Gasteruption reductum Tan & van Achterberg, 2021

Tan, Jiang-Li, Achterberg, Cornelis van, Wu, Jia-Xuan, Wang, Hang & Zhang, Qi-Jing, 2021, An illustrated key to the species of Gasteruption Latreille (Hymenoptera, Gasteruptiidae) from Palaearctic China, with description of four new species, ZooKeys 1038, pp. 1-103 : 1

Gasteruption reductum Tan & van Achterberg sp. nov. Figs 253 , 254-263 , 264-271

Type material.

Holotype, ♀ (NWUX), "NW China: Shaanxi, [ Xi’an,] Baolongyu, Ziwuzhen, 34.02°N, 108.91°E, 10.iii.-27.v.2018, y[ellow] Mal[aise] trap, 948 m alt., QQ Tan, RN Zhang, NWUX". Paratypes: 3 ♀ + 1 ♂ (NWUX, RMNH), "Shaanxi, Xiangfang, Shuanglong, Huangling, Yan’an, 35.63°N, 108.87°E, 4.viii.2019, 1271 m alt., Jiangli Tan, NWUX"; 1 ♀ (NWUX), id., but 31.vii.2019, 1007 m alt.; 1 ♀ (RMNH), "NW China: Shaanxi, Huaishuzhuang Rev. St., Ziwuling NNR, Fuxian, Yanan, sweep net, 35.86°N, 108.74°E, 2.viii.2019, 1127 m alt., Jiangli Tan, NWUX"; 1 ♀ (SCAU), "[NE China:] Hebei, Chicheng Co., Songshan NNR, 1440 m alt., 40.53067°N, 115.74772°E, 11-18.vii.2012, M[alaise]T[rap], Changqing Xia".

Diagnosis.

Head in dorsal view distinctly narrowed, moderately convex and medio-posteriorly flat, without a depression in front of occipital carina; mandibular condylus near lower level of eyes; temple dorsally dull and finely coriaceous; fourth antennal segment of ♀ 1.2-1.3 × as long as third segment; third antennal segment of ♂ 1.4 × as long as second segment; occipital carina non-lamelliform medio-dorsally propleuron; 0.8-0.9 × as long as mesoscutum in front of tegula; notauli narrow, finely crenulate and posteriorly reduced and with transverse rugae; mesoscutum rather flat, with satin sheen and without rugae or punctures in lateral view; mesoscutum mainly very finely coriaceous mixed with very fine transverse rugulae, but medio-posteriorly with distinct transverse rugae; hind femur and tibia slender; ovipositor sheath 1.0-1.1 × as long as body; apical white part of ovipositor sheath 1.2-2.5 × as long as hind basitarsus; apical sternite of ♂ entirely dark brown and paramere densely whitish setose, with its apex dark brown.

Gasteruption reductum shares with G. graciloides van Achterberg, 2019, from Far East Russia, the peculiar sculpture of the mesoscutum and the slender body, but the new species has the notauli narrow, finely crenulate and posteriorly reduced and with transverse rugae (notauli medium-sized, moderately crenulate and posteriorly distinctly impressed and only crenulate in G. graciloides ) and the vertex distinctly protruding above level of ocelli (hardly protruding above level ocelli in G. graciloides ). The new species differs from G. pedion sp. nov. mainly by the reduced notauli (distinctly impressed in G. pedion ), the propleuron distinctly narrowed anteriorly in ventral view (hardly narrowed), the very finely transversely rugulose mesoscutum (only very finely granulate-coriaceous) and the small ocelli (larger).

Description.

Holotype, female, length of body 9.1 mm, of fore wing 4.3 mm.

Head. Frons very finely coriaceous and with satin sheen; vertex very finely coriaceous with very fine transverse rugulae, moderately convex and medio-posteriorly flat, without a depression; head rather gradually contracted behind eyes in dorsal view and temples slightly rounded (Fig. 259 ); temple 0.8 × as long as eye in dorsal view; fourth antennal segment 1.3 × as long as third segment and 0.8 × as long as second and third segments combined, fifth antennal segment as long as third segment, third antennal segment 1.8 × as long as second segment (Fig. 262 ); occipital carina narrow and non-lamelliform medio-dorsally (Fig. 259 ); OOL 1.4 × as long as diameter of posterior ocellus and POL about 1.5 × OOL; face 2.4 × as broad as high (Fig. 258 ); combined height of eye and malar space 1.9 × minimum width of face; malar space not protruding below lower level of eyes (Fig. 258 ), its minimum width 0.2 × basal width of mandible and area behind incision nearly triangular and elongate (Fig. 254 ); clypeus only medio-ventrally shallowly depressed and ventro-lateral corners protruding (Fig. 258 ); eye virtually glabrous.

