Pristaulacus bicoloratus Long & Jennings, 2024

Pham, Nhi Thi, Long, Khuat Dang, Dzuong, Nguyen Van, Mai, Pham Quynh & Turrisi, Giuseppe Fabrizio, 2024, The genus Pristaulacus Kieffer, 1900 (Hymenoptera: Aulacidae) in Vietnam and Northeastern Laos with descriptions of ten new species, Zootaxa 5432 (2), pp. 213-249 : 220-223

Pristaulacus bicoloratus Long & Jennings , sp. nov.

Figures 3–4, 23

Type material. VIETNAM: holotype, ♀, labelled “Aulac. 013 ” ( IEBR), NE Vietnam: Tuyen Quang, Na Hang Nature Reserve forest , 22°19’59.6’’N 105°26’01’’E, 369m, sweep, 11.vi.2015, LIEN & DAI .

Etymology. From “bi” (Latin for “two”), and “coloris” (Latin for “hue, tint”), because of the two-coloured body.

Diagnosis. Head, from above 1.2 × wider than long dorsally; temple rather long, mostly parallel behind eyes; occipital carina complete, very thin and slightly concave medially ( Fig. 4A), 0.1 × diameter of an ocellus; frons, vertex and temple mostly smooth, with sparse fine superficial punctures; fore wing vein 2-Rs+M short; discal cell elongate and distinctly narrowed anteriorly ( Fig. 4K); fore wing with three separate dark spots: substigmal spot, spots in basal and subbasal cells apically and in second discal cell basally; hind femur 0.6 × length of hind tibia; hind tarsal claw with four tooth-like processes; petiole broadly widened apically, 1.9 × its apical width; metasoma mostly polished and shiny ( Fig. 4G); ovipositor 1.2 × fore wing length.

Description. (holotype, ♀), body length: 15.0 mm; antenna length: 8.3 mm; fore wing length: 13.4 mm; ovipositor length: 15.8 mm ( Fig. 3).

Colour. Head, scape, pedicel and first-second flagellomeres reddish orange; remaining flagellomeres brown to dark brown toward apex; mesosoma, fore and middle legs reddish orange; hind coxa and femur blackish brown, except apex of femur reddish orange; hind tibia and tarsus pale brown; wing membrane and veins yellow; fore wing with three separate dark spots: substigmal, in basal and subbasal cells apically and in second discal cell basally ( Fig. 4K); metasoma and ovipositor sheath dark brown; ovipositor brown.

Head. From above 1.2 × wider than long dorsally; temple rather long, mostly paralleling behind eyes, and 1.1 × as long as eye length dorsally ( Fig. 4A); occipital carina complete, very narrow and slightly concave medially ( Fig. 4A), 0.1 × diameter of an ocellus; scape 1.6 × length pedicel; first flagellomere 1.4 × as long as scape, and 0.8 × length of second flagellomere; POL: OOL = 14: 15; frons coriaceous; clypeus punctate with sparse long setae, 2.5 × as wide as long; mandible with sparse long setae ( Fig. 4B); malar space with short setae, 0.3× eye length dorsally; frons, vertex and temple mostly smooth, with sparse fine superficial punctures.

Mesosoma . Pronotum in lateral view with one short obtuse projecting tooth-like process ( Fig. 4E); lateral surface propleuron crenulate medially; areolate-rugulose dorsally, pubescence sparse and long; mesoscutum in lateral view slightly protruding anteriorly above pronotum; medial groove shallow, crenulate; lateral lobes areolate rugose, with short setae ( Fig. 4D); scutellum with sparse transverse rugosity; axillae areolate-rugose; mesepisternum reticulate with short pubescence; metapostnotum deep, finely crenulate ( Fig. 4F); metapleuron and propodeum reticulate-rugose, with short pubescence ( Fig. 4F); fore wing with vein 1-M much shorter (0.3 ×) than vein 1m-cu; vein 1cu-a postfurcal; first and second submarginal cells contiguous, without vein 2r-m; vein 2-Rs+M short, discal cell elongate, distinctly narrowed anteriorly and widened posteriorly ( Figs 3A, 4K); length of stigma, median width = 50: 14; r: 3-Rs = 20: 32; 2-Ma+3-Ma: 3-Mb = 42: 17; vein 3r-m strongly curved outwards. Hind coxa robust, subapical groove of hind coxa (ovipositor guide) slightly oblique, wide, mostly smooth, with sparse setae on groove ( Fig. 3B); hind femur 0.6 × length of hind tibia, rugose-punctate laterally ( Fig. 4J); inner spur: outer spur = 15: 12; hind basitarsus 1.2 × length of tarsomeres 2–5 combined ( Fig. 4I); hind basitarsus 3.3 × length of second tarsomere 2; second tarsomere 1.5 × length of third (15:10); third tarsomere 2.0 × length of fourth; fourth tarsomere 0.5 × length of fifth; hind tarsal claw with four tooth-like processes ( Fig. 4H).

Metasoma. Pyriform (lateral view), weakly compressed laterally; petiole broadly widened apically ( Fig. 4G), 1.9 × its apical width; metasoma mostly polished and shiny; ovipositor 1.2 × fore wing length.

Male. Unknown.

Taxonomic remarks. The new species belongs to the informal “ flavipennis group” (Turrisi, unpubl.), currently grouping four similar species (Smith, 1997; Smith, 2017; Smith & Turrisi, 2020; Turrisi & Smith, 2020) characterized by the large size (more than 13 mm up to 19 mm), mesosoma almost entirely areolate rugose without transverse carinae, and colour of the body extensively orange, yellowish wings with various dark marks. Based on the shape of the head, it is mostly similar to P. flavipennis (Cameron) , from Sri Lanka, but it can be readily distinguished as follows: 1) Antenna basally yellow, then brown (entirely blackish in P. flavipennis ); 2) Fore wing with stigma pale orange and several dark marks (fore wing with stigma dark brown, a small substigmal dark spot and apicoventral margin blackish in P. flavipennis ). It is distinguished from P. erythrocephalus Cameron , from Malaysia and Philippines ( Smith, 2017: 482), by having: 1) Antenna yellow basally, dark brown apically (antenna black with scape orange in P. erythrocephalus ); 2) Metapleuron and propodeum yellow (black in P. erythrocephalus ); 3) Fore wing with three separate dark spots (fore wing entirely dark brown to black in P. erythrocephalus ); 4) Hind leg with coxa blackish brown to black, yellow basally, femur dark brown, yellow apically, tibia and tarsus yellowish brown (hind leg black in P. erythrocephalus ).

The new species can be distinguished from P. exuberans Turrisi & Smith, 2011 , from Thailand, as follows: 1) Shape of the head, 1.2 × wider than long dorsally (1.0 × in P. exuberans ); 2) Mesosoma entirely yellow (orange with most of mesopleuron and propodeum blackish in P. exuberans ); 3) Fore wing less extensively darkened apically with stigma orange (apex extensively darkened with stigma brownish in P. exuberans ); 4) Ovipositor longer, 1.2 × fore wing length (1.0 × in P. exuberans ).

The new species also resembles P. luteus Smith & Turrisi, 2020 , described from India, but it can be distinguished as follows: 1) Temple rather long, more than eye length dorsally (0.8 × in P. luteus ); 2) Antenna basally yellow, then brown (entirely blackish in P. luteus ); 3) Stigma yellow (blackish in P. luteus ); 4) Ovipositor 1.2 × fore wing length (1.4 × in P. luteus ).

Biology. Unknown.

Distribution. Northeastern Vietnam (Tuyen Quang province) ( Fig. 23).