Tanytarsus brundini Lindeberg 1963

Tanytarsus brundini Lindeberg, 1963

(Figs 1, 5–9, 19, 22, 25)

Tanytarsus (Tanytarsus) curticornis Kieffer, 1911: Edwards 1929: 415 (partim). Tanytarsus brundini Lindeberg, 1963: 127; Reiss & Fittkau 1971: 98.

Material examined. FINLAND. Hietanen near Peranka, 2 August 2002, 6 males, W. Giłka. Inari,

Vuopajanniemi, 28 July 2002, 1 male, 4 August 2003, 12 males, W. Giłka. Jänisjärvi near Näätämö, 26 July 2002, 1 male, W. Giłka. Korettoja on Utsjoki river, 26 July 2003, 1 male, W. Giłka. Kotka, Santalahti, 5 August 2002, 6 males, W. Giłka. Olhava near Oulu, Bothnian Gulf, 13 July 2002, 4 males, W. Giłka. Päijänne, 27 May 2003, 1 male, L. Paasivirta. Supru, Kuosnajärvi, 26 July 2002, 6 males, W. Giłka. Tervola on Kemijoki river, 13 July 2002, 1 male, 22 July 2003, 5 males, 19 July 2006, 4 males, W. Giłka. Vesijärvi near Lahti, 11 July 2002, 1 male, W. Giłka. SWEDEN. Bureå, Skelleftebukten, Bothnian Gulf, 9 August 2003, 11 males, W. Giłka. Ljusnan river, 10 km E of Sveg, 19 July 2003, 2 males, W. Giłka. Sikeå, Bothnian Gulf, 20 August 2004, 3 males, W. Giłka.

Diagnostic description. Adult male (measurements in Table).

Ground colour of thorax, scutellum, haltere, legs and abdomen green to brownish green; antennal pedicel, tentorium, scutal stripes, postnotum and sternum brown to dark brown or black (rarely light brown or orange in freshly emerged specimens); wing membrane pale, greenish, with C, M and radial veins somewhat darker, olive. Frontal tubercles usually absent or present as tiny swellings. Third palpomere shorter than fourth. Wing membrane below veins M and R4+5, including almost entire area under M3+4, Cu1 and An covered with macrotrichia; very short proximal section of R4+5 and 1/3 part of Cu and neighbouring false veins bare (Fig. 1).

Gonostylus with slight narrowing distally. Anal tergite with pair of median setae. Basilateral setae absent. Anal point stout, armed with 4–7 (usually 4 or 5) spinulae, usually with lanceolate apical expansion (Figs 5– 9). Superior volsella with enlarged anterolateral part and posteromedian lobe, median margin concave. Pearshaped apical lobe of digitus relatively small in comparison with stout superior volsella, bearing narrow conical tip (Fig. 19). Inner margin of coxite above median volsella distinctly concave (Fig. 22). Inferior volsella slender, apically rounded, slightly wrinkled on its dorsomedian surface (Fig. 25).

Discussion. Lindeberg (1963) considered adult males of Tanytarsus brundini and T. curticornis as very similar based on their hypopygial structure. The male of Tanytarsus brundini (1) can be easily distinguished from those of T. curticornis (2) and T. salmelai (3) by the combination of characters presented below.

At least one pair of median setae on the anal tergite present (1, 3) or median setae absent (2). Basilateral setae absent (1, 3) or single strong seta on each side of the anal tergite present (2). Anal point slightly lanceolate, usually with 4 or 5 spinulae (1), anal point broadly rounded or slightly cut apically, usually with 7 or 8 spinulae (2) or anal point distinctly narrowed and strongly elongated, usually with 4 spinulae (3) (Figs 5– 9, 10–14, 15–18 respectively). Superior volsella concave (1) or transversally cut (2, 3) (Figs 19–21). Pearshaped lobe of digitus with narrow conical tip, relatively small in comparison with superior volsella (1, 3) or pear-shaped lobe of digitus roundish, relatively stout in comparison with superior volsella (2) (Figs 19–21). Inner margin of coxite above median volsella distinctly concave (1), straight (2) or slightly concave (3) (Figs 22–24).

The shape of inferior volsellae of the species compared is also distinct when the structures are examined in properly mounted specimens (Figs 25–27). The wing of Tanytarsus salmelai has a distinct shape, colouration and chaetotaxy (Fig. 3), whereas the wings of T. brundini and T. curticornis are very similar (Figs 1 and 2). Slight differences can be observed in the chaetotaxy, i.e. the number of macrotrichia in cells under M3+4, Cu1, An and on veins R4+5, Cu and neighbouring false veins (higher number in T. brundini). For differences in measurable characters of males Tanytarsus brundini Lindeberg, T. curticornis Kieffer and T. salmelai, see Table.

In addition, Lindeberg (l.c.) based his separation of Tanytarsus brundini and T. curticornis on observations of their swarming behaviour. We confirm that swarms containing both species appear rarely. Only one sample collected at Vesijärvi contained specimens of both species flying together in a large swarm consisting of several tanytarsine species.