Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 96. (Budapest 2004)

Glöer, P. ; Fehér, Z.: Bithynia leachii (Sheppard, 1823) and Bithynia troschelii (Paasch, 1842) in Hungary (Prosobranchia: Bithyniidae)

The height of the shell and the form of the aperture and the operculum are variable. To determine the small Bithynia troschelii (5 mm) we have to look at the flatter suture and whorls. The aperture is, even if it appears ovally rounded, slightly concave at the point of contact with the last whorl. Both taxa live in small brooks up to big lakes, but are found in shallow areas of slowly running waters, too. As far as degree of pollution of the water is concerned, Bithynia troschelii seems to be less particular than B. leachii, as we found in a dammed-up part of a river in Hamburg abundances of 1,300 individuals per m

2 coexisting with 2,680 individuals of Bithynia tentaculata per m

2 (0.25 m

2 counted and extrapolated to 1 m

2

). Both taxa prefer the lowlands, with Bithynia troschelii preferring continental climate, in contrast with Bithynia leachii that lives in maritime climates of west European sites as well (GLÖER 2002a). Distribution of the two taxa in Central Europe is considered well known, because an important gap of the distribution in Hungary could be closed now. The distribution of Bithynia leachii and B. troschelii in the Baltic region and in Eastern Europe is still unknown. DISTRIBUTION OF THE TWO SPECIES IN HUNGARY Bithynia leachii (SHEPPARD, 1823) (Fig. 18) BS - 73: Dombóvár: Szarvasd (leg. L. VÖRÖSS, 1956). BT-71: Balatonalmádi (leg. J. PODANI, 1969); Balatonalmádi: Káptalanfüred, Balaton (leg. GY. KOVÁCS, 1983); Balatonfűzfő (leg. J. PODANI, 1979). - 81: Balatonkenese (leg. K. VARGA, 1988). - 89: Komárom: W of the Monostori-erőd (leg. A. SZAKOLCZAI, 1987). - 92: Sárszentmihály: at the lignit mine (leg. FŰKÖH & KROLOPP 1982). CR-29: Mohács: Mohácsi-sz. (leg. A. GEBHARDT, 1959). CS - 18: Cece: Sárvíz (leg. I. PINTÉR, 1982). -24: Sióagárd: Sárvíz (leg. I. PINTÉR, 1984).41: Baja [in a ditch] (leg. I. PINTÉR, 1976); Baja: Ferenc-csatorna (leg. T. DOMOKOS, 1976, GY. KOVÁCS, 1971, 1976). -97: Bugac (leg. M. NEIGER, 1984). CT-01: Soponya: E of the village, Halastavak (leg. G. MAJOROS, 1984, 1985, 1987). - 10: Sárkeresztúr: Sárvíz (leg. G. MAJOROS, 1985). - 39: Esztergom: Primás-sz., Duna (leg. G. MAJOROS, 1986, 1987, L. PINTÉR, 1965). - 49: Pilismarót: Duna [fluvial drift] (leg. I. FÜRJES, 1983, L. Fürjes, 1984, 1986, 1987). - 56: Budapest ( - ); Budapest: Rákospalota, Szilas-patak (leg. E. PETRÓ, 1968). - 57: Budakalász: Luppa-sziget, Duna (leg. G. MAJOROS, 1981); Budapest: Római-part (leg. GY. KOVÁCS, 1961).-63: Ócsa (leg. HALÁSZFY, 1953, M. MOGER, 1957, O. SÁNDOR, 1956);Ócsa [alder fen] (leg. P. AGÓCSY, 1958); Ócsa: Felsőbabád (leg. G. MAJOROS, 1982, 1983, 1987, 1996, 1997, 1998, 1999); Ócsa: Mádencia, forester's hut (leg. G. MAJOROS, 1987); Ócsa: Nagy-erdő (leg. L. DRIMMER, 1990); Ócsa: Turjános (leg. G. MAJOROS, 1980, 1982). - 66: Budapest: Cinkota,