Coelichneumon septenus ( Townes, Momoi & Townes, 1965 )

Riedel, Matthias & Watanabe, Kyohei, 2021, The genus Coelichneumon Thomson in Japan (Hymenoptera, Ichneumonidae, Ichneumoninae), Zootaxa 4948 (4), pp. 501-545 : 536-537

Coelichneumon septenus ( Townes, Momoi & Townes, 1965)

Ichneumon septemguttatus Matsumura, 1912: 94 ♂, preoccupied by Gravenhorst, 1829.

Ichneumon septenus Townes, Momoi & Townes, 1965: 528 , new name for C. septemguttatus .

Holotype of I. septemguttatus : ♂ “[Jozankei] 9/9; [red] Type Matsumura; Ichneumon 7-guttatus n.sp. ” (Sapporo), type studied. Missing: left flagellomeres from 34 th on and right flagellomeres from 3 rd on.

Non-type material: JAPAN: 1 ♂, Tochigi Pref., Kuriyama Vil., Kinunuma , 1–14.viii.2004, H. Makihara leg. , MT; 1 ♂, Gunma Pref., Katashina Vil., 36.49°N 139.22°E, 1730 m alt., 12–13.vii.2014, K. Watanabe leg. ; 1 ♂, Niigata Pref., Nagaoka City, Urase-machi , 35 m alt., 37.2748°N 138.5423°E, 6–25.vii.2015, R. Shimizu and Y. Shimizu leg.

Description (based on Far East Russian material): ♀: Body length 15‒20 mm. Flagellum with 36‒43 flagello- meres, strongly lanceolate; 1 st flagellomere 1.9‒2.2× longer than wide, 2 nd flagellomere 2.0‒2.3× longer than wide, combined length 0.5‒0.6× eye length; c.11 th flagellomere square; widest flagellomere 2.1‒2.5× wider than long. Temple slightly widened behind eye, roundly narrowed apically. OED 1.1‒1.7× ocellar diameter. Frons rugosepunctate medially, punctate laterally. Face with dense punctures, granulate. Inner eye margins divergent ventrally. Clypeus with coarse punctures, smooth, apical margins slightly concave. Gena wide and swollen, laterally 1.1‒1.3× wider than eye, with very scattered punctures. MI 0.5‒0.6.

Mesosoma with dense pale brownish hairs. Side of pronotum densely punctate dorsally and striate ventrally and caudally. Notaulus impressed in frontal fourth of mesoscutum. Lateral field of mesoscutum densely punctate, granulate. Mesopleuron densely punctate, speculum smooth. Metapleuron partly rugose-punctate, juxtacoxal carina strong. Scutellum slightly wider than long, with scattered punctures, lateral carina in basal 0.2. Area superomedia about as long as wide, smoothened, frontal carina obsolete; anterior transversal carina distinctly caudal to the middle. Area externa punctate, with very fine transversal striae; area petiolaris with lateral carina, rugose. Coxae and femora densely punctate. Hind coxa punctate and granulate, with scopa (0.2‒0.3× coxal length). Hind femur 3.3‒3.4× longer than wide; 3 rd mid tarsomere 1.5‒1.6× longer than wide.

Areolet pentagonal, frontal distance between veins 2rs-m and 3rs-m 1‒2× their width; vein 2m-cu in or distad its middle. Vein 1cu-a postfurcal by 1× its width.

Lateral field of postpetiolus 0.6‒0.7× as wide as median field, median field with c.12 striae. 2 nd tergite 0.85‒ 0.95× as long as wide. Thyridium transverse, 1.3‒1.5× wider than the interval, interval about as wide as the median field of postpetiolus. 2 nd to 4 th tergites densely punctate, ± aciculate medially, 5 th tergite with very scattered punctures, shining. Seen from dorsal, ovipositor sheath 0.2‒0.5× as long as 7 th tergite.

Color: Black. Flagellomeres 7/8‒12/14, wide frontal orbit confluent with vertical spot, small spot on subtegular ridge, apical 1/2 to 2/3 of scutellum and posterolateral spots on 1 st to 4 th tergites (largest spots on 2 nd tergite) yellowish. Legs black, fore femora apically and fore tibia frontally yellowish; mid tibia paler frontally. Pterostigma red-brown.

