Diamesa sakartvella Kownacki et Kownacka, 1983

Makarchenko, Eugenyi A., Semenchenko, Alexander A. & Palatov, Dmitry M., 2022, Taxonomy of Diamesa steinboecki group (Diptera: Chironomidae: Diamesinae) with description and DNA barcoding of new species. I. Subgroups steinboecki and longipes, Zootaxa 5125 (5), pp. 483-512 : 501-502

Diamesa sakartvella Kownacki et Kownacka

( Figs. 38, 42 , 45, 50–51, 57 , 74 )

Diamesa sakartvella Kownacki et Kownacka, 1973: 21 ; Langton & Visser 2003: 43; Ashe & O’Connor 2009: 284.

Material examened. 11 adult males, RUSSIA: Greater Caucasus, Republic of North Ossetia-Alania, Alagirsky District , Skazdon River near the Tsey (Tseyskoe gorge) ski resort, altitude 1943 m above sea level, N 42.784167, E 43.903667, 27.VII.2019, leg. D. Palatov.

Description

Adult male (n = 5, except when otherwise stated). Total length 2.9–3.1 m. Total length/wing length 1.04–1.19.

Coloration. Brown to dark brown. Head, thorax and abdomen dark brown. Legs brown. Wings brownish gray, with brownish veins.

Head. Eyes hairy, reniform. Temporal setae including 7–8 frontals, 7–8 orbitals, 7–9 verticals and 3–4 postorbitals. Frontal tubercles 12 μm height and 56–60 μm width. Clypeus with 9 setae. Antenna with 8 flagellomeres and reduced plume of setae; number and length of these setae on 1–7 flagellomeres respectively: 1–2 (52 μm), 2 (60–72 μm), 2 (60–76 μm), 1–2 (76 μm), 0, 0; terminal flagellomere with 3–4 setae, 60–80 μm long in basal part and with 2 subapical setae, 28–32 μm long. Length of 1–8 flagellomeres (μm): 80, 40, 40, 32, 32, 28, 32, 164; AR 0.58. Palpomere length (μm): 40, 76, 128, 92, 112. Palpomere 3 in distal part with sensilla capitata with diameter 28 μm. Head width/palpal length 0.91. Antennal length/palpal length 1.0.

Thorax. Antepronotum with 11–13 ventrolateral setae, 36–48 μm long. Dorsocentrals 11–18, 92–120 μm long (2 rows in front); prealars 3–7, 92–104 μm long. Scutellum with 10–12 setae.

Wing ( Fig. 42 ). Length 2.4–2.8 mm, width 0.72–0.84 mm. Anal lobe reduced. Squama with 9–14 setae, 52–60 μm long. R and R 1 with 22–25 setae, R 4+5 with 5 (in distal part). Costal extension 48–68 μm. RM/MCu 1.9–2.0.

Legs. Spur of front tibia 28–32 µm long. Spurs of mid tibia equal length (32 µm). Spurs of hind tibia 68 µm and 36–40 µm long. Hind tibial comb with 24–26 setae. Length (μm) and proportions of leg segments are as in Table 9 .

Hypopygium ( Figs. 38 , 45, 50–51, 57 ). Tergite IX densely covered with strong macrotrichia apices of which are directed anteriorly, with 17–19 setae, 20–96 µm long and with narrow (14–16 µm), chitinized and naked anal point, 120–156 µm long. Laterosternite IX with 12–14 setae, 20–24 µm long. Transverse sternopodeme (TSA) wide triangular, 68–92 µm high, 172–192 µm wide at the base ( Figs. 50–51 ); TSA height/TSA width 0.36–0.50. Aedeagal lobe 140 µm long (n=1); phallapodeme sclerotized, 120 µm long (n=1). Gonocoxite 372–379 µm long; superior volsellae rounded, along margin with 4–7 setae, 20–40 µm long ( Fig. 57 ). Gonostylus 160–184 µm long, almost not expanded in the distal half along the outer edge ( Fig. 45 ); in apical part with megaseta in form of wide terminal spine, ca 12 μm long and tooth the same size, next to it there is two setae approximately of the same length. HR 2.02–2.10.

