Megischus shixiangi Ge & Tan, 2023

Ge, Si-Xun, Ren, Li-Li & Tan, Jiang-Li, 2023, A new species and a new record species of Megischus Brulle (Hymenoptera, Stephanidae) from Vietnam, Journal of Hymenoptera Research 96, pp. 723-734 : 723

Megischus shixiangi Ge & Tan sp. nov.

Figs 1-4 , 5-7 , 8-11 , 12-14 , 15

Material examined.

Holotype, ♀ (BFU), Tuong Duong , Nghe An, Vietnam XI. 2021, leg. Local collector.

Etymology.

We named the new species after Prof. Shi-Xiang Zong. To thank him for his kind support for the first author’s taxonomy research.

Diagnosis.

Head with blackish vertex distinctly contrasting with dark reddish temple; Vertex irregular rugosity, with three or four (the last one rather weak and incomplete) strong regularly curved lamelliform carinae behind posterior teeth. Pronotum comparatively slender, pronotal fold distinct developed; neck at distinct lower level than the middle part of pronotum in lateral view; Forewing with vein 2Cub distinctly shorter than vein cu+a; Hind tibia with its widened part rather weakly concaves basally in lateral view.

Description.

Holotype. ♀, length of body 22 mm. Forewing 12 mm long; ovipositor sheath 24.5 mm long.

Head. Antenna incomplete; frons strongly reticulate-rugose (Fig. 3 ); three anterior coronal teeth large and lobe-shaped, while the posterior two relatively small and wide. Three or four (the last one rather weak and incomplete) regularly curved lamelliform carinae behind posterior teeth. Vertex with a large irregularly rugose area almost reaching occipital carina (Fig. 3 ); temple moderately bulging, smooth and shiny, except for some fine punctures (Fig. 2 ).

Mesosoma. Neck robust and with both complete and incomplete carina anteriorly (Fig. 4 ), at lower level than middle pronotum postero-dorsally. Pronotal fold distinct and with its before area rather shallowly concave; middle part of pronotum transversely rugose (Fig. 4 ); middle part of pronotum weakly differentiated from posterior part; middle and posterior part of pronotum generally with rather sparse and long setosity, propleuron more or less granular to reticulate-rugose; mesopleuron strongly reticulate-rugose with sparsely long setosity (Fig. 6 ); mesosternum largely smooth (except some fine punctures); scutellum with its margin large foveolae and smooth medially (Fig. 5 ); propodeum with sparsely large foveolate (Fig. 5 ).

Wings. Fore wing: wing membrane subhyaline (Fig. 7 ), and surface evenly bristly; vein 1-M straight, 6.5 × as long as vein 1-SR and 1.2 × vein m-cu; vein 2-SR 1.05 × as long as vein r; vein r ends 0.5 × length of pterostigma behind the level of apex of pterostigma; vein 1-SR 0.52 × as long as parastigmal vein; vein 2-CUb distinctly pigmented and curved apically; vein 2-1A straight, basally sclerotized, distinctly extended beyond Cu-a.

Legs. Hind coxa strong, annular, sparsely transverse striate, with long whitish setosity (Fig. 8 ); hind femur robust, largely smooth to coriaceous with long whitish setosity (Fig. 9 ), hind femur ventrally with two large teeth and six-minute teeth behind large posterior tooth; hind tibia robust, distinctly curved basally (Fig. 10 ), basal narrow part 0.7 × as long as apical widened part; apical widened part of hind tibia rather weakly concave basally in lateral view; hind basitarsus parallel-sided, bristly setose ventrally, ventral length 5.8 × its maximum width (Fig. 11 ).

Metasoma. Tergite I (TI) finely reticulate to transversely-rugose (Fig. 12 ), ca 14 × as long as its maximum width, 2.5 × as long as TII; remaining tergites largely coriaceous (Fig. 13 ); pygidial area coriaceous dorsally, medially moderately convex and distinctly punctate medially; Ovipositor sheath with length of subapical whitish band 2.6 × as long as dark apical part (Fig. 14 ).

Colour. Generally blackish to brownish; frons dark reddish to blackish; vertex blackish (Fig. 3 ), temple ventrally dark reddish along compound eye, distinctly contrasting with frons and vertex; wing membrane slightly brownish, subhyaline (Fig. 7 ), wing veins dark brownish to blackish; hind femur, hind tibia and metasoma largely dark brownish to blackish; ovipositor sheath largely black and with whitish subapical band.

Distribution.

Vietnam.

Biology.

Collected in November. Host is unknown.

Note.

The new species resembles the sympatric M. tonkinensis van Achterberg, 2002, but differs from the color and sculpture on the vertex (in the new species with vertex blackish, more or less reticulate, while in M. tonkinensis reddish and more regular); the pronotum (in the new species slender but in M. tonkinensis comparatively strong and short); the veination (the new species with vein 2Cub distinct shorter than vein cu+a, while in M. tonkinensis vein 2Cub about as long as vein cu+a); as well as the pronodum (sparsely large foveolate in M. shixiangi but coarsely and densely foveolate in M. tonkinensis ).

Figures

Figure 15. Habitus of Megischus shixiangi Ge & Tan, sp. nov. Holotype ♀.

Figures 1 - 4. Megischus shixiangi Ge & Tan, sp. nov. Holotype ♀ 1 head, frontal view 2 head, dorsal view 3 head, lateral view 4 pronotum, dorsal view.

Figures 5 - 7. Megischus shixiangi Ge & Tan, sp. nov. Holotype ♀ 5 mesosoma, dorsal view 6 mesosoma, lateral view 7 wings.

Figures 8 - 11. Megischus shixiangi Ge & Tan, sp. nov. Holotype ♀ 8 hind coxa 9 hind femur 10 hind tibia 11 hind tarsi.

Figures 12 - 14. Megischus shixiangi Ge & Tan, sp. nov. Holotype ♀ 12 tergite I, dorsal view 13 tergite II- VIII, dorsal view 14 distal part of ovipositor and sheath, lateral view.