Neozavrelia minuta ( Linevich, 1963 )

Orel, Oksana V., 2021, Revision of the genus Neozavrelia Goetghebuer, Thienemann, 1941 (Diptera Chironomidae) from Eastern Siberia and the Russian Far East, with the description of new species, Zootaxa 4938 (3), pp. 251-297 : 270-272

Neozavrelia minuta ( Linevich, 1963)

( Figs 53–59 )

Tanytarsus minutus Linevich, 1963: 10 , Fig. 2 .

Neozavrelia minuta ( Linevich, 1963) , Reiss 1971: 10, Fig. 1 .

Material examined. 8 males, RUSSIA, IRKUTSK REGION, Slyudyansky district, basin of Baikal Lake, Harlaht River , 15.vii.1985, leg. L. Kravtsova.

Description. Adult male (n=6). Total length 2.8–3.4 mm; wing length 2.6–2.7 mm. Total length/wing length 1.08–1.27.

Colouration. Ground colour of thorax, scutellum, maxillary palpomeres and abdomen yellowish brown; halters yellowish; antenna, scutal stripes, median band on distal half of mesonotum and postnotum, legs yellowish brown.

Head ( Figs 56–57 ). Frontal tubercles absent. Temporal setae 8–12. Clypeus with 17–24 setae. Antenna with 10 flagellomeres, 1192–1256 μm long; ultimate flagellomere 600–664 μm, swollen apically. AR 0.99–1.14. Maxillary palpomeres 2–4 combined 600–656 μm long, their individual lengths (in μm): 64–80: 144–160: 144–168: 224–280. Antenna length/palp length 1.85–1.99.

Thorax. Acrostichals 17–22, dorsocentrals 10–13, prealars 1–2. Scutellum with 8–11 setae.

Wing width 0.69–0.84 mm. VR 1.11–1.20. R with 17–21, R 1 with 0–4, R 4+5 with 11–16, M 1+2 with 20–26, M 3+4 with 4–6 setae, Cu 1 without setae, An with 0–9 setae. Cell r 2+3, r 4+5, m 1+2, m 3+4 with setae. Brachiolum with 1–2 setae.

Legs (see Table 7). Apical curved tibial spur of fore leg 48–58 μm long. Combs of mid and hind tibiae separated; each comb bears straight or slightly curved spur, 24–44 μm (mid tibia) to 41–51 μm long (hind tibia). Basitarsus of mid leg with 2–4 sensilla chaetica.

Hypopygium ( Figs 53–55 , 58–59 ). Anal tergite with V-shaped bands and posterolateral lobes 17–27 μm long; anterior margin triangular-shaped. The anal point narrow, parallel-sided, rounded apically, dorsally cover with several small spinulae and bearing 11–15 lateral setae on each side of anal point, 48–51 μm long and 17 μm wide on dorsal view. Gonocoxite 194–238 μm long, along the inner margin with 5–8 setae. The width of the transverse sternapodema 75–78 µm. Superior volsella oval-shaped (51–54 μm long, 27–31 μm wide), bearing 3–6 strong apical and 5–10 fine dorsal setae, microtrichia present. Digitus 34 μm long and 10 μm wide. Stem of median volsella straight and parallel-sided, 44–51 μm long, bearing slender lamelliform setae; total length of median volsella 85 μm. Inferior volsella curved and rounded apically, 136–143 μm long, with 17–18 setae. Gonostylus straight, 133–150 μm long and expanded at about median (51–65 μm). HR 1.41–1.66.

Pupa and the larva are shown in the figure 2 ( Linevich 1963, p. 11). Unfortunately, a detailed morphological description of the pupa and larva are still missing.

Remarks. Anna Andreevna Linevich (1963) describes the life cycle in detail of N. minuta , but does not provide a morphological description of the imago, pupa, and larva. A brief description of the males of N. minuta , collected on Lake Baikal near the village of B. Koty, was given by Riess (1971). When compared with males collected on the Kharlakta River (basin of Lake Baikal), only one difference was revealed—all males had 2 spurs on the hind tibia.

The males of N. minuta well differ in the following features: have a dark brown body color, body length about 3.5 мм; frontal tubercles absent; antenna about 1200 μm; R 1 with 0–4 setae; gonostylus 133–150 μm long.

Distribution. Basin of Lake Baikal ( Russia, Irkutsk Region).

Figures

FIGURES 53–55. Details of the structure of the male of Neozavrelia minuta (Linevich). 53—total view of hypopygium; 54—lateral view of hypopygium; 55—gonostylus. Scale bar 50 μm.

FIGURES 56–59. The male of Neozavrelia minuta (Linevich). 56—head and maxillar palp; 57—antenna; 58, 59—total view of hypopygium. Scale bar 50 μm.

FIGURES 1–8. The male of Neozavrelia fengchengensis Wang, Wang. 1—frontal tubercles; 2—maxilar palp and clypeus; 3—antenna; 4—apical part of wing; 5, 6—total view of hypopygium; 7, 8—lateral view of hypopygium. Scale bar 50 μm.