Pararrhynchium simsanum Nguyen & Tran, 2021

Nguyen, Lien Thi Phuong, Tran, Ngat Thi, Bui, Dien Trong & Ljubomirov, Toshko, 2021, Contribution to the genus Pararrhynchium de Saussure (Hymenoptera: Vespidae Eumeninae), with description of two new species from Vietnam, Zootaxa 5082 (2), pp. 159-168 : 160-163

Pararrhynchium simsanum Nguyen & Tran , sp. nov.

Diagnosis. This species can be distinguished from all other known species of the genus Pararrhynchium by the following combination of characters: female clypeus pear shaped, truncated at apex, in frontal view about 1.14 times as high as wide; gena almost as wide as eye; propodeum with posterior surface clearly separated from dorsal surface by an upper sharp and well-developed carina, the carina surrounds metanotum from behind and produces to a sharp tubercle at lower lateral corners; mesepisternum without epicnemial carina; T1–5 with thick smooth band apically; male vertex also with cephalic foveae situated far from each other, about 0.85 times as wide as distance between posterior ocelli.

Material examined. Holotype, female, Vietnam: Simsan, Y Ty, Bat Xat , Lao Cai, 22°37’48”N, 103°34’52”E, alt. 1324 m, 2 Aug. 2019, LTP Nguyen, CQ Nguyen, NT Tran leg., deposited in IEBR.

Paratypes: 2 females, 1 male, same data as holotype; Vietnam: Ha Giang : 1 female, Bat Dai Son, Quan Ba, NR, 750 m, 18 May 2018, LTP Nguyen leg., deposited in IEBR .

Description. Female. Body length 13.2–13.5 mm (holotype: 13.5 mm); fore wing length 12.8–13.0 mm (holotype: 13.0 mm).

Head in frontal view subcircular, slightly wider than high ( Fig. 1 ). Vertex with cephalic foveae situated far from each other, distance between them slightly greater than half distance between posterior ocelli ( Fig. 2 ). Distance from posterior ocelli to apical margin of vertex 2.5 times distance from posterior ocellus to inner eye margin ( Fig. 2 ). Gena almost as wide as eye; occipital carina complete, present along entire length of the gena, somewhat weak at dorsal part. Inner eye margins convergent ventrally; in frontal view nearly 1.18 times further apart from each other at vertex than at clypeus. Clypeus in lateral view prominently convex at basal half, then straight to apical margin; in frontal view about 1.14 times as high as wide ( Fig. 1 ), with basal margin slightly convex medially and distinctly separated from antennal sockets; apical margin almost truncated medially, width of the truncation slightly greater than 1/3 width of clypeus between inner eye margin. Mandible with four prominent teeth. Antennal scape about 4 times as long as its maximum width, slightly curved; F1 about 1.6 times longer than wide, F2 longer than wide, F3 – 9 wider than long, terminal flagellomere bullet-shaped, 0.86 times as long as its basal width ( Fig. 1 ). Mesosoma longer than wide in dorsal view ( Fig. 3 ). Pronotal carina strongly raised, reaching ventral corner of pronotum. Mesoscutum weakly convex, 1.1 times as long as wide between tegulae, with two longitudinal smooth and shiny area (close to tegula and parategula) running from apical margin to one-third length of the mesoscutum, with two depressed furrow running from apical margin to one-fourth length of the mesoscutum ( Fig. 3 ). Disc of scutellum slightly convex, in lateral view at the same level of mesoscutum ( Fig. 4 ). Metanotum weakly convex. Propodeum ( Fig. 5 ) with horizontal area about half as long as the length of metanotum), concavity margined by a crest, posterior surface clearly separated from dorsal side by an upper sharp and well-developed carina, the carina surrounds metanotum from behind and produces to a sharp tubercle at lower lateral corner ( Fig. 5 ). Metasomal segment 1 slightly narrower than segment 2, truncate at base; anterior vertical surface flat, with dense coarse punctures, clearly separable from posterior horizontal part, with partial carina, visible on lateral sides. T 1 in dorsal view about 1.86 times as wide as long; T2 about 1.14 times as long as wide in dorsal view; S2 strongly depressed at base, in lateral view almost straight from base to one-fifth, strongly curve, then straight to apical margin ( Fig. 7 ); T1–5 with thick smooth band apically.

