Diamesa insignipes Kieffer

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 : 193-195

Diamesa insignipes Kieffer

( Figs. 6–7, 9–10 )

Diamesa insignipes Kieffer in Kiffer & Thienemann 1908: 3; Pagast 1947: 478; Wülker 1959: 348; Serra-Tosio 1964: 44, 1971: 215; Langton & Pinder 2007: 57, Fig. 130 C; Ashe & O’Connor 2009: 277; Rossaro & Lencioni 2015a-b: 72; Montagna et al. 2016: 327 .

Material examined. FRANCE: 1 adult male, National Wildlife Area of Chastreix-Sancy (Puy-de-Dôme French department), Chastreix, La Gagne , 21.07.2016, alt. 1300 m a.s.l., N45°30'09", E 02°45'51", leg. Gennaro Coppa ; ITALY: 2 adult males, Abruzzes, NW Aquila, Passo di Capanelle , spring 1200m, 42.4624N, 13.3548E, 4.04.2015, leg. Gilles Vinçon.

Remark. Data of Serra-Tosio (1971) in our description are highlighted by bold in parentheses.

Description

Adult male (n = 4, except when otherwise stated). Total length 4.0–4.3 (5.1) mm. Wing length 3.6–4.0 (3.6) mm. Total length/wing length 1.09–1.13.

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

Head. Eyes hairy and not extended dorsomedially. Temporal setae including 3–4 (2–3) preoculars, 11–14 verticals and postorbitals invisible. Clypeus with 10–12 (7) setae. Antenna with 13 flagellomeres and developed plume; pedicel with 2 setae; terminal flagellomere with 1 subapical setae 32–36 (50) μm long; AR 1.34–1.69 (1.38). Palpomere lengths (in μm) (n=2): 60–68; 108–112; 164–172; 168–172; 224–252. Palpomere 3 distally with sensilla capitata (diameter 18–20 μm). Palpomeres 1–5 length/head width 1.04–1.06.

Thorax. Antepronotum with 12–14 (14) lateral setae. Acrostichals absent, dorsocentrals 9–12 (9) (uniserial), prealars 7–8 (9), scutellars ca 30.

Wing. Length 3.6–4.0 mm; width 1.1–1.2 mm. R and R 1 with 24–29 setae, R 4+5 with 9–16 setae. Costa extension 28–36 μm long. RM length/MCu length 2.7. Anal lobe developed, outline rounded. Squama with 26–35 (50) setae, in 1–2 rows. VR 0.90.

Legs. Spur of fore tibia 60–76 μm long; spurs of mid tibia same length 52–64 μm; of hind tibia 52 μm and 72–88 μm long. Hind tibial comb with 13–17 setae. LR 1 0.63–0.70 (0.68), LR 2 0.48–0.50 (0.45), LR 3 0.63 (0.63); BV 1 3.33–3.45 (3.37), BV 2 4.05–4.21 (4.01), BV 3 3.64–3.82 (3.79); SV 1 2.59–2.76 (2.63), SV 2 3.92–4.20 (4.40), SV 3 2.97 (3.06).

Hypopygium ( Figs. 6–7, 9–10 ). Tergite IX with 11–13 (15) setae on each side. Anal point strong, gradually broadening basally, apparently without or with only minute apical peg, 248–272 μm long ( Figs. 6, 7, 10 ). Laterosternite IX with 11–12 setae. Gonocoxite long (340–400 μm); medial field well developed, without microtrichia, 160–180 μm long, finger-like in distal part, with 4–5 setae 72–104 (65) μm long at basal part and 2–4 setae 56–72 (30) μm long at distal end ( Figs. 6, 10 ). Gonostylus long (264–268 μm), with round-triangular protuberance on the medial side at about half its length, preapical part is not expanded along outer edge, and apical part with short megaseta 12 μm long ( Figs. 6, 7, 10 ). HR 1.44–1.49. Transverse sternapodeme (TSA) 152–164 μm long and 28–30 μm wide, with weak antero-lateral projections ( Fig. 9 ); length TSA/width TSA 5.4–5.9. Phallapodeme 104 μm long, aedeagal lobe 140 μm long.

Distribution. Widespread in the Western Palaearctic ( Ashe & O'Connor 2009; Spies & Saether 2013; Rossaro & Lencioni 2015a-b).

Remarks. We feel that these two closely related species can be differentiated based on differences in specific aspects of their morphology. DNA barcoding would be most helpful to confirm, or refute, this decision.

Figures

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.