Enicospilus limnophilus Shimizu, 2020

Shimizu, So, Broad, Gavin R. & Maeto, Kaoru, 2020, Integrative taxonomy and analysis of species richness patterns of nocturnal Darwin wasps of the genus Enicospilus Stephens (Hymenoptera, Ichneumonidae, Ophioninae) in Japan, ZooKeys 990, pp. 1-144 : 1

Enicospilus limnophilus Shimizu sp. nov. Figure 25

Etymology.

This species probably prefers lakes. Hence, the specific name is derived from the Greek limne + philos meaning lake and lover respectively.

Type series.

Total of 37 specimens (18♀♀19♂♂): Japan (18♀♀19♂♂).

HT: ♀, marsh of Nakaikemi, Tsuruga City, Fukui Pref., Hokuriku, JAPAN, 19.IX-16.X.2016, A. Noishiki leg. (MsT) (MNHA).

PT: 1♀, Toro-ko, Kushiro City, Hokkaidô, JAPAN, 26.VII.1986, S. Nomura leg. (NIAES); 1♀, Kushiro-shitsugen, Kushiro City, Hokkaidô, JAPAN, 29.VII.1991, Y. Karasawa leg. (LT) (NIAES); 1♀, Sapporo, Hokkaidô, JAPAN, 9.VIII.1960, S. Ueda leg. (MNHA); 9♀♀5♂♂, same data as HT (3♀♀1♂, MNHA; 2♀♀, OMNH; 1♀1♂, KPMNH; 1♀, NHMUK; 1♀2♂♂, EUM; 1♀1♂, SEHU); 1♀, same data as HT except for 31.VII-14.VIII.2016 (NIAES); 1♀11♂♂, same data as HT except for 14-30.VIII.2016 (3♂♂, NIAES; 3♂♂, NSMT; 1♂, EMUS; 1♀2♂♂, MNHA; 2♂♂, SEHU); 2♀♀1♂, same data as HT except for 10-31.VII.2016 (1♀1♂, OMNH; 1♀, CNC); 1♀, same data as HT except for 24.V-17.VI.2016 (EMUS); 2♂♂, same data as HT except for 17.VI-10.VII.2016 (1♂, CNC; 1♂, NHMUK).

Distribution.

Eastern Palaearctic region.

JAPAN: [ Hokkaidô]; [Hokuriku] Fukui.

Bionomics.

All specimens have been collected from marshes or lakes of rather cooler regions, suggesting that it is restricted to hosts that inhabit open, aquatic conditions. However, some factors, such as a progression of plant succession, isolation of habitats, and increasingly dry conditions, have led many wetland insects to become endangered in Japan (e.g., Yoshida et al. 2019).

Differential diagnosis.

The distally setose fore wing fenestra is unique to this species within the Asian Enicospilus fauna (Fig. 25F ), hence E. limnophilus sp. nov. is morphologically very easily recognisable.

Description.

Female (n = 18). Body length 15.0-18.0 (HT: ca. 17.5) mm.

Head with GOI = 1.9-2.9 (HT: 2.8) (Fig. 25D ). Lower face 0.7-0.8 × (HT: 0.8) as wide as high, moderately shiny, and entirely punctate with setae (Fig. 25B ). Clypeus 1.5-1.7 × (HT: 1.7) as wide as high, smooth with setae, weakly convex, and ventral margin impressed (Fig. 25B, D ). Malar space 0.3 × as long as basal mandibular width (Fig. 25B, D ). Mandible twisted by 35-40° (HT: 40°), rather short, evenly narrowed, outer surface with diagonal setose groove (Fig. 25B, D ). Upper tooth of mandible 1.4-1.6 × (HT: 1.4) as long as lower (Fig. 25B ). Frons, vertex and gena shiny with setae (Fig. 25B-D ). Posterior ocellus almost touching eye (Fig. 25B-D ). Ventral end of occipital carina joining oral carina. Antennae with 58-62 (HT: 61) flagellomeres; first flagellomere 1.7-1.8 × (HT: 1.8) as long as second; 20th flagellomere 1.7-1.8 × (HT: 1.7) as long as wide.

Mesosoma entirely weakly to moderately shiny with setae (Fig. 25E ). Pronotum finely punctate to diagonally striate (Fig. 25E ). Mesoscutum 1.5 × as long as maximum width, moderately shiny and punctate with setae, and evenly rounded in profile (Fig. 25E ). Notauli absent (Fig. 25E ). Scutellum moderately convex, smooth and strongly shiny, with lateral longitudinal carinae along anterior 0.1-1.0 of scutellum. Epicnemium densely punctate with setae. Epicnemial carina present, evenly slightly curved, inclined to anterior, dorsal end distinctly separated from anterior margin of mesopleuron (Fig. 25E ). Mesopleuron densely punctate to punctostriate (Fig. 25E ). Submetapleural carina broadened anteriorly (Fig. 25E ). Metapleuron entirely very densely punctate, (sub-)matt (Fig. 25E ). Propodeum evenly rounded in profile; anterior transverse carina complete centrally and absent laterally; anterior area longitudinally striate; spiracular and posterior areas entirely densely punctate to finely reticulate; propodeal spiracle elliptical and joining pleural carina by strong ridge (Fig. 25E ).

Wings (Fig. 25F ). Fore wing length 10.5-11.0 (HT: 11.0) mm with AI = 0.9-1.0 (HT: 0.9), CI = 0.2, DI = 0.4, ICI = 0.6, SDI = 1.2, SI = 0.1, SRI = 0.3; vein 1m-cu&M sinuous; vein 2r&RS slightly sinuous; vein RS evenly curved; fenestra and sclerites of discosubmarginal cell as in Fig. 25F ; proximal sclerite triangular and strongly sclerotised; central sclerite moderately large, roundish, strongly sclerotised gradually from proximal to distal, and positioned in around centrodistal part of fenestra; distal sclerite vestigial and slightly pigmented; distal part of fenestra between central and distal sclerites setose; proximal corner of marginal cell evenly setose; posterodistal corner of second discal cell ca. 85° and of subbasal cell nearly at right angle; vein 1cu-a antefurcal to M&RS by 0.3-0.4 × (HT: 0.4) length of 1cu-a. Hind wing with NI = 1.5-1.6 (HT: 1.5); vein RS straight; vein RA with 5-6 (HT: 5) uniform hamuli.

Legs. Hind leg with coxa in profile 1.7-1.9 × (HT: 1.7) as long as deep; basitarsus 2.0 × as long as second tarsomere; fourth tarsomere 3.1-4.2 × (HT: 4.2) as long as wide; tarsal claw simply pectinate.

Metasoma with DMI = 1.4, PI = 2.9-3.1 (HT: 3.1), THI = 3.5; thyridium elongate oval; ovipositor sheath not longer than posterior depth of metasoma (Fig. 25A ).

Colour (Fig. 25 ). Entirely reddish yellow but head lighter than meso- and metasoma, apex of mandible infuscate. Wings hyaline; proximal sclerite pigmented and amber; veins brown.

Male (n = 19). Very similar to female.

Remarks.

This is a fairly morphologically uniform species, although GOI (= 1.9-2.9) and length of lateral longitudinal carinae of scutellum (along anterior 0.1-0.9 of scutellum) exhibit a very wide range of variation within the same population.

Figures

Figure 25. Enicospilus limnophilus Shimizu, sp. nov. ♀ (A-E HT F PT) from Japan A habitus B head, frontal view C head, dorsal view D head, lateral view E mesosoma, lateral view F central part of fore wing.