Vestiture. Body covered with short, silver hairs.

Sculpture. Clypeus with dense, coarse punctures, border between punctures raised, each puncture bearing a very short bristle. Frons densely covered with very coarse punctures, border between punctures smooth and raised to form reticulations. Vertex with punctures similar to those on frons; gena with strong punctures, border between punctures smooth and much larger than those on vertex. Pronotum with punctures coarser than punctures on vertex. Mesoscutum densely and coarsely covered with flat-bottomed punctures, border between punctures raised to form longitudinal striae at apical half; punctures on scutellum dense, coarse and equal to those on mesoscutum, punctures on metanotum smaller. Mesepisternum with flat-bottomed punctures, punctures coarser to those on pronotum posterodorsally, minute punctured anteroventrally; border between posterodorsal and anteroventral parts distinct, without epicnemial carina. Dorsal part of metapleuron with several striae, ventral metapleural part with dense and strong punctures. Propodeum with very coarse and dense punctures on dorsal and lateral parts, border between punctures strongly raised to form reticulation; posterior surface shiny, smooth largely, with some small and shallow punctures at sides, and with dense oblique striations near median carina. T1 covered with strong punctures, border between punctures with minute punctures and sometimes larger than puncture diameter; punctures near apex of T2–5 much denser; T6 with weaker and smaller punctures.

Colour. Body black, the following part yellow: small triangular spot near base of mandible, antennal scape beneath, inner side of fore tibiae. Wing strongly infuscated, with purple reflexion, veins dark brown ( Fig. 8 ).

Male ( Fig. 12 ). Body length 10.3 mm; fore wing length 10.0 mm. Structure as in female, but differing from the latter as follows: head proportionally smaller, transverse, 1.14 times as wide as high in frontal view ( Fig. 9 ); vertex also with cephalic foveae situated far from each other ( Fig. 10 ), about 0.85 times as wide as distance between posterior ocelli; distance from posterior ocelli to apical margin of vertex nearly 2.3 times distance from posterior ocelli to inner eye margin ( Fig. 10 ); inner eye margins strongly convergent, 1.56 times further apart from each other at vertex than at clypeus ( Fig. 9 ); clypeus in frontal view 1.17 times as long as wide, apical margin deeply emarginated medially, forming sharp pointed tooth on each lateral side ( Fig. 9 ), with of emargination slightly greater than half of clypeus with; mandible with four prominent teeth. Antenna slightly slender than in female, flagellomere 1 about 2 times as long as wide, F2–5 longer than wide, F6–9 wider than long, F10 much smaller than F9, the terminal flagellomere elongate, slightly curved, about 2 times as long as its basal width ( Fig. 11 ).

Sculpture. Body surface sculptured as in female, but clypeus with smaller punctures.

Colour. Similar to female, but mandible entirely black, yellow strip on scape much shorter. Legs entirely black.

Distribution. North Vietnam.

Etymology. The specific name refers to the locality name, Simsan village, where species was collected; it is to be treated as a noun in apposition.

Remarks. This species is close to P. oceanicum Sk. Yamane, 1990 in having the epicnemial carina absent, but it has the propodeum with a distinct shelf between the crest and metanotum (versus the propodeum without a shelf in P. oceanicum ), and the anterior vertical face of T1 without a median longitudinal carina (versus anterior vertical face of T1 with a median longitudinal carina in P. oceanicum ).

Figures

FIGURES 1–8. Pararrhynchium simsanum Nguyen & Tran, sp. nov., holotype, female. 1. Head, frontal view. 2. Head, dorsal view. 3. Mesosoma, dorsal view. 4. Mesosoma, lateral view. 5. Propodeum, posterior view, 6. Metasoma, dorsal view. 7. Metasoma, lateral view. 8. Fore wing. Scale bar: 1mm.

FIGURES 9–12. Pararrhynchium simsanum Nguyen & Tran, sp. nov., male. 9. Head, frontal view. 10. Head, dorsal view. 11. Left antenna. 12. Habitus. Scale bar: 1 mm.