Trichonta comis Gagné, 1981

Kolcsár, Levente-Péter & Salmela, Jukka, 2017, New taxonomic and faunistic records of fungus gnats (Insecta, Diptera) from Montenegro, Romania, and Serbia, Check List 13 (5), pp. 533-559 : 546-547

Trichonta comis Gagné, 1981

Gagné 1981: 17 (figs 126–128)

Material examined. Holotype male. Finland, Kuusamo , Juuma , 21 August 1964 R. Tuomikoski leg., pinned specimen, abdomen in a microvial in glycerol ( MZHF). Romania: Repedea, Maramureé Mt., wet naturally opened area in a spruce forest with fallen trees, 788 m a.s.l., 47.8867° N, 024.3904° E, 17 May 2014, Kolcsár L.-P. leg., DIPT-JS-2016-0220, 1 male. Figure 1.

Redescription of male. Head. Dark brown, vertex with numerous short pale setae. Lateral ocelli touching eye margins, median ocellus small, arranged in a shallow triangle. Ommatidia pubescent. Clypeus rounded, length/ width ratio 0.30. Face and clypeus light brown, bearing light setae. Mouthparts light brown. Palpus 5-segmented, segments yellowish brown, segments 3–5 apically

slightly infuscated. Palpal segments 2–5 bearing strong dark dorso-apical setae, their length about as long as or shorter than respective palpus width. Ratios of 3 apical palpal segments (3:4, 4:5): 0.79, 0.65. Sensilla cochle- ariformis present on base of third palpomere, arranged in a regular circular shape. Scape and pedicel yellowish brown, first flagellomere basally yellowish brown, apically darker; flagellomeres 2–14 dark brown. Scape elongated, conical, pedicel globular, their length ratio (length of scape/pedicel) 1.69. Flagellomeres cylindrical, except last one slightly conical, length/width ratios of first, second, fifth and last flagellomeres 2.72, 1.82, 2.0 and 4.1, respectively.

Thorax. Mainly brown, anterior corners of scutellum, antepronotum and proepisternum yellowish. Anepisternum with 5 or 6 strong setae and with several inconspicuous setae. Laterotergite setose, other pleural plates glabrous. Halteres yellow, stem sparsely setose.

Legs. Coxae yellowish, apically infuscated, anterior edge of fore coxa bearing several light setae. Hind coxa with a posterobasal seta and hind tibia without posteroventral and anteroventral setae. Trochanters yellowish, ventrally black. Femora yellowish, with a narrow ventral band fading toward femoral apices. Tibiae and tarsi yel- lowish. Anteroapical depressed area of fore tibia ovate, bearing a comb of circa 26 hyaline setae. Length ratios of femur to tibia for fore-, mid- and hind legs: 1.0, 0.95, 0.88. Length ratios of tibia to basitarsus for fore-, mid- and hind legs: 1.24, 1.5, 1.62.

Wing. Hyaline, length 3.2 mm. C and R veins dark brown, M1 and M2 mostly brown, CuA and M4 brown; veins r-m, first sector of M4, M1+2 and bases of M1 and M2 pale. These pale veins and Rs are also glabrous, bear- ing no stout, dark setae.

Abdomen. Brown, bearing light setae. Ninth tergite and cerci as in Figure 18. Gonocoxite dark brown, bear- ing numerous light setae ( Fig. 19); ventrocaudal margin with a very modest median elevation. Gonostylus composed of two main lobes, dorsal and ventral ( Fig. 20). Dorsal lobe ( Fig. 21) is simple, lingulate, widest medially and narrowing apically; 14 stout setae on inner surface and four setae in a row on dorsal margin. Ventral lobe is intricate, consisting of the lobe itself and median projections. Apical half of the ventral lobe of gonostylus is rectangular; caudal outer corner is angular, bearing a dense dark setosity; inner corner with a finger-like pro- jection and with a long subapical seta ( Fig. 22); caudal margin even/truncated, with rather long pale setae. One of the projections of the ventral lobe is conspicuous, erect, dark brown; its stalk is widest basally, glabrous, narrowing toward apex; the apex is a beak-like structure, having a larger, pointed tooth and a comb consisting of ca 7–10 blunt teeth ( Fig. 23). Aedeagus is rather wide, with a deep U-shaped median incision; apex truncated, rounded; caudal lateral corners with several sharp teeth ( Fig. 24).

Female. Unknown.

Biology. Immature stages of the species are unknown, but adults have often been collected from forests (see Taxon discussion below).

Taxonomic discussion. Holarctic species of the genus Trichonta were revised by Gagné (1981), and since then, 20 northern hemisphere species have been described ( Chandler 1992, 2009, Bragina 1994, Chandler and Ribeiro 1995, Wu et al. 1995; Zaitzev 2003, Hong et al. 2007). Trichonta comis is characterized by the presence of single posterobasal seta on hind coxa, absence of ventral setae on hind tibia, setosity of Cu petiole and hyaline wing lamina. In addition, the apical half of ventral lobe of gonostylus is bears a long seta. The aedeagus, not illustrated or verbally described by Gagné (1981), is also quite peculiar due to its spinose caudal corners. The type locality in Finland (Kuusamo, Juuma) is not known in detail, but is most likely within Oulanka National Park; the holotype male is the only specimen recorded from Finland. In Norway the species has been collected from both birch ( Betula ) ( Søli 1994) and spruce ( Picea ) ( Økland and Zaitzev 1997) dominated forests. The spe- cies is also known from the Czech Republic ( Ševčík 1999, collected from a virgin beech forest) and Slovakia ( Ševčík and Košel 2009b). It is new to the Romanian fauna. Trichonta comis is most likely a rare, boreo-montane forest-dwelling species, showing affinities to pristine forests. Larvae of Trichonta are predominantly associated with wood-decaying fungi (e.g., Jakovlev 2011)