Filchneria mesasiatica Zhiltzova, 1971

Teslenko, Valentina A. & Palatov, Dmitry M., 2023, Redescription of a few Filchneria Klapálek, 1908 (Plecoptera, Perlodidae) species on the type and fresh material, Zootaxa 5277 (2), pp. 287-312 : 298-300

Filchneria mesasiatica Zhiltzova, 1971

Figs. 35–48

Zhiltzova, 1971: 1036–1038, fig. 2. Holotype and allotype deposited in ZIN, St. Petersburg, Russia; Zwick, 1973: 229; Zhiltzova, 1995: 9; Zwick, 1997: 494–495, fig. 7b; Teslenko & Zhiltzova, 2009: 23–24, figs. 93–97.

Diagnosis. Filchneria mesasiatica is a relatively large species, differing in the strongly raised triangular posterior margin of tergum 10 whose tip is acute, angled (about 80°), and rounded. The paraproctal sclerite is triangular with a wide base that is narrowed distally, and the tip is slightly sclerotized, indistinct, but without a tooth, and the inner edge is slightly concave. The paraproctal membranous lobe is narrow. The ELP enlarges into a membranous lobe with a small papilla atop. The female subgenital plate is species specific, resembling a wrench head. Its form is bilobed, with U-shaped rounded and deep notch, the lobes prolonged, triangular with wide base, apices pointed, directed inward, outer lateral edges obliquely cut. Eggs are relatively large sized, oval, and trilateral; its longitudinal and transverse ridges are slightly bulged and indistinct. The collar is formed by weakly noticeable extensions of the three longitudinal ridges, the edge being irregularly incised. The chorion is rough with numerous raised tubercles, densely deposited over the entire surface.

Complementary description. Male. Holotype. Body length is 19.0 mm; brachypterous, wings slightly exceeding tergum 3 ( Fig. 36 ). Abdominal terga 6–8 humped laterally; brown, color pattern indistinct, paired narrow pale patches are obvious on posterolateral margins of each tergum, terga 6‒7 bear medial triangular pale spots narrowed to posterior margins ( Fig. 36 ). Tergum 8 brown, divided by a triangular median pale spot anteriorly; two submedial swellings densely covered by sensilla basiconica and brownish hairs posterolaterally. Tergum 9 has an anteromedial triangular membranous area hidden under tergum 8; sclerotized laterally; posteromedial half slightly sclerotized with two swellings covered by sparse thick sensilla basiconica and brownish hairs posterolaterally ( Figs. 36, 37 ). In the lateral and caudal views posterior margin of tergum 10 is strongly raised, acute angled, tip rounded, directed upward; in dorsal view, the posteromedial margin triangular, covered with a patch of sensilla basiconica in V-shaped direction from tip to lateral edges, occupying one-thirds of the tergum length in the middle ( Figs. 36–38, 40 ). At rest, the paraproct is triangular with convex dorsomedial edge ( Figs. 36, 37 ). The paraproct sclerite is triangular, with wide and sclerotized base, narrowed distally, top slightly sclerotized, indistinct, but without tooth, inner edge concave, membranous, covered with tiny, light brown sensory spines and sparse fine sensory hairs ( Figs. 36, 37 ). Artificially everted eversible paraproct lobe (EPL) enlarges into a membranous lobe with a small papilla atop, and covered by sparse fine sensory hairs ( Figs. 38, 39 ).

Female. Allotype. Body length 22.5 mm, macropterous, forewing length 22.0 mm, wingspan 31.0 mm. Sternum 8 pale with a few pairs of brown spots laterally and medially, anterior half brownish, a pair of oblique dark brown lateral sclerites surrounds subgenital plate anterolaterally ( Fig. 42 ). Subgenital plate large, bilobed resembles a wrench, wide at the base, occupies more than half of the sternum 8 widths and of the sternum 9 lengths ( Fig. 42 ). Notch U-shaped, rounded, deep; depth exceeds half of the lobes length; lobes triangular, wide at the bases, prolonged, apices pointed, dark brown, directed inward, outer lateral edges obliquely cut ( Fig. 42 ). Subgenital plate mostly pale covered with sparse, tiny, dark setae, a paired small brown lateral spots at the lobe bases indistinct ( Fig. 42 ). Sternum 9 pale medially with pair of brown rounded spots laterally extending to curve brown bands directed upward under the subgenital plate lobes ( Fig. 42 ). Abdominal sternum 10 is pale.

