Pagastia (P.) hanseni Makarchenko, Semenchenko et Palatov, 1959

Makarchenko, Eugenyi A., Semenchenko, Alexander A. & Palatov, Dmitry M., 2021, New species and findings of Pagastia Oliver (Diptera: Chironomidae: Diamesinae) from Central Asia, with DNA barcoding of known species of the genus, Zootaxa 4951 (3), pp. 559-570 : 565

Pagastia (P.) hanseni Makarchenko, Semenchenko et Palatov , sp. nov.

( Figs. 5–7 , 10–11 )

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Material. Holotype: adult male, Central Asia, Tajikistan, Gorno-Badakhshan Autonomous Region, Roshtqal’a District , Soktosh River , 2.3 km west of the ruins of the Derouj fortress, 2.VII.2016, alt. 3366 m above sea level, N 37°22.717’, E 72°20.961’, leg. D. Palatov. Paratypes: 1 adult male, 12 larvae, same data as holotype ; 10 larvae, Tajikistan, Gorno-Badakhshan Autonomous Region, Shughnon District, aryk in the valley of the Toguzbulok River , at the beginning of the road to the Maysara Pass , 01.07.2016, alt. 3717 m above sea level, N 37°30.822’, E 72°40.545’, leg. D. Palatov.

Derivatio nominis. The species is named in honour of the American chironomid taxonomist of Diamesinae Dean Cyrus Hansen.

Adult male (n = 1).

Total length 5.0 mm. Total length/wing length 1.0.

Coloration. Head, thorax, legs, and abdomen brown to dark brown; antennae light brown or yellowish-brown; wings greyish.

Head. Eyes bare and extended dorsomedially. Temporal setae consisting of 4 coronals, 30–33 orbitals, 8 verticals, and 15–18 postorbitals. Clypeus with ca 90 setae. Antenna with 13 flagellomeres and a well developed plume; pedicel with 2–3 setae; terminal flagellomere with 1 subapical setae 48 μm long. AR 3.80. Palpomere lengths (in μm): 72; 136; 249; 304; 356. Distal part of palpomere 3 with sensilla capitata of 16–20 μm diameter. Palpomeres 1–5 length/head width 1.09.

Thorax.Antepronotum completely covered with 51 setae, 100–268 μm long ( Fig 6 ). Acrostichals 14 (80–88 μm long); dorsocentrals 53–54 (168–260 μm long), in posterior part in 4 rows, in middle and anterior parts in 2–3 rows; prealars 47–50 (152–260 μm long); scutellars 73.

Wing. Length 4.96 mm; width 1.16 mm. Membrane without setae. R and R 1 with 21–22 setae; R 1 in distal part without setae; R 4+5 without setae. Costa extension 72 μm long. RM length/MCu length 3.25. Anal lobe developed, rounded and slightly protrude. Squama with 36–44 setae in 2–3 rows. Alula without setae. VR 0.84.

Legs. Spur of fore tibia 128 μm long; spurs of mid tibia 92 μm and 100 μm long; spurs of hind tibia 136 μm and 92 μm long. Hind tibial comb with 12–13 setae. Lengths and proportions of leg segments as in Table 2.

Hypopygium ( Figs. 5, 7 , 10–11 ). Tergite IX with 29–30 setae on each side and with an anal point 88 μm long, apically with peg 28 μm long. Tergite IX laterally from anal point on each side with rounded small lobe ( Fig. 11 ). Laterosternite IX with 11–12 setae. Transverse sternapodeme trapezoidal, 212 μm long. Phallapodeme 48–52 μm long. Gonocoxite 384–392 μm long; basal lobe of medium size, rounded, with long setae along inner margin and with 4 setae at inner part, 28–32 μm long ( Figs. 5 , 10 ). Median aedeagal lobe 72 μm long, wedge-shaped, with fin- gerlike apex, 72 μm long; lateral aedeagal lobe narrow, 132–140 μm long ( Fig. 7 ). Gonostylus 280 μm long, slender, almost straight, of same thickness, sometimes slightly widened at the base, slightly curved apically with megaseta 16–20 μm long. HR 1.37–1.40.

Pupa unknown.

Larva not separable from P. (P.) caelestomontana sp. nov., can be distinguished only by molecular genetic data.

Diagnosis. The male of this new species is most closely related to P. (P.) caelestomontana sp. nov. See the diagnosis of this species for details, the key and results of DNA barcoding.

Ecology. Larvae were collected from stones and bowlders sometimes covered with algae and moss in mountain rivers, located at an altitude of 2016–3717 m, at a flow rate of 0.4–1.0 m/s, with water temperature ca 12°C.

Distribution. Known only from the type locality in Pamir Mountains ( Tajikistan) ( Fig. 13 ).

Figures

FIGURES 1–7. Pagastia (P.) caelestomontana sp. nov. (1–4) and P. (P.) hanseni sp. nov. (5–7), males. 1, 6, anteropronotum in dorsal view; 2, 7, aedeagal lobes; 3, 5, hypopygium in dorsal view; 4, anal point. Bl, basal lobe of gonocoxite; LAl, lateral aedeagal lobe; MAl, median aedeagal lobe TSa, transverse sternapodeme. Scale bars for figures 1, 3, 5, 6 – 200 µm, for figures 2, 4, 7 – 50 µm.

FIGURES 8–11. Pagastia (P.) caelestomontana sp. nov. (8–9) and P. (P.) hanseni sp. nov. (10–11), males. 8, 10, hypopygium in dorsal view; 9, gonostylus; 11, anal point.

FIGURES 12–15. Type localities of Pagastia (P.) caelestomontana sp. nov. (12), P. (P.) hanseni sp. nov. (13), and P. (P.) aff. lanceolata (Tokunaga) (14–15). 12, Otmek River, Talas district, Kirgizstan (photo by E.S. Chertoprud); 13, Soktosh River, Gorno-Badakhshan Autonomous Region, Roshtqal’a District, Tajikistan (photo by D.M. Palatov); 14, Tuzumtaikul River, Gorno- Badakhshan Autonomous Region, Shughnon District, Tajikistan (photo by M.V. Vinarski); 15, spring in front of the mouth of the Bartang River, Gorno-Badakhshan Autonomous Region, Rushanskiy District, Tajikistan (photo by M.V. Vinarski).