Anisotacrus senticosus 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 senticosus Sheng & Sun sp. nov.

Figures 13 , 14-22

Description.

Body length 8.7 mm. Fore wing length 6.9 mm. Ovipositor sheath 0.5 mm.

Head. Inner margins of eyes (Fig. 14 ) slightly concave near antennal sockets. Face (Fig. 14 ) 1.2 × as wide as long, almost flat, shagreened, with dense fine indistinct punctures and yellowish white setae; upper margin with median narrow smooth longitudinal stripe and a small median tubercle. Clypeus approximately 3.3 × as wide as long, shagreened, lateral portion with sparse fine punctures, apical median smooth, shiny; apical margin slightly arcuate. Mandible with sparse punctures and dense long yellowish white setae; lower tooth distinctly wider and slightly longer than upper tooth. Malar space about 0.4 × as long as basal width of mandible. Gena (Figs 15 , 16 ), vertex (Fig. 16 ) and frons shagreened, with dense yellowish brown setae. Gena strongly convergent backward. Postocellar line approximately 0.6 × as long as ocular-ocellar line. Antenna with 38 flagellomeres; ratio of length from first to fifth flagellomeres: 2.4:1.3:1.1:1.0:1.0. Occipital carina complete, genal carina joining hypostomal carina above base of mandible.

Mesosoma. Pronotum, mesoscutum, mesopleuron and metapleuron shagreened, almost entirely with fine indistinct punctures. Epomia present. Mesoscutum (Fig. 17 ) evenly convex, anteromedian portion almost shiny; notauli impressed in the frontal 0.3 × of mesoscutum. Scutoscutellar groove slightly smooth. Scutellum and postscutellum weakly granulate. Postscutellum transversely convex, anterior portion deeply concave. Mesopleuron (Fig. 18 ) flat. Speculum small, with sparse fine punctures. Upper end of epicnemial carina not reaching to the front margin of mesopleuron and reaching 0.5 height of mesopleuron. Metapleuron weakly convex; juxtacoxal carina absent; submetapleural carina complete, strong. Tibiae with sparse long thorns (Fig. 19 ). Hind femur 5.6 × as long as its maximum width. Ratio of length of hind tarsomeres from first to fifth: 5.5:2.7:2.0:1.0:1.4. Claw simple. Wings slightly infuscate. Fore wing with vein 1cu-a postfurcal by 0.2 × length of 1cu-a. Areolet obliquely quadrangular, distinctly stalked frontally, receiving vein 2m-cu approximately in its distal 0.7. Postnervulus intercepted at middle. Hind wing vein 1-cu 1.5 × as long as cu-a. Propodeum evenly convex, with dense yellowish white setae; anterior portions of lateromedian longitudinal carinae and posterior portions of lateral longitudinal carinae present. Propodeal spiracle circular, convex.

Metasoma. First tergite (Fig. 20 ) approximately 2.7 × as long as posterior width, straight, shagreened, apical half with sparse fine indistinct punctures; latero-median and dorso-lateral carinae absent; ventro-lateral carinae complete; spiracle small, circular, distinctly convex, located at 0.5 of first tergite. Second and third tergites (Fig. 21 ) shagreened. Second tergite approximately as long as apical width, anteromedian portion with weak indistinct transverse wrinkles; thyridium transverse, distance to basal margin of second tergite about as its length. Third tergite (Fig. 21 ) parallel laterally, 0.85 × as long as wide. Ovipositor sheath (Fig. 22 ) 5.5 × as long as maximum width, 0.2 × as long as hind tibia, upper and lower margins almost parallel.

Coloration (Fig. 13 ). Black, except for following: Lateral side of face widely and irregularly, labrum, mandible except teeth and dorso-posterior corners of pronotum yellowish white. Maxillary and labial palpi dark brown. Fore and middle tibiae and tarsomeres 1-4 brownish yellow. Basal half of hind tibia except basal end and tibial spurs reddish brown. Posterior portion of tergite 2, tergite 3 entirely and 4 except posterior margin brownish red. Pterostigma brownish black. Veins blackish brown.

Etymology.

The specific name is derived from the tibia with thorns.

Material examined.

Holotype: China • ♀; Beijing, Huairou, Labagoumen ; 15.VIII.2016; IT by Shi-Xiang Zong.

Distribution.

China.

Differential diagnosis.

The new species is similar to A. xanthostigma (Gravenhorst, 1829), but can be distinguished from the latter by the following combination of characters: areolet distinctly quadrilateral; first tergite evenly convex, without longitudinal groove; second tergite as long as apical width; third tergite distinctly shorter than its width; mesoscutum, tegulae, all coxae and trochanters black. Anisotacrus xanthostigma : areolet triangular; first tergite with longitudinal groove; second tergite longer than apical width; third tergite as long as apical width; anterolateral portion of mesoscutum with yellow spots; tegulae yellow; fore coxae and parts of trochanters yellow.

Figures

Figure 13. Anisotacrus senticosus Sheng & Sun, sp. nov. Holotype. Female habitus.

Figures 14 - 22. Anisotacrus senticosus Sheng & Sun, sp. nov. Holotype. Female 14 head, anterior view 15 head, lateral view 16 head, dorsal view 17 mesoscutum, dorsal view 18 mesosoma, lateral view 19 hind tibia, lateral view 20 first tergite, dorsal view 21 second and third tergites, dorsal view 22 apical portion of metasoma, lateral view.