♂: Body length 18.5‒20 mm. Flagellum with 40 flagellomeres, 1 st flagellomere 1.7‒1.9× longer than wide. Ty- loids on flagellomeres 7‒17, oval, centrally situated, maximally 0.5× as long as the flagellomeres. Temple parallel or slightly narrowed behind eye and moderately narrowed apically OED 1.4‒1.5× and OOD 1.4× ocellar diameter. Face densely punctate and finely granulate, ± matt. Clypeus with scattered punctures, smooth and shining, apical margin slightly concave. Mandible with two teeth, lower tooth much smaller and moderately bent inwards. Gena with scattered punctures, 1.1‒1.3× wide than eye. MI 0.3‒0.4. Genal carina reaching hypostomal carina far from mandibular base.

Mesoscutum covered with grey to brownish hairs. Notaulus distinct in frontal 1/3‒1/5 of mesoscutum. Me- soscutum densely punctate and finely granulate, shining. Mesopleuron with dense punctures, speculum smooth. Metapleuron and propodeum coarsely reticulate-rugose; juxtacoxal carina strong, sometimes indicate by irregular ridge. Scutellum moderately elevated, slightly wider than long, with fine scattered punctures, without or with lateral carina basally. Area superomedia heart-shaped, as long as wide or wider than long, coarsely rugose, sometimes confluent with area basalis; anterior transversal carina in caudal third. Areae externa and petiolaris coarsely rugose. Fore metatarsus without apical tooth. Hind femur punctate, 3.2‒3.6× longer than wide.

Lateral field of postpetiolus 0.5× as wide as the median field, median field with regular sometimes superficial longitudinal rugae. Gastrocoelus strongly impressed, with oblique ridges. Thyridium transverse, 0.9‒1.1× as wide as the interval. 2 nd tergite 0.90‒0.95× as long as wide. 2 nd to 4 th tergites densely punctate; 2 nd and 3 rd tergites finely striate medially; 5 th tergite with superficial punctures. 2 nd to 4 th sternites with median folds.

Color: Black. Palps, spot on mandible, side of clypeus, wide facial and narrow frontal orbits, spot on vertex, stripe on outer orbit, scape ventrally, spot on collare and hind edge of pronotum, spot on tegula and on subtegular ridge, apical transversal stripe on scutellum and posterolateral spots on 1 st to 4 th tergites ivory. Legs black; fore and mid femora apically, fore and mid tibiae and tarsi frontally ivory; hind tibia with external ivory stripe in basal third. Wings ± brownish infuscate, pterostigma brown to black.

Remarks: Uchida (1935: 14) had described Japanese ♀♀ from Tosa ( Kochi Pref., Shikoku) which he pro- posed as conspecific with the ♂ holotype of Ichneumon septenguttatus Matsumura (recte: Coelichneumon septenus Townes at al.), but their coloration pattern differ substantially from the type species (e.g. scutellum and 4 th tergite without ivory spots). The description of the ♀ presented here bases on a specimen from Far East Russia (see Riedel 2020).

Coelichneumon septenus Townes et al. is closely related to Coelichneumon sugillatorius (Linnaeus) which have also been found in the East Palaearctic region. Females of C. septenus can be differentiated by: temple ± widened behind eye (distinctly narrowed in C. sugillatorius ) and hind femur stouter (3.3‒3.4× in C. septenus ; 3.7‒4.0× in C. sugillatorius ). East Palaearctic males of C. sugillatorius usually have ivory flagellar stripes or rings, whereas males of C. septenus have black flagella.

The first author has recently seen some other Coelichneumon females from Northern China which had intermediate and/or slightly different morphological characters. We therefore suggest that there might be more closely related taxa of the sugillatorius species-group, e.g. Coelichneumon species with posterolateral ivory spots on basal tergites and without yellow tibial rings, and further studies with more material will be necessary to solve the taxonomy of this species-group in the East Palaearctic region.

Distribution: Japan (Hokkaido, Honshu and Shikoku) and Far East Russia ( Uchida 1935; present study).