Tetragoneura ambigua Grzegorzek, 1885

Polevoi, Alexei & Jakovlev, Jevgeni, 2011, A review of the European species of the genus Tetragoneura Winnertz (Diptera: Mycetophilidae), Zootaxa 3062, pp. 1-12 : 4

2. Tetragoneura ambigua Grzegorzek, 1885

( Figs. 1 : A–C; 3: A, B)

Parastemma ambigua Grzegorzek, 1885: 199 ? = Sciophila dissimilis Zetterstedt 1852: 4137

Material examined. FINLAND: 1 3, Kb: Ilomantsi, Koitajoki, 20.9.– 01.10.1996 ( FRIP, Tietäväinen leg.); 3 Ƥ, same place, 02.9.–08.9.1998 ( FRIP, Tietäväinen leg.); 1 3, Kb: Ilomantsi, Syväjärvi, 14.6.– 17.6.1996 ( FRIP, Tietäväinen leg.); 1 3, Ta: Lammi, Kotinen strict nature reserve ( METLA, J.Jakovlev leg.) 15.9.– 03.10.2003; 1 3, same place ( METLA, J.Jakovlev leg.) 28.8.– 04.10.2004; 1 3, Ta: Lammi, Evo, Leipäsuonaho ( METLA, J.Jakovlev leg.) 01.9.– 10.9.2003; 1 3, St: Ikaalinen, Seitseminen National Park ( METLA, J.Jakovlev leg.) 29.7.2008. RUSSIA, KARELIA: 1 3, Kon: Kivach, 0 3.9.2002, ( FRIP, Polevoi leg.); 1 3, Kb: Tolvojarvi, 29.8.– 11.9.1998; 1 3, 1 Ƥ, same place, 26.8–07.9.1999, ( FRIP, Tietäväinen leg.).

Description. Male (n=5)

Head dark-brown to black, thinly grey dusted, with numerous hairs and several long black setae. Lateral ocellus separated from eye margin by the distance of 1.4–2.1 times its own diameter. Palpus yellow. Clypeus darkbrown, densely covered with short hairs. Antennae brown, pedicel yellow. Fifth flagellomere 1.4–1.7 times as long as wide. Scape and pedicel with long black setae apically. Eyes densely covered with minute hairs.

Thorax. Scutum and scutellum dark-brown to black black with gray polinosity. Scutum with short biserial ac, biserial dc and some long black setae by lateral margin. Pleurae dark-brown, thinly grey dusted. Antepronotum and proepisternum haired and with black bristles, the rest of the pleurae bare.

Wing length 2.64–3.13 [mean value 2.86] mm. Wing hyaline, veins yellow, costa and radius brownish. C extending slightly beyond the middle of the distance between R5 and M1. Sc short, ending free. R4 absent. R1 about as long as ta. Stem of M-fork 1.3–1.4 times as long as ta. Base of CuA-fork lies under the middle of ta. Macrotrichia well developed on all veins with exception of Sc and proximal part of M. Haltere yellow.

Legs yellow, hind femur vaguely darkened apically. Front tibia without bristles. Mid tibia with 1–3 ad, 2 pd, 3– 4 p and 1–4 pv. Hind tibia with 9–11 ad, 13–18 pd. Ratio of tibia to first tarsomere for front, mid and hind legs: 1.20–1.32 [1.27]; 1.54–1.62 [1.59]; 1.75–1.88 [1.82]. Front and mid tibia with one spur, hind tibia with two spurs of subequal length. Mid tibia with well developed ovate sensory organ dorsally on basal third.

Abdomen brown, covered with dark hairs, tergites I and II yellow ventrally, tergite III with yellow lateral spot at base. Terminalia ( Fig. 1 : A–C), brown. Gonocoxites with narrow median cleft almost reaching their base. Gonostylus elongated with apical "nose", strongly sclerotised, bearing sparse short hairs apically. Aedeagus long well protruding beyond apical margin of tergite 9, bifid apically and with wing-like appendices at sides. Tergite 9 with two submedian lobes separated from the rest of tergite by deep excavations, cerci reduced.

Female. (n=4). Lateral ocellus separated from eye margin by the distance of 1.2–1.4 times its own diameter. Fifth flagellomere 1.3–1.6 times as long as wide. Wing length 3.04–3.26 [3.10] mm. R1 about as long as ta. Stem of M-fork 1.2–1.4 times as long as ta. Ratio of tibia to first tarsomere for front, mid and hind legs: 1.36–1.53 [1.43]; 1.55–1.70 [1.64]; 1.75–1.86 [1.80]. Front tibia with one spur, mid tibia with av spur about 3/4 as long as pv spur, hind tibia with av spur subequal to pv spur. Mid tibia without sensory organ. Abdomen with yellow spots on tergites I–III, tergites IV and V yellowish basally. In other respect similar to male. Terminalia as in Fig. 3 : A, B. Gonocoxite 8 triangular in lateral view, with several stronger setae posteriorly. Tergite 8 partly fused with tergite 9. Hypoproct with setae laterally, two basal ones distinctly longer. First segment of cerci in ventral view with apical margin distinctly produced internally. Second segment circular in lateral view and ovate in ventral view.

Distribution. Widespread in Europe; recorded from Bulgaria, Czech Republic, Finland, Germany, Hungary, Poland, Russia (North and NW), Slovakia, Sweden and Yugoslavia ( Chandler 2011). In Sweden the species has been found only in NW province Jämtland ( Kjaerandsen et al. 2007) while in Finland and Russian Karelia—in southern and central provinces Ta, St, Kb and Kon.

Biology. Collected with Malaise trap and sweep netting mostly in spruce dominated forests, but also in clearcuts.

Larval microhabitats. Unknown

Figures

FIGURE 1. Male terminalia. A. T. ambigua, dorsal view. B. T. ambigua, ventral view. C. T. ambigua, lateral view. D. T. pudogensis sp. n., dorsal view. E. T. pudogensis sp. n., ventral view. F. T. pudogensis sp. n., lateral view. Scale bars = 0.2 mm. Abbreviations: ae = aedeagus, gc = gonocoxite, gst = gonostylus, tg = tergite, sml = submedian lobe.

FIGURE 3. Female terminalia. A. T. ambigua, lateral view. B. T. ambigua, ventral view. C. T. ruuhijarvii sp. n., lateral view. D. T. ruuhijarvii sp. n., ventral view. E. T. sylvatica, lateral view. F. T. sylvatica, ventral view. Scale bars = 0.2 mm. Abbreviations: cerc = cercus, gc = gonocoxite, hyp = hypoproct, tg = tergite.