Pararrhynchium striatum Nguyen

Nguyen, Lien Thi Phuong, 2015, Two new species of the genus Pararrhynchium de Saussure (Hymenoptera: Vespidae: Eumeninae) from northern Vietnam, Zootaxa 3974 (2), pp. 170-176 : 171-174

Pararrhynchium striatum Nguyen , sp. nov.

( Figs 1–8 )

Material examined. HOLOTYPE, ♀ [ IEBR], “ VIETNAM, Lac Thinh, Yen Thuy, Hoa Binh, 22°14'N, 106°05'E, 2.v.2002, Hoang Vu Tru”. PARATYPES: VIETNAM: [ IEBR] 1 ♂, Phuc Xuyen, Dai Tu, Thai Nguyen, 23.iv.2012, Long D. Khuat; 1 ♀, Son Kim, Huong Son, Ha Tinh, 6.v.2004, Lam X. Truong; 1 ♀, Son Tho, Vu Quang, Ha Tinh, 24.v.2008, Insect Systematic Department collectors; 2 ♀, Bac Vang ranger station, Na Hang NR, Na Hang, Tuyen Quang, 20°20'53"N 105°25'49"E, 121 m, 10.vi.2015, L.T.P. Nguyen, D.D. Nguyen & L.X. Truong; [ VNMN] 4 ♀, Bac Vang ranger station, Na Hang NR, Na Hang, Tuyen Quang, 20°20'53"N 105°25'49"E, 121 m, 10.vi.2015, L.T.P. Nguyen, D.D. Nguyen & L.X. Truong.

Diagnosis. A new species can be distinguished from all other congeners by following combination of characters: frontal face of pronotum with dense small punctures along pronotal carina; clypeus in frontal view much wider than high, about 1.2 × as wide as high; horizontal area of propodeum as long as metanotum, posterior surface of propodeum with oblique striations along its height, upper half of median carina of propodeum with several transverse striae; T1 with partial transverse carina at base which visible at lateral sides.

Description. Female. Body length 10–11.8 mm (holotype: 11.2 mm); fore wing length 8.8–10.2 mm (holotype: 9.8 mm). Head in frontal view nearly circular, about as wide as high ( Fig. 1 ). Vertex ( Fig. 3 ) strongly produce behind eye, with cephalic foveae small, bearing dense pubescence, situated close to each other with distance between foveae about half diameter of front ocellus; depression for cephalic foveae obsolete. Frontal face of pronotum with dense small punctures along pronotal carina, punctures larger and denser at lateral sides. Distance from posterior ocelli to apical margin of vertex slightly greater than 2 × distance from posterior ocelli to inner eye margin ( Fig. 3 ). Gena narrower than eye, strongly depress near occipital carina, in lateral view 0.8 × as wide as eye; occipital carina complete, present along entire length of gena, but dorsally somewhat weak. Inner eye margins strongly convergent ventrally; in frontal view about 1.3 × further apart from each other at vertex than at clypeus. Clypeus in lateral view weakly and smoothly convex; in frontal view 1.2 × as wide as high ( Fig. 2 ), with basal margin slightly convex medially and slightly separated from antennal sockets; apical margin deeply emarginate medially, forming sharp tooth on each lateral side ( Fig. 2 ); width of emargination less than 1/3 width of clypeus between inner eye margin. Mandible with four prominent teeth, second to fourth teeth triangular, outer one bluntly pointed apically. Antennal scape 3.3 × as long as its maximum width; F1 1.3 × as long as its width, F2 as long as wide, F3–9 wider than long, F10 bullet-shaped, as long as basal width.

