L. Forró - É. Murai szerk.: Miscellanea Zoologica Hungarica 6. 1991 (Budapest, 1991)
Nesemann, H.: Zoogeography and composition of leech fauna of Danubian lowland rivers in the Kisalföld compared with some molluscs (Hirudinea, Gastropoda)
Basin. The species was known only from the type locality near Montpellier in France. It was never recognized in Central European rivers. Therefore we can assume a new working hypothesis of a wide Ponto-Mediterranean range. A short description of the outer morphology for the Rábca-material is given in NESEMANN (1991c). Fam. Erpobdellidae Erpobdella nigricollis (Brandes, 1900) (Fig. 10) Localities: Danube near Ásványráró (H), Dunaág, Felsősziget, km 1817. 23. Oct. 1990; Danube at Gönyü (H), km 1791.4, 23. Oct. 1990; Soroksári Duna at Dunaharaszti (H), 20. Jan. 1989, leg. FORRÓ & NESEMANN; Ráckevei Duna at Szigethalom (H), 8. Jan. 1991, leg. FORRÓ & NESEMANN; Mosoni Duna between Bocsa and Vének (H), 23. Oct. 1990; Leitha (Lajta) upstream Nickelsdorf (A), 26. Oct. 1990; Zala SE Fenékpuszta (H), 20. Jun. 1990, leg. FORRÓ & NESEMANN; Zala in the Kis-Balaton reach (H), 21. Jun. 1990, leg. NESEMANN; Rába at Győr (H), 28. Jul. 1990; Rába near Rábapatona (H), 28. Jul. 1990; Rába near Szany (H), Aug. 1990; Rába near Vág (H), Aug. 1990; Rábca near Győr (H), 19. Jan. 1991, leg. MÖSSMER & NESEMANN; March (Morava), from ten localities in the main stream between Markthof and Hohenau (A), Apr.-Aug. 1990; Thaya near Hohenau (A), Aug. 1990; Thaya near Rabensburg (A, CS), Aug. 1990; Thaya near Bernhartsthal (A, CS), 27. Oct. 1990. For further records (H) see SOÓS (1963,1967). E. nigricollis is distributed in Central and Eastern Europe. The species was found from the southern parts of Finland (KOLI 1961) to Syria (RÜCKERT 1985). Hitherto its occurrence has not been ascertained for the British Isles, the Iberian and Italian Peninsula and for Greece. E. nigricollis belongs to the Potamon (Eulimnion-) biocoenosis without exception. It is one of the most important leech species in large rivers and occurs very frequently in slowly flowing reaches. In the Danube Basin E. nigricollis has a disjunct range, the species has not occurred upstream the Moson reach and it is completely lacking from Austria. A separated colonization was detected in the Bavarian reach between Regensburg and Passau. This fact is understandable as a postglacial relict (Atlanticum) of its former distribution. Several aquatic animals show the same distribution pattern in the Danube Basin. Erpobdella testacea (Savigny, 1822) (Fig. 11) Localities: Zala SE Fenékpuszta (H), 20. Jun. 1990, leg. FORRÓ & NESEMANN; Zala in the Kis-Balaton reach (H), 21. Jun. 1990, leg. NESEMANN; March (Morava) near Schlosshof (A) in a dead-water reach, from three samples, 21. Feb., 22. and 23. Apr. 1990; March (Morava) near Sierndorf (A) in a secondary branch, 20. May 1990; Loimersdorfer Graben E Engelhartstetten (A), a small tributary of the River Russbach W Devin, Oct. 1990. For further records (YU) see MIKUSKA & GEC (1970). The species has a distribution pattern similar to that of E. nigricollis. In contrast it prefers swampy running waters with a slow velocity of flow. It is often very abundant in the shallow littoral zone of lakes. Its disjunct range of distribution includes the western Palaearctis. In some parts of the Mediterranean drainage area, E. testacea can be common locally in Potamon and Eulimnion biocoenoses of lowland rivers and lakes (CHIAUDANI & MARCHETTI 1984, JOHANSSON
