Zethus nullimarginatus Wang & Li, 2019

Wang, Hua-Chuan, Chen, Bin & Li, Ting-Jing, 2019, Three new species of the genus Zethus Fabricius, 1804 (Hymenoptera, Vespidae, Eumeninae) from China, with an updated key to the Oriental species, Journal of Hymenoptera Research 71, pp. 209-224 : 216

Zethus nullimarginatus Wang & Li sp. nov.

Figs 26-35

Material examined.

Holotype, ♀: CHINA, Fujian, Longyan City, Changting County, Sidu Town , 25°39.126'N, 116°12.253'E, 1.V.1951, Gentao Jin & Yangming Lin leg. (SEM).

Description.

Female: body length 15.2 mm ( Fig. 26 ), fore wing length 13.5 mm. Almost black, the following parts yellow: spot on dorso-inner margin of antennal socket ( Fig. 27 ), apical interrupted band on T1, apical complete band on T2; tegula dark brown ( Fig. 29 ).

Head. Head wider than high, about 1.3 × as wide as high in frontal view ( Fig. 27 ), about 1.8 × wider than long in dorsal view ( Fig. 28 ); mandible with four teeth and dense setae, its outer surface with irregular punctures; clypeus convex in lateral view and about 1.6 × as wide as high, with basal margin straight, apical margin near truncated, width of truncation 1/3 × width of clypeus between inner eye margins, clypeus punctate-reticulate with dense long setae ( Fig. 27 ); punctures on frons reticulate; vertex and gena with dense punctures; gena without longitudinal carina in lateral view; distance from posterior ocelli to apical margin of vertex 1.8 × as long as distance from posterior ocelli to inner eye margin ( Fig. 28 ); occipital carina complete ( Fig. 28 ); antennal scape 2.8 × as long as its maximum width, A3 1.7 × as long as its maximum width, A4 slightly longer than its maximum width, A5-11 wider than long, A12 bullet-shaped, slightly longer than its basal width.

Mesosoma. Length of mesosoma about 1.4 × as long as wide in dorsal view ( Fig. 29 ); pronotal carina complete and developed, pronotum with coarse punctures dorsally, weak striae in lower lateral surface; notaulix complete, mesoscutum with dense punctures, gradually shallow from the anterior to posterior portion ( Fig. 29 ); tegula smooth, with dense and short setae on its anterior and posterior lobe, its posterior lobe truncated ( Fig. 29 ); mesopleura with dense punctures, slightly sparse ventrally; scutellum flattened, and with shallow punctures and weak middle longitudinal furrow; punctures on metanotum dense and coarse; metapleuron smooth; propodeum dull, with coarse surface in dorsal view and lateral carina very weak, without submedian carina ( Fig. 30 ), its lateral surface with sporadic punctures and without striae ( Fig. 31 ), submarginal lamella almost absent above propodeal valvulae ( Fig. 32 ).

Metasoma. T1 about 2.5 × as long as wide, with medial carina from basal margin to one-fourth of tergum, gradually widening from one-fifth of the base, then distinctly narrow toward apex, with maximum width 3 × its basal width, T1 with punctures, distance between punctures about equal to the diameter ( Fig. 34 ), lateral carina of T1 disappeared ventrally ( Fig. 35 ); BS of S1 with sparse punctures, AE of S1 with weak and irregular striae and sporadic punctures ( Fig. 35 ); T2 gradually swollen from the base to apical margin in lateral view, with developed apical lamella, about 1.2 × as long as wide in dorsal view, T2 with sparse punctures, area between punctures with fine punctures, distance between punctures 1-2 × larger than puncture diameter ( Fig. 33 ); S2 gradually swollen from basal to apical margin in profile ( Fig. 33 ); punctures on S2 slightly larger than those on T2, punctures on center area of S2 sparse, S2 with apical lamella; T3 with dense punctures and thick apical lamella; apical margin of S3 with dense punctures like those on T3; subsequent terga and sterna with slightly sparse micropunctures.

Male. Unknown.

Distribution.

China: Fujian.

Remarks.

The species resembles Z. velamellatus Tan, 2018 from Zhejiang, China by propodeum without submarginal lamella ( Fig. 32 ), S2 gradually swollen from basal to apical margin in profile ( Fig. 33 ). It differs from Z. velamellatus and all other members of the genus by the following character combination: apical margin of clypeus truncated ( Fig. 27 ), the posterior lobe of tegula truncated ( Fig. 29 ), propodeum without submarginal lamella ( Fig. 32 ), T1 about 2.5 × as long as wide, narrowly toward apex ( Fig. 34 ), lateral carina of T1 disappeared ventrally ( Fig. 35 ).

Etymology.

The specific name Zethus nullimarginatus is derived from two Latin words: null and marginatus, referring to lateral carina of T1 disappeared ventrally.

Figures

Figures 26 - 35. Zethus nullimarginatus sp. nov., holotype 26 habitus in dorsal view, ♀ 27 head in frontal view, ♀ 28 vertex, ♀ 29 mesosoma, ♀ 30 propodeum in dorsal view, ♀ 31 propodeum in lateral view, ♀ 32 propodeum in dorsal-lateral view, ♀ 33 metasoma in lateral view, ♀ 34 T 1, ♀ 35 S 1, ♀.