Palpostilpnus melinhensis 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 : 537-539

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

( Figures 2F , 9 )

Material examined. Holotype: ♀ ( IEBR), VIETNAM, Vinh Phuc Province, Me Linh Station for Biodiversity , 21°23’03”N 105°42’54’E, 83 m a.s.l., 1–10 September 2021, Malaise trap, Tran D.D. coll. Paratypes: 1♀ 1♂ ( IEBR), same locality and collector as holotype, 10–20 July 2021 ; 1♀ ( IEBR), Tuyen Quang Province, Na Hang, Son Phu , 22°17’32”N 105°28’19”E, 573 m a.s.l., 1–10 June 2017, Malaise trap, Khuat D.L. coll.

Diagnosis. Reddish yellow body with black markings; occipital carina complete dorsally; postero-ocellar distance 1.7× ocular-ocellar distance; ventral side of F8 onwards of female flattened and thickened; combined area superomedia and area petiolaris of propodeum open anteriorly; area postero-externa incomplete.

Description of holotype. Face 1.2× as wide as high, granulose, with setae, centrally weakly convex. Clypeal suture indistinct. Clypeus 1.8× as wide as high, convex, wrinkled, with setae except smooth apically, ventral margin weakly impressed. Mandible stout, weakly narrow to apex, teeth sharp, lower tooth slightly longer than upper tooth. Malar space punctate, with setae, 0.6× as wide as mandibular basal width ( Fig. 9A ). Gena subpolished, finely punctate, with setae. Frons and vertex with rugose punctate, posterior portion from behind ocelli to occipital carina steeply sloping. Postero-ocellar distance 1.7× ocular-ocellar distance, 1.1× median ocellus diameter ( Fig. 9B ). Antenna with 25 flagellomeres, ventral side of F8 onwards flattened and thickened ( Fig. 9E ). Occipital carina complete.

Mesosoma. Pronotum striate medially and punctate dorsally. Epomia present ( Fig. 9F ). Mesoscutum 0.9× as long as its maximum width, with dense punctures, anterior margin relatively straight. Notaulus absent. Scutellum moderately weakly convex, subpolished, densely punctate, with setae, except impunctate posteriorly, lateral carina present basally ( Fig. 9C ). Mesopleuron polished, punctate, with setae, except impunctate medially; epicnemial carina distinct on ventral 0.7 of mesopleuron. Sternaulus distinct on 0.5 anterior to posterior corner of mesopleuron. Metapleuron subpolished, punctate, with setae. Juxtacoxal carina complete ( Fig. 9F ). Propodeum gradually sloping in lateral view, with dense punctures, except smooth area at level of junctions between posterior transverse carina and lateromedian longitudinal carina and somewhat anteriorly at level of lateromedian longitudinal carina. Combined area superomedia and area petiolaris open anteriorly. Area postero-externa incomplete ( Fig. 9G ). Spiracle small, oval.

Wings. Fore wing length ca. 4.1 mm, vein 1cu-a postfurcal to M&RS about 0.2× length of 1cu-a, 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, vein 1m-cu&M with ramulus, length of CU between 1m-cu&M and 2cu-a 1.2× length of 2cu-a. Hind wing with distal abscissa of CU present, length of CU between M and cu-a 2.3× length of cu-a.

Legs. Inner profile of basal portion of fore basitarsus distinctly bent. Hind coxa with distinct punctures. Hind femur 3.8× as long as its maximum width, 0.8× as long as hind tibia length. Hind basitarsus 0.48× as long as tarsus.

Metasoma. T1 1.7× as long as apical width, polished, sparsely punctate 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 1.1× as long as basal width, 0.6× as long as apical width ( Fig. 9H ). Ovipositor very thin, ovipositor tip slightly down-curved ( Fig. 9D ); ovipositor sheath 0.8× as long as hind tibia, 1.6× as long as hind basitarsus, distinct longer than apical depth of metasoma.

Colour. Reddish yellow with black markings. Head black, clypeus reddish, mandible (except apex), palpi and scape yellow, flagellomeres black dorsally, F1–F3 reddish ventrally. Mesoscutum with two black streaks before scuto-scutellar groove. Hind leg with apical half of tibia and fifth tarsomere black. Metasomal tergites each with a transverse black band.

Variations.Antenna of the female paratype from Vinh Phuc Province has 26 flagellomeres, its ovipositor sheath 0.7× as long as hind tibia, 1.4× as long as hind basitarsus. Female paratype from Tuyen Quang Province has black clypeus and longer ovipositor sheath (0.9× as long as hind tibia, 1.8× as long as hind basitarsus).

Male. Similar to females except antenna has 25 flagellomeres and gradually narrow apically, without reddish brown flattened apical flagellomeres. Mesoscutum has a square black mark in front of scuto-scutellar groove instead of two black streaks. Fore wing vein 1m-cu &M without ramulus.

Comparative notes. This new species can be distinguished from P. aki by its narrower face (1.2× as wide as high vs. 1.7×), the shorter T1 (1.7× as long as its apical width vs. 2.35×) and the longer ovipositor sheath. In addition, the new species has sternaulus on anterior 0.5 of mesopleuron and juxtacoxal carina on metapleuron (both are absent in P. aki ) and the new species has fewer black markings on mesosoma and T1 than P. aki .

Etymology. The species name refers to the type locality, Me Linh Station for Biodiversity.

Distribution. Currently known only from secondary lowland forest at Me Linh Station for Biodiversity, Vinh Phuc Province and from Son Phu commune, Na Hang district, Tuyen Quang Province.

Figures

FIGURE 9. Palpostilpnus melinhensis sp. nov., holotype female:A. head, frontal view; B. head, dorsal view; C. mesonotum; D. ovipositor; E. flagellomeres 8–25, ventral view; F. mesosoma, lateral view; G. propodeum; H. 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).