Parachironomus khatyrka, Orel, 2017

Orel, Oksana V., 2017, Two new species and new records of the genus Parachironomus Lenz, 1921 (Diptera, Chironomidae) from northern Russia, Zootaxa 4312 (3), pp. 531-546 : 539-545

Parachironomus khatyrka sp. n.

( Figs 31–41 )

Type material. Holotype: male, Russia, Chukotka Autonomous Region, basin of Khatyrka River, Myssovye Lakes , 27.vii.1980, leg. E. Makarchenko. Paratypes: 3 males, same data.

Etymology. From the Latin khatyrka , named for the Khatyrka River basin in which the material was collected.

Diagnostic characters. The adult male of P. khatyrka sp. n. is distinguished by the following combination of features: frontal tubercles present; wing length 2.7–2.9 mm; AR 3.18; LR P1 1.33; tergite IX with longitudinal anal tergite band; anal point shorter than superior volsella, in lateral view its dorsal contour weakly curved; SVo with long apical projection in the form of a cap; IVo with prominence to median; gonostylus in dorsal view slightly curved, in lateral view expanded in the middle.

Adult male (n=3). See also Table 5.

Total length 5.0– 5.5 mm.

Coloration brown.

Head. Frontal tubercles small, 6.8 µm long and 5.1 µm wide. Temporal setae 25–28. Clypeus with 26–33 setae. Antenna 1336 µm long. AR 3.18. Maxillary palpomeres 2–4 combined 724–802 µm long, their individual lengths (in µm): 68; 221–238; 197–224; 238–272. Antenna length/palp length 1.67.

Thorax. Antepronotals 6–10, acrostichals 16–25, dorsocentrals 25–28, prealars 6–8, supraalars 1–2. Scutellum with 22–24 setae.

Wing. Length 2.7–2.9 mm, without microtrichia. VR 1.08. R with 25–29, R1 with 18–20, R4+5 with 26–27 setae in distal 2/3, M1+2 without setae. Squama with 17–21 setae.

Legs. See Table 4. Each mid and hind tibia with 2 fused combs and 2 spurs (length 40 µm). BR P1 9.3, BR P2 4.2, BR P3 9.0.

continued.

1.11 1.10 1.09"1.13 1.11"1.19 1.09"1.18 1.08 1.12

setae 23"26 23 24"31 16"34 26, 30 25"29 28"29 15"16 21 21"25 14"26 22, 26 18"20 22"25

+5 30"32 25 25"35 20"34 37, 40 26"27 37

1+2 0 8 0 0"7 17"32 0 0

uamal setae 22 12 21 "31 8"24 15 17"21 13"23

……continued on the next page Hypopygium ( Figs 31–41 ). Laterosternite IX with 1–4 setae. Anal tergite with median longitudinal band, ventrolateral shoulders on posterior margin weakly developed. Anal point in dorsal view length 99–119 µm, parallel-sided free section length 54–58 µm; in lateral view the base carries microtrichia and 6–12 lateral and 18– 23 dorsal setae at the base of the anal point, apical part narrow and slightly crescent-shaped ( Fig. 32 ). Portal setae 3–4 on each side. Gonocoxite 197–204 µm long, with 4 setae on inner margin. Transverse sternapodeme 116 µm long. Phallapodeme 112–136 µm long. Superior volsella (126–136 µm long) slightly curved, little to moderately expanded at the base, apically with long apical projection in the form of a cap (17–27 µm), with 1 terminal seta (51 µm) located in 17–20 µm wide pit and 1 medial seta (34 µm) located in 8.5–10 µm wide pit, distance between setae 10 µm. Inferior volsella broadly rounded, with prominence to median, its microtrichia not elongate. Gonostylus 272–296 µm long, in dorsal view slightly curved, the proximal part 41 µm wide with 8–13 latero-ventral setae, distally adjacent section narrower and bare or with 1 seta; in lateral view gonostylus expanded in the middle (up to 58–65 µm high), distally gradually tapering, with a row of 6 distal-median setae. HR 0.69–0.73.

Female, pupa and larva unknown.

Remarks. The adult male of P. khatyrka sp. n. is most similar to that of P. paradigitalis Brundin, 1949 but can be distinguished by the presence of small frontal tubercles, AR 3.18, Ac 16–25, Dc 25–28, Scts 22–24, LR P1 1.33, and by the superior volsella with a long apical projection that is narrow triangular with pointed tip (see Table 6).

Distribution. Known only from the basin of Khatyrka River ( Russia, Chukotka Autonomous Region).

Figures

FIGURES 31 – 34. Details of hypopygium structure of P. khatyrka sp. n. 31 — hypopygium in dorsal view, 32 — tergite IX, gonocoxite, gonostylus and volsellae in lateral view; 33, 34 — superior and inferior volsellae in lateral view. Scale bars 50 µm

FIGURES 35 – 41. Adult male of P. khatyrka sp. n. 35 — frontal tubercles; 36 — hypopygium in dorsal view; 37 — hypopygium in ventral view; 38 — gonocoxite, gonostylus and volsellae in lateral view; 39 — superior and inferior volsellae in ventral view; 40 – 41 — tergite IX and anal point in lateral view. Scale bars 500 µm.