Enicospilus kikuchii, Shimizu, 2017

Shimizu, So, 2017, Description of a new species and revised key to species of the Enicospilus antefurcalis species-group from Japan (Hymenoptera: Ichneumonidae: Ophioninae), Acta Entomologica Musei Nationalis Pragae 57 (1), pp. 183-194 : 187-191

Enicospilus kikuchii sp. nov.

[Japanese name: Kikuchi-hoshi-amebachi] ( Figs 1–9 )

Type locality. Japan, Saitama Prefecture, Chichibu, Kawamata.

Type material. HOLOTYPE: ♀, “ JAPAN: Saitama Pref. / Chichibu / Kawamata / 28–30. VIII. 2012 / Namiki Kikuchi leg. // HOLOTYPE / [ Ophioninae : Enicospilini ] / Enicospilus kikuchii Shimizu, 2017 /Acta.Entomol.Mus.Natl. Pragae, 57: 183–194.” ( NIAES) . PARATYPE: 1 J, “Eboshi-dake / Kagoshima / 4. V. 1969 / K. Kusigemati leg. // PARATYPE / [ Ophioninae : Enicospilini ] / Enicospilus kikuchii Shimizu, 2017 / Acta. Entomol. Mus. Natl. Pragae, 57: 183–194.” ( SEHU: Kusigemati Collection).

Diagnosis. This species is characterized by the following combination of character states: darkened mesosoma, T1, T2, and T5–8 ( Fig. 1 ); metapleuron roughly diagonally punctostrigose ( Fig. 6 ); and proximal sclerite of the discosubmarginal cell of the fore wing triangular and confluent with distal sclerite, and central sclerite suboval and positioned on distal part of fenestra ( Fig. 5 ).

Differential diagnosis. Within the E. antefurcalis species-group, this new species closely resembles E. melanocarpus in morphology, although distinct in colour, but they can be distinguished from each other by the following combination of characteristics: mesosoma, T1, T2, and T5–8 dark-brown to black in E. kikuchii , but usually most of body yellowish brown and T5–8 usually blackish in E. melanocarpus ; and metapleuron roughly diagonally punctostrigose in E. kikuchii , but uniformly punctate or finely diagonally punctostriate in E. melanocarpus . Enicospilus kikuchii also resembles E. combustus (Gravenhorst, 1829) and E. nigropectus Cameron, 1905 , within the Palaearctic Region, in its colour pattern. However, E. combustus and E. nigropectus do not belong to the E. antefurcalis species-group and are distinguishable from E. kikuchii by the characteristics presented to the species-group already. Additionally, the latter species is easily distinguishable from any other species of the E. antefurcalis species-group using the key (see below).

Description. Female (holotype) ( Figs 1–9 ). Body length ca. 20.5 mm.

Head ( Figs 2–4 ) with FI = 0.6 ( Fig. 2 ); GOI = 2.8 ( Fig. 3 ). Lower face 0.8 times as wide as high ( Fig. 2 ), weakly polished, entirely covered with punctures and setae. Clypeus 1.7 times as wide as high ( Fig. 2 ), polished with punctures and setae, moderately convex in lateral profile ( Fig. 3 ), its lower margin impressed ( Fig. 2 ). Malar space 0.4 times as long as basal width of mandible ( Figs 2, 3 ). Mandible evenly narrowed, its outer surface with a diagonal hirsute groove between upper proximal corner and base of teeth ( Figs 2, 3 ). Upper tooth of mandible 1.5 times as long as lower one ( Figs 2, 3 ). Frons, vertex and gena weakly polished with sparse setae. Posterior ocellus not contiguous to eye, but large and moderately close to eye ( Figs 2–4 ). Antenna with 59 flagellomeres. First flagellomere 5.2 times as long as wide and 1.3 times as long as second flagellomere. 20th flagellomere 2.1 times as long as wide.

Mesosoma ( Figs 6, 7 ) weakly polished, entirely covered with white setae. Postero-dorsal part of pronotum punctate with setae, antero-ventral part rugose to coriaceous, ventral 0.3 with dense long setae ( Fig. 6 ). Mesoscutum 1.4 times as long as wide and evenly covered with fine dense punctures and setae, evenly rounded in lateral profile ( Fig. 6 ). Notauli absent ( Fig. 6 ). Scutellum moderately convex in lateral profile ( Fig. 6 ), finely punctate with setae, transversely undulate, with lateral longitudinal carinae reaching its posterior margin ( Figs 6, 7 ). Epicnemium densely punctate or pustulate ( Fig. 6 ). Epicnemial carina inclined to anterior margin of mesopleuron, and its dorsal end not reaching anterior margin of mesopleuron ( Fig. 6 ). Dorsal part of mesopleuron punctate to punctostriate, median part punctate to coriaceous, and ventral part strongly roughly strigose ( Fig. 6 ). Submetapleural carina complete and entirely parallel-sided, not broadened anteriorly ( Fig. 6 ). Metapleuron roughly diagonally punctostrigose ( Fig. 6 ). Propodeum in lateral profile weakly evenly rounded ( Fig. 6 ). Anterior transverse carina of propodeum complete, anterior area striate, spiracular area smooth and strongly polished, posterior area rather coarsely irregularly wrinkled to reticulate ( Fig. 7 ). Propodeal spiracle elliptical, its outer margin joined to lateral longitudinal carina of propodeum by ridges ( Figs 6, 7 ).