Mesosoma. Length of mesosoma 1.9 × its height; propleuron moderately robust, shiny and 0.9 × as long as mesoscutum in front of tegula; pronotal side granulate-coriaceous, except for wide crenulate-rugose grooves and sparsely setose, with distinct acute tooth antero-ventrally (Figs 255 and 256 ); antesternal carina narrow and non-lamelliform; mesosternal sulcus very wide and coarsely crenulate; notauli narrow, finely crenulate and posteriorly reduced and with transverse rugae; mesoscutum rather flat, with satin sheen and without rugae or punctures in lateral view; dorsally middle lobe of mesoscutum very finely coriaceous and mixed with very fine transverse rugulae, becoming stronger posteriorly; lateral lobes of mesoscutum mainly very finely coriaceous, but medio-posteriorly with distinct transverse rugae (Figs 255 and 256 ); scutellum rather matt and very finely and densely coriaceous (Fig. 256 ; propodeum irregular reticulate-rugose, rather shiny and without median carina or wide smooth stripe. Wings. First discal cell narrow, slightly narrowed apically and with outer posterior corner obsolescent and with vein 3-CU1 near its apical fifth (Fig. 260 ). Legs. Hind coxa finely coriaceous, but dorsally irregularly transversely rugulose; length of hind femur, tibia and basitarsus 4.6, 4.9 and 7.4 × their width, respectively; hind tibia moderately inflated (Fig. 257 ); middle tarsus 1.3 × as long as middle tibia; middle femur subparallel-sided and distinctly more slender than fore femur.

Metasoma. Ovipositor sheath 9.7 mm, 1.1 × as long as body, 1.5 × as long as metasoma and 5.5 × as long as hind tibia; ovipositor sheath with dense cover of fine adpressed setae, its white apical part 1.7 × longer than hind basitarsus; apical half of hypopygium emarginate medially.

Colour. Black; apex of apical antennal segment brown; basal half of mandible dark brown and apical half dark reddish-brown; tegulum, humeral plate, veins and pterostigma largely brown; fore and middle tibiae (but basally and apically somewhat paler) and tarsi, trochantelli and hind tarsus dark brown; hind tibia baso-ventrally with elongate ivory patch; hind tibial spurs brown; wing membrane slightly brownish; ivory or whitish apex of ovipositor sheath basally brownish and remainder of sheath dark brown (Fig. 263 ).

Male. Similar to female (including very fine transverse sculpture of mesoscutum: Fig. 267 ), but head shorter in dorsal view and notauli posteriorly impressed and finely crenulate (Fig. 267 ), without transverse rugae; third antennal segment 1.4 × as long as second segment; fourth antennal segment nearly twice as long as third segment and 1.1 × as long as second and third segments combined and fifth antennal segment twice as long as third segment (Fig. 271 ); apical sternite entirely dark brown; paramere densely whitish setose and its apex dark brown (Fig. 269 ).

Variations.

Body length of ♀ 9.1-11.5 mm, of ♂ 9.5 mm; fourth antennal segment of ♀ 1.2-1.3 × as long as third segment; ovipositor sheath 1.0-1.1 × as long as body; apical white part of ovipositor sheath 1.2-2.5 × as long as hind basitarsus; propleuron 0.8-0.9 × as long as mesoscutum in front of tegula.

Distribution.

China (Shaanxi, Hebei).

Etymology.

Name derived from “reductus” (Latin for “withdrawn”) because of the narrow and posteriorly reduced notauli.

Figures

Figure 253. Gasteruption reductum Tan & van Achterberg, sp. nov., female, holotype, habitus lateral.

Figures 254 - 263. Gasteruption reductum Tan & van Achterberg, sp. nov., female, holotype 254 head lateral 255 mesosoma lateral 256 mesosoma dorsal 257 hind leg 258 head anterior 259 head dorsal 260 fore wing 261 apex of metasoma ventral 262 base of antenna 263 apex of ovipositor sheath.

Figures 264 - 271. Gasteruption reductum Tan & van Achterberg, sp. nov., male, paratype 264 habitus lateral 265 head lateral 266 mesosoma lateral 267 mesosoma dorsal 268 head dorsal 269 apex of metasoma lateral 270 hind leg 271 base of antenna.