Tanytarsus latens Giłka & Paasivirta & Gadawski & Grabowski 2018, sp. nov.

Tanytarsus latens sp. nov.

Type material. Holotype (DIZUG), adult male specimen (excl. thorax) slide-mounted in Canada balsam: FINLAND, OSTROBOTHNIA BOREALIS, Palokkaanlampi and Rumajärvi ca. 40 km W of Rovaniemi (66°26'N 24°56'E), 7–28 August 2017, Malaise trap, J. Salmela. Paratypes: sampling data as holotype: 1 male (excl. thorax) in Canada balsam, 5 males + 1 hypopygium in Euparal (DIZUG); SATAKUNTA, Kauklastenjärvi ca. 15 km SE of Rauma (61°04'N 21°46'E), 17 August 2010, 1 male (in Euparal), hand net, L. Paasivirta (LP). DNA voucher: DNA extracted from thorax tissue in elution buffer (MIZ PAS).

Derivatio nominis. From the Latin adjective meaning concealed or disguised by others.

Diagnosis. Darkly coloured, relatively big [wing length: 2245–2540 (2430) µm]. Frontal tubercles small, 2–12 µm long at most. Anal tergite bands of H-type, with broad median connection. Anal point slender, with narrowly rounded apex and 2–3 spinulae. Superior volsella rounded at base, elongate, tapering towards tip, usually with apical nose curved medially. Stem of median volsella straight, slightly swollen in distal half, with irregularly arranged subulate lamellae.

Description. Adult male (n = 8 + 1 male hypopygium).

Colouration (in alcohol). Eyes black. Antenna, tentorium, scutal stripes, scutellum, postnotum, sternum, hypopygial apodemes and proximal leg segments, incl. femora and tibiae dark brown to black. Head capsule, mouthparts, ground colour of thorax, tarsi and abdomen brown with slight olive undertone. Wing and haltere pale brownish.

Head. Eyes reniform, with dorsomedian extension gradually narrowing from 5 facets at base to 4: 4: 3/2 facets medially. Antenna with 13 distinct flagellomeres, AR 1.53–1.78 (1.66), plume fully-developed. Frontal tubercles minute, usually in shape of tiny swellings (2–3 µm), rarely conical or cylindrical, 12 µm long at most (Fig. 1A, B). Lengths of palpomeres 2–5 (in µm): 60–72 (63), 155–183 (172), 143–163 (156), 198–258 (244); pm3 always longer than pm4. Clypeus with 17–24 setae.

Thorax chaetotaxy (n = 5). Ac 20–22, biserial, with several setae arranged in small field near antepronotum; Dc 11–14 on each side; Pa 1–2 on each side; Scts 4–8, usually 8.

Wing (Fig. 1C). Length 2245–2540 (2430) µm. Venation pattern and chaetotaxy typical of the genus, as shown in Fig 1C; VR Cu 1.14–1.16 (n = 2).

Legs. Fore leg tibia with slightly curved distally spur 25–30 µm long. Mid and hind leg tibiae with combs separated, each comb bearing spur; spurs straight or slightly curved, 28–36 µm long on mid leg and 40–55 µm long on hind leg. Basitarsus of mid leg with 4–7 sensilla chaetica. Lengths of leg segments and leg ratios as shown in Table 1.

Hypopygium (Figs 2, 3). Gonostylus 160–180 µm, longer than gonocoxite. Anal tergite bands of H-type, with broad median connection (Fig. 2A). Anal tergite usually with 2 long median setae, rarely 3 setae present (n = 2) or median setae absent (n = 1); extensive microtrichia-free area surrounding posterior sections of anal tergite bands; lateral teeth and lateral setae absent; shoulders on posterior margin weak (Figs 2A, 3A). Anal point slender, evenly tapering towards narrowly rounded apex, bearing 2–3 well-developed spinulae placed between crests (Figs 2A, 3A). Superior volsella rounded at base, elongate, tapering towards narrow tip, usually with apical nose curved medially, 4–6 dorsal setae and 3 setae on anteromedian margin (proximal seta weaker), microtrichia absent; digitus long, but not extending beyond margin of superior volsella, pointed (Figs 2, 3B). Stem of median volsella 40–45 µm long, straight, slightly swollen in distal half, bearing several setiform and subulate, irregularly arranged lamellae (Fig 2B). Inferior volsella straight, stout, with distal part swollen, roundish, bearing numerous strong setae (Figs 2A, B).