Enicospilus Stephens, 1835

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

publication ID	https://dx.doi.org/10.3897/zookeys.990.55542
publication LSID	lsid:zoobank.org:pub:7B73642C-278D-40F8-9091-B26213C9A704
persistent identifier	https://treatment.plazi.org/id/BA26F7DF-CCDE-5E55-A217-5606F27447D8
treatment provided by	ZooKeys by Pensoft
scientific name	Enicospilus Stephens, 1835
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Genus Enicospilus Stephens, 1835

Enicospilus Stephens, 1835: 126; type species, Ophion merdarius Gravenhorst sensu Stephens (= Ichneumon ramidulus Linnaeus), by monotypy ( Stephens 1845).

Henicospilus Agassiz 1846: 138; unjustified emendation.

Allocamptus Förster, 1869: 150; type species, Ophion undulatus Gravenhorst, 1829, by subsequent designation ( Thomson 1888: 1189).

Dispilus Kriechbaumer, 1894: 309; type species, Ophion (Dispilus) natalensis Kriechbaumer, 1894, by monotypy.

Pleuroneurophion Ashmead, 1900: 86; type species, Pleuroneurophion hawaiiensis Ashmead, 1900, by original designation.

Banchogastra Ashmead, 1900: 87; type species, Banchogastra niger Ashmead, 1900, by original designation.

Pycnophion Ashmead, 1900: 87; type species, Pycnophion molokaiensis Ashmead, 1900, by original designation.

Cymatoneura Kriechbaumer, 1901a: 22; type species, Ophion undulatus Gravenhorst, 1829, by subsequent designation ( Viereck 1914: 8).

Pterospilus Kriechbaumer, 1901b: 156; type species, Ophion (Enicospilus) dubius Tosquinet, 1896, by subsequent designation ( Viereck 1914: 126); junior homonym of Pterospilus Rondani, 1856.

Trispilus Kriechbaumer, 1901b: 156; type species, Ophion (Enicospilus) trimaculatus Tosquinet, 1896, by monotypy.

Abanchogastra Perkins, 1902: 141; type species, Abanchogastra debilis Perkins, 1902, by monotypy.

Metophion Szépligeti, 1905: 28; type species, Metophion bicolor Szépligeti, 1905, by subsequent designation ( Viereck 1914: 94).

Ceratospilus Szépligeti, 1905: 28; type species, Ceratospilus biroi Szépligeti, 1905, by monotypy.

Atoponeura Szépligeti, 1905: 34; type species, Atoponeura concolor Szépligeti, 1905 (= Enicospilus atoponeurus Cushman, 1947), by monotypy.

Ophiomorpha Szépligeti, 1905: 34; type species, Ophion curvinervis Cameron, 1886 (= Enicospilus cameronii Dalla Torre, 1901), by subsequent designation ( Hooker 1912: 134); junior homonym of Ophiomorpha Nilsson, 1836.

Cryptocamptus Brèthes, 1909: 230; unnecessary replacement name for Allocamptus Förster, 1869.

Amesospilus Enderlein, 1914: 222; type species, Ophion unicallosus Vollenhoven, 1878, by original designation.

Eremotyloides Perkins, 1915: 530; type species, Eremotylus orbitalis Ashmead, 1901, by monotypy.

Schizospilus Seyrig, 1935: 79; type species, Schizospilus divisus Seyrig, 1935, by original designation.

Distribution.

Afrotropical, Australasian, Holarctic, Neotropical, Oceanic, and Oriental regions ( Yu et al. 2016).

Bionomics.

According to the available evidence, species of Enicospilus are koinobiont endoparasitoids of usually late instar Lepidoptera larvae, but sometimes ovipositing in early instars (see summary in Broad et al. 2018). Many lepidopteran families, such as Noctuidae , Notodontidae and Saturniidae , are recorded as hosts (e.g., Gauld and Mitchell 1978, 1981; Gauld 1988; Broad and Shaw 2016). They are frequently collected at light and usually considered to be nocturnal or crepuscular (e.g., Gauld and Mitchell 1981; Gauld 1988; Shimizu and Maeto 2016; Shimizu 2017). Some Enicospilus are parasitoids of economically important Lepidoptera pests (e.g., Nagatomi et al. 1972; Kusigemati 1976). For instance, Enicospilus signativentris (Tosquinet, 1903) is a parasitoid of Poaceae pests, such as the noctuid moths Anadevidia peponis Fabricius, 1775, Autographa nigrisigna Walker, 1857 and Trichoplusia intermixta (Warren, 1913) ( Kusigemati 1976, 1981; Kusigemati and Tanaka 1992); and E. sakaguchii (Matsumura & Uchida, 1926) is also known as a parasitoid of the rice pests Sesamia turpis (Butler, 1879) and S. inferens (Walker, 1856) ( Nagatomi et al. 1972). Hence, Ophioninae could potentially be useful for agriculture as biocontrol agents (e.g., Gauld and Mitchell 1978, 1981; Gauld 1988).

