Tersilochus (Tersilochus) serratoides Khalaim, 2022

Khalaim, Andrey I., 2022, Tersilochinae (Hymenoptera: Ichneumonidae) of Japan: two new species, a new combination and 23 new country records, Zootaxa 5174 (4), pp. 301-330 : 323-326

Tersilochus (Tersilochus) serratoides Khalaim , sp. nov.

( Figs 61–68 )

Material examined. Holotype female ( EUM) Japan, Shikoku I., Ehime Pref., Mt. Kasatori , 21–31.V.2013, coll. Eiji Yamamoto.

Description. Female. Body length 4.0 mm. Fore wing length 3.7 mm.

Head, in dorsal view, weakly rounded and strongly constricted posterior to eyes ( Fig. 64 ); gena 0.75× as long as eye width. Eyes with short sparse setae ( Fig. 63 ). Clypeus about 2.6× as broad as long, in front view almost lenticular, with lower margin slightly truncate ( Fig. 63 ), separated from face by deep impression, bent backwards in lower 0.3 (i.e. with transverse bend); clypeus smooth in lower 0.3 and distinctly punctate on finely granulate background in upper 0.7. Mandible moderately robust, slightly tapered in basal 0.4 and with upper and lower margins subparallel in apical 0.6; upper tooth somewhat longer than the lower. Malar space about 0.9× as long as basal mandibular width. Antennal flagellum ( Fig. 62 ) filiform, with 18 flagellomeres; subbasal flagellomeres 1.6–1.8× and subapical flagellomeres about 1.2× as long as broad; flagellomeres 3 to 5 with distinct subapical finger-shaped structures on outer surface ( Fig. 62 ). Face with elongate median prominence. Face, frons, vertex and gena distinctly granulate, dull, virtually impunctate (gena with very fine inconspicuous punctures). Occipital carina complete.

Mesosoma entirely granulate, dull to weakly shining, mostly impunctate; with more or less distinct punctures on mesopleuron centrally. Notaulus with short and weak longitudinal wrinkle on anterolateral side of mesoscutum ( Fig. 64 ). Scutellum with lateral longitudinal carinae present at its front 0.2. Epicnemial carina with upper end distinctly curved to reach front margin of mesopleuron. Foveate groove completely absent ( Fig. 67 ). Propodeal spiracle separated from pleural carina by distance shorter than one diameter of spiracle ( Fig. 67 ). Propodeum with basal keel which is about 0.3× as long as apical area ( Fig. 68 ); apical area slightly impressed along midline, rounded anteriorly; apical longitudinal carinae reaching transverse carina anteriorly ( Fig. 68 ).

Fore wing with second recurrent vein (2m-cu) distinctly postfurcal, unpigmented in anterior half and distinct in posterior half. Intercubitus (2rs-m) moderately long and thick, about as long as abscissa of cubitus between intercubitus and second recurrent vein (abscissa of M between 2rs-m and 2m-cu). First abscissa of radius (Rs+2r) straight, longer than width of pterostigma. First and second abscissae of radius (Rs+2r and Rs) meeting at slightly acute angle. Metacarpus (R1) not reaching apex of fore wing. Hind wing with nervellus (cu1&cu-a) slightly reclivous, almost vertical. Legs slender. Tarsal claws not pectinate.

First tergite 2.9× as long as posteriorly broad, predominantly smooth, petiole with shallow longitudinal striae in posterior part dorsally and laterally, and with deep longitudinal impression dorsally in posterior part; first tergite, in cross-section centrally, trapeziform (lateral carinae strong in anterior half of tergite, petiole dorsally flat). Glymma large and deep, situated somewhat behind centre of tergite, joining by strong furrow to ventral part of postpetiole. Second tergite as long as anteriorly broad ( Fig. 65 ). Thyridial depression about as long as broad ( Fig. 65 ). Ovipositor long and slender, weakly bent upwards in basal 0.8 and strongly upcurved in apical 0.2, with two distinct dorsal subapical teeth and several fine teeth ventrally ( Fig. 66 ); sheath about 2.4× as long as first tergite ( Fig. 61 ).

Head, mesosoma and first tergite of metasoma black; lower 0.3 of clypeus, mouthparts and mandible (teeth reddish black) yellow-black. Antenna black, apical margins of scape and pedicel brownish. Tegula and pterostigma brown. Legs predominantly yellow-brown, all coxae and hind femur centrally darkened with brown. Metasoma posterior to first tergite dark brown.

Male. Unknown.

Etymology. The species is named after its similarity to T. serratus Khalaim & Lee.

Distribution. Japan (Shikoku I.).

Comparison. In the key to the species occurring in Korea ( Khalaim et al. 2014), the new species runs to T. uncinatus Khalaim & Lee in couplet 9, but differs from this species by the ovipositor with two distinct dorsal subapical teeth and several fine teeth ventrally ( Fig. 66 ) (apically thin and with a weak dorsal notch in T. uncinatus ). In the shape of the ovipositor, T. serratoides sp. nov. resembles another Korean species— T. serratus Khalaim & Lee ( Khalaim et al. 2014) .

In the key to the species of the Russian Far East and Japan (Khalaim 2012), T. serratoides sp. nov. runs to T. juxtus in couplet 8, but in the new species the gena is shorter and less rounded posterior to eyes ( Fig. 64 ), and ovipositor is with distinct dorsal subapical teeth ( Fig. 66 ).

Tersilochus serratoides sp. nov. also differs from the occurring in China T. ningxiator Khalaim & Sheng ( Khalaim & Sheng 2009) by completely lacking foveate groove of the mesopleuron ( Fig. 67 ) and longer ovipositor ( Fig. 61 ), and from T. runatus Khalaim & Sheng ( Khalaim & Sheng 2009) by shorter gena, flagellum with 18 flagellomeres (15–16 in T. runatus ) and more slender ovipositor ( Fig. 61 ).

Figures

FIGURES 61–66. Tersilochus serratoides sp. nov., holotype, ♀: 61—habitus, lateral; 62—antennae, lateral; 63—head, front; 64—head and mesoscutum, dorsal; 65—posterior part of first tergite and tergite 2, dorsal; 66—apex of ovipositor, lateral.

FIGURES 67–68. Tersilochus serratoides sp. nov., holotype, ♀: 67—mesosoma and base of metasoma, lateral; 68—propodeum, dorso-lateral.