Wings ( Fig. 5 ). Fore wing length ca. 13.0 mm with AI = 0.7; CI = 0.5; DI = 0.4; ICI = 0.4; SDI = 1.2 ( Fig. 5 ). 1m-cu of fore wing evenly curved ( Fig. 5 ). Rs+M and Rs+2r of fore wing almost straight ( Fig. 5 ). Fenestra and sclerites of discosubmarginal cell of fore wing as in Fig. 5 . Proximal sclerite triangular and confluent with distal sclerite ( Fig. 5 ). Central sclerite suboval and positioned on distal part of fenestra ( Fig. 5 ). Sclerites moderately to strongly pigmented ( Fig. 5 ). Vein cu-a of fore wing proximal to Rs+M separated by 0.2 times its own length ( Fig. 5 ). Postero-distal corner of second discal cell ca. 95°. Postero-distal corner of subbasal cell ca. 70°. Hind wing with RI = 2.2; NI = 1.3. Rs of hind wing straight. R1 of hind wing with 6 hamuli of uniform length.

Legs ( Figs 1 , 8 ). Distal 0.6 of outer surface of fore tibia with sparse short spines ( Fig. 8 ). Hind coxa 1.7 times as long as wide. Hind trochanter 1.3 times as long as trochantellus in ventral view. Hind trochantelli simple. Hind femur 0.9 times as long as tibia. Hind basitarsus 1.7 times as long as second tarsomere. Fourth hind tarsomere 3.0 times as long as wide. Hind tarsal claw pectinate.

Metasoma ( Figs 1 , 9 ) weakly to moderately polished with setae, moderately long and slender, with PI = 3.1; DMI = 1.1. Thyridium moderately large, elliptical, and separated from anterior margin of tergite by 2.0 times length of its longest axis ( Fig. 9 ). Ovipositor 0.8 times as long as T2, 0.5 times as long as hind tibia, straight ( Fig. 1 ).

Colour ( Fig. 1 ). Head entirely yellowish brown except dark brown to black apex of mandible and median part of frons. Mesosoma entirely dark brown to black except yellowish brown margin of pronotum, mesoscutum, mesopleuron, scutellum, metapleuron, propodeum, and entire anterior area of propodeum. Wing cells hyaline. Sclerites of wings yellowish brown, venation and setae dark brown to black. Legs yellowish brown except all coxae that are dark brown to black. T1–2, T5–8 and ovipositor sheath dark brown to black; T3–4, S2–4, and ovipositor yellowish brown.

Male. Very similar to female except for the following characters. Body length ca. 22.0 mm.

Head with GOI = 2.9. Apex of antennae incomplete. First flagellomere 5.0 times as long as wide. 20th flagellomere 2.2 times as long as wide.

Wings. Fore wing length ca. 13.0 mm with AI = 0.4; SDI = 1.1. Hind wing with RI = 2.0; NI = 1.2.

Legs. Hind basitarsus 1.8 times as long as second tarsomere.

Metasoma with PI = 2.9; DMI = 1.2.

Colour. Mesosoma entirely dark brown to black except reddish brown margin of pronotum, mesoscutum, mesopleuron, scutellum, metapleuron, propodeum, and entire anterior area of propodeum.

Bionomics. Unknown.

Etymology. The specific name is derived from the collector of the holotype specimen, Mr Namiki Kikuchi (Hokkaido University), who is one of the greatest young Japanese ichneumonologists.

Distribution. Japan: Honshû (Saitama Pref.) and Kyûshû (Kagoshima Pref.).

Remarks. Unfortunately, in this study, the author could only locate two type specimens. However, the specimens represent a distinct new species within the genus and the speciesgroup. Moreover, it is easily distinguishable from any other Indo-Papuan Enicospilus species based on the addition of the following couplets for the key to Indo-Papuan Enicospilus species by GAULD & MITCHELL (1981):

230 (229) Central sclerite positioned in middle of fenestra; distal side of proximal sclerite more or less forming a right angle with margin of distal sclerite; metapleuron punctate. Solomon Islands. ..................................................... E. xaivus Gauld & Mitchell, 1981

‒ Central sclerite positioned towards distal edge of fenestra ( Fig. 5 ); distal side of proximal sclerite and margin of distal sclerite more or less forming an even curve ( Fig. 5 ); metapleuron usually punctostriate ( Fig. 6 ). ................................................................... 230a

230a (230) Usually most of body yellowish brown and T5–8 blackish, but rarely body entirely yellowish brown; metapleuron uniformly punctate or finely diagonally punctostriate. ................................................................. E. melanocarpus Cameron, 1905

‒ Mesosoma , coxae, T1–2, T5–8 dark-brown to black ( Fig. 1 ); metapleuron roughly diagonally punctostrigose ( Fig. 6 ). ........................................................ E. kikuchii sp. nov.

The new species is also easily distinguished from any other species within the speciesgroup using the key to species of the E. antefurcalis species-group, partially modified from GAULD & MITCHELL (1981) and GAULD (1982), as below:

Figures

Fig. 1. Lateral habitus of Enicospilus kikuchii sp. nov. (holotype).

Figs 2–5. Partial views of Enicospilus kikuchii sp. nov. (holotype). 2–4 – head in frontal (2), lateral (3), and dorsal views (4); 5 – part of fore wing.

Figs 6–11. SEM images of Enicospilus kikuchii sp. nov. (holotype). 6 – mesosoma in lateral view; 7 – propodeum in dorso-lateral view; 8 – fore tibia in lateral view; 9 – anterior part of T2 in lateral view.