Pristaulacus phiaoacus Long, 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 : 231-233

Pristaulacus phiaoacus Long , sp. nov.

Figures 11–12, 23

Type material. VIETNAM: holotype, ♂, labelled “Aulac. 014 ” ( IEBR), NE Vietnam: Cao Bang, Nguyen Binh, Phia Den, Phia Oac forest , 22°34’ N 105°52’E, 1206m, sweep, 8.v.2013, Hoang VT .

Etymology. The new species is named after the holotype locality (Phia Oac NP, Northeastern Vietnam).

Diagnosis. Head from above 1.1 × wider than long dorsally; occipital carina 0.3 × diameter of ocellus, interrupted medially; median occipital groove deep, U - shaped ( Fig. 12A); pronotum, in lateral view, with one long and acute projecting tooth-like process; mesoscutum in dorsal view with short and narrow median longitudinal impression and two transverse carinate lobes; scutellum largely transversely striate; fore wing with vein 1cu-a postfurcal, vein 2- Rs+M short, discal cell more or less quadrate ( Fig. 12I); fore wing with large pale brown substigmal spot, membrane slightly infuscate apically; hind femur 0.7 × length of hind tibia; tarsal claw with three tooth-like processes ( Fig. 12G); petiole elongate, slender, slightly widened apically, 5.4 × its apical width.

Description. (holotype, ♂), body length: 10.8 mm; antenna length: 6.2 mm; fore wing length: 8.1 mm ( Fig. 11).

Colour. Head black; scape yellow; pedicel and flagellum blackish-brown; mandible yellow basally, dark to blackish brown apically; palpi pale brown to brown; mesosoma black; fore and middle legs yellow, except coxa blackish brown; hind coxa black; hind trochanter and femur brown, except extreme base and apex of femur yellow; trochantellus yellow; hind tibia pale brown, but extreme base and apical one third yellow; hind tarsus yellow; fore wing veins brown; wing membrane yellow; fore wing with large pale brown substigmal spot, membrane slightly infuscate apically ( Fig. 12I); petiole black; second-fifth blackish brown apically, reddish-yellow ventrally and laterally ( Fig. 12J); tergites 6–5 blackish brown to black.

Head. Head from above 1.1 × wider than long dorsally; occipital carina narrow, 0.3 × diameter of ocellus, interrupted medially, median occipital groove deep, U - shaped ( Fig. 12A); scape 1.8 × length pedicel; first flagellomere as long as scape, and 0.5 × length of second flagellomere; POL: OOL = 8: 8 ( Fig. 12A).

Mesosoma . Pronotum, in lateral view, with one long and acute projecting tooth-like process ( Fig. 12E); propleuron areolate-rugulose, pubescence short; mesoscutum mostly perpendicular above pronotum in lateral view; mesoprescutum and axillae areolate-rugulose; notauli largely crenulate; mesoscutum in dorsal view with short and narrow median longitudinal impression and two transverse carinate lobes; scutellum largely transverse striate ( Fig. 12D); metapostnotum wide, largely crenulate ( Fig. 12F); metapleuron and propodeum areolate-rugose, with setae long and sparse; fore wing with vein 1-M 0.7 × vein 1m-cu; vein 1cu-a postfurcal; r: 3-Rs = 12: 25; discal cell nearly parallel-sided; 2-Rs+M very short, nearly quadrate; 2-Ma: 3-Ma: 3-Mb = 29: 12: 14 ( Fig. 12I); hind femur 0.7 × length of hind tibia; hind tibial spurs straight ( Fig. 12H); inner spur as long as outer spur = 9: 9; hind basitarsus 1.3 × length of tarsomeres 2–5 combined; tarsomere 1 3.5 × length of tarsomere 2; tarsomere 2, 1.4 × length of tarsomere 3; tarsomere 3, 2.4 × length of tarsomere 4; tarsomere 4, 0.5 × length of tarsomere 5; hind tarsal claw with three short robust tooth-like processes ( Fig. 12G).

Metasoma. Pyriform (lateral view), weakly compressed laterally; petiole elongate, slender, slightly widened apically, 5.4 × its apical width ( Fig. 12J); petiole and segment 1 polished and shiny; remaining segments with dense fine punctures and short setae.

Female. Unknown.

Taxonomic remarks. The new species resembles P. calidus Chen, Turrisi, Xu, 2016 , described from China (Yunnan province), for the appearance and the shape of the occipital groove, but it is distinguished mainly by: 1) Shape of the head, with temple strongly convergent at the end behind eye, and distinctly longer than eye length dorsally (regularly rounded, and equal to eye length in P. calidus ); 2) Head blackish (lower part of head extensively reddish orange, see Chen et al. 2016, Fig. 15); 3) Wing membrane yellow (hyaline in P. calidus ); 4) Metasoma extensively reddish orange (black with posterior margin of first tergite brown in P. calidus ); 5) Setae of the body goldish (whitish in P. calidus ). It is also readily distinguished from P. comptipennis for the colour pattern, especially the fore wing hyaline with brown substigmal spot, and the hind tarsus yellow (fore wing largely infuscate with several brown spots, and hind tarsus blackish brown in P. comptipennis ), the shape of the head and the occipital medial groove (comparewith Turrisi & Smith 2011, Fig. 19), and the occipital carina narrow, 0.3 × diameter of ocellus (broad, 0.6–0.8 × diameter of ocellus in P. comptipennis ).

Biology. Unknown.

Distribution. Northeastern Vietnam (Cao Bang province) ( Fig. 23).