Review of the genus Tersilochus Holmgren ( Hymenoptera , Ichneumonidae , Tersilochinae ) from South Korea

Ten species of the genus Tersilochus are found to occur in South Korea. Eight species belonging to the subgenus Tersilochus are described as new: T. fidicinus sp. n., T. gangwonus sp. n., T. iracundus sp. n., T. nigellus sp. n., T. obstinatus sp. n., T. punctator sp. n., T. serratus sp. n., and T. uncinatus sp. n. One abundant and widely distributed Palaearctic species, T. (Gonolochus) caudatus Holmgren, is recorded from South Korea for the first time. A key to 10 South Korean species of the genus Tersilochus is provided. Recently discovered finger-shaped flagellar structures are found and described in all Korean species of Tersilochus.


Introduction
Extensive study of South Korean Tersilochinae was initiated 2 years ago by A. Khalaim and co-authors based on materials from Yeungnam University (Gyeongsan, South Korea).Six Tersilochinae genera were recognized in the Korean fauna, and four of them, Barycnemis Förster (two species), Diaparsis Förster (11 species, including one new species and two unidentified species), Gelanes Horstmann (eight species, including four new species), and Phradis Förster (two species), have been reviewed in three papers (Balueva et al. 2013a(Balueva et al. , 2013b;;Kim et al. 2013).The genus Probles Förster was also partly revised; three new species of this genus are described (Khalaim et al. 2013) and one abundant species will be described in our forthcoming paper (Balueva et al., unpublished).
In this paper, we review one of the largest tersilochine genera, Tersilochus Holmgren.This predominantly Holarctic genus comprises three subgenera with about 65 species: Gonolochus Förster (six species), Pectinolochus Aubert (19 species), and Tersilochus s. str.(40 species).Most species of the genus Tersilochus occur in Europe (Horstmann 1971(Horstmann , 1981)), and only a few species are known from Nearctic (Horstmann 2001), Afrotropical (Khalaim 2013), and probably Oriental (Khalaim 2011) regions.In the East Palaearctic region, eight species of subgenus Pectinolochus were recorded from Mongolia, Russian Siberia, and the Far East (Khalaim 2007), three species were recorded from the Palaearctic part of China (Khalaim and Sheng 2009), one species was described from South Korea (Khalaim 2011), and nine species (including seven new species) were recorded from the Russian Far East and Japan (Khalaim 2012).The most abundant species of the genus, T. (G.) caudatus Holmgren, is widely distributed within the Palaearctic region (Khalaim 2007) but has not been recorded from South Korea till now.
Only one species of the genus Tersilochus, T. (T.) granulatus Khalaim, was known from South Korea hitherto.The aim of this work is to describe eight new species and provide a key for identification of ten Korean species of the genus Tersilochus.

Materials and methods
The ichneumonid collection of Yeungnam University, Gyeongsan, South Korea (further YUG), was studied.From this material, nine species of the genus Tersilochus were recognized (eight of them are new to science), and one recently described species, T. granulatus, deposited in the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia (further ZISP), was re-examined and photographed.All new species are described from females.Unfortunately, we were unable to identify six males.
Most specimens, including all holotypes, are kept at Yeungnam University, and some specimens are deposited in ZISP.
Photographs were taken at ZISP using a DFC290 digital camera attached to a Leica MZ16 stereomicroscope.Partially focused photographs were combined using Helicon Focus software.In the Material examined section, we provide abbreviations for Korean provinces in addition to the complete names, as abbreviations are widely used in our previous papers on Korean Tersilochinae.Morphological terminology predominantly follows Townes (1969Townes ( , 1971) ) with changes according to Khalaim (2011).Additional characters in the key are given in square brackets.
All Korean species have occipital carina complete, scutellum with lateral longitudinal carinae developed only at its basal part, fore wing with second recurrent vein distinctly postfurcal and legs slender with tarsal claws not pectinate.

Key to species of Tersilochus occurring in South Korea
Second tergite 2.0-2.5 times as long as anteriorly broad.Thyridial depression distinctly elongate.First tergite very slender, about 5.0 times as long as posteriorly broad, smooth, with small glymma situated in apical 0.6-0.7 of first tergite.
