Polistes (Polistella) brunetus Nguyen & Kojima

Nguyen, Lien Thi Phuong & Kojima, Jun-ichi, 2014, Distribution and nests of paper wasps of Polistes (Polistella) in northeastern Vietnam, with description of a new species (Hymenoptera, Vespidae, Polistinae), ZooKeys 368, pp. 45-63 : 51-56

Polistes (Polistella) brunetus Nguyen & Kojima sp. n.

Type−locality.

Vietnam, Bac Kan: Kim Hi National Park, Lang San, Na Ri, 22°19'N, 105°54'E, 600−700 m.

Type specimens.

Holotype, female, pinned (deposited in the Institute of Ecology and Biological Resources, Hanoi). Original label: "VIETNAM, Kim Hy NP, Lang San, Na Ri, Bac Kan, 22°19'N, 105°54'E, 600−700 m, Nest#VN−NE2012−P−02, 4.viii.2012, J.Kojima, L.T.P. Nguyen & IED−c". Paratypes: Bac Kan: 2 females & 1 male, 1 female (Natural History Collection at Ibaraki University, Mito), same data as holotype.

Other material examined.

Northeastern provinces: Ha Giang: 1 female, Tung Ba, Vi Xuyen, 3.VII.2013, T.V. Nguyen; Lang Son: 1female, Bac Son, 21°54'N, 106°19'E, 1.VII.2003, L.X. Truong; Bac Giang: Son Dong, P.H. Pham [2 females, Tay Yen Tu NP, 21°24'N, 106°54'E, alt. ca 200−300 m, 3.VII.2010; 1 male, 1 female, Thanh Lam, 21°19'N, 106°20'E, alt. ca 120 m, 4.VII.2010]; 1 female, Khe Ro, Son Dong, 17.V.2013, D.D. Nguyen. Other provinces: Hai Phong: 1 male, Cat Ba NP, 20°42'N, 107°4'E, 15−18.VIII.2003, L.T.P. Nguyen; Phu Tho: Xuan Son NP, 21°8'N, 104°59'E, alt. ca 400−600 m [2 females, 11.VI.2004; 1 female, 13.VI.2004; 1 female, 16.VI.2004], L.T.P. Nguyen; Hoa Binh: 1 male, Lac Thinh, Yen Thuy, 20°24'N, 105°33'E, 30.IV.2002, L.D. Khuat; 1 female, Da Phuc, Yen Thuy, 20°24'N, 105°33'E, 27.VII.2000, L.X. Truong; Ninh Binh: 1 male, 2 females, Cuc Phuong NP, 20 °18'N, 105°37'E, 7.V.2002, T. V. Hoang; Thanh Hoa: 1 female, Bat Mot, Thuong Xuan, Xuan Lien NP, 19°59'N, 104°59'E, ca 705 m, 23.IV.2013, L.T.P. Nguyen; Nghe An: 1 female, Chau Cuong, Quy Hop, 19°21'N, 105°6'E, 14−19.VII.2004, H.X. Le; Thua Thien Hue: 1 female, Phu Loc, Bach Ma NP, 30.V.2001, L.D. Khuat.

Diagnosis.

This species can be distinguished from the other Polistes (Polistella) species by the following combination of characters: pronotum with dense and coarse punctures, their edges forming reticulation; metasomal sternum II in lateral view swollen ventrally in anterior half; sternum IV with two long parallel longitudinal ridges medially (this character also occurs in Polistes japonicus ); proximal margin of the penis valve of the male genitalia in lateral view produced ventrally at proximoventral to form a small tooth.

Description.

Female. Body length 15-16.5 mm (holotype: about 16 mm); fore wing length 16-17 mm (holotype: about 16.5 mm).

Head in frontal view about 1.1 times as wide as high (Fig. 2); in dorsal view weakly swollen laterally behind eyes, then narrowed posteriorly, with posterior margin shallowly and broadly emarginate. Vertex slightly raised in area among ocelli, slightly sloped down behind posterior ocelli towards occipital carina; POD:OOD = about 1:1.7; POD about 1.2 times Od (Fig. 3). Gena, in lateral view about 0.8 times as wide as eye (Fig. 4); occipital carina fine, evanescent in ventral one third of gena. Inner eye margins weakly convergent ventrally, in frontal view about 1.1 times further apart from each other at clypeus than at vertex (Fig. 2). Antennal sockets closer to inner eye margin than to each other; anterior tentorial pit slightly further apart from antennal socket than from inner eye margin; interantennal space weakly raised. Clypeus in frontal view as wide as high, produced ventrally into blunt angle; in lateral view weakly swollen anteriorly (Fig. 3); length of lateral margin of clypeus lying along inner eye margin longer than diameter of antennal socket and about as long as the length of malar space. Antenna (Fig. 5): scape more than 3 times as long as its maximum width; flagellomere I about 3 times as long as its maximum width, about 1.2 times as long as the length of flagellomeres II and III combined; flagellomere II and III longer than wide; terminal flagellomere bullet−shaped, about 1.4 times as long as its basal width.

