Filchneria wusuensis Chen, 2019

Teslenko, Valentina A. & Palatov, Dmitry M., 2021, A poorly known species and new records of Plecoptera from the Eastern Tien Shan, Xinjiang Uygur Autonomous Region, China, Zootaxa 4950 (1), pp. 123-136 : 129-133

Filchneria wusuensis Chen, 2019

Figs. 13–30

Chen, 2019:512, figs. 1–7.

Material examined. China, the Xinjiang Uygur Autonomous Region, Eastern Tien Shan : 1 male, 1 female, 1 nymph, Bogdo-Ula Range, Urumqi city, Dabancheng District , Zienzan stream in the headwaters of the Malu River , an altitude 2,443 m above sea level. 09.VII.2017, N 43°49.738’, E 88°10.351’, leg. D.M. P .; 2 males, 1 female, Bogdo-Ula Range, Urumqi city, Dabancheng District , Sangecha Stream , 35 km N of Dabancheng, an altitude 2,356 m above sea level, 13.VII.2017, N 43°40.583’, E 88°17.006’, leg. D.M. P .; 6 males, 1 female, Karlyktag Range, Hami city, Ayar-Gol Stream , 60 km NE of Hami, an altitude 2,426 m above sea level, 21.VII.2017, N 43°12.225’, E 94°07.128’, leg. D.M. P .

Supplementary description. Adult habitus. The head is brown, with an indistinct M-line, tentorial callosities on the clypeus pale, a pair of narrow transverse, and yellow marks above the lateral ocelli and small black spots inside ( Figs. 13 , 23 ). The interocellar area has a large, tire-shaped yellow spot that widens anteriorly and is open posteriorly, an almost square, pale-brown spot is present anterior to the median ocellus and a vague M-line. The occipital area bears a transverse yellow band that extends along the epicranial suture ( Figs. 13 , 23 ). The submental gills are short. The pronotum is brown, with a large median yellow band that occasionally includes a thin brown stripe along the median pronotal line and two thin incomplete brown stripes laterally ( Fig. 13 ). The lateral arms of the mesofurcasternum reach the posterior corners of the furcal pits, with dark beak-like spots at the inner edges of each furcal pit, a dark brown transverse suture occurs on the mesosternum that is unclear and incomplete anteromedially. The abdomen is covered with colorless clothing hairs ( Figs. 13, 14 ), and segments 1–3 are divided by a pleural membrane laterally. The pleural folds on segment 4 are vague, and the other segments are undivided. The legs are yellow with brown bands ( Fig. 13 ). Dorsally, the femur has a dark brown band that widens basally closer to the inner margin, while the outer margin is pale. The tibia has a dark brown band in the basal quarter ( Fig. 13 ). The cerci are bicolored, each segment with a narrow yellow band basally and a wide brown band distally ( Fig. 13 ). The color pattern of the female is similar to that of the male, with the exception that the interocellar spot is nearly closed posteriorly while the pronotal median band is narrower and widest posteriorly ( Fig. 23 ).

Male. The body is 15.2–19.7 mm in length (n=9). The male is brachypterous, wings not exceeding tergum 6 ( Figs. 13, 14 ). Abdominal terga 6–8 are humped laterally; medial indistinct pale spots expand anteriorly and are divided by a longitudinal, dark brown median band ( Fig. 14 ). Tergum 8 bears two submedial swellings densely covered by short sensilla basiconica and long colorless hairs posterolaterally. Tergum 9 has an anteromedial arrowshaped membranous area that may be almost hidden under tergum 8 ( Figs. 14, 15 ). Similar but smaller posteromedial swellings occur on tergum 9 and are covered by thick sensilla basiconica and colorless hairs posterolaterally ( Fig. 15 ). The sensilla basiconica appear much less frequently than on tergum 8 and their bases are clearly outlined with pale brown pigments. In the lateral view, posterior margin of tergum 10 is strongly raised, obtusely angled, and directed forward and upward. In the dorsal view, tergum 10 is rounded posteriorly and is mostly pale with small round membranous marks anteromedially and a pair of diffuse paramedial brown spots ( Figs. 15 , 22 ). Short sensilla basiconica are distributed radially from the posterior margin to two-thirds of the tergite length in the middle ( Fig. 15 ).

At rest, the paraprocts are triangular with convex dorsomedial edges ( Fig. 16 ). The paraproct sclerite is triangular, wide, heavily sclerotized basally, and narrowed distally with a pointed tip that is occasionally truncated and slightly sclerotized ( Figs. 14 , 19 ). In the caudal view, the paraproct sclerite surrounds a gray oval paraproct lobe covered with dense, tiny, dark brown sensory spines and sparse fine sensory hairs ( Figs. 16–20 ). The naturally everted eversible paraproct lobe (EPL) enlarges into a cylindrical membranous lobe with a small papilla atop, and is covered dorsally by sparse fine sensory hairs ( Figs. 18, 19 ). In the caudal view, the EPL margin close to the base bears a small, rounded swelling directed inside that is covered with dense, tiny, dark brown sensory spines and sparse fine sensory hairs ( Fig. 19 ). The naturally everted aedeagus is variable in shape, membranous, short and wide, and bears unpaired anterodorsal and posterodorsal lobes, and has two pairs of lateral lobes ( Figs. 21, 22 ). The anterodorsal lobe looks like a low, wide, and round arch that emerges above the aedeagus with paired small round cuticular swellings laterally ( Fig. 21 ). Each anterolateral lobe is smaller than the posterolateral lobe, with small, round, or papilla cuticular swellings at the apex ( Fig. 21 ). Each posterolateral lobe is extended and rounded laterally, occasionally with round cuticular swellings at the apex directed upward. The posterodorsal lobe is wide at the base with a triangular top reaching the bases of the lateral cuticular swellings of the anterodorsal lobe ( Fig. 21 ).