Ovipositor much longer, apically thin and strongly upcurved, its sheath almost 3.0 times as long as first tergite (Fig. 68 Description.Female (holotype).Body length 4.8 mm.Fore wing length about 3.9 mm (apices of both wings absent).Head roundly constricted behind eyes in dorsal view (as in Fig. 6); temple 0.84 times as long as eye width.Inner eye orbits parallel.Mandible with upper tooth much longer than lower tooth.Clypeus lenticular, 3.0 times as broad as long, in profile convex, with lower 0.3 bent backwards; sparsely punctate, very finely granulate and dull in upper 0.7.Malar space 0.5-0.6 times as long as basal width of mandible.Flagellum of antenna filiform, with 19 segments in holotype and 17 in paratype (Fig. 1); subbasal flagellomeres about 1.4 times and subapical flagellomeres about 1.2 times as long as broad; flagellomeres 4 to 6 with distinct subapical finger-shaped structures on outer surface.Face, frons, vertex, and temple distinctly granulate, dull, and impunctate.Mesosoma almost entirely densely granulate; lateral lobes of mesoscutum with fine punctures, and upper posterior corner of mesopleuron finely punctate on almost smooth and shining background.Notaulus very weak, with indistinct wrinkles.Foveate groove very weak, narrow, and short, situated in center of mesopleuron (Fig. 2).Propodeum mediodorsally with fine longitudinal wrinkles; basal part 0.43 times as long as apical area.Propodeal spiracle separated from pleural carina by 1.5-2.0times diameter of spiracle (Fig. 2).Apical area almost flat, anteriorly widely rounded.Apical longitudinal carinae weak but complete.Fore wing with intercubitus rather long, equal Head (including clypeus), mesosoma, and first tergite black; palpi brownish yellow to brown; tegula yellow.Mandible blackish in basal 0.4, reddish brown centrally and with teeth reddish black.Antenna entirely black.Pterostigma brown with whitish marks on proximal and distal corners.Legs brownish yellow; coxae brownish black; first trochanters brownish.Metasoma behind first tergite predominantly dark brown. Male.Unknown.
Variation.Paratype almost exactly corresponds with the holotype.In paratype, flagellomeres are slightly shorter, propodeum is with weak basal keel, and ovipositor is slightly shorter than in the holotype.
Distribution.South Korea.
Comparison.Differs from other Korean species of the genus Tersilochus by the combination of inner eye orbits convergent dorsally (Fig. 5), and short and clavate ovipositor apically with rather sharp dorsal subapical depression (Figs 12,14).
Variation.Paratype corresponds well with the holotype but has somewhat less clavate ovipositor and shorter thyridial depression.
Distribution.South Korea.
Mesosoma entirely granulate, dull, impunctate; mesopleuron centrally with fine oblique striae on granulate background (Fig. 24).Notaulus absent.Foveate groove weak and short, oblique, situated in anterior half of mesopleuron (Fig. 24).Propodeum with narrow basal area, which is 0.4 times as long as apical area (Fig. 22).Propodeal spiracle separated from pleural carina by 1.5 times diameter of spiracle.Apical area slightly impressed, anteriorly rounded (Fig. 22).Apical longitudinal carinae developed in posterior half, anteriorly absent.Fore wing (Fig. 25) with intercubitus thickened, as long as abscissa of cubitus between intercubitus and second recurrent vein.First abscissa of radius slightly longer than width of pterostigma.Metacarpus ending far from apex of fore wing.Postnervulus intercepted below middle.Hind wing with nervellus vertical.First tergite almost 3.0 times as long as broad posteriorly, mostly smooth, with petiole more or less round in cross-section, well separated from postpetiole in dorsal view, finely striate laterally before glymma (Fig. 27).Glymma deep, situated somewhat behind center of first tergite, joining by distinct furrow to ventral part of postpetiole (Fig. 26).Second tergite as long as anteriorly broad (Fig. 27).Thyridial depression short, transverse.Ovipositor short, slender, almost straight basally and upcurved in apical 0.3, with fine teeth dorsally and ventrally at apex (Fig. 26); sheath 0.7 times as long as first tergite.