Pronotal carina sharply raised, produced dorsally into thin lamella in dorsal part, slightly sinuate backward on lateral side, reaching ventral corner of pronotum. Mesocutum weakly convex, about 0.9 times as long as wide between tegulae; anterior margin broadly rounded. Scutellum convex, slightly concave medially. Metanotum weakly convex, disc nearly flat but strongly depressed anterior margin. Propodeum short; posterior face widely (about half the maximum width of propodeum) and shallowly excavated medially, more or less smoothly passing into lateral faces; propodeal orifice elongate, about 1.8 times as long as wide (measured at widest part), somewhat narrowed in dorsal half. Wings hyaline, jugal lobe of hind wing rounded (Fig. 7).

Metasomal tergum I short and thick, about 0.8 times as long as its apical width, in lateral view abruptly swollen dorsally just behind basal slit for reception of propodeal suspensory ligament; corner between anterior and dorsal faces bluntly angled (Fig. 8). Sternum II in lateral view swollen ventrally in smoothly curved line in anterior half, then ventral margin nearly straight line parallel to ventral margin of the tergum.

Clypeus with scattered large punctures, each bearing sharply pointed golden bristle; tomentum on clypeus medially restricted in dorsal one-fourth of clypeus, laterally extending ventrally. Mandible with several small and shallow punctures at base and deep punctures at anterior margin. Frons covered with deep punctures. Vertex and gena with sparse small and shallow punctures; area around ocelli smooth; ventral one third of gena with coarse punctures. Pronotum with dense, coarse punctures, their edges forming reticulation (Fig. 6). Mesocutum densely with coarse flat-bottomed punctures; punctures on scutellum and metanotum dense coarser but smaller than those on mesoscutum. Mesepisternum with dense coarse well−defined punctures in posterodorsal part (punctures in dorsal margin similar to those on pronotum), scattered punctured in anteroventral part; border between posterodorsal and anteroventral parts indistinct. Dorsal metapleuron with striae and shallow large punctures; ventral metapleuron with sparse strong punctures. Propodeum with strong transverse striae; lateral face with sparse ill−defined punctures. Metasomal segements covered with minute punctures in addition to scattered small punctures (stronger and larger on sterna) except sternum IV with two long medial parallel longitudinal ridges along sternum and several shorter ridges on each side of the long one ended by large shallow punctures (Fig. 9), area between paired longitudinal ridges smooth; sternum II−IV each with a stuff of long hair at apical margin, sternum V and VI entirely covered with long hairs.

Dark brown; following parts yellow to orange-yellow: clypeus except apical black margin, mandible except a black spot at base and apical margin, and narrow band along inner eye margin extending from bottom of frons to middle of eye emargination; following parts black: area around ocelli, apical margin and a longitudinal line along lateral faces and at the middle of propodeum, spot on valvula, mid and hind coxae and trochanters beneath.

Male. Body length about 13.5-15.5 mm; fore wing length about 15.5-16.5 mm.

Like female, but differing from the latter as follows: head about 1.2 times as wide as high in frontal view (Fig. 10); eye strongly swollen laterally; inner eye margins about as long from each other at vertex as at clypeus; gena in lateral view about half as wide as eye (Fig. 11), with weakly raised blunt ridge running along posterior margin of eye; clypeus in frontal view about as wide as high (Fig. 10), only slightly produced ventrally, evenly and slightly convex apically, in lateral view weakly convex in dorsal part (Fig. 11). Antenna (Fig. 12) slenderer than in female; scape short, about 2.8 times as long as its maximum width; flagellomere I longer than length of flagellomeres II and III combined; flagellomeres II and III each longer than wide; terminal flagellomere elongate, slightly curved, about 2.5 times as long as its basal width. Metasomal sternum VII depressed medially (Fig. 13), without tubercle (Fig. 14).

Body surface sculpture as in female, but clypeus without large punctures and densely covered with long golden hairs and with a faint longitudinal ridge medially.

Genitalia in general as that of Polistes species, with the following specific characters: digitus in inner aspect of paramere (Fig. 15) about 3.2 times 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; aedeagal penis valves (Figs 16−17) slightly longer than aedeagal basal apodeme, in ventral view narrowest near mid−length, weakly swollen proximally 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 weakly and smoothly sinuate, with proximoventral corner produced into abuse angle (Fig. 17); ventral margins of penis valves finely serrated along entire length.

Color and marking pattern similar to female, but more extensively marked with yellow as follows: clypeus except a broad longitudinal median band, narrow long band on gena along posterodorsal margin of eye, antennal flagellomeres beneath, narrow band along pronotal lamella, narrow band on basal metanotum, paired longitudinal lines on lateral face of propodeum, valvulae, narrow band at apical margin of tergum I−III and sternum II and III; more extensively black marked as follow: two longitudi nal bands at lateral margin on mesoscutum, a wide band on basal margin of tergum I and II (sometimes on tergum III); spot at upper corner of meseposternum (closed to dorsal part of metapleuron); propodeum and legs more black.

Etymology.

The specific name, brunetus, is a Latin adjective, referring to the brown body color.

Distribution.

Known only from localities in northern Vietnam listed above.