Mesosoma longer than wide in dorsal view, 1.3 × as long as wide. Pronotal carina slightly raised, produced at humeral angles, reaching ventral corner of pronotum. Mesoscutum with prescutal furrows (extending from scutellum to near middle of mesoscutum), weakly convex, slightly longer than wide between tegulae; anterior margin broadly rounded. Scutellum flattened, in lateral view at same level with mesoscutum, strongly depressed along anterior margin with 7–9 short longitudinal carinae. Metanotum slightly sloping down to apical margin, forming part of dorsal surface of mesonotum. Propodeum with horizontal area about as long as metanotum, posterior surface slightly concave, bordered by pronounced carina with V-shaped incision in middle above, with oblique faint striations along its height, upper part of propodeum forming pair of blunt teeth behind metanotum ( Fig. 4 ), median carina indistinct at upper half with several transversal striae, at short distance from apical of valvula carina bent forwards, thus separating larger upper part of lateral areas of propodeum from narrow, slightly concave, strip above apical valvula.

Metasomal segment 1 slightly narrower than 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; apical margin of T1 slightly depressed. T 1 in dorsal view slightly less than 1.5 × as wide as long; T2 wider than long, about 1.1 × as wide as long, slightly raised apically ( Fig. 5 ); S2 slightly depressed basally, in lateral view flat basally then slightly convex to apical margin.

Body covered with short, silver setae except clypeus and front with slightly longer setae.

Clypeus with dense, large punctures, each bearing silver bristle, punctures at center lager than at sides. Mandible with several shallow small punctures. Frons densely covered with very coarse, flat-bottomed punctures, punctures strongly raised to form reticulation. Vertex and gena with punctures similar to those on frons. Pronotum with punctures coarser than punctures in vertex and gena, spaces between punctures very narrow, strongly raised to form reticulation. Mesocutum densely and coarsely covered with flat-bottomed punctures, punctures on scutellum and metanotum dense, coarse and equal to those on mesoscutum. Mesepisternum with dense, coarse, well-defined punctures posterodorsally, barely punctured anteroventrally; border between posterodorsal and anteroventral parts distinct. Dorsal metapleuron with strong striae, ventral metapleuron with sparse shallow punctures. Propodeum with punctures on lateral parts similar to those on mesopleuron, dorsal part with large and well-defined punctures, posterior surface with ill-defined shallow, sparse punctures. Metasomal segments densely covered with strong punctures, punctures on T1 coarser than punctures on T2, T3–4 with small and shallow punctures at distance from apical margin, other part smooth, S2 with punctures similar to those on lateral margin of T2, T5–6 and S5–6 with minute punctures.

Color. Black; following parts yellow: spots on upper lateral corner and spots on lower lateral corner of clypeus (combined on some specimens), spot on frons, most part of mandible, antennal scape beneath. Antennal flagellomeres beneath and propodeal valvulae dark brown. Wings dark brown, strongly infuscate, veins dark brown.

Male. Body length about 9.5 mm; fore wing length about 8.5 mm. Structure as in female, but differing from latter as follows: head proportionally smaller, transverse, 1.2 × as wide as high in frontal view; inner eye margins strongly convergent, slightly greater than 1.5 × further apart from each other at vertex than at clypeus; gena narrow, in lateral view 0.5 × as wide as eye; clypeus in frontal view slightly wider than high, only slightly produced ventrally, in lateral view slightly convex from base to apical margin, apical margin deeply emarginate medially, forming sharp pointed tooth on each lateral side ( Fig. 7 ); mandible with four prominent teeth. Antenna slightly slender than in female, scape short, about 3 × as long as its maximum width; F1 about 2 × as wide as long, F2–9 longer than wide, F10 much smaller than F9, F11 elongate, curved, about 1.5 × as long as its basal width ( Fig. 8 ).

Body surface sculpture as in female, but clypeus without large punctures, punctures sparse and small.

Color. Similar to female, but clypeus yellow except black apical margin and strip at outer part of fore tibia yellow.

Distribution. Northern Vietnam: Hoa Binh, Thai Nguyen, Ha Tinh.

Etymology. The specific name refers to the striations on the propodeum in this species.

Figures

FIGURES 1 – 6. Pararrhynchium striatum sp. nov., holotype, ♀. 1. Head in frontal view, 2. Clypeus in frontal view, 3. Vertex in dorsal view, 4. Propodeum, 5. T 1 – 2 in dorsal view, 6. Habitus.

FIGURES 7 – 8. Pararrhynchium striatum sp. nov., ♂. 7. Clypeus in frontal view, 8. Left antenna.