Polistes (Polistella) adsimilis Nguyen & Carpenter

Nguyen, Lien T. P. & Carpenter, James M., 2016, Review of the Polistes (Polistella) " Stenopolistes " species-group (Hymenoptera: Vespidae: Polistinae) from Vietnam, with description of a new species and key to species, Zootaxa 4088 (4), pp. 583-593 : 588-592

Polistes (Polistella) adsimilis Nguyen & Carpenter , sp. nov.

( Figs 18–27 )

Material examined. HOLOTYPE, ♀, “ VIETNAM, Muong Fang, Dien Bien, 500 m, 23.vii.2009, LTP Nguyen, HP Pham & J Kojima [IEBR]. PARATYPES: VIETNAM: [IEBR] Dien Bien: 1 ♀, Muong Fang, 1000 m, 13.vi.2001, ISD-c; Hoa Binh: 4 ♂, Pa Co, Mai Chau, 1000 m, 23.viii.2005, LTP Nguyen & J Kojima; 1 ♀, Pa Co, Mai Chau, 900 m, 26.vi.2001, ISD-c; Hanoi: 1 ♂, Van Hoa, Ba Vi, 3.vi.2001, LTP Nguyen; [VNMN]; Vinh Phuc: 1 ♀, Tam Dao, 800 m, 2–4.vii.2003, LTP Nguyen.

Diagnosis. The new species can be distinguished from all other species of the subgenus Polistella by the following combination of characters: propodeum shallowly excavated medially, with weak transverse striae. Metasomal tergum 1 1.2 × as long as its apical width, and 2 × as long as its height (less than 1.5 × in almost all other Polistella species except P. meadeanus which has a very long petiole, and P. delhiensis with rather long petiole).

Description. Female. Body length 9.0– 9.5 mm (holotype 9.0 mm); fore wing length 11.2–12.2 mm (holotype 11.2 mm). Head in frontal view 1.1 × as wide as high ( Fig. 18 ); in dorsal view weakly swollen laterally just behind eyes, then narrowed posteriorly, with posterior margin shallowly and broadly emarginate. Vertex slightly raised area inside ocelli, slightly sloped down behind posterior ocelli towards occpital carina; POD:OOD = 1:3; POD as long as Od ( Fig. 19 ). Gena in lateral view 0.8 × as wide as eye; occipital carina fine, evanescent in ventral third of gena. Inner eye margins weakly convergent ventrally, in frontal view 1.1 × further apart from each other at vertex than at clypeus ( Fig. 18 ). Antennal sockets slightly closer to inner eye margin than to each other; anterior tentorial pit 1.8 × as long from antennal socket as from inner eye margin; interantennal space weakly raised. Clypeus in frontal view slightly higher than wide, 1.1 × as high as wide, produced ventrally into blunt angle; in lateral view convex; lateral margin of clypeus lying along inner eye margin as long as diameter of antennal socket and length of malar space. Scape 3 × as long as its maximum width; flagellomere 1 more than 3 × as long as its maximum width, 1.2 × as long as flagellomeres 2 and 3 combined; flagellomere 2 longer than wide, flagellomere 3 as long as wide; terminal flagellomere bullet-shaped, 1.4 × as long as its basal width.

Pronotal carina sharply raised, produced dorsally into thin lamella, slightly sinuate backward on lateral sides, reaching ventral corner of pronotum. Mesocutum strongly convex, as long as wide between tegulae; anterior margin broadly rounded. Scutellum convex, disc flat. Metanotum weakly convex. Propodeum short; posterior face narrowly (one sixth of maximum propodeal width) and shallowly excavated medially, more or less smoothly passing into lateral faces; propodeal orifice elongate, 1.9 × as long as wide (measured at widest part), somewhat narrowed in dorsal half. Fore wing with dark spot at apex of marginal cell ( Fig. 21 ), jugal lobe much reduced.

Metasomal tergum 1 long, 1.2 × as long as its apical width, and 2 × as long as its height (less than 1.5 × in almost all other Polistella species except P. meadeanus which has a very long petiole, and P. delhiensis with rather long petiole), in lateral view gradually swollen dorsally just behind basal slit for reception of propodeal suspensory ligament ( Fig. 20 ). Sternum 2 in lateral view gradually swollen ventrally.

