Stenodema pilosa (Jakovlev, 1889)

Figs 1 A, G, Q, 2 D, 3 G – I, 4 E, H, 6 N – P, R, S, 9 A – D

Brachytropis pilosa Jakovlev, 1889: 243 (original description).

Stenodema pilosum: Reuter 1904: 3 (comb. nov., key to species).

Stenodema pilosa: Muminov 1989: 127 (key to species).

Stenodema trispinosum Reuter, 1904: 8 (original description); Carvalho 1959: 301 (catalogue); Wagner and Weber 1964: 93 (key to species); Kerzhner and Jaczewski 1964: 958 (key to species); Wagner 1974: 110 (key to species). New synonym.

Stenodema trispinosa: Kerzhner 1988: 99 (key to species); Muminov 1989: 126 (key to species); Vinokurov and Kanyukova 1995: 98 (key to species); Kerzhner and Josifov 1999: 191 (catalogue); Yasunaga 2019: 301 (key to species). 4

Type material examined.

Lectotype of Brachytropis pilosa Jakovlev, 1889: China • ♀; Xinjang: Quiemo [oasis Tschertschen]; 38.14 ° N, 85.53 ° E; 11 Jun 1885; NM Przhevalsky; (ZISP_ENT 00015588); (ZISP) .

Lectotype of Stenodema trispinosum Reuter, 1904: Russia: • ♀; Yakutia Rep., Batylim, Lena River; 62.02 ° N, 129.73 ° E; 18–19 Jul 1901; B. Poppius; (http://id.luomus.fi/GZ.56520); (MZH) .

Paralectotypes of Stenodema trispinosum Reuter, 1904: Russia • ♀; Arkhangelsk Prov.: Solovetsky Islands; 65.08 ° N, 35.88 ° E; no date provided; Levander; (http://id.luomus.fi/GZ.25545); (MZH) • 3 ♀; Buryatia Rep.: Dauria; 53 ° N, 115 ° E; 1842; R. F. Sahlberg; (http://id.luomus.fi/GZ.56517, http://id.luomus.fi/GZ.56518, http://id.luomus.fi/GZ.56519); (MZH) • ♀; Khakassia Rep.: Sayanogorsk [Osnatjennaja]; 53.09 ° N, 91.40 ° E; 1885; R. E. Hammarström; (http://id.luomus.fi/GZ.56523); (MZH) • ♀; Khanty-Mansi Autonomous Okrug: Leushi [Leusch]; 56.62 ° N, 65.72 ° E; no date provided; N. Sundman; (http://id.luomus.fi/GZ.56516); (MZH) • ♀; Yakutia Rep.: Olekminsk; 60.37 ° N, 120.43 ° E; 1901; B. Poppius; (http://id.luomus.fi/GZ.56521); (MZH) • ♀; Ust-Aldan 63.52 ° N, 129.41 ° E; 13 Jul 1901; B. Poppius; (http://id.luomus.fi/GZ.56524); (MZH) • ♀; Yakutsk, 62.03 ° N, 129.73 ° E; 1901; B. Poppius; (http://id.luomus.fi/GZ.56522); (MZH) .

Diagnosis.

Body length in male 5.4–6.4, in female 6.0–6.3; frons not protruding above clypeus base (as in Fig. I); labium reaching middle coxa but not surpassing it; hind femur only slightly tapering toward apex, with three spines ventroapically; setae on posterior margin of hind femur as dense as on other parts of femur, distinctly shorter than hind femur width (Fig. 2 D); hind tibia straight basally (as in Fig. 2 G); swelling above propleura suture straight (as in Fig. 1 I); groove on posterior part of mesopleuron absent (as in Fig. 1 M); paired pits between calli small, not discernible from punctures or absent (Fig. 1 G); genital capsule slightly longer than wide; apex of genital capsule acute and curved left; left paramere socket with outgrowth (Fig. 6 S); apical half of right paramere as wide as basal half, not bifurcate apically (Fig. 6 N, O); left paramere with apical process acute and elongate in posterior view (Fig. 6 P) and with swollen sensory lobe (Fig. 6 M); vesica with two membranous lobes (Fig. 3 G – I); dorsal labiate plate ~ 1.5 × as long as wide; sclerotized ring ~ 1.5 × as wide as long; distance between sclerotized rings ~ 0.3–0.4 × as long as sclerotized ring width; membranous swelling on dorsal labiate plate absent (Fig. 4 H); posterior wall without dorsal structure between interramal lobes (Fig. 4 E).

Distribution.

In its currently accepted concept, S. pilosa is a Holarctic species with a wide circumpolar distribution. It extends south to California, New Mexico, Texas, and Georgia in the Nearctic, and to France, Romania, Turkey, Transcaucasia, Central Asia, Central China, and Korea in the Palearctic (Wheeler and Henry 1992; Kerzhner and Josifov 1999). Based on the distribution pattern, S. trispinosa, here synonymized with S. pilosa, is considered a true Holarctic species, with possible post-Pleistocene expansion from the Beringia refugium (Lattin and Oman 1983; Wheeler and Henry 1992).

Notes.

Stenodema pilosa was initially described within the genus Brachytropis Fieber, 1858 (Jakovlev 1889), an unnecessary new name for Brachystira Fieber, 1858, currently recognized as a subgenus of Stenodema (Reuter 1904) . In the original description Jakovlev (1889) mentioned that this species had two spines on the hind femur. Reuter (1904) described Stenodema trispinosa as a distinctive species with three spines on the hind femur. He included S. pilosa in his key to species based solely on the original description, noting that he had not personally examined specimens of this species. Muminov (1989) designated the lectotype of B. pilosa and mentioned that it had three spines on the hind femur, and that S. pilosa and S. trispinosa did not have any differences in the male genitalia structures. He hypothesized that Jakovlev (1889) indicated the presence of two spines on the hind femur in B. pilosa due to the relatively small size of the basal one. However, he followed Reuter’s key in other respects and differentiated these two species by the length of antennal segment I, although exact measurements or ratios were not provided, and by the length of setae on this segment and hind tibiae.

We examined the lectotypes of both species as well as other specimens authentically identified as S. pilosa, and did not find any characters separating this species from S. trispinosa . Most probably, S. trispinosa was treated as a separate new species by Reuter (1904), because of the mistake in the description of S. pilosa . According to our measurements, S. pilosa and S. trispinosa do not differ in the antennal segment II length and we could not find any differences in the setae on the hind tibia. We fully concur with Muminov (1989) regarding the lack of differences in the male genitalia structure, and we were unable to identify any distinctions in the female genitalia either. Therefore, we synonymize S. trispinosa Reuter, 1904 with S. pilosa (Jakovlev, 1889) .