Gyraulus stroemi (Westