Diamesa pseudoinsignipes Makarchenko et Hansen, 2022

Makarchenko, Eugenyi A. & Hansen, Dean C., 2022, On the taxonomy and distribution of Diamesa insignipes Kieffer (Diptera Chironomidae: Diamesinae), Zootaxa 5138 (2), pp. 191-195 : 191-193

Diamesa pseudoinsignipes Makarchenko et Hansen , sp. nov.

http://zoobank.org/NomenclaturalActs/ 61A15C00-2445-42A5-AB9B-69AB0D5A809

( Figs. 1–5 , 8 )

Diamesa insignipes Kieffer ; Hansen & Cook 1976: 103; Makarchenko 1985: 83; Linevich & Makarchenko 1989: 29; Makarchenko 2006: 266; Ashe & O'Connor 2009 (partly), misidentification.

Material examined. Holotype: adult male (slide number 326), U.S.A.: Wyoming, Teton County, Snake River at Highway 22 west of Jackson , 6.III.1965, leg. A. V. Nebeker . Paratypes: 2 adult males, the same data as holotype ; 1 adult male, RUSSIA: Kamchatka Peninsula, Petropavlovsk-Kamchatskyi City , 31.V.1908, leg. A.N. Derzhavin ; 12 adult males, RUSSIA: Baikal Lake basin, Slyudyanka River, 2.5 km from the shore of Baikal Lake , 1.V.1956, leg. A.A. Linevich.

Derivatio nominis. The species name consists of two parts – pseudo and insignipes which indicates a close relationship of the new species with Diamesa insignipes Kieffer.

Description

Adult male (n = 6, except when otherwise stated). Total length 4.0– 5.7 mm. Wing length

3.4–4.1 mm. Total length/wing length 1.11–1.15.

Coloration. Head, thorax and abdomen dark brown; legs brown to light brown; wings greyish.

Head. Eyes hairy and not extended dorsomedially. Temporal setae including 4–7 preoculars, 12–16 verticals and 8– 16 postorbitals. Clypeus with 8–15 setae. Antenna with 13 flagellomeres and developed plume; pedicel with 1 or 2 setae; terminal flagellomere with 1 subapical setae 51–63 μm long; AR 1.12–1.26. Palpomere lengths (in μm) (n=2): 60; 128; 180; 128; 184. Palpomere 3 distally with sensilla capitata (diameter 20 μm). Palpomeres 1–5 length/head width 1.09.

Thorax. Antepronotum with 9–14 lateral setae. Acrostichals absent, dorsocentrals 9–15 (uniserial), prealars 5–11, scutellars ca 30.

Wing. Length 3.4–4.1 mm; width 0.8–1.0 mm (1.12–1.19 mm in Wyoming specimens). R and R 1 with 18–27 setae, R 4+5 with 9–14 setae. Costa extension 79–101 μm long. RM length/MCu length 2.5–3.0. Anal lobe developed, outline rounded. Squama with 34–56 setae, in 2 rows. VR 0.90.

Legs. Spur of fore tibia 64–89 μm long; spurs of mid tibia 48–55 μm and 45–63 μm; of hind tibia 45–92 μm and 76–106 μm long. Hind tibial comb with 20–21setae. LR 1 0.61–0.65, LR 2 0.45–0.47, LR 3 0.59–0.68; BV 1 3.47–3.65, BV 2 3.82–4.15, BV 3 3.76–4.13; SV 1 2.88–2.95, SV 2 4.30–4.58, SV 3 3.06–4.13 (3.06–3.26 in Wyoming specimens).

Hypopygium ( Figs. 1–5 , 8 ). Tergite IX with 10–18 setae on each side. Anal point strong, gradually broadening basally, apparently without or with only minute apical peg, 356–376 μm long ( Figs. 1, 5 ). Laterosternite IX with 9–16 setae. Gonocoxite very long (392–449 μm) (426–449 µm in Wyoming specimens); basal plate weak, without microtrichia ventrally; medial field well developed, without microtrichia, 164–196 μm long, finger-like in distal part, with 2–4 setae 128–144 μm long at about 0.4 its length and 2–4 setae 84–100 μm long at distal end ( Figs. 1, 4–5 ). Gonostylus very long (276–350 μm) (320–350 μm in Wyoming specimens), quite broad, distal 0.2 slightly expanded along inner edge; preapical part is expanded along outer edge, and apical part is beak-shaped ( Figs. 1–5 ). Megaseta small (3.5 µm), shorter but thicker than nearby setae, with larger base. HR 1.24–1.42. Transverse sternapodeme (TSA) 125–160 μm long and 52–90 μm wide, with weak antero-lateral projections ( Fig. 8 ); length TSA/width TSA 1.40–2.5. Phallapodeme 140 μm long, aedeagal lobe 132–140 μm long.

Diagnosis. The male of D. pseudoinsignipes sp. nov. is closely related to D. insignipes from which it differs in the structure of the hypopygium, particularly in the shape of gonostylus and transverse sternapodeme, and in the antennal ratio. The male gonostylus of the new species 276–350 μm long, without round-triangular protuberance on the medial side at about half its length, sometimes only with a low flat tubercle in distal half, preapical part is expanded along outer edge, and apically is beak-shaped; transverse sternapodeme broad medially, length TSA/width TSA 1.4–2.5; anal point 392–420 μm long; AR 1.12–1.26. Gonostylus of D. insignipes 264–268 μm long, with round-triangular protuberance on the medial side at about half its length, preapical part is not expanded along outer edge, and apically is not beak-shaped; transverse sternapodeme narrow medially, length TSA/width TSA 5.4–5.9; anal point 248–272 μm long; AR 1.34–1.80.

Distribution. Known from East Siberia (Baikal Lake basin and Kamchatka Peninsula) and North America ( U.S.A.: Utah, Wyoming, Michigan).

Figures

FIGURES 1–5. Adult males of Diamesa pseudoinsignipes sp. nov. from Wyoming (1–2), Baikal Lake basin (3–4) and Kamchatka (5). 1, 5, hypopygium in dorsal view; 2–3, gonostylus; 4, part of hypopygium without tergite IX.

FIGURES 6–10. Adult males of Diamesa insignipes Kieffer (6–7, 9–10) from France (6–7, 9) and Italy (10), and D. pseudoinsignipes sp. nov. from Baikal Lake basin (8). 6–7, 10, hypopygium in dorsal view; 8–9, transverse sternapodeme (TSA). Scale bars: 50 µm. L – length of TSA, W – width of TSA.