Female. The body is 23.5 mm in length, macropterous, and has a forewing length of 14.0 mm and a wingspan of 31.0 mm. The forewing is brownish, while the hind wing is paler ( Figs. 25, 26 ). The venation includes an irregular net near the apex comprising three rows of cells. The forewing has three cross-veins between C and Sc and five apical veins between Sc and R 1 ( Fig. 25 ). Rs bears three apical branches. There are seven apical veins between М and Cu 2, and three anal veins. The hind wing has a large anal area, and A 2, A 3 and A 5 are forked.

Sternum 8 is brown in the anteromedian half, and a pair of oblique dark brown lateral sclerites surrounds a pale subgenital plate anterolaterally ( Fig. 24 ). The subgenital plate is bilobed, large, extending almost half the length of sternum 9. The posterior margin has an U-shaped notch that separates two large lobes with almost straight inner angles. Sparse, tiny, dark setae form a field at the base of the U-shaped notch ( Fig. 24 ).

Egg. This is large, rather circular than trilateral in cross-section (the last feature is typical for Filchneria ) with dimensions of 715×475 μm. The longitudinal ridges are not specially marked ( Figs. 27–29 ). The collar is short and formed by weak, barely noticeable extensions of the three longitudinal ridges, and the inner edges of the collar are slightly curved ( Figs. 28, 29 ). The sides of the collar bear short longitudinal carinae ( Fig. 28 ). The margin of the shoulder transitions smoothly to the egg chorion surface ( Fig. 28 ). A transverse row of two to seven micropyles is subequatorial; micropyles have a small, short lipped orifice ( Fig. 30 ). The anchor is mushroom-shaped, with single globular bodies on the anchor plate ( Fig. 27 ). The margin of the anchor covers the collar completely ( Fig. 27 ). The chorionic surface is rough with small, light tubercles ( Fig. 28 ).

Note. In our material that was collected at an altitude of 2,300 –2,400 m, F. wusuensis males had a darker, more contrasting body color pattern, especially on the pronotum, than the holotype. This may be due to the maturity of the adults as well as differences in environmental conditions (increased ultraviolet radiation, decreased temperature, etc.) compared with the type locality at 1,700 m above sea level. On the other hand, the male described in our material is identical to the holotype of F. wusuensis in its pale color pattern on tergum 10, location of the sensilla basiconica on terga 8–10, cylindrical shape of the naturally everted EPL, and small papilla at the tip of EPL ( Fig. 19 ). In general, the penial armature is similar, but in the male described from our material, the aedeagus is turned out more than in the holotype; therefore, the membranous lobes are more distinct. Females from fresh material were similar to Chen’s (2019) paratype. They had a similar color pattern on the head, pronotum, and shape of the notch on the bilobed subgenital plate, with almost straight inner angles as in the paratype ( Fig. 24 ). The collar on the egg in the paratype appeared to be present but was poorly visible due to use of a low magnification and lack of scanning electronic imaging, making it impossible to compare the features of the сhorion structure.

Distribution and ecology. The distribution of F. wusuensis is limited to the Eastern Tien Shan and was first described in China, in the Xinjiang Uygur Autonomous Region, Wusu City, and Bayingou River located in the Eastern Tien Shan. Our specimens were collected in the streams of the neighboring locality, in Bogdo-Ula and Karlyktag Ridges. Filchneria wusuensis inhabited mountain streams at altitudes of 2,300–2450 m above sea level, including those fed by glaciers ( Figs. 35–37 ). Adults were found in July.

Figures

FIGURES 13–15. Filchneria wusuensis, male. 13. Habitus. 14. Abdomen, dorsal. 15. Tergum 9–10, dorsal.

FIGURES 16–22. Filchneria wusuensis, male. 16. Paraprocts, not everted, caudal. 17–18. The eversible paraproct lobes, caudal. 19. Eversible paraproct lobes, naturally everted, caudal. 20. Sensory spines and hairs at the tip of the paraproct lobes, ventral. 21. Naturally everted paraproct lobes and aedeagus, caudal: a—anterodorsal lobe, p—posterodorsal lobe al–anterolateral lobe, pl—posterolateral lobe. 22. Aedeagus, lateral.

FIGURES 23–26. Filchneria wusuensis, female. 23. Head and pronotum, dorsal. 24. Abdominal tip, ventral. 25. Forewing. 26. Hind wing.

FIGURES 27–30. Filchneria wusuensis, eggs. 27.Egg with papillated anchor. 28. Collar with carina and chorionic surface. 29. Micropyle row. 30. Micropylar orifice.

FIGURES 33–37. Сollecting places in the Xinjiang Uygur Autonomous Region, the Eastern Tien Shan. 33. Bogdo-Ula Range, a glacier near Lake Sangecha. 34. Lake Sangecha. 35. Sangecha Stream. 36. Bogdo-Ula Range, Zienzan Stream. 37. Karlyktag Range, Ayar-Gol Stream.