Parancistrocerus fragilitergus Qin, Chen, & Li, 2023

Qin, Jiong, Chen, Bin & Li, Ting-Jing, 2023, Additions to the knowledge of the genus Parancistrocerus Bequaert, 1925 from China (Hymenoptera: Vespidae: Eumeninae), Zootaxa 5256 (4), pp. 345-357 : 347

Parancistrocerus fragilitergus Qin, Chen, & Li sp. n.

Figs 1–7

Material examined. Holotype, ♀, China, Guangxi Province, Guilin City, Longsheng County, Sanmen Town , Huaping Natural Reserve , 25°624′N, 109°916′E, 16.VII.2018, Xue Zhang ( CNU) . Paratype, 1♀, same as holotype.

Diagnosis. This species is easily distinguished from other congeners by the following combination of characters: occipital carina complete, median sloping area of anterior face of pronotum polished, transverse carina of T1 weak, T2 with shallow preapical bulge, apexes of both T3 and S3 slightly prolonged medially; apical prolongation margin of T3 punctate and coarse, punctures as long as diameters ( Fig. 5 )

Description. Female ( Fig. 1 ): body length 6.95–7.10 mm, holotype length 6.95 mm. Body black, with sparse and short setae; following parts yellow: clypeus except dark apex, ventral side of scape, one spot in ocular sinus, small inter-antennal spot on lower frons ( Fig. 2 ), a spot on upper gena ( Fig. 3 ), two large anterior connected spots on pronotum, metanotum, parategula apically, a band of fore tibia ( Fig. 1 ), wide apical bands of T1–T2, and narrow apical band of S2 ( Figs 5–6 ); tegula dark brown; wings pale brown.

Head ( Fig. 2 ). Slightly wider than long in frontal view, maximum width of head 1.03× its length; clypeus densely punctate, clypeal maximum width 1.06× its length, slightly convex, apex emarginate forming two lateral teeth, apical width 0.72× distance between antennal sockets; inter-antennal area with longitudinal carina; frons coarsely punctate and distinctly reticulated, punctures on vertex and gena similar to those of frons; POL 0.91× OOL; distance between anterior and posterior ocelli 0.5× diameter of anterior ocellus; occipital carina complete ( Fig. 3 ).

Mesosoma. Median sloping area of anterior face of pronotum obviously polished ( Fig. 3 ), with two small and separated foveae medially; pronotal carina tapered dorsally; pronotum, mesoscutum and scutellum coarsely punctate, punctures similar to those on vertex; median length of mesoscutum 1.02× its maximum width; metanotum with coarse punctures, interspaces carinate, sharply and minutely dentiform ( Fig. 4 ); mesopleuron coarsely punctate and reticulated; epicnemial carina present and strong; metapleuron with few transverse striae; propodeum sloping downward just behind metanotum ( Fig. 4 ), coarsely punctate, punctures large, shallow, flat bottomed and interspaces present as reticulate carinae, dorsal carina weak; posterior face of propodeum slightly concave, with median longitudinal carina, and a few thin transverse striae; lateral face of propodeum with minute and dense transverse striae.

Metasoma ( Figs 5–7 ). Transverse carina ( Fig. 4 ) of T1 weak, indistinctly raised; vertical anterior face shorter than dorsal horizontal one, dorsal face much wider than long, 1.71× its median length, coarsely punctate, punctures similar to those on mesoscutum, and without regular rows of punctures on yellow band; median length of T2 0.96× its maximum width ( Fig. 5 ), punctures obviously sparser than those of T1, T2 with a row of large and regular punctures close to margin, with shallow preapical bulge, margin wide and smooth, not prolonged medially ( Fig. 5 ); S2 slightly convex basally, medially depressed and with a deep median longitudinal furrow ( Figs 6–7 ); both T3 and S3 prolonged medially, prolongation of S3 a little longer than that of T3 ( Figs 5–6 ), apical prolongation margin of T3 punctate and coarse, punctures as long as diameters; other metasomal segments normal ( Fig. 6 ).

Male. Unknown.

Distribution. China (Guangxi).

Etymology. The specific name fragilitergus is derived from two Latin words: fragilis (=weak) and tergum, referring to the weak transverse carina of T1.

Figures

FIGURES 1–7. Parancistrocerus fragilitergus sp. n., holotype, ♀. 1. Habitus (dorsal view); 2. Clypeus; 3. Head and pronotum (dorsal view); 4. Propodeum and T1 (dorsal view); 5. Metasoma (dorsal view); 6. S2–S6 (ventral view); 7. Metasomal segments 2–6 (lateral view).