Kostjukovius arkharensis, Kosheleva, 2023

Kostjukovius arkharensis sp.n.

Figs 1–5 View Figs 1–6 , 7–10 View Figs 7–10 .

MATERIAL: Holotype ♀ ( ZISP): Russia, Amur Province: Arkhara Vill., forest, 17.VIII.2022, V. G. Chemyreva. Paratype 1 ♂ ( ZISP), Amur Province: 3 km E Uril Vill., Tarmanchukan River , 3–4.VIII.2022, V. G. Chemyreva .

DESCRIPTION. Female (holotype) ( Figs 1–5 View Figs 1–6 ). Body length 1.53 mm. Head 1.05 times as broad as mesoscutum, 2.90 times as broad as long (in dorsal view), 1.18 times as broad as high (in frontal view); temples about 0.14 length of eyes; POL 1.43 OOL, OOL 1.75 OD. Eyes 1.86 times as long as broad (dorsal view). Frons with median longitudinal line, frontofacial sutures are widely separated dorsally with the outer arms not extending lateral to the lateral ocellus. Malar space 0.60 height of eye, malar sulcus straight. Mouth 1.36 malar space. Antennal toruli situated slightly below ventral edge of eyes. Antenna with scape 0.83 height of eye, 3 times as long as broad; pedicel 1.75 times as long as broad and 1.40 times as long as F1; F1–F3 = 1.19, 0.96, 0.82 times as long as broad, respectively; clava 1.90 times as long as broad, with C1 0.66 times as long as broad, C2 as long as C1, C3 0.75 length of C2. Pedicellus and flagellum with a few outstanding strong setae.

Mesosoma 1.89 times as long as broad. Pronotum conical anteriorly, with subparallel lateral sides posteriorly, 0.55 (dorsal view) or 0.73 (lateral view) as long as mesoscutum. Mid lobe of mesoscutum as long as broad, median line absent; with marks from two adnotaular setae on each side; surface shiny, with fine and very delicate alutaceous sculpture. Scutellum 0.70 times as long as mesoscutum, 1.29 times as broad as long, without submedian lines, with marks from two pairs of setae in posterior part, surface shiny, like mesoscutum; posterior edge straight and raised above dorsellum. Dorsellum half as long as scutellum, 1.67 times as broad as long. Propodeum medially 1.67 times as long as dorsellum; with spiracles, separated by their diameter from hind edge of metanotum, surface relatively dull, with fine slightly raised reticulation, median carina distinctly raised. Fore femora thickened, 2.80 times as long as broad; spur of fore tibia slightly longer than basitarsus, apical segment of tarsus about twice as long as each segment; hind femora widened, 2.50 times as long as broad. Forewing 2.50 times as long as broad; costal cell as long as M, SM with 1 dorsal seta; M 3.70 times length of ST, thickened proximally; PM absent, speculum small; parastigma separated from M by a distinct hyaline spot; cilia 1.14 length of ST. Hindwing obtuse, cilia 0.35 breadth of wing.

Metasoma. Gaster ovate, broadest a little behind the middle and pointed apically, 1.20 times as long as thorax, about as long as head plus thorax, 1.85 times as long as broad; surface shiny, smooth with very fine superficial alutaceous reticulation; last tergite broader than long; longest seta of each cercus 1.50 length of next longest seta, slightly curved.

Color. Head and mesosoma black, gaster black-brown; antenna dark brown; coxae and femora black, tibia brown, fore tibia with spur fuscous apically, tarsi yellowish, except apical segment fuscous. Wings hyaline with venation yellowishbrown.

Male (paratype) ( Figs 7–10 View Figs 7–10 ). Differs from female as follows. Body length 1.3 mm. Head and mesosoma with moderately long erect setae. Antenna with scape 0.90 height of eye, 2.20 times as long as broad, its dorsal surface with many rather long setae; ventral plaque 0.37 length of scape; pedicel plus flagellum 1.56 times breadth of mesoscutum; pedicel 1.57 times as long as broad and 1.17 as long as F1; F1 as long as F2, 1.2 times as long as broad, F3 as long as F4, 1.30 times as long as broad; clava as broad as F4, 1.14 times as long as F3+F4, 2.87 times as long as broad. Fore femora not thickened, 3.50 times as long as broad.

Biology unknown.

ETYMOLOGY. The name of this species is an adjective referring to the area where the holotype was collected, near the village of Arkhara.

COMPARATIVE DIAGNOSIS. Kostjukovius arkharensis sp.n. is similar to K. platycephalae by scutellum without submedian lines and mid lobe of mesoscutum without median line ( Figs 2, 3, 5, 6 View Figs 1–6 ), clava twice as long as broad ( Fig. 4 View Figs 1–6 ), forewing 2.5 times as long as broad ( Fig. 3 View Figs 1–6 ), mid lobe of mesoscutum, and scutellum, each with two pairs of setae ( Figs 5, 6 View Figs 1–6 ) and gaster longer than thorax (but not as longer as in K. platycephalae [ Dyurich, Kostjukov, 1978: 24]). The new species differs from K. platycephalae in the frontofacial sutures, which are widely separated dorsally (in K. platycephalae the sutures are narrowly separated [comparative material: holotype: ♀, Kishinev environs, ex. Platycephala umbraculata F., 30.V.1973, G. Dyurich]), scape 3 times as long as broad (2 times in K. platycephalae , see Dyurich, Kostjukov [1978: 24, fig. 2]), pronotum conical anteriorly, with subparallel lateral sides posteriorly (fully conical in K. platycephalae , see Dyurich, Kostjukov [1978: 23–24, fig. 1]), scutellum 0.7 times as long as mesoscutum (0.5 times in K. platycephalae , see Dyurich, Kostjukov [1978: 24, fig. 1]), and dorsellum half as long as scutellum (3 times in K. platycephalae , see Dyurich, Kostjukov [1978: 24, fig. 1]).

The new species is close to the other two known species, K. grahami and K. keralensis , in having the frons with frontofacial sutures widely separated dorsally, but differs from both latter species in having the outer arms of these sutures not extending lateral to the lateral ocellus ( Figs 4 View Figs 1–6 , 9 View Figs 7–10 ) (in K. grahami and K. keralensi s the outer arms of frontofacial sutures extend lateral to the lateral ocellus [ LaSalle, 1994: 209; Narendran, 2007: 126]. K. grahami and K. keralensis also differ from K. arkharensis sp.n. and K. platycephalae in having the submedian lines on scutellum and the median line on mid lobe of mesoscutum, which are absent in both latter species.

Acknowledgements. I am grateful to my colleagues at the Zoological Institute RAS: to Vasilisa G. Chemyreva for providing interesting material for the present study, to Ekaterina V. Tselikh for constructive and critical comments on this paper, and to Sergey A. Belokobylskij for the opportunity to work with the chalcid collection at ZISP. The work was funded by the All-Russian Institute of Plant Protection, Project No. FGEU-2022-0002.