Generic diagnosis.

Enicospilus species are moderately to very large insects, fore wing length usually 10.0-30.0 mm, with ophionoid facies. Easily distinguishable from other Ophioninae by the following characters: fore wing discosubmarginal cell with extensive glabrous area (fenestra), often with one or more sclerites (e.g., Fig. 4 View Figure 4 ); mandibles narrow, slightly to strongly twisted (e.g., Fig. 2 View Figure 2 ); inner surface of fore tibial spur lacking membranous flange. Enicospilus species can be confused with the genus Dicamptus but easily distinguished by the weakly to strongly tapered and twisted mandible (mandible very weakly tapered and never strongly twisted in Dicamptus ). A key to the Japanese genera of Ophioninae has also been provided by Shimizu and Watanabe (2017).

Generic description.

Middle- to large-sized wasps (fore wing length usually 10.0-30.0 mm).

Head. Clypeus flat to strongly convex in profile, ventral margin acute, blunt, or impressed. Mandible weakly to strongly tapered and twisted, usually moderately long, outer surface with or without diagonal setose groove or line of punctures, and bidentate apically. Frons, vertex and gena shiny and smooth. Ocelli usually very large and posterior ocellus often close to or touching eye. Occipital carina usually complete, ventrally reaching oral carina or not. Antennae usually longer than fore wing, with usually more than 50 flagellomeres.

Mesosoma entirely weakly to moderately shiny with setae. Pronotum finely punctate or diagonally wrinkled and not specialised. Mesoscutum shiny and punctate to smooth with setae, evenly rounded in profile, and notauli usually absent. Scutellum moderately convex and usually with lateral longitudinal carinae. Epicnemium usually densely punctate with setae. Epicnemial carina present, straight to curved, inclined to curved to anterior margin of mesopleuron. Posterior transverse carina of mesosternum usually complete. Propodeum evenly rounded or declivous in profile; anterior transverse carina usually complete; anterior area longitudinally striate; spiracular area usually smooth; posterior area reticulate, wrinkled, striate, or rugose; and posterior transverse carina usually absent.

Wings. Fore wing pterostigma fairly slender; vein 1m-cu&M evenly curved, angulate or sinuate, usually without a ramulus; vein 2r&RS usually more or less widened and sinuate; discosubmarginal cell usually with bare fenestra, often with one or more sclerotised sclerites. Hind wing vein RS usually straight and rarely weakly curved; vein RA usually with 4-12 uniform hamuli.

Legs. Inner mesal surface of fore tibial spur without membranous flange. Outer distal margin of mid and hind trochantelli usually simple without decurved tooth. Hind tarsal claw moderately to strongly curved and usually simply pectinate.

Metasoma very slender. Spiracle of T1 far behind middle. Thyridium well developed. Ovipositor straight and almost always not longer than posterior depth of metasoma.

Colour. General body colour usually entirely testaceous, with posterior metasomal segments sometimes darker, but body sometimes entirely dark brown to black or pale. Wings usually entirely hyaline or weakly infuscate, but wings with strong infumate area in a few species; fenestra always hyaline; sclerites weakly to strongly pigmented amber.

Species criteria.

We summarise the especially important diagnostic characters to identify Enicospilus species below.

Head (Fig. 2 View Figure 2 ). The head provides many good characters to define species, as many previous authors have indicated (e.g., Gauld and Mitchell 1978, 1981; Gauld 1988; Schwarzfeld and Sperling 2014; Johansson and Cederberg 2019). Among them, the width of lower face as well as of clypeus, colour of interocellar area (or stemmaticum), shape of clypeus, and mandibular characters are especially useful and easy to use.

Width of the lower face is usually stable within a species group and/or species, even if the species is widespread, and sometimes provides enough gaps between species, although a few species, such as E. capensis , exhibit considerable variation.

Although body colour can be very variable within species, the colour of the interocellar area is usually stable at the species level and a good diagnostic character.

The shape of the clypeus is also very useful. For instance, the nasute clypeus is one of the most critical diagnostic characters of E. riukiuensis and related species (Fig. 40D View Figure 40 ), and the flat and projecting clypeus of E. sakaguchii is distinctive (Fig. 41D View Figure 41 ). The shape of the ventral margin, i.e., acute, blunt, or impressed, is also a very useful diagnostic character.

Features of mandibles are some of the most important diagnostic characters of Enicospilus species. First, the outer mandibular surface sculpture, especially presence or absence of a diagonal setose groove or line of punctures between the dorsoproximal corner and base of the apical teeth, is important. For example, the outer mandible surface of E. ramidulus has a diagonal setose groove (Fig. 39B, D View Figure 39 ), but of E. pungens is smooth (Fig. 38B, D View Figure 38 ). Second, the torsion of the mandible is a useful character, although it is rather difficult to measure. For instance, the strongly twisted mandible of E. acutus sp. nov. is one of the most important diagnostic characters for this species (Fig. 11B, D View Figure 11 ). Finally, length and shape also provide good characters. For instance, the mandible of E. shikokuensis is very long, slender, strongly tapered proximally, and subparallel-sided distally (Fig. 44B, D View Figure 44 ), but of E. sakaguchii is very short, stout, and evenly tapered (Fig. 41B, D View Figure 41 ).