Pupa and larva unknown.

Diagnosis. The male of D. sakartvella is closely related in the subgroup to D. zagrosica sp. nov and D. moubayedi sp. nov. from which it can be distinguished by shape and structure of transverse sternopodeme, inferior volsellae and gonostylus. Transverse sternopodeme of D. sakartvella is wide triangular ( Figs. 50–51 ), of low height (68–88 µm) and very wide basally (172–188 µm), the ratio of its height to width is 0.36–0.50; superior volsellae rounded ( Fig. 57 ); gonostylus almost not expanded in the distal half along the outer edge and without projection basally ( Fig.45 ). Transverse sternopodeme of D. zagrosica sp. nov. is regular triangular shape ( Figs. 53–54 ), of medium height (84–108 µm) and not very wide basally (162–172 µm), the ratio of its height to width is 0.49–0.67; superior volsellae rounded–angular ( Fig. 56 ); gonostylus slightly expanded in the distal half along the outer edge and with small rounded projection basally ( Figs.48–49 ). Transverse sternopodeme of D. moubayedi sp. nov. is triangular shape ( Fig. 52 ), of great height (104–140 µm) and not very wide basally (148–184 µm), the ratio of its height to width is 0.80–0.89; superior volsellae angular ( Fig. 55 ); gonostylus expanded in the distal half along the outer edge and with rounded–angular projection basally ( Fig.47 ).

Ecology. Adult males were collected from stones and boulders at the source of a mountain river, located at an altitude of 1943 m, at a flow rate of 0.3–0.8 m /s, with water temperatures ca 7°C.

Distribution. Known only from Caucasus ( Fig. 74 ).

Figures

FIGURES 37–44. Males of Diamesa zagrosica sp. nov. (37, 41), D. sakartvella Kownacki et Kownacka (38, 42) and D. moubayedi sp. nov. (39–40, 43–44). 37, head; 38, 41, hypopygium in dorsal view; 40, hypopygium in dorsal view without tergite IX; 42, wing; 43, tergite IX; 44, anal point in lateral view.

FIGURES 45–57. Some details of male’s hypopygium of Diamesa sakartvella Kownacki et Kownacka (45, 50–51, 57), D. moubayedi sp. nov. (46–47, 52, 55), D. zagrosica sp. nov. (48–49, 53–54, 56). 45–49, gonostylus; 46, apex of gonostylus; 50–54, transverse sternapodeme; 55–57, superior volsellae.

FIGURES 68–74. Type localities of Diamesa dragani sp. nov. (68), D. kownackii sp. nov. (69–70), D. maisaraensis sp. nov. (71), D. marinskiyi sp. nov. (72), D. steinboecki Goetghebuer (73) and D. sakartvella Kownacki et Kownacka (74). 68, unnamed stream of Bolshoi On River basin, alt. 2063 m a. sea l., Sayan Mountains (photo by S.V. Dragan); 69, unnamed stream of Somnitelnaya River basin, Wrangel Island (photo by E.A. Makarchenko); 70, Somnitelnaya River, upper stream, alt. 205–210 m a. sea l., Wrangel Island (photo by O.A. Khruleva); 71, Maisara River near Maisara Pass, alt. 4168 m a. sea l., Pamir Mountains (photo by D.M. Palatov); 72, Zienzan River, Tien Shan Mountains, alt. 1923 m a. sea l., Xinjiang Uygur Autonomous Region, China (photo by D.M. Palatov); 73, Balm stream, Massif of Aiguilles–Rouges, French Alps (photo by Pierre Clévenot); 74, Skazdon River near the Tsey (Tseyskoe gorge), alt. 1943 m a. sea l., North Caucasus (photo by D.M. Palatov).