Nemotelus (Nemotelus) notatus Zetterstedt, 1842

Kahanpää, Jere, 2010, Finnish species of Nemotelus (Diptera: Stratiomyidae), with description of a new species, Zootaxa 2401, pp. 30-40 : 34

Nemotelus (Nemotelus) notatus Zetterstedt, 1842

( Figures 3 , 9 )

Material examined. Finland Al: 737Ƥ Aland (Tengström, E.J. Bonsdorff, Palmén, Mäklin); 13 Hammarland (Hellén); 535Ƥ Jomala (W. & M. Hellén, Platonoff, R. Frey, Nordman); 13 Finström (Hellén); 13 Finström, 27.VI.1922 (H. Lindberg); 232Ƥ Finström, 13.VII.1922 (R. Frey); 23 Föglö (R. Forsius); 1Ƥ Geta (B. Poppius); 1Ƥ Bomarsund (Hellén); 231Ƥ Lemland (Hellén, Nordman); 1Ƥ Lemland, 27.VI.1947 (A. Nordman); 1Ƥ Mariehamn (A. Nordman); 1Ƥ Eckerö (Hellén); 1Ƥ Eckerö, 29.VI.1953 (W. Hellén). Ab: 8310Ƥ Uusikaupunki (W. & M. Hellén); 132Ƥ Houtskari 14.VII.1947 (A. Wegelius); 13 Houtskari 9.VII.1976 (H. Silfverberg); 13 Bromarv 6642:281, 17.VI.1975 (A. Albrecht); 13 Bromarv, 25.VII.1977 (A. Albrecht). N: 2Ƥ Hanko Täcktom (R. Frey); 131Ƥ Helsinge (W. Hellén); 1Ƥ Borgå (S. Hellén).

Diagnosis. Rostrum short, triangular, tip not downcurved. Sides of rostrum with rather dense silvery hairs which obscures the black ground colour in some lights. These hairs are easily rubbed off and often missing in old or damaged specimens. Postpronotum yellow. Subnotopleural stripe considerably widened towards wing base. Fore and mid tibiae yellow or yellow-brown medially. Wing vein R4+5 forked.

3: Eyes separated with a very narrow frontal vitta (minimum separation 0.5 times the width of the anterior ocellus). Eyes with large dorsal and small ventral facets. Lower frons with a white spot which is separated from the antennal bases by a black band. T2–T3 predominantly white, T3 usually with a black central spot or triangle. Genitalia: Rozkošný (1973), Rozkošný (1983).

Ƥ: Frons with a pair of short-triangular spots. Tergites black, lateral margins yellow. Posterior margins of tergites yellow or with yellow posterolateral corners and posteromedial triangles.

Distribution. European. In Finland N. notatus is restricted to the south-western archipelago between Helsinki (24° 56' E) in the east and Uusikaupunki (60° 48' N) in the north. Most records are from the Åland islands between Finland and Sweden.

Comments. Nemotelus notatus is a halobiont with a preference for salt marshes with low vegetation. The aquatic larvae develop in shallow brackish pools and ditches ( Rozkošný 1983). There are few new Finnish records of N. notatus . This may be due to large-scale habitat loss in the last 50 years caused by eutrophication of the Baltic Sea and the cessation of grazing on salt marshes, which has allowed Phragmites communis to take over most such sites in Finland.

Figures

FIGURES 1 – 3. Nemotelus males in a) dorsal view, b) lateral view. 1. N. nigrinus Fallén. 2. N. infortunatus sp. nov. 3. N. notatus Zetterstedt.

FIGURES 7 – 9. Nemotelus females in a) dorsal view, b) lateral view. 7. N. nigrinus Fallén. 8. N. infortunatus sp. nov. 9. N. notatus Zetterstedt.