L. Forró szerk.: Miscellanea Zoologica Hungarica 10. 1995 (Budapest, 1995)

Nesemann, H., Pöckl, M.; Wittmann, K. J.: Distribution of epigean Malacostraca in the middle and upper Danube (Hungary, Austria, Germany)

Family Corophiidae Corophium curvispinum Sars, 1895 Material: see Wittmann (1995); further records: Danube at Harta, 05. 09. 1991; Szentendrei Duna near Leányfalu, 04. 09. 1991, leg. Ofenböck, T. & H. Nesemann; Danube downstream from Hainburg, on rocky slopes, 22. 02. 1991; Danube near Stopfenreuth, 21. 02. 1991; Danube at Bad Deutsch-Altenburg, 16. 02. 1991; Danube near Regelsbrunn, 11. 02. 1991; Danube, in a side-branch at Regelsbrunn, 14. 03. 1991; Danube at Schönau, 13. 02. 1991; Danube at Mannswörth, 20. 02. 1991; Danube, in a deadwater reach Kühwörther Wasser between Schönau and Mühlleiten, 20. 10. 1990; Danube near Korneuburg, 14. 02. 1991, leg. Schay, G. & H. Nesemann; Danube at Zwentendorf, 20. 04. 1991; Danube, from numerous collecting sites between Altenwörth and Krems, 1985-1990, leg. Pöckl, M.; Danube (rkm 2111) at Mauthausen, 29. 09. 1993, leg. K. J. Wittmann; Danube upstream from Aschach, 13. 11. 1989, leg. Schwammer, H.; Danube at Schlögen, 13. 11. 1989; Danube at Engelhartszell, 14. 11. 1991 ; Danube on the Jochstein rocks near Engelhartszell, 14. 11. 1991, leg. Zerz, J. & H. Nesemann; Danube near Gaishofen, 30. 09. 1990; Danube at Aicha, 08. 1991, Danube at Wörth, 08. 1991; Danube downstream from Barbing, 01. 07. 1990; Danube, in a side-branch near Tegernheim, 30. 09. 1990; Rába at Győr, 28. 07. 1990, leg. Nesemann, H. C. curvispinum is the most widely distributed Ponto-Caspian corophiid species, which has - probably since the beginning of this century - rapidly expanded its initial area to the north and northwest. It has reached the basin of the Baltic and North Sea. At first it was found beyond the Ponto-Caspian basin and was described under the name Corophium devium Wundsch, 1912 in the vicinity of Berlin. In Belgium (Wouters 1985, D'Udekem et al. 1988) and the Netherlands (Van Der Brink et al. 1989) C. curvispinum is still spreading in a southern (Meuse) and western direction (Rhine, Schöll 1990). The occurrence of the species in England (Crawford 1937, Gledhill et al. 1976) is somewhat isolated from the populations on the continent. The population of C. curvispinum in the Danube was early noted (Unger 1918, Kothé 1968). The species was recorded as far as the German section (Vornatscher 1965, Dudich 1967) upstream to the narrow valley "Weltenburger Enge" (rkm 2415) near Kehlheim. It has been noted along all downstream sections. In the lower parts of the large Danubian tributaries Tisza, Körös (Botos et al. 1990), and Rába. Its arrival in Lake Balaton via the River Sió and its quick spreading in this basin was dated rather precisely to the early 1930s (Moon 1934, Sebestyén 1934, 1937). In our material from the middle and upper Danube, C. curvispinum was the only Corophium species, showing a very high intraspecific morphological variation. Corophium sowinskyi Martinov, which was discriminated from C. curvispinum by Straskraba (1962), has not been found in the samples, nor in the museum collections examined. In contrast to Straskraba'

s description, we assume that C. sowinskyi from the Slovakian section of the river Danube is only an ecological form of C. curvispinum. The species prefers large, slowly flowing and stagnant waters such as the lower reaches of the potamon rivers. It lives on the bottom and in the littoral zone on stones, wooden piles, aquatic macrophytes, algae, silt and sponge debris on the brickwork of locks and bridges. On these substrates it builds U-shaped tunnels made of grains of sand and excretion fluids. Under optimal conditions, densities of several hundreds or even thousands of specimens per square meter were recorded, covering the whole surface with their tubes (Schellenberg 1942, D'Udekem et al. 1988).