Clypeus with scattered large punctures in lower one third from margin, each bearing sharply pointed golden bristle, tomentum on clypeus restricted in its dorsal one fourth to one third with lateral part extending ventrally (very narrow in one specimen). Mandible with scattered large punctures. Frons with shallow indefinite punctures. Vertex and gena smooth; area around ocelli smooth; ventral third of gena with scattered shallow punctures. Pronotum with shallow large punctures. Mesocutum with punctures similar to those on pronotum; punctures on scutellum stronger, and punctures on metanotum weaker than those on mesoscutum. Mesepisternum with dense coarse well-defined punctures in posterodorsal part, smooth in anteroventral part; border between posterodorsal and anteroventral parts indistinct. Dorsal metapleuron with weak punctures; ventral metapleuron with sparse shallow punctures. Propodeum with weak transverse striae. Metasomal segments with minute punctures.

Color. Dark brown, following parts yellow: faint band along inner eye margin extending from bottom of frons to middle of eye emargination, narrow band along eye margin in dorsal part of gena, flagellomeres beneath, narrow band along pronotal carina, anterior transverse band on metanotum, longitudinal line along lateral faces of propodeum, valvula, narrow band at apical margin of tergum 1 (extending laterally toward its base) and 2; following parts black: area around ocelli, band at apical margin of mesoscutum, propodeum, spot at upper corner of mesepisternum (close to dorsal metapleuron).

Male. Body length mm 8.6–9.0 mm; fore wing length 10.4–12.2 mm. Structure as in female, but differing as follows: head 1.2 × as wide as high in frontal view ( Fig. 23 ); eye strongly swollen laterally; inner eye margins 1.4 × as long from each other at vertex as at clypeus; gena narrow, in lateral view 0.6 × as wide as eye; clypeus in frontal view 0.8 × as wide as high ( Fig. 23 ), strongly produced ventrally, evenly and very weakly rounded apically, in lateral view weakly convex dorsally. Antenna slenderer than in female ( Fig. 24 ); scape short, 2.9 × as long as its maximum width; flagellomere 1 longer than length of flagellomeres 2 and 3 combined; flagellomeres 2 and 3 each longer than wide; terminal flagellomere elongate, slightly curved, 2.5 × as long as its basal width. Metasomal sternum 7 depressed medially, with tubercle.

Body surface sculpture as in female, but clypeus without large punctures, with dense long golden setae and with faint longitudinal ridge medially.

Color. Similar to female except yellow band along eye margin in dorsal part of gena wider, and legs more black.

Male genitalia. Generally similar to that of P. clandestinus (Nguyen et al., 2011) . Digitus in inner aspect of paramere ( Fig. 25 ) 3.2 × as long as wide (measured at widest part), distinctly swollen near base, gradually narrowed apically to mid-length, then slightly swollen towards the rounded apex. Aedeagus ( Figs 26, 27 ), penial valves 1.2 × longer than basal apodeme, in ventral view narrowest near mid-length, nearly straight from mid-length then strongly swollen and distinctly produced laterally near proximal margins, in lateral view slightly thickened in proximal one fourth and with dorsal margin strongly sinuate, with proximoventral corner produced into acute angle ( Fig. 27 ); ventral margin of penial valves finely serrated along entire length.

Remarks. This species is very similar to P. delhiensis Das & Gupta, 1989 but differs by the following characters: propodeum with weaker transverse striae, metasomal tergum 1 1.2 × as long as its apical width (less than 1.2 × in P. delhiensis ), mesoscutum as long as wide between tegulae (wider than long in P. delhiensis ). Etymology. The specific name refers to the similarity of the species compared to P. delhiensis . Distribution. Vietnam (northern provinces).

Figures

FIGURES 18 – 22. Polistes adsimilis sp. nov., ♀, holotype. 18. Head, frontal view. 19. Vertex, dorsal view. 20. Metasoma, lateral view. 21. Fore wing. 22. Habitus.

FIGURES 23 – 27. Polistes adsimilis sp. nov., ♂, paratype. 23. Head, frontal view. 24. Right antenna. 25 – 27. Genitalia. Scale 1 mm. 25. Inner aspect of paramere with digitus and volsella. 26, 27. Aedeagus (26. Ventral and 27. Lateral view).