Palpostilpnus melanothoracicus Pham, Sheng, Park, Tran & Reshchikov, 2024

Pham, Nhi Thi, Sheng, Mao-Ling, Park, Clara, Tran, Duong Dinh & Reshchikov, Alexey, 2024, First record of the genus Palpostilpnus Aubert (Ichneumonidae: Phygadeuontinae) from Vietnam, with descriptions of eight new species, Zootaxa 5514 (6), pp. 525-549 : 536-537

Palpostilpnus melanothoracicus Pham, Sheng, Park, Tran & Reshchikov , sp. nov.

( Figures 2C , 8 )

Diagnosis. Black body with yellow markings; occipital carina complete dorsally; postero-ocellar distance 3.2× ocular-ocellar distance; combined area superomedia and area petiolaris of propodeum open anteriorly; area postero-externa complete.

Material examined. Holotype: ♂ ( IEBR), VIETNAM, Vinh Phuc Province, Me Linh Station for Biodiversity , 21°23’22”N 105°42’48’E, 65 m a.s.l., 10–20 July 2021, Malaise trap, Tran D.D. coll. Paratypes: 1♂ ( IEBR), same data as holotype ; 1♂ ( IEBR), same locality as holotype, 21°23.157’N 105°42.740’E, 80 m a.s.l., 20–30 November 2014, Malaise trap, Pham T.N. coll ; 1♂ ( IEBR), same locality and collector as holotype, 20–30 April 2021 ; 1♂ ( IEBR), same locality and collector as holotype, 1–10 May 2021 ; 1♂ ( IEBR), VIETNAM, Lao Cai Province, Bao Yen, Xuan Thuong , 22°14’15.864”N 104°32’52.011”E, 151 m a.s.l., 4–6 April 2024, Malaise trap, Tran D.D. coll.

Description of holotype. Face 1.4× as wide as high, granulate, with setae, centrally weakly convex. Clypeal suture indistinct. Clypeus 2.0× as wide as high, convex, similar sculpture as face, with setae, ventral margin weakly impressed. Mandible moderately stout, gradually narrowed to apex, teeth sharp, upper tooth broader and slightly longer than lower tooth. Malar space mat, equal to mandibular basal width ( Fig. 8A ). Gena punctate, with setae. Frons and vertex rugose punctate, posterior portion from behind ocelli to occipital carina steeply sloping. Postero-ocellar distance 3.2× ocular-ocellar distance, 2.0× median ocellus diameter ( Fig. 8B ).Antenna with 23 flagellomeres. Occipital carina complete.

Mesosoma. Pronotum puncto-striate. Epomia present ( Fig. 8D ). Mesoscutum granulose, 0.9× as long as its maximum width. Notaulus indistinct. Scutellum moderately convex, subpolished, punctate, with setae, except narrowly impunctate posteriorly, lateral carina present basally ( Fig. 8E ). Mesopleuron polished, punctate, except widely impunctate medially; epicnemial carina distinct on ventral 0.8 of mesopleuron. Sternaulus distinct, reaching hind margin of mesopleuron, far above lower posterior corner of mesopleuron. Metapleuron subpolished, punctate, with setae. Juxtacoxal carina complete ( Fig. 8D ). Propodeum gradually sloping in lateral view, polished, with moderately dense punctures laterally, medially with sparse punctures, lateromedian longitudinal carina present posteriorly, not extending anteriorly after meeting lateral part of posterior transverse carina. Combined area superomedia and area petiolaris open anteriorly. Area postero-externa complete, weakly rugose ( Fig. 8C ). Spiracle small, circular.

Wings. Fore wing length ca 3.0 mm, vein 1cu-a, slightly postfurcal to M&RS, inclivous, postero-distal corner of subbasal cell ca. 70°, vein 3rs-m absent, vein 2rs-m about 2.0× length of M between 2rs-m and 2m-cu, length of CU between 1m-cu&M and 2cu-a 0.9× length of 2cu-a. Hind wing with distal abscissa of CU present, obsolescent near wing margin, length of CU between M and cu-a 4.5× length of cu-a.

Legs. Inner profile of basal portion of fore basitarsus distinctly bent. Hind coxa with distinct punctures. Hind femur 3.9× as long as its maximum width, 0.9× as long as hind tibia length. Hind basitarsus 0.45× as long as tarsus.

Metasoma. T1 2.2× as long as apical width, polished, with sparse punctures medially, posteriorly densely punctate, with dorso-lateral carinae; petiole flat; postpetiole broad; ventrolateral carina distinct; spiracle small, round. T2 onwards densely punctate, with setae. T2 1.2× as long as basal width, 0.6× as long as apical width ( Fig. 8F ).

Colour. Black with yellow markings. Head black, mandible (except apex), palpi, scape and pedicel yellow, F1–F2 reddish. Mesoscutum with antero-laterally yellow. Fore and mid legs yellow. Hind leg reddish with coxa, trochanter and apical 0.25 of tibia with black markings, tarsus 1–4 yellow, tarsus 5 brown. T1 black, except anterior 0.4 reddish brown. T2 onwards reddish, each with a transverse black band.

Variation. Antenna of male paratypes 22–24 flagellomeres. Fore wing length varies from 2.7–2.9 mm, vein 1cu-a interstitial to slightly postfurcal to M&RS. T1 entirely black to with reddish brown anteriorly. Male paratype collected on 30.iv.2021 has anterior 0.6 of scutellum yellow, fore wing vein 1m-cu&M with short ramulus.

Female. Unknown.

Comparative notes. This new species keys to P. trifolium in the key of Reshchikov et al. (2019). It can be recognized from the latter by its narrower face (1.4× as wide as high vs. 2.0×), its broader postero-ocellar distance (3.2× ocular-ocellar distance vs. 1.5×), the shorter lateromedian longitudinal carina, and by coloration of mesosoma (black vs. reddish yellow).

Etymology. The species name is derived from Greek “μέλας” and Latin “thorax” and refers to largely black thorax in order to distinguish it from the mainly reddish yellow thorax of P. trifolium .

Distribution. Currently known only from secondary lowland forest at Me Linh Station for Biodiversity, Vinh Phuc Province and Xuan Thuong commune, Bao Yen district, Lao Cai Province.

Figures

FIGURE 8. Palpostilpnus melanothoracicus sp. nov., holotype male:A. head, frontal view; B. head, dorsal view; C. propodeum; D. mesosoma, lateral view; E. mesonotum; F. tergites (scale bar = 0.2 mm).

FIGURE2. Habitusof new species of Palpostilpnus fromVietnam:A.P.cattienensis sp. nov., holotypemale;B.P.hoanglienensis sp. nov., holotype female; C. P. melanothoracicus sp. nov., holotype male; D. P. incompletus sp. nov., holotype male; E. P. ngoclinhensis sp. nov., holotype male; F. P. melinhensis sp. nov., holotype female; G. P. taynguyenensis sp. nov., holotype female; H. P. meovacensis sp. nov., holotype female (scale bar = 1 mm).