex in T. cingulatus ); combined length of pedicel and flagellum as wide as width of head (about 1.2× as wide as width of head in T. cingulatus ); each funicular segment bearing longitudinal sensilla arranged in one row (two rows in T. cingulatus ); upper surface of costal cell with a complete setal row (becomes double row apically in T. cingulatus ); hind femur 4.2–4.3× as long as wide (4.9–5.1× as long as wide in T. cingulatus ).

Figures

FIGURE 1 a–d. ♀, lateral view. a, T. achyranthii; b, T. aciculatus; c, T. acutissimus; d, T. angustitemple.

FIGURE 5 a–h. Antenna. a, T. achyranthii ♀; b, T. achyranthii ♂; c, T. aciculatus ♀; d, T. aciculatus ♂; e, T. acutissimus ♀; f, T. acutissimus ♂; g, T. angustitemple ♀; h, T. brevicaudatus ♀. Scale lines 0.25 mm.

FIGURE 8 a–d. T. achyranthii ♀. a, head, frontal view; b, mesoscutum, dorsal view; c, scutellum, dorsal view; d, propodeum, dorsal view.

FIGURE 24 a–h. ♀ fore wing upper surface. a, T. achyranthii; b, T. aciculatus; c, T. acutissimus; d, T. angustitemple; e, T. brevicaudatus; f, T. hirtipennis; g, T. macrops; h, T. matsunagae. Scale lines 0.5 mm.