Polistes (Polistella) caobangensis, Lien, 2020

Lien, Nguyen Thi Phuong, 2020, Contribution to the taxonomy of the paper wasp genus Polistes (Polistella) (Hymenoptera: Vespidae: Polistinae) from Vietnam, with description of a new species, Zootaxa 4759 (2), pp. 252-260 : 253-255

Polistes (Polistella) caobangensis , sp. nov.

( Figs. 1–10 )

Polistes nipponensis Pérez, 1905 : Nguyen, 2017: 225, misidentification.

Material examined. Holotype, female [ IEBR], labeled “ VIETNAM, Phia Oac, Pha Den, Nguyen Binh , Cao Bang, 22°35′07.7″N 105°51′59.8″E, alt. 900–1100m, Nest#VN-CB-2014-P-01, 25–28 May 2014, coll. T. V. Hoang . Paratypes: VIETNAM: 15 females, 25 males, same data as holotype ( IEBR) , 3 females, same data as holotype ( VNMN) .

Diagnosis. The new species can be distinguished from all other species of the subgenus Polistella by the combination of the following characters: female clypeus in frontal view 1.1 times as wide as high, with tomentum on clypeus extended to its dorsal three fifth to two third from its base; vertex strongly sloping down behind posterior ocelli towards occipital carina; pronotal carina sharply raised; S 2 in lateral view strongly swollen ventrally in anterior half, then ventral margin bluntly angled into nearly straight line parallel to dorsal margin of the tergum; male clypeus in frontal view 1.1 times as wide as high; S7 with large and round tubercle; genitalia with penis valves 0.8 times longer than basal apodeme, in lateral view with proximoventral corner produced into nearly right angle; ventral margin of penis valves finely serrated along entire the length; jugal lobe of hind wing rounded.

Description. Female. Body length 10.6–11.6 mm (holotype 11.0 mm); fore wing length 10.0– 10.9 mm (holotype 10.5 mm).

Holotype ( Fig. 5 ). Head in frontal view nearly 1.2 × as wide as high ( Fig. 1 ); in dorsal view weakly swollen laterally just behind eyes, and then narrowed posteriorly. Vertex with slightly raised area inside ocelli, greatly sloping down behind posterior ocelli towards occipital carina; POD: OOD = 1:1.7; POD about two times Od ( Fig. 2 ). Gena in lateral view 0.9 × as wide as eye; occipital carina fine, evanescent in ventral one-third of gena. Inner eye margins in frontal view slightly further apart from each other at vertex than at clypeus ( Fig. 1 ). Distance between inner margins of antennal sockets about 1.7 × of distance from outer margin of antennal socket to inner eye margin; anterior tentorial pit as distant from antennal socket as from inner eye margin; interantennal space weakly raised. Clypeus in frontal view 1.1 × as wide as high ( Fig. 1 ), produced ventrally into blunt angle; in lateral view convex from base to apical margin; lateral margin of clypeus lying along inner eye margin as long as diameter of antennal socket and length of malar space. Antennal scape 3 × as long as its maximum width; F1 2.9 × as long as its maximum width, 1.2 × as long as F2 and 3 combined; F2 longer than wide, F3 & 4 as long as wide; F5–9 wider than long; terminal flagellomere bullet-shaped, 1.2 × 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. Mesoscutum strongly convex, slightly longer than wide between tegulae; anterior margin broadly rounded. Scutellum convex, disc slightly concave at middle. Disc of metanotum almost flat. Propodeum ( Fig. 3 ) short; posterior face widely (nearly half of maximum propodeal width) and shallowly excavated medially, more or less smoothly passing into lateral face; propodeal orifice elongate, 2.0 × as long as wide (measured at widest part), somewhat narrowed in dorsal half. Fore wing brown, transparent, vein dark brown.

T1 short and thick, about 0.4 × as long as its apical width, in lateral view abruptly swollen dorsally just behind propodeal orifice; corner between anterior and dorsal faces bluntly angled. S 2 in lateral view ( Fig. 4 ) strongly swollen ventrally in anterior one half, then ventral margin bluntly angled into nearly straight line parallel to dorsal margin of the tergum.

Body with short, golden setae except posterior part of propodeum with long silver setae. Clypeus with dense large punctures at basal half and scattered large punctures at apical half, each bearing a sharply pointed golden bristle, tomentum on clypeus restricted to its dorsal one half. Mandible with scattered medium punctures. Frons with deep definite punctures. Vertex and gena with sparse and strong punctures; area around ocelli smooth; ventral one third of gena with scattered strong punctures. Pronotum with dense deep punctures; space between punctures very narrow, slightly raised to form reticulation. Mesoscutum with coarse dense flat-bottom punctures; punctures on scutellum and metanotum coarse and dense, smaller than those on mesoscutum. Mesepisternum with punctures similar to those on pronotum, densely with punctures in posterodorsal part and scattered punctures in anteroventral part; border between them indistinct. Dorsal metapleuron with large smooth area, with some striae and sparse punctures, ventral metapleuron with sparse punctures in between smooth areas. Propodeum with strong sharply-raised transverse striae. Metasomal segments densely covered with minute punctures in addition to sparse small punctures (ill-defined on terga; more or less well-defined on sternum).