Some mandibular diagnostic characters at the species level, such as degree of torsion and length of teeth are possibly adaptive characters and have been considered to be related to modes of emergence from host insects; hence, these characters are usually easily modified and not phylogenetically restricted, so it is indeed useful for species level taxonomy.

Mesosoma (Fig. 3 View Figure 3 ). Mesosomal characters are also very informative. Surface microsculuptures of meso- and metapleuron are rather stable within species and also show large gaps between species and/or species groups. For example, the mesopleuron is coarsely longitudinally striate and metapleuron coarsely rugose in E. nigristigma (Fig. 31E View Figure 31 ), but the meso- and metapleuron are evenly moderately punctate and strongly shiny in E. unctus sp. nov. (Fig. 50E View Figure 50 ). Propodeum characters are useful as well. The posterior transverse carina of the propodeum of E. signativentris is unique in the Japanese species (Fig. 46E View Figure 46 ), and globally few Enicospilus species possess this carina. In other cases, the posterior area can be entirely densely punctate to finely reticulate in E. limnophilus sp. nov. (Fig. 25E View Figure 25 ), but coarsely concentrically striate in E. insinuator (Fig. 19E View Figure 19 ), providing an easy means to separate them. In this way, the propodeum is useful for definition of the species or species group when combined with other characters. Characters of the scutellum are also sometimes good for species recognition. For example, the quadrate scutellum of E. formosensis contributes to its identification, with the scutellum more or less trapezoidal or triangular in most Enicospilus species. Additionally, the length of the lateral longitudinal carinae of the scutellum is almost always stable within species and useful, with very rare exceptions, such as in E. limnophilus sp. nov., that exhibits a very wide range of variation (length of the carinae varies from 0.1-1.0 × scutellum length).

Wings (Fig. 4 View Figure 4 ). Wing characters have probably been regarded as the most important diagnostic characters in nocturnal Ophioninae by many previous authors (e.g., Gauld 1977; Gauld and Mitchell 1981; Shimizu 2020). These are much easier to use than other characters and can easily be measured.

First, the number, shape, and position of sclerites of the fore wing fenestra is usually very useful in Enicospilus . The number of sclerites varies in Enicospilus species from zero to four, but is nearly always stable within a species. The shape and position of sclerites are also very diverse, and some previous research has suggested that some species exhibit a wide range of intraspecific variation (e.g., Gauld and Mitchell 1981). However, it is stable in many cases and, if a species shows a wide range of intraspecific variation, it is likely that cryptic species are involved.

Second, the shape and setosity of the fore wing fenestra is sometimes a very useful character. For example, among Japanese species, the fenestra of E. nigribasalis and E. stenophleps is long and its anterodistal corner interstitial to fore wing vein RS (Figs 30F View Figure 30 , 47F View Figure 47 ), but in other Japanese species the fenestra is shorter and its anterodistal corner clearly antefurcal to RS (e.g., Figs 25F View Figure 25 , 36F View Figure 36 ).

Finally, the length and shape of wing veins also offer very good diagnostic characters. For example, the shape of fore wing veins 1m-cu&M and 2r&RS, the position of fore wing vein 1cu-a, and values of indices (e.g., AI, CI, ICI) are useful to distinguish species.

Legs. Legs do not seem to provide many useful characters, but some characters, such as the density of spines on the outer surface of the fore tibia, and pectination of the hind tarsal claw, are useful in species definition. For example, E. maruyamanus and E. pudibundae are very difficult to distinguish from each other, but the hind tarsal claw of the former is entirely uniformly pectinate, and the latter is not pectinate proximally.

Metasoma (Fig. 5 View Figure 5 ). The shape of the first metasomal segment (e.g., sinuous or straight in profile, slender or stout) is useful ( Broad and Shaw 2016; Johansson and Cederberg 2019).

Body size. Measuring body length is rather difficult due to the wide range of contraction or expansion of metasomal segments after death, hence fore wing length is a more useful character. However, body size shows a very wide range of variation in many species, such as E. pseudoconspersae , although it is stable in a few species (e.g., E. concentralis and E. nigronotatus ). Therefore, this character is occasionally useful for species definition.

Colour. As mentioned above, this character can easily change intraspecifically. For instance, E. nigropectus and E. signativentris show a considerable range of colour variation (body entirely blackish to entirely testaceous). However, this character is stable within some species (e.g., E. acutus sp. nov. and E. nigribasalis , as in Figs 11 View Figure 11 , 30 View Figure 30 ). Hence, this is also a useful critical character, but we need to be careful when relying on colour pattern.

Kingdom	Animalia
Phylum	Arthropoda
Class	Insecta
Order	Hymenoptera
Family	Ichneumonidae