Diamesa urvantsevi Krasheninnikov et Makarchenko, 2020

Krasheninnikov, Andrey B., Makarchenko, Eugenyi A., Semenchenko, Alexander A., Gavrilo, Maria V. & Vshivkova, Kristina A., 2020, Morphological description and DNA barcoding of some Diamesinae (Diptera Chironomidae) from the Severnaya Zemlya Archipelago and the Vaigach Island (Russian Arctic), Zootaxa 4802 (3), pp. 587-600 : 589-590

Diamesa urvantsevi Krasheninnikov et Makarchenko , sp. nov.

http://zoobank.org/NomenclaturalActs/ 2106E8A2-D575-4435-981C-8D4B844676C9

( Figs. 1–4 , 8–10 )

Type material. Holotype, adult male, RUSSIA: Severnaya Zemlya Archipelago , Bolshevik Island , Mikoyan Bay, Chernaya River, N 79.20768 E 102.3109, 01.IX.2019, leg. A. Krasheninnikov. Paratypes: 7 adult males, the same data as holotype .

Derivatio nominis. The species is named in honor of Nikolay Nikolayevich Urvantsev (1893–1985). He was a Soviet geologist and explorer who together with Georgy Ushakov investigated the Severnaya Zemlya Archipelago and made it first map.

Adult male (n = 3). Total length 3.5–3.8 mm. Wing length 3.30–3.84 mm. Total length/wing length 0.98–1.05. Wing length/length of profemur 2.41–2.50.

Colouration. Head, thorax, legs and hypopygium dark brown; antenna brown; palpomeres light brown; abdomen light brown to brown; wing veins yellowish brown.

Head. Eyes hairy, i.e., length of eye microtrichia about 1.5 or more times the height of ommatidial lenses and visible along lateral eye margin when head is viewed from front (after: Hansen & Cook 1976). Temporal setae 27–32, including about 9–18 verticals, 7–8 preoculars, 6 postorbitals. Clypeus with 17–21 setae. Antenna with 13 flagellomeres and well-developed plume; terminal flagellomere 132–140 μm long, with rounded apex and 2–3 subapical setae 20–76 μm long. AR 1.06–1.19. Palpomeres lengths (in μm): 40–44; 84–96; 120–148; 120–132; 148–168. Palpomere 3 in distal part with sensilla capitata (sunken organ) with diameter 16–24 μm. Palpomeres 1–5 length/head width 0.79–0.92.

Thorax. Antepronotum with 6–8 ventrolateral setae. Dorsocentrals 5–9, prealars 5–10, scutellars 17–23.

Wing. R with 2–3 setae in basal 1/3, R 1 with 7–10 setae; R 4+5 with 5–8 setae in distal 1/3. Costa extension 49–66 μm long. RM length/MCu length 3.0–3.6. Brachiolum with 1–2 setae. Anal lobe well developed, angularly rounded. Squama with 29–36 setae 84–144 μm long. VR 0.88–0.94.

Legs. Spur of fore tibia 60–64 μm long; spurs of mid tibia 40–44 μm and 44–52 μm long; of hind tibia 72 μm and 48–52 μm long. Hind tibial comb with 16–18 setae. Lengths and proportions of leg segments as in Table 1.

Hypopygium ( Figs. 1–4 , 8–10 ). Tergite IX with 14–18 setae (from one side), 16–32 μm long and with very short hyaline “anal point” 12.0–16.4 μm long, which is often missing or not visible, as it tucks under tergite IX ( Figs. 3–4 , 9 ). Laterosternite IX with 13–16 setae 28–40 μm long. Phallapodeme 188–224 μm long. Transverse sternapodeme triangular 80–180 μm long. Gonocoxite 408–476 μm long. Medial field well developed, wide and flat, covered with setae 40–80 μm long; distal end often free. Basimedial setal cluster absent. Gonostylus dark brown to black, darker than gonocoxite, 296–328 μm long, massive, parallel-sided, only slightly curved in basal part, densely covered with microtrichiae and short setae; megaseta 8–9 μm long. HR 1.32–1.45.

Pupa and larva unknown.

Diagnostic characters. The new species is distinguished from all known members of the genus Diamesa by the following features. Eyes hairy; antenna with 13 flagellomeres and well-developed plume; AR 1.06–1.19. Dorsocentrals 5–9, prealars 5–10, scutellars 17–23. R with 2–3 setae only in basal 1/3; costa extension 49–66 μm long; anal lobe well developed. LR 1 0.54–0.62. Tergite IX with very short hyaline “anal point” 12.0–16.4 μm long, which is often not visible or missing; basimedial setal cluster absent; gonostylus much darker than gonocoxite, massive, parallel-sided, only slightly curved in basal part, densely covered with microtrichia and short setae.

It should be noted that only the African species D. ruvenzoriensis Freeman ( Willassen & Cranston 1986) , D. akhrorovi Makarchenko et Semenchenko , D. alibaevae Makarchenko et Semenchenko from Central Asia ( Makarchenko et al. 2018) and D. stenonyx Serra-Tosio from Nepal ( Serra-Tosio 1983) have the similar structure and shape of gonostylus, and such a small “anal point” of tergite IX, as in D. urvantsevi sp. nov., does not have any males of known species of the genus Diamesa .

Data obtained after DNA barcoding allows us to bring a new species closer to an undescribed species from northeastern Canada (see below).

Figures

FIGURES 1–7. Diamesa urvantsevi sp. nov. (1–4) and D. arctica (Boheman) (5–7), males. 1, 6, hypopygium in dorsal view; 2, gonostylus; 3–4, “anal point”; 5, inner structures of hypopygium; 6, distal part of gonostylus. Scale bar 20 μm.

FIGURES 8–12. Diamesa urvantsevi sp. nov. (8–10), D. amplexivirilia Hansen (11) and Pseudokiefferiella sp. (12), males. 8, 10–12, hypopygium in dorsal view; 9, “anal point”. ap—“anal point”.