Dolichomitus flavicrus Matsumoto, 2018

Matsumoto, Rikio, 2018, Review of the mandibularis group of the genus Dolichomitus (Hymenoptera, Ichneumonidae, Pimplinae), Journal of Hymenoptera Research 62, pp. 73-82 : 74-77

Dolichomitus flavicrus Matsumoto sp. n.

Figs 1a-d, f, h , 2 , 3

Description. Female.

Head (Fig. 1a ). Antennal flagellum with 40-41 segments; face densely covered with pubescence, between antennal socket and supraclypeal suture 0.5 × as long as its minimum width between eyes; clypeus flat, about 2.3 × as wide as high, with apical margin bilobed, deeply incised medially; distance between eye and lateral ocellus 1.5 × as long as maximum diameter of latter; mandible moderately tapered, at middle about 0.5 × as wide as basal width; malar space about 0.3 × basal width of mandible; vertex with inter-ocellar area weakly raised; outline of gena moderately rounded in dorsal view.

Mesosoma. Pronotum with anterior edge incised medially, medially thickened to form a posteriorly directed tooth, followed by median longitudinal groove reaching to posterior margin; epomia curved, lower end turning backwards; mesoscutum in front of scuto-scutellar groove 1.5-1.6 × as long as wide in dorsal view, covered with moderately dense pubescence; mesopleuron moderately punctate and pubescent, with area below episternal scrobe moderately depressed, mesopleural suture distinctly foveolate, below episternal scrobe, foveae indistinct above episternal scrobe; scutellum moderately convex; metapleuron moderately convex medially, entirely reticulate-ru gose; propodeum (Fig. 1b ) entirely reticulate-rugose, moderately densely covered with pubescence, with lateromedian longitudinal carinae present from base to middle, almost replaced by wrinkles; lateral longitudinal carina indistinct anteriorly, replaced by rugosity; submetapleural carina distinct, posteriorly fused with fine ventral transverse wrinkles in front of each hind coxal cavity.

Wings (Fig. 3a ). Fore wing with vein Rs+M opposite cu-a; 2rs-m as long as 3rs-m, slightly shorter than vein M between 2rs-m and 2m-cu; vein M between 3rs-m and 2m-cu about 0.2 × length of M between 2rs-m and 2m-cu, vein Cu1a separated from 1m-cu by about 1.2 × length of Cu1b; vein cu-a weakly inclivous. Hind wing with vein M+Cu almost straight; distal abscissa of Cu1 present, reaching wing margin; vein Cu1 separated from M by 0.5 × length of cu-a; vein cu-a reclivous to vein 1A.

Legs. Fore femur moderately inflated, 4.3-4.4 × as long as wide; hind femur moderately stout, about 4 × as long as its maximum width; hind tibia about 10.5 × as long as its apical width; first tarsal segment of hind leg slightly longer than second and third segments combined; fifth segment about as long as second.

Metasoma. First metasomal tergite (Fig. 1d ) with median longitudinal carinae distinct, moderately convergent posteriorly in dorsal view, extending to 0.5 of T1; median part between median longitudinal carinae strongly raised posteriorly, with median basal depression nearly smooth, densely puncto-reticulate posteriorly, lateral surface rugose; posterior half of lateral longitudinal carina distinct; spiracle situated at basal 0.35 of T1, slightly below level of lateral carina, encircled by deep oblong groove; T2 with antero-lateral corners strongly impressed in front of pair of anterolateral oblique grooves; central area of T2 strongly raised, with punctures very dense on dorsal surface and rather sparse laterally. First metasomal tergite 2.0 × as long as its apical width; T2 about 1.1 × as long as T1 and about 1.5 × as long as its apical width. Ovipositor very long, about 70 mm, projecting beyond apex of metasoma by 10.0 × length of hind tibia; ovipositor with expanded area of lower valve bearing 5 grooves, the most proximal 4 of which are reclivous, followed by apical 7 teeth (Fig. 1h ); ovipositor sheath bearing short setae which are about 1.1 × as long as width of sheath.

Coloration. Head, mesosoma and metasoma including mesosternum and membranous area between sclerites black (Figs 1f , 3c ); lower half of clypeus tinged with reddish brown (Fig. 1a ); labrum, maxillary and labial palpi yellow. Tegula and parategula yellow. Wings weakly tinged with yellowish brown, slightly darkened along distal margin. Legs largely vivid yellow, except for black coxae, short longitudinal dark stripe on posterior surface of fore femur (Fig. 1c ) and dark brown tip of tarsal claw.

Male.

Very similar to female in morphology and colouration. Flagellum with 40 segments. Genitalia as in Fig. 2 ; subgenital plate (Fig. 2e ) transverse, moderately covered with short pubescence, weakly incised at the middle, posteriorly; paramere (Fig. 2c, d ) moderately long, angular, with ventral margin concave, apical half of outer side bearing rather dense short pubescence; apex of distivolsella flat (Fig. 2d ); gonolacinia slightly turned inwards (Fig. 2a ); aedeagus (Fig. 2f, g ) stout and flat, with lateral sides almost parallel, slightly divergent toward apex; tip of aedeagus weakly incised at middle, laterally squarish.

Length. Fore wing 20- 22 mm in ♀ (21 mm in holotype), 18 mm in ♂.

Type series.

Holotype. ♀ (Fig. 3 ), pinned, 22. V. 2016, Akazai-keikoku (35.2149°N, 134.4936°E, (WGS 84), 510m a.s.l.), Shisou-shi, Hyogo Pref., Japan (Rikio Matsumoto), OMNH TI-522, DNA sample: OMNH_Pol-420, INSD accession number LC337798.

Paratypes. 2♀, same data as holotype; 1♂3♀, 11.VI.2001, same locality as holotype (1♀ in BMNH).

Distribution.

Japan (Honshu).

Remarks.

This species is closely related to D. khasianus , from which it can be separated by a short and longitudinal dark stripe on the posterior surface of the fore femur, less developed epomia and lack of fine transverse striations on the antero-median part of the first metasomal tergite between the latero-median carinae.

All known specimens were collected while flying around nearly dead Pterocarya rhoifolia Sieb. et Zucc trees ( Juglandaceae ). In several cases, females were observed investigating the trunk of the tree with their antennae and thrusting their ovipositors into it. A male was also observed flying around the trunk.

Etymology.

The specific name refers to the golden yellow legs contrasting with the black mesosoma and metasoma.

Figures

Figure 1. Dolichomitus species of the Dolichomitus mandibularis group: a-d, f, h D. flavicrus sp n. (paratype) e D. khasianus (Holotype) g D. mandibularis a head in frontal aspect b propodeum in dorsal aspect c fore femur in posterior aspect d, e first metasomal tergite in dorsal aspect f, g first to third metasomal segments in ventral aspect h ovipositor tip in lateral aspect. Scale bars: 0.5 mm (a, b, c, h); 1 mm (d, e, f, g).

Figure 2. Male genitalia of D. flavicrus sp. n. (paratype): a ventral aspect b dorsal aspect c paramere, lateral aspect d paramere, inner aspect e subgenital plate, ventral aspect f aedeagus, ventral aspect g aedeagus, lateral aspect. Scale bar: 1 mm.

Figure 3. Holotype female of D. flavicrus sp. n.: a dorsal aspect b lateral aspect c ventral aspect. Scale bar: 10 mm.