Anisotacrus externus Sheng & Sun, 2021

Sun, Shu-Ping, Li, Tao, Zong, Shi-Xiang & Sheng, Mao-Ling, 2021, Two new species of Anisotacrus Schmiedeknecht (Hymenoptera, Ichneumonidae, Ctenopelmatinae) with a key to Eastern Palaearctic species, Journal of Hymenoptera Research 82, pp. 187-197 : 187

Anisotacrus externus Sheng & Sun sp. nov.

Figures 1-5 , 6-12

Description.

Body length 6.0 mm. Fore wing length 4.6 mm. Ovipositor sheath 0.5 mm long.

Head. Inner margins of eyes (Fig. 2 ) almost parallel, scarcely concave near antennal sockets. Face (Fig. 2 ) approximately 1.5 × as wide as long, shagreened, with yellow setae; slightly convex medially; upper lateral between eye and antennal socket with weak longitudinal depression. Clypeus with relatively large punctures; 3.2 × as wide as long; apical margin almost truncate. Mandible (Figs 2 , 3 ) strong, with dense yellowish brown setae; lower tooth distinctly longer than upper tooth. Malar space with dense yellow setae, about 0.6 × as long as basal width of mandible. Gena (Figs 3 , 4 ) evenly and strongly convergent backward, shagreened. Vertex (Fig. 4 ) shagreened, with dense yellowish brown setae; posteromedian portion distinctly concave. Postocellar line approximately 0.7 × as long as ocular-ocellar line. Frons almost flat, slightly concave under median ocellus, shagreened. Antenna with 32 flagellomeres; ratio of length from first to fifth flagellomeres: 2.1:1.3:1.2:1.0:1.0. Occipital carina (Figs 3 , 4 ) complete, dorsal portion relatively strong, genal carina joining hypostomal carina above base of mandible.

Mesosoma. Anterior margin of pronotum (Fig. 6 ) with dense short irregular longitudinal wrinkles; lateral concavity with dense transverse wrinkles; dorsoposterior portion with dense fine punctures and yellowish brown setae. Epomia indistinct. Mesoscutum (Fig. 5 ) almost shiny, anterior and lateral portions with fine punctures, distance between punctures 0.5-2.0 × diameter of puncture; posteromedian portion with dense indistinct irregular punctures. Notauli evident on anterior portion of mesoscutum. Scuto-scutellar groove deep, relatively wide, shiny, with shin setae. Scutellum distinctly convex, shiny, with fine irregular punctures. Postscutellum with fine indistinct punctures, anterior portion concave. Upper half of mesopleuron (Fig. 6 ) shiny, with distinct punctures, distance between punctures 1.0-2.5 × diameter of punctures; lower half with dense yellowish white setae and indistinct punctures; beneath speculum and lower posterior portions with indistinct fine wrinkles. Speculum relatively large, smooth, shiny. Upper end of epicnemial carina almost reaching front edge of mesopleuron, about 0.6 distance to subtegular ridge. Mesosternum (Fig. 7 ) with dense punctures, distance between punctures 1.0-2.0 × diameter of punctures; median sternal groove relatively deep, with transverse carinae. Metapleuron with surface structure as lower portion of mesopleuron, evenly convex. Juxtacoxal carina absent. Hind leg slender. Hind femur 5.2 × as long as its maximum width. Ratio of length of hind tarsomeres from first to fifth: 3.8:2.0:1.5:1.0:1.2. Claw simple. Wings slightly yellowish, hyaline. Fore wing with vein 1cu-a interstitial. Areolet small, triangular, distinctly stalked frontally; vein 2m-cu reaching vein M slightly distal of areolet (Fig. 8 ). Postnervulus intercepted at lower 0.45. Hind wing vein 1-cu 3.0 × as long as cu-a. Propodeum (Fig. 9 ) evenly convex, shiny, with irregular indistinct longitudinal wrinkles and brownish setae; lateromedian longitudinal carinae irregular; apicomedian portion with strong longitudinal wrinkles. Propodeal spiracle circular.

Metasoma. First tergite (Figs 10 , 11 ) 2.3 × as long as apical width, evenly widened posteriorly, anterior portion shiny, median portion shagreened; posterior portion smooth, with fine punctures; without glymma; latero-median absent; dorso-lateral carinae weakly present; ventro-lateral carinae complete; spiracle located almost at middle. Second tergite 0.75 × as long as posterior width, almost shiny, anterior median portion shagreened. Third and subsequent tergites with dense yellowish brown setae. Third tergite 0.9 × as long as posterior width. Ovipositor (Fig. 12 ) straight, with a large, deep dorsal notch.

Coloration (Fig. 1 ). Black, except for following: Face, clypeus except a small dark brown spot at the center of clypeal sulcus, mandible except teeth, malar space, maxillary palpi, labial palpi, ventral profiles of scape and pedicel, upper-posterior corner of pronotum, anterolateral portion of mesoscutum, tegula, subtegular ridge, fore and middle coxae, trochanters, hind trochantellus yellowish white. Dorsal profiles of scape and pedicel, basal portion of flagellum darkish brown; remainder of flagellum yellowish brown. Fore and mid femora, tibiae and tarsi, basal portion of hind tibia yellow brown. Hind tarsus brownish black. Posterior portion of second tergite, third and fourth tergites entirely brownish red. Metasomal sternites 2 and 3 whitish yellow, with small lateral longitudinal brown spots; sternites 4-6 almost entirely reddish brown. Ovipositor sheath irregularly blackish brown. Pterostigma and veins brownish black.

Etymology.

The specific name is derived from the fore wing vein 2m-cu connecting to cubitus distal of lower-posterior corner of areolet.

Material examined.

Holotype: China • ♀; Beijing, Huairou, Labagoumen ; 9.VII.2016; IT by Shi-Xiang Zong.

Distribution.

China.

Differential diagnosis.

The new species is similar to A. albinotatus Kasparyan, 2007, but can be distinguished from the latter by the following combination of characters: malar space about 0.6 × as long as basal width of mandible; areolet triangular, 2m-cu connecting to cubitus slightly distal of areolet (Fig. 8 ); hind coxa and posterior tergites of metasoma black. Anisotacrus albinotatus : malar space about 0.9 × as long as basal width of mandible; areolet receiving vein 2m-cu basal of lower posterior corner; hind coxa, second and subsequent tergites reddish brown.

Figures

Figures 1 - 5. Anisotacrus externus Sheng & Sun, sp. nov. Holotype. Female 1 habitus, lateral view 2 head, anterior view 3 head, lateral view 4 head, dorsal view 5 mesoscutum and scutellum, dorsal view

Figures 6 - 12. Anisotacrus externus Sheng & Sun, sp. nov. Holotype. Female 6 mesosoma, lateral view 7 mesosoma, ventral view 8 areolet 9 propodeum 10 first and second tergites, dorsal view 11 first and second tergites, lateral view 12 apical portion of metasoma, lateral view.