Color. Black, following parts dark brown: clypeus except basal margin, gena, mandible, antennal scape and all flagellomeres beneath, pronotum entirely, tegulae, scutellum, metanotum; a spot on upper part of mesepisternum; half of T1 and 2 at apical margin, T3–6 entirely, S2–6 except black band at basal margin of S2; apical half of fore femur and tibia; upper part of middle and hind femur and middle and hind tibia entirely, tarsi of fore legs except a brighter brown longitudinal band on tarsus 5. Two spots on each side of propodeum and valvula yellow.

Male. Body length 10.2–11.4 mm; fore wing length 9.0–10.0 mm. Structure as in female, but differing as follows: head 1.3 × as wide as high in frontal view ( Fig. 6 ); eye strongly swollen laterally; inner eye margins 1.2 × as distant from each other at vertex as at clypeus; gena narrow, in lateral view 0.4 × as wide as eye; clypeus in frontal view 1.1 × as wide as high ( Fig. 5 ), slightly produced ventrally, evenly and very weakly rounded apically, in lateral view weakly convex dorsally. Antenna slenderer than in female ( Fig. 7 ); scape short, 2.3 × as long as its maximum width; F1 about 0.8 × as long as the length of the length of F2 and 3 combined; F1–11each longer than wide; terminal flagellomere elongate, slightly curved, 3.3 × as long as its basal width. S7 with large and round tubercle.

Body surface sculpture as in female except clypeus with tomentum entirely on its surface.

Color. Similar to female except with more yellow parts: clypeus to ocular sinus, antennal beneath, a thin band along gena just behind eye, margins of pronotum, spots on lateral sides of scutellum, spots on lateral sides at basal margin, large spots on each side of propodeum, and underneath of body.

Male genitalia. Generally similar to that of P. affinis Gusenleitner, 2006 and P. nipponensis Pérez, 1905 . Digitus in inner aspect of paramere ( Fig. 8 ) 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. 9, 10 ), penis valves 0.8 × longer than basal apodeme, in ventral view narrowest at two fifth from base, nearly straight from two fifth then strongly diversion 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 nearly right angle ( Fig. 10 ); ventral margin of penis valves finely serrated along entire length.

Remarks. This species is similar to P. nipponensis Pérez, 1905 and P. affinis Gusenleitner, 2006 , but differs in the following characters: female and male clypeus in frontal view 1.1 × as wide as high (as wide as high in P. nipponensis and P. affinis ); vertex strongly sloping down behind posterior ocelli towards occipital carina (slightly sloping down behind posterior ocelli towards occipical carina in P. nipponensis and P. affinis ); male gena in lateral view 0.4 × as wide as eye (0.3 × as wide as eye in P. affinis ); female F5–6 wider than long (as wide as long in P. affinis and P. nipponensis ); S 2 in lateral view swollen ventrally in anterior one half (S 2 in lateral view swollen ventrally in anterior one-third in P. nipponensis and P. affinis ); male S7 with large and round tubercle (without tubercle in P. nipponensis ); body color black and brown with some yellow mark, metasomal terga without yellow band at apical margin (body color black with extensive yellow mark, metasomal terga with thick yellow band at apical margin of each tergum in P. nipponensis ).

This species is also similar to P. mandarinus de Saussure, 1853 but differs in the following characters: female head in frontal view 1.2 times as wide as high (1.1 times as wide as high in P. mandarinus ); vertex strongly sloping down behind posterior ocelli towards occipital carina (slightly sloping down behind posterior ocelli towards occipical carina in P. mandarinus ); male S7 with large and round tubercle (without tubercle in P. mandarinus ); penis valves in lateral view with proximoventral corner produced into nearly right angle (penis valves in lateral view with proximoventral corner not produced into right angle in P. mandarinus , only slightly produced ( Nguyen et al., 2011)).

In the previous study, P. mandarinus was also recorded from Phia Oac NR, Cao Bang together with its nest ( Nguyen & Kojima, 2014), but this nest has white cocoons while the nest of P. caobangensis has yellow cocoons.

Etymology. The specific name refers to the type locality, Cao Bang province in the northern part of Vietnam.

Distribution. Northern Vietnam.

Figures

FIGURES 1–5. Polistes caobangensis, new species, female (holotype): 1. Head, frontal view. 2. Head, dorsal view. 3. Scutellum, metanotum and propodeum, dorsal view. 4. Metasomal segments 1–6, lateral view. 5. Habitus.

FIGURES 6–10. Polistes caobangensis, new species, male: 6. Head, frontal view. 7. Part of head with left antenna. Genitalia. 8. Inner aspect of paramere with digitus and volsella. 9, 10. Aedeagus. (9. Ventral and 10. Lateral view). Scale 1mm.