Longipectus planus, Pham & Cao, 2025

Pham, Nhi Thi & Cao, Nga Thi Quynh, 2025, A new genus and three new species of the subfamily Phygadeuontinae (Hymenoptera: Ichneumonidae) from northern Vietnam, European Journal of Taxonomy 1026, pp. 236-249 : 242-245

Longipectus planus gen. et sp. nov.

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Figs 3–5

Diagnosis

Antenna with F9 onwards thickened and flattened ventrally; sternaulus indistinct; area superomedia open laterally; ovipositor sheath 0.18–0.19 × as long as hind tibia.

Etymology

The specific name ‘ planus ’ is a Latin adjective meaning ‘flat’, referring to its distally flattened antenna.

Type material

Holotype

VIETNAM • ♀; Cao Bang Province, Phia Oac-Phia Den National Park ; 22°36ʹ12ʺ N, 105°53ʹ10ʺ E; 980 m a.s.l.; 30 Apr. 2022; D.D. Tran leg.; Malaise trap; IB.

Paratypes

VIETNAM • 1 ♀; Hoa Binh Province, Mai Chau district, Hang Kia commune; 1400 m a.s.l.; 10 Oct. 2019; Long D.K. leg.; sweep net; IB • 1 ♂; Son La Province, Thuan Chau district, Co Ma commune; 21 ° 19ʹ2.2ʺ N, 103°35ʹ14.1ʺ E; 1,591 m a.s. l.; 27 Apr.–2 May 2016; T. V. Hoang and B. V. Nguyen leg.; Malaise trap; IB .

Description

Female

HEAD. Face 0.8 × as wide as high, granulate, with setae. Clypeal suture indistinct. Clypeus 1.7 × as wide as high, similar sculptures as face, ventral margin weakly impressed. Mandible short, 2.5 × as long as median width, gradually narrowed towards apex, teeth sharp, upper tooth longer than lower tooth. Malar space finely granulate, 0.4 × as wide as mandibular basal width ( Fig. 4A). Gena, frons and vertex finely granulate, with setae. Postero-ocellar distance 0.9 × ocular-ocellar distance, 0.8 × median ocellus diameter ( Fig. 4B). Antenna with 26 flagellomeres, F1 9.0 × as long as wide, 1.2 × as long as F2, ventral side of F9 onwards flattened and thickened. Occipital carina complete, ventrally meeting hypostomal carina about 1.0 × basal mandibular width from base of mandible.

MESOSOMA. 0.7 × as long as metasoma ( Fig. 3). Pronotum 0.3 × as long as mesosoma, polished, finely granulate anteriorly and posteriorly, medially strongly impressed, smooth. Epomia short ( Fig. 4E). Mesoscutum 1.5 × as long as its maximum width, granulate. Notauli present on anterior 2/3 of mesoscutum. Scutellum moderately convex, finely granulate, except impunctate posteriorly, lateral carina present basally ( Fig. 4D). Mesopleuron finely granulate, with setae; epicnemial carina distinct on ventral 0.7 of mesopleuron. Sternaulus indistinct. Metapleuron finely granulate. Juxtacoxal carina absent ( Fig. 4E). Propodeum gradually sloping in lateral view, punctate dorsally, smooth at level of area superomedia and area petiolaris. Area superomedia open laterally. Area petiolaris defined ( Fig. 4H). Spiracle small, round.

WINGS. Fore wing length ca 4.1 mm, vein 1cu-a interstitial to M&RS, weakly curved ventrally, vein 3rs-m absent, vein 2rs-m slightly longer than length of M between 2rs-m and 2m-cu, length of CU between 1m-cu&M and 2cu-a 1.1 × length of 2cu-a. Hind wing with distal abscissa of CU present, length of CU between M and cu-a 1.1 × length of cu-a.

LEGS. Hind coxa matt. Hind femur 6.2 × as long as its maximum width, 0.8× as long as hind tibia length. Hind tarsus 1.2× hind tibia. Hind basitarsus 0.48 × as long as tarsus.

METASOMA. T1 subpolished, with longitudinal wrinkles, T2 matt, with longitudinal wrinkles, T3 onwards matt, densely punctate. T1 1.7 × as long as posterior width, ventrolateral carina distinct; spiracle small, round. T2 2.2 × as long as T1, 3.4 × as long as anterior width, 1.7 × as long as posterior width ( Fig. 4F). Ovipositor thin, straight, lower valve with teeth apically ( Fig. 4K); ovipositor sheath 0.19 × as long as hind tibia.

COLOUR. Black. Scape reddish, flattened part of F9 onwards brown. Palpi yellow. T6 onward reddish brown. Fore and mid legs reddish brown, except coxae, trochanters, trochantelli yellow. Hind leg reddish brown with black markings. Wings hyaline, wing veins brown.

Variation

Female paratype with 27 antennal flagellomeres. Postero-ocellar distance 1.2 × ocular - ocellar distance, 0.6 × median ocellus diameter. Mesoscutum 1.3 × as long as maximum width. Fore wing 4.0 mm long, length of hind wing CU between M and cu-a 1.6 × length of cu-a. Metasomal T2 1.7 × as long as T1, 2.6 × as long as anterior width, 1.5 × as long as posterior width. Ovipositor sheath 0.18 × as long as hind tibia.

Male

Male paratype with 27 antennal flagellomeres, F1 5.0 × as long as wide, without any flattened and thickened flagellomeres. Postero-ocellar distance 1.1 × ocular - ocellar distance, 0.6 × median ocellus diameter ( Fig. 5C). Mesoscutum is 1.2 × as long as maximum width ( Fig. 5E). Fore wing 4.0 mm long, length of hind wing CU between M and cu-a 1.6 × length of cu-a. Sternaulus present on anterior 0.4 of mesopleuron. Metapleuron with juxtacoxal carina complete. Metasomal T1 1.8 × as long as posterior width, T2 1.8 × as long as T1, 2.6 × as long as anterior width, 1.5 × as long as posterior width.

Distribution

Currently known only from evergreen montane forests in Cao Bang, Hoa Binh and Son La provinces, North Vietnam.