Tetragoneura sylvatica ( Curtis, 1837 )

Polevoi, Alexei & Jakovlev, Jevgeni, 2011, A review of the European species of the genus Tetragoneura Winnertz (Diptera: Mycetophilidae), Zootaxa 3062, pp. 1-12 : 3

1. Tetragoneura sylvatica ( Curtis, 1837)

( Figs. 2 : A, B; 3: E, F)

Sciophila sylvatica Curtis, 1837: 641

= Sciophila compressa Walker, 1856: 42 = Tetragoneura distincta Winnertz, 1846: 19

Material examined. FINLAND: 2 3, 2 Ƥ, Ta: Padasjoki, Vesijako Strict Nature Reserve, 27.5.– 26.7.2005 ( METLA, J. Jakovlev leg.); 1 3, Ta: Lammi, Kotinen Strict Nature Reserve, 28.6.–02.8.2006 ( METLA, J. Jakovlev leg.); 8 Ƥ, Ab: Karjalohja, Karkali Strict Nature Reserve, 27.7.–04.8. 2006 ( METLA, J. Jakovlev leg.). NORWAY: 1 3, AK: Østmarka Nature Reserve, Tappenberg, 27.6.– 13.8.1991 ( FRIP, Økland & Hågvar leg.); RUSSIA, KAR- ELIA: 2 3, Kpoc: Maslozero, Kuzharvi lake, 21.6.2000 ( FRIP, Polevoi leg.); 1 3, Kol: Mikhailovskoe, Novikovo, 0 2.7.2008 ( FRIP, Polevoi leg.); 1 3, Kp: Prirechnyi, 3 km SW, 24.6.– 13.8.2009 ( FRIP, Polevoi leg.); 2 3, Kp: Ust– Reka, Chumbozero, 20.6.– 25.6.2009 ( FRIP, Polevoi leg.).

Description. Male (n=4)

Head black, densely grey dusted, covered with short pale hairs and with several longer bristles. Lateral ocellus separated from eye margin by distance of 2.1–3.4 times its own diameter. Palpus yellow. Clypeus black densely covered with short hairs. Antenna dark-brown, pedicel yellow. Fifth flagellomere 1.3–1.5 times as long as wide. Scape and pedicel with only relatively short pale bristles. Eyes densely covered with minute hairs.

Thorax. Scutum black, thinly grey dusted, clothed with evenly distributed pale hairs and longer bristles. Scutellum and pleurae black, thinly grey dusted. Antepronotum and proepisternum haired and with bristles, the rest of the pleurae bare.

Wing length 2.79–2.88 [mean value 2.83] mm. Wing hyaline, veins yellow, costa and radius brownish. C extending distinctly beyond the middle of distance between R5 and M1. Sc short, ending free. R4 usually developed, forming small cell (normally 3–4 times longer than wide, but sometimes strongly reduced or totally absent on one or both wings). R1, ta and stem of M-fork approximately equal in length. Base of CuA-fork lies under the middle of ta. Macrotichia well developed on all veins except Sc and proximal part of M. Haltere yellow.

Legs yellow, trochanters and femora all at base darkened ventrally, hind femur also darkened at apex. Front tibia without bristles. Mid tibia with 4–7 ad 3–4 pd, 5–6 p and 4–6 pv. Hind tibia with 11–16 ad, 10–14 pd. Ratio of tibia to first tarsomere for fore, mid and hind legs: 1.22–1.37 [1.31]; 1.4–1.51 [1.47]; 1.77–1.87 [1.81]. Front tibia with one spur, mid tibia with two spurs (av spur about 3/4 as long as pv spur), hind tibia with two spurs (av spur is about 3/4 as long as pv spur). Sensory organ on t2 not developed.

Abdomen dark-brown to black, covered with pale hairs. Terminalia ( Fig. 2 : A, B) dark-brown. Gonostylus with strongly sclerotised, blade-like subapical process and two–three strong setae near its base. Tergite 9 narrow transverse, cerci elongated ovate.

Female. (n=1). Wing length 3.18 mm. Ratio of tibia to first tarsomere for front, mid and hind legs: 1.59; 1.63; 1.8. In other respect similar to male. Terminalia as in Fig. 3 : E, F. Gonocoxite 8 elongated in lateral view, rounded apically and with several stronger setae posteriorly. Hypoproct with setae laterally, two longer ones at base. First segment of cerci in ventral view with apical margin slightly produced internally. Second segment circular in lateral view and ovate in ventral view.

Remarks. Association of females is based on co-occurrence in the emergence trap.

Distribution. Widespread in Europe; recorded from Austria, Belgium, Bulgaria, Czech Republic, Croatia, Denmark, Finland, France, Germany, Hungary, Ireland, Italy, Latvia, the Netherlands, Norway, Poland, Romania, Russia (NET), Slovakia, Sweden, Switzerland, UK, and Yugoslavia. Found also in East Palaearctic ( Chandler 2011).

Biology. Some specimens were obtained with emergence traps placed over decaying log of silver birch ( Betula pendula ) bearing fruiting bodies of polypores ( Fomes fomentarius , Phlebia tremellosa ) and wood-growing agarics ( Armillaria mellea -group), over decaying log of aspen ( Populus tremula ) bearing fruiting bodies of Ganoderma lipsiense , Trametes ochracea and Tomentella crinalis . Other material originates from Malaise trap catches and sweep netting in different types (mostly spruce dominated) of coniferous forests.

Larval microhabitats. Larvae live in slight slimy tubes on mouldy branches ( Edwards 1925) and on the edges of resupinate fruiting bodies of Hyphodontia paradoxa and H. radula where they are attached to bark and beneath loose bark ( Madwar 1937; Jakovlev 2011).

Figures

FIGURE 2. Male terminalia. A. T. sylvatica, dorsal view. B. T. sylvatica, ventral view. C. T. obirata, dorsal view. D. T. obirata, ventral view. E. T. ruuhijarvii sp. n., dorsal view. F. T. ruuhijarvii sp. n., ventral view. Scale bars = 0.2 mm. Abbreviations: ca = complementary appendage, cerc = cercus, gc = gonocoxite, gst = gonostylus, tg = tergite, sap = subapical process, 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.