Comparison.Differs from other Palaearctic species of Tersilochus by the combination short malar space, reddish brown behind first tergite of metasoma (Figs 26,27) and short ovipositor (Fig. 26).
Distribution.South Korea.
Etymology.Named after the Latin iracundus (angry, hot-tempered, furious).Description.Female (holotype).Body length 5.1 mm.Fore wing length 3.8 mm.Head strongly rounded behind eyes in dorsal view; temple 0.85 times as long as eye width.Inner eye orbits parallel.Mandible with upper tooth distinctly longer than lower tooth.Clypeus lenticular, 2.7 times as broad as long, in profile slightly convex, with lower 0.3 bent backwards; sparsely punctate, finely granulate, and dull in upper half.Malar space almost as long as basal width of mandible.Flagellum of antenna weakly tapered towards apex, with 21 segments in the holotype and 20 segments in the paratype (Fig. 28); subbasal flagellomeres 1.3-1.5 times and subapical flagellomeres 1.2-1.3times as long as broad; flagellomeres 4 to 7 with subapical finger-shaped structures on outer surface.Face, frons, vertex, and temple distinctly granulate and dull; face and frons of holotype also with indis- tinct punctures.Mesosoma entirely granulate, dull, and mostly impunctate; mesopleuron finely and rather densely punctate on finely granulate background (Fig. 29).Notaulus as very weak wrinkle or tubercle.Foveate groove weak and short, situated in anterior half of mesopleuron.Propodeum with basal keel, which is 0.31 times as long as apical area (Fig. 30).Propodeal spiracle separated from pleural carina by 2.0-2.5 times diameter of spiracle (Fig. 29).Apical area flat, anteriorly slightly pointed (Fig. 30).Apical longitudinal carinae anteriorly weak.Fore wing with intercubitus longer than abscissa of cubitus between intercubitus and second recurrent vein.First abscissa of radius distinctly longer than width of pterostigma.Metacarpus not reaching apex of fore wing.Postnervulus intercepted below middle.Hind wing with nervellus vertical or slightly reclivous.Metasoma: first tergite 2.6 times as long as broad posteriorly, mostly smooth, with petiole slightly depressed, oval in cross-section, well separated from postpetiole in dorsal view, finely striate laterally before glymma.Glymma deep, situated in apical 0.6 of first tergite, joining by distinct furrow to ventral part of postpetiole.Second tergite as long as anteriorly broad (Fig. 30).Thyridial depression short, transverse (Fig. 30).Ovipositor evenly upcurved, thickened near apex, with deep and sharp dorsal subapical notch; sheath 1.25 times as long as first tergite.

Tersilochus (Tersilochus) nigellus
Head, mesosoma, and first tergite black; palpi and lower 0.3 of clypeus reddish brown; mandible reddish brown with blackish base and teeth; tegula yellow.Antenna with scape and pedicel brownish black and flagellum entirely black.Pterostigma brown.Legs brownish yellow; fore coxa brown basally; mid and hind coxae brownish black; first trochanter of hind leg dark brown.Metasoma behind first tergite dark brown ventrally to brownish black dorsally. Male.Unknown.
Variation.Paratype almost exactly corresponds with the holotype with no obvious variation.
