Gyraulus kruglowiae (Johansen, 1937)

(Table 6, figS. 7 B, C)

Regional distribution. We identified SeVeral tenS of empty ShellS from the Tolbo Nuur Lake, WeStern Mongolia (29.03.1981, leg. D. ZhaltSanoVa) aS belonging to Gyraulus kruglowiae . PopoVa (1981) diScoVered thiS SpecieS in the PleiStocene depoSitS of the Darkhad depreSSion ( Northern Mongolia).

Extra-limital distribution. JohanSen (1937) deScribed thiS SpecieS from the Ten’ga Lake Situated in the RuSSian part of the Altai MtS. A Sample of ShellS of thiS SpecieS collected by JohanSen from the type locality and kept in ZMMU waS alSo examined by uS (See fig. 7 B). ItS nomenclatorial StatuS iS unclear (probable SyntypeS). We haVe to StreSS that the Tolbo Nuur Lake lieS in the Mongolian part of the Altai MtS. not Very far from the type locality of G. kruglowiae .

Morphology. G. kruglowiae can be diStinguiShed from the reSt of Gyraulus SpecieS by itS Very prominent Spiral Sculpture that iS repreSented by low rough ribS (See fig. 7 C). Some authorS (Zhadin 1952; Meier-Brook 1983) do not accept it aS a Valid SpecieS.