Stenodyneriellus capillus, Lien & Ngat & Hoa & Thai, 2019

Lien, Nguyen Thi Phuong, Ngat, Tran Thi, Hoa, Dang Thi & Thai, Mai Van, 2019, Potter wasps of the genus Stenodyneriellus Giordani Soika (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with description of a new species, Raffles Bulletin of Zoology 67, pp. 396-402 : 398-399

Stenodyneriellus capillus , new species

( Figs. 1–7 )

Material examined. Holotype, male, labeled “ VIETNAM: Binh Trai , Nam Xuan Lac NR, Bac Kan, alt. 760 m, 22°19′45″N 105°28′31″E, 23.v.2018, L. T. P. Nguyen ( IEBR) . Paratypes ( IEBR): VIETNAM: 1 male, same data as holotype .

Diagnosis. Based on the key to species from Giordani Soika (1994), this species can be distinguished from other Stenodyneriellus by eyes with short hairs on all its surface, the clypeus slightly higher than wide, occipital carina complete and widen at lower half of the gena, mesoscutum with two longitudinal carina, propodeum protruding to form two teeth behind metanotum, T2 without apical lamella, F11 not reaching the base of F 10 in curved position, interspace between punctures on pronotum, mesoscutum and mesepisternum with minute punctures.

Description. Male ( Fig. 7 ). Body length 10.5–11 mm (holotype: 10.5 mm); fore wing length 8.6–9.6 mm (holotype: 8.6 mm). Head in frontal view subcircular, 1.1× as wide as high ( Fig. 1 ). Vertex sloping down behind posterior ocelli towards occipital carina, with cephalic foveae each bearing dense pubescence, situated close to each other with distance between foveae about half diameter of front ocellus. Distance from posterior ocelli to apical margin of vertex 1.5× distance from posterior ocelli to inner eye margin ( Fig. 2 ). Gena much narrower than eye, in lateral view 0.3× as wide as eye ( Fig. 3 ). Occipital carina complete, present clearly along entire length of gena, widen at lower half of the gena. Inner eye margins strongly convergent ventrally; in frontal view 1.5× as further apart from each other at vertex as at clypeus. Clypeus in lateral view convex at basal two-third, then straight to apical margin; in frontal view slightly higher than wide ( Fig. 1 ), with basal margin slightly concave medially and distinctly separated from antennal sockets; apical margin emarginate medially ( Fig. 1 ); width of emargination greater than 1/3 width of clypeus between inner eye margins (about 0.38×). Mandible with prominent teeth, fourth tooth long and pointed apically. Antennal scape 3.3× as long as its maximum width; F1 short, 1.2× as long as wide, F2 slightly longer than wide, F3–9 wider than long, F10 small, as long as wide, F11 slightly curved, slightly more than 2× as long as its basal width, not reaching the base of F10 ( Fig. 4 ).

Mesosoma longer than wide in dorsal view. Pronotal carina slightly raised, reaching ventral corner of pronotum. Mesoscutum convex, slightly shorter than wide between tegulae, with two longitudinal carina (close to tegulae and parategulae) running from apical margin to the half length of the mesoscutum ( Fig. 5 ); anterior margin broadly rounded. Disc of scutellum slightly convex. Metanotum almost flat. Propodeum excavated medially, with posterior surface distinctly concave, protruding upward to form two blunt teeth behind metanotum, propodeal groove distinct from a long and narrow fovea to apex ( Fig. 6 ).

T 1 in dorsal view 1.75× as wide as long, rounded basally, gradually widen near base to apical margin ( Fig. 5 ); T 2 in

dorsal view 1.2× as wide as long, without apical lamella; S 2 in lateral view depressed basally at basal half, and slightly convex to apical margin.

Body covered with long silver setae. Clypeus with undefined large punctures at center, punctures at sides smaller. Mandible with several shallow small punctures. Frons densely covered with deep large coarse punctures. Vertex and gena with deep and well-defined punctures, interspaces between punctures with minute punctures. Pronotum with coarse punctures, spaces between punctures with minute punctures, strongly raised to form reticulation. Mesoscutum densely and coarsely covered with deep and large punctures, puncture near apical margin (in between two carinae) very deep, spaces between punctures with minute punctures, strongly raised to form reticulation. Punctures on scutellum similar to those on mesoscutum but smaller. Punctures on metanotum very coarse and dense with flat-bottom, with interspaces raised to form reticulation. Mesepisternum with big and coarse punctures posterodorsally as in pronotum, barely punctured anteroventrally; border between posterodorsal and anteroventral parts indistinct. Metapleuron with strong striae in dorsal area, with sparse shallow punctures in ventral area. Propodeum with punctures on dorsal surface similar to those on metanotum, punctures on lateral parts less coarse than in dorsal part. T1 covered with shallow and small punctures, with interspace larger than puncture diameter at apical margin, punctures on T2 deeper than those on T1, coarser at lateral parts; punctures on T3–5 much smaller and weaker than those on T1–2; T6 with minute punctures; punctures on S2 sparse, deep and large.

Colour. Black. The following parts yellow: clypeus except round black spot in the middle and light brown margins at apical half, mandibles except black base and teeth, a band from ocular sinus to clypeus, an irregular large mark between antenna extended to near front ocellus, antennal scape beneath, long line at vertex behind eye, thick transverse band at dorsal part of pronotum, almost all margin of tegulae, parategulae, transverse line on scutellum near anterior margin, four spots on propodeum, apical thick band on T1 and T2 (emarginated medially), apical thin band on T3-6, spot on lateral side of S2, a large spot at upper part of mesepisternum, all femora at apex, all tibia nearly entirely (except some brown mark), all tarsus. Propodeal valvulae, upper side at base of fore and mid- tibia, spot on fore and mid- femora at apex, dark brown. Wings dark brown, slightly infuscate, veins dark brown.

Female. Unknown.

Distribution. North Vietnam.

Remarks. This species can be distinguished from S. rufoflavus Selis, 2016 from Thailand and other Stenodyneriellus species by the combination of the following characters: eyes with short hairs on all its surface, ocular sinus punctured, propodeum without striations, T2 without apical lamella, and in the colour pattern.

Etymology. The specific name refers to the hairs ( capillus in Latin) on the surface of the compound eyes.

Figures

Figs 1–7. Stenodyneriellus capillus, new species, holotype, male. 1, head, frontal view; 2, vertex and pronotum, dorsal view; 3, head, lateral view; 4, right antenna; 5, mesoscutum, scutellum, metanotum, propodeum, T1&2, dorsal view; 6, propodeum, dorsoposterior view; 7, habitus. Scale = 1 mm.