Etymology.Named after the Latin nigellus (somewhat black), on account of its almost entirely black body.Head very strongly rounded behind eyes in dorsal view (Fig. 33); temple short, almost 0.6 times as long as eye width.Inner eye orbits weakly but distinctly convergent dorsally (Fig. 32).Mandible with upper tooth distinctly longer than lower tooth.Clypeus probably abnormal, with lower margin abruptly bent backwards (Fig. 32); distinctly and sparsely punctate on finely granulate and dull background.Malar space 0.85 times as long as basal width of mandible.Flagellum of antenna filiform, with 18 segments (Fig. 31); subbasal flagellomeres about 1.5 times as long as broad, subapical flagellomeres slightly elongate; flagellomeres 3 to 7 with distinct subapical finger-shaped structures on outer surface (Fig. 34).Face, frons, vertex, and temple distinctly granulate, dull, and impunctate.Mesosoma entirely granulate, dull, and mostly impunctate; mesoscutum laterally with indistinct punctures.Notaulus absent.Foveate groove situated in anterior half of mesopleuron, not reaching prepectal carina anteriorly, almost straight, narrow, slightly oblique, with transverse wrinkles ventrally (Fig. 31).Propodeum with basal keel (and few fine subparallel wrinkles), which is 0.37 times as long as apical area (Fig. 38).Propodeal spiracle separated from pleural carina by 1.75 times diameter of spiracle.Apical area flat, anteriorly widely rounded (Fig. 38).Apical longitudinal carinae distinct only posteriorly, anteriorly absent.Fore wing (Fig. 35) with intercubitus thick, shorter than abscissa of cubitus between intercubitus and second recurrent vein.First abscissa of radius almost as long as width of pterostigma.Metacarpus ending far from apex of fore wing.Postnervulus intercepted somewhat below middle.Hind wing with nervellus vertical.Metasoma: first tergite 2.5 times as long as broad posteriorly (Fig. 40), with petiole trapeziform in cross-section, well separated from postpetiole in dorsal view, mostly smooth dorsally and laterally, finely striate laterally before glymma, and with postpetiole striate dorsally.Glymma deep, situated at center of first tergite, joining by distinct furrow to ventral part of postpetiole (Fig. 39).Second tergite as long as anteriorly broad (Fig. 40).Thyridial depression short, transverse (Fig. 40).Ovipositor short, weakly upcurved, with moderately deep and sharp dorsal subapical notch (Fig. 37); sheath about as long as first tergite (Fig. 36).
Distribution.South Korea.
Etymology.Named after the Latin obstinatus (firm, resolved, resolute, obstinate).Head rounded behind eyes in dorsal view (Fig. 41); temple 0.72 times as long as eye width.Inner eye orbits more or less parallel (Fig. 42).Mandible with upper tooth somewhat longer than lower tooth.Clypeus lenticular with lower margin slightly truncate, 2.9 times as broad as long, smooth, and sparsely punctate in upper 0.6, in profile weakly convex (Fig. 42).Malar space 0.8 times as long as basal width of mandible.Flagellum of antenna distinctly tapered towards apex, with 26 segments (Fig. 43); subbasal flagellomeres 1.5-1.6 times and subapical flagellomeres 1.2-1.3times as long as broad; flagellomeres 2 to 6 with small subapical finger-shaped structures on outer surface (Fig. 44, arrows).Face, frons, and vertex densely punctate on granulate surface and dull (Figs 41,42).Temple moderately densely punctate, almost smooth, and weakly shining between punctures.Notaulus with irregular wrinkles.Mesoscutum granulate, finely and densely punctate.Foveate groove about 0.8 times as long as mesopleuron, weakly curved, narrow, with fine transverse wrinkles, not reaching prepectal carina anteriorly (Fig. 46).Mesopleuron distinctly punctate, granulate, and dull below foveate groove, and mostly smooth and shining between punctures above foveate groove (Fig. 46).Propodeum mediodorsally with strong median and two weaker lateral wrinkles, basal part 0.38 times as long as apical area (Fig. 47).Dorsolateral area of propodeum finely granulate, finely and sparsely punctate.Propodeal spiracle separated from pleural carina by almost 2.0 times diameter of spiracle (Fig. 45).Apical area flat, anteriorly rounded (Fig. 47).Apical longitudinal carinae distinct posteriorly and indistinct anteriorly.Fore wing with intercubitus thickened, somewhat longer than abscissa of cubitus between intercubitus and second recurrent vein.First abscissa of radius longer than width of pterostigma.Metacarpus almost reaching apex of fore wing.Postnervulus intercepted below middle.Hind wing with nervellus vertical.Metasoma: first tergite 2.5 times as long as broad posteriorly, mostly smooth, with petiole trapeziform in cross-section and well separated from postpetiole in dorsal view.Glymma small, situated in apical 0.6 of first tergite, joining by distinct furrow to ventral part of postpetiole (Figs 45,48).Second tergite distinctly transverse, 0.8 times as long as anteriorly broad (Fig. 49).Thyridial depression as long as broad (Fig. 49).Ovipositor very short, weakly upcurved, thickened near apex, with dorsal subapical depression and small notch before this depression (Fig. 50, arrow); sheath 0.6 times as long as first tergite.
Comparison.This is the only species of the genus Tersilochus in South Korea with densely punctate mesopleuron (Fig. 46).It differs from other Palaearctic species of Tersilochus by the combination of densely punctate and smooth mesopleuron between punctures, well-developed foveate groove (Fig. 46), long metacarpus, and very short ovipositor (Figs 48,50).It is similar to the Russian Far East T. grandiculus Khalaim but distinct in having less slender flagellum of antenna, less punctate head, and shorter second tergite.
Remarks.One female from southeast China generally corresponds well with this species (including small subapical finger-shaped structures on flagellomeres 2-5) but has a flagellum with 20 segments, mesopleuron with weaker punctures and centrally mostly finely granulate, propodeal spiracle separated from pleural carina by half diameter of spiracle, thyridial depression almost twice as long as broad, and ovipositor strongly clavate, with conspicuous dorsal subapical depression and rounded tooth before this depression (Fig. 51).This specimen may belong to an undescribed species, so study of an additional material is needed.
Head, mesosoma, and first tergite black; palpi, mandible (except reddish black teeth), and lower 0.3 of clypeus yellow-brown; tegula yellow.Antenna dark brown.Pterostigma brown with conspicuous white spots on its proximal and distal corners (Fig. 58).Legs brownish yellow; fore and mid coxae weakly, and hind coxa strongly darkened with brown.Metasoma behind first tergite yellow-brown ventrally and pre-dominantly dark brown to brownish black laterally and dorsally; tergites 2 and 3 with narrow pale posterior band (Fig. 59). Male.Unknown.
Comparison.Differs from other Korean species of the genus by the combination of head weakly rounded and very strongly tapered behind eyes in dorsal view (Fig. 53), flat clypeus (Fig. 52), strongly striate dorsally first metasomal tergite (Fig. 60), and shape of the ovipositor (Fig. 61).This is the only Korean species of the genus Tersilochus that possesses an ovipositor with two distinct dorsal subapical teeth (Fig. 61) and thus belongs to the cognatus species group (correct name for the jocator species group according to Horstmann 2005); T. iracundus sp.n. and T. punctator sp.n. have ovipositors with rather weak and inconspicuous dorsal subapical teeth (Figs 26,50,51).
Distribution.South Korea.

Tersilochus (Tersilochus) uncinatus
Head (including clypeus), mesosoma, and first tergite black; palpi brown; mandible fuscous basally and with reddish black teeth; tegula yellow.Antenna entirely black.Pterostigma brown with white spot on distal corner.Legs brown; hind leg with coxa and base of first trochanter strongly darkened with brown.Metasoma behind first tergite brownish black. Male.Unknown.
Comparison.Differs from other Korean species of the genus Tersilochus by the long ovipositor with apex thin and strongly upcurved (Fig. 68).
Distribution.South Korea.
Etymology.Named after the Latin uncinatus (hooked), on account of its apically strongly upcurved ovipositor.

Discussion
All Korean species of Tersilochus are rare, being represented in our material by only one or few specimens, whereas in the Russian Far East this genus is conspicuously much more abundant (Khalaim 2012, pers. data).Almost all specimens were collected in Korea from April to early June, except the paratype of T. fidicinus sp.n. (collected in June/July) and the holotype of T. uncinatus sp.n. (collected between June and September).Thus, the flight period of the genus in Korea is generally restricted to spring and early summer.
Subapical finger-shaped structures on outer side of subbasal flagellomeres were found and described for all Korean species of Tersilochus, and number and location of these structures were used for species separation in the key.Finger-shaped structures on flagellomeres of two European species of Phradis Förster were discovered for the first time by Khalaim et al. (2009).Later, these structures were found in many other tersilochine genera, e.g. in Neotropical species of Allophrys Förster, Barycnemis Förster and Meggoleus Townes (Khalaim and Broad 2012), and East Palaearctic species of Tersilochus (Khalaim 2012).The finding of finger-shaped structures in Korean species of Tersilochus indicates that these structures are widely distributed within the subfamily, and we show that these structures may be used for diagnosing species.