Egg. Allotype. Large, oval, and trilateral, with mean dimensions of 786×504 μm (n=4). The longitudinal ridges are slightly bulged; transverse bridges indistinct ( Figs. 43, 44 ). The collar short, formed by weak, barely noticeable extensions of the three longitudinal ridges, the edges irregularly incised ( Fig. 46 ).The anchor plate mushroom-shaped covered with sparse, large globular bodies, especially at edge ( Figs. 44, 45 ). A transverse row of 4‒6 micropyles subequatorial, their orifices lipped, some set close to micropylar mounds ( Figs. 43, 48 ); the height of the micropyles is equal to or slightly exceeds the height of the chorionic tubercles. The chorion surface is rough with numerous raised tubercles evenly and densely located over the entire surface of the egg ( Figs. 43, 46, 48 ).

Material examined. Holotype male. Allotype female. Kyrgyzstan, Tian Shan, Alamedin River at the Strelnikova farm, to the south of Frunze town [now Arshan vill., near Bishkek town, authors comments], 11.05.1967, coll. L. Zhiltzova ( ZIN) . Additional material: 2 males, 2 females, Kyrgyzstan, Alay Ridge, Kirgiz-ata River, 22.06.1970, coll. L. Zhiltzova ( ZIN); 1 female, Kyrgyzstan, Chui Region, Ala-Archa River at the confluence of the Karabulak River , altitude 2.061 m above sea level, a rocky canyon 5 m wide, 0.5 m deep, current speed 0.3–1.0 m/s, water temperature 12 °C, sand near the coast, N 42°36.200’, E 74°28.819’, 28.05.2016, coll. DMP ( VLA); Tajikistan. Pamir-Alai mountain system, Gorno-Badakhshan Autonomous Region : 1 male, Shugnan District , Bogevdara R., 1 km above the mouth, near the Bogev vill., 6.06.2012, N 37°33.5184’, E 71°44.1642’, coll. DMP ( VLA); 1 male, 1 female, Shugnan District, Gunt River , left tributary near the Kolkhozobol vill., altitude 2.450 m above sea level, 3.06.2012, N 37°33.5184’, E 71°44.1642’, coll. DMP ( VLA) .

Remarks. Paraproctal sclerite of F. mesasiatica is similar in shape to that of F. irani and to F. wusuensis Chen, 2019 described recently from East Tien Shan, China ( Chen 2019, Teslenko & Palatov 2021). The female subgenital plates of F. mesasiatica and F. irani are very different, while F. mesasiatica and F. wusuensis females have a similar shape of the notch on the bilobed subgenital plate, with almost straight inner angles. The egg structures of F. wusuensis are poorly visible due to use of a low magnification and lack of scanning electronic imaging, making it impossible to compare with that of F. mesasiatica . Further research will show whether F. wusuensis is a valid species or a junior synonym of F. mesasiatica .

Distribution. North and Central Tian Shan and Pamir-Alai mountain system ( Kyrgyzstan, Tajikistan). Emergence period is in May-June.

Figures

FIGURES 35–40. Filchneria mesasiatica Zhiltzova, 1971 from Tian Shan, Kyrgyzstan, Alamedin River and Kirgiz-ata River, Alay Ridge. Figs. 35–37. Holotype male: 35. Head and pronotum, dorsal. 36.Abdominal tip, dorsal. 37. Paraprocts, not everted, caudal. 38. Tergum 10 and paraprocts everted, dorsal. 39. Paraprocts everted ventral. 40. Tergum 10 covered sensilla basiconica, right paraproct with paraproctal sclerite, lateral.

FIGURES 41–42. Filchneria mesasiatica Zhiltzova, 1971 from Tian Shan, Kyrgyzstan, Alamedin River. Allotype female: 41. Head and pronotum, dorsal. 42. Abdominal tip with subgenital plate, ventral.

FIGURES 43–48. Filchneria mesasiatica Zhiltzova, 1971. Allotype egg: 43. Longitudinal ridges, without anchor, lateral. 44. Same, with mushroom-shaped anchor plate. 45. Posterior pole with anchor plate, covered globular bodies at the edge, lateral. 46. Posterior pole with collar, lateral. 47. Posterior pole, dorsal. 48. Chorion surface with raised, rounded tubercles, row of micropyles with lipped orifices.