Stenodema sibirica Bergroth, 1914

Figs 1 M, 2 F, 6 E – H, I, U, 10 B, F, 12 E – G, 13

Miris virens lateralis Sahlberg, 1873: 23 (original description).

Stenodema lateralis: Reuter 1891: 187 (comb. nov.).

Stenodema sibiricum Bergroth, 1914: 183 (new name for junior secondary homonym of Stenodema lateralis (Geoffroy, 1785)); Carvalho 1959: 306 (catalogue).

Stenodema sibirica; Kerzhner 1988: 99 (key to species); Muminov 1989: 127 (key to species); Vinokurov and Kanyukova 1995: 98 (key to species); Kerzhner and Josifov 1999: 196 (catalogue); Yasunaga 2019: 301 (key to species). 5

Type material examined.

Lectotype of Miris virens lateralis Sahlberg, 1873: Russia • ♀; Krasnoyarsk Terr., Yeniseysk [Jeniseisk]; 58.45 ° N, 92.18 ° E; no date provided; J. Sahlberg; (http://id.luomus.fi/GZ.56515); (MZH).

Diagnosis.

Body length in male 5.8–6.5, in female 6.2–6.8; frons protruding above clypeus base (as in Fig. 1 H, I); setae on hemelytron simple; hemelytron brown to dark brown medially and yellow to pale brown along outer margin (Fig. 12 E – G); male vertex width / eye ratio 2.1–2.4; labium reaching mesocoxa but not surpassing it (as in Fig. 1 N); hind femur only slightly tapering towards apex, without spines; setae on posterior margin of hind femur as dense as on other parts of femur, shorter than half of hind femur (Fig. 2 F); hind tibia not curved basally (as in Fig. 2 J); swelling on propleura curved (Fig. 1 H); antennal segment I length / head width ratio in male 1.0, in female 0.9–1.0; antennal segment I / pronotum lengths ratio 0.8–0.9 in male, 0.8 in female; antennal segment I as wide as or slightly narrower than eye diameter; groove on posterior part of mesopleuron absent (Fig. 1 M); paired pits between calli absent (as in Fig. 1 G), setae on antennal segment I shorter than antennal segment I width; genital capsule ~ 1.5 × as long as wide, more or less acute apically, with outgrowth near left paramere socket (Fig. 6 T, U); right paramere ca 3 × as long as wide, its apical part slightly wider than basal part, its apical process bifurcate, ca 0.1 × as long as rest of paramere (Fig. 6 E, I); left paramere with apical process acute at posterior view (Fig. 6 K, P), its sensory lobe swollen (Fig. 6 J, M); vesica with one large and two small membranous lobes (Fig. 13); dorsal labiate plate slightly longer than wide; sclerotized ring ~ 3 × as wide as long; distance between sclerotized rings ~ 0.3–0.5 × as long as sclerotized ring width (Fig. 10 B); posterior wall with sigmoid process between interramal lobes (Fig. 10 F).

Distribution.

Stenodema sibirica is known from Siberia, northern China, Mongolia, the Russian Far East, and Korea (Kerzhner and Josifov 1999).

Notes.

Among the material preserved at ZISP, we found specimens with two types of vesica. They differ in the shape of the membranous lobes and the length of the ridge with sclerotized teeth (cf. Fig. 13 A – C and Fig. 13 D – F). The genital capsule and parameres of specimens with these two types of vesica were very similar (cf. Fig. 6 E – H, U and Fig. 6 I – L, T). We found only two males with the short, sclerotized ridge, and there were no females from the same series. There were no differences in the habitus between the specimens with two types of male genitalia. The lectotype preserved at the Finnish Museum of Natural History is a female, and we refrained from dissecting its genitalia, as it will not provide us with additional information on the issue. Therefore, we treat widespread form as S. sibirica and refrain from making any taxonomic decisions on the two specimens with another type of vesica, as the corresponding species may have been already described from China (see below for comparisons).

Stenodema sibirica is very similar to S. rubrinervis Horváth, 1905 . They have minor differences in the measurements i. e., vertex width / eye diameter ratio in male (2.1–2.4 in S. sibirica and 1.7–2.0 in S. rubrinervis) and length of antennal segment I (1.8–2.1 in S. sibirica and 2.5–3.0 in S. rubrinervis) (Table 1). The genitalia of those two species are very similar, and vesica of S. rubrinervis also has a long ridge of sclerotized teeth (Yasunaga 2019: fig. 8 C).