Diamesa loeffleri Reiss, 1968

Makarchenko, Eugenyi A., Semenchenko, Alexander A. & Palatov, Dmitry M., 2022, Taxonomy of Diamesa steinboecki group (Diptera: Chironomidae: Diamesinae) with description and DNA barcoding of known species. II. Subgroups davisi, leona and loeffleri, Zootaxa 5190 (3), pp. 361-392 : 386-388

Diamesa loeffleri Reiss

( Figs. 61–67 )

Diamesa loeffleri Reiss, 1968: 56 ; Ashe & O’Connor 2009: 281; Lin et al. 2021: 110.

Diamesa culicoides Heeger ; Tokunaga 1966: 275, Figs. 8–14 .

Material examined. NEPAL: 1 adult male, Langtang Region, pond near Khyimjung Glacier , alt. 4175 m a.s.l., 4. VIII.1999, leg. R. Endo . INDIA: 1 adult male Uttarakhand, Chamoli District, Rishi Ganga River, right tributary of the Alaknanda River near the Badrinath City , alt. 3128 m a.s.l., 12. V.2018, 30.740733 N, 79.48875 E, leg. D. Palatov ; 1 adult male, the same data except Alaknanda River below Badrinath City, 13. V.2018, 30.738128 N, 79.492719 E, leg. D. Palatov.

Description

Adult male (n=3, except when otherwise stated). Total length 3.2–3.8 mm. Total length/wing length 1.0–1.34.

Coloration. Dark brown. Wings grayish, with brownish venation.

Head. Eyes hairy, reniform. Temporal setae including 3–7 preoculars, 7–8 verticals. Clypeus with 6–8 setae. Antenna with 13 flagellomeres and partly reduced plume of setae ( Figs. 61–62 ); maximal length of plume setae 459 μm. Length of 1–13 flagellomeres (n=1) (μm): 68, 36, 36, 40, 36, 36, 40,40, 44, 36, 48, 44, 316; terminal flagellomere with 2 subapical setae, 20–24 μm long; AR 0.63–0.72. Palpomeres 1–5 length (μm): 36–40, 68–88, 116–124, 92–104, 115–164. Palpomere 3 in distal part with sensilla capitata with diameter 16–20 μm. Head width/ palpal length 1.04–1.13.

Thorax. Antepronotum with 2–8 ventrolateral setae. Dorsocentrals 5–7, prealars 5–6, scutellars 6–8.

Wing. Length 2.8–3.5 mm, width 0.72–1.04 mm. Anal lobe round angular. Squama with 24–28 setae. R and R 1 with 23–26 setae, R 4+5 with 4–6 setae in distal part. RM/MCu 2.7–3.0.

Legs. Spur of front tibia 60–98 µm long. Spurs of mid tibia 36–40 µm long. Spurs of hind tibia 68–76 µm and 36–40 µm long. Hind tibial comb with 14–16 setae. Length (μm) and proportions of leg segments are as in Table 13.

Hypopygium ( Figs. 63–67 ). Tergite IX with 6–12 weak setae, laterosternite IX with 4–5 setae. Anal point 188–204 µm long, slightly tapering to subapical ( Fig. 63 ), 20–40 µm wide at base;12–16 µm wide at apex; with strong anteriorly directed microtrichia in basal half and on tergite IX. Phallapodeme 92–112 µm long. Transverse sternapodeme (TSA) triangular, 68–92 µm high, 124–144 µm wide at the base; TSA height/TSA width 0.55–0.64. Gonocoxite 296–332 µm long; inferior volsella in the form of small lobe covered with micro- and macrotrichia and adjacent to a protuberance with some long setae ( Figs. 64–65, 67 ). Superior volsella in form of small rounded angular tubercle. Gonostylus 132–164 µm long, slightly curved, tapering to apex, 204 µm long; megaseta 10–12 µm long. HR 2.02–2.24.

Pupa and larva unknown.

Remarks. Lin et al (2021) redescribed of D. loeffleri from Tibet Plateau of China by male which has a common similar structure including the hypopygium but differs of some characters ( Table 14 ). Thus, specimens from China are larger (4.13–4.51 mm) than Himalayan ones, total length/wing length 1.38–1.43, clypeals 30–32, AR 0.70– 0.82, acrostichals on the mesonotum 9–11, dorsocentrals 14, anal point of hypopygium length 240–250 µm. For males from our Himalayas material the meanings of these characters are as follows. Total length 3.2–3.8 mm, total length/wing length 1.0–1.34, clypeals 6–8, AR 0.63–0.72, acrostichals on the mesonotum absent, dorsocentrals 5–7, anal point of hypopygium length 188–204 µm. Since the number of compared males of this species from the Himalayas and Tibet Plateau is small, one would assume that this is a geographical variability, but a comparison of the barcoding data showed that these are two different species (see below), that is, the population from China, apparently, should be attributed to a new species.

Figures

FIGURES 61–67. Adult males of Diamesa loeffleri Reiss from Indian Himalayas (61) and Nepal Himalayas (62–67). 61–62, antenna; 63, distal part of anal point; 64–65, inferior volsellae; 66, hypopygium in dorsal view; 67, central part of hypopygium without tergite IX. Scale bar 50 μm.

FIGURES 8–15.Adult males of Diamesa amplexivirilia Hansen from Chukotka Region (8–11) and Diamesa saetheri Willassen from Chukotka Region (12–15). 8–9, 12–13, hypopygium in dorsal view; 10, 14, anal point in lateral view; 11, 15, apical part of gonostylus. Figs. 9–11, 13–15 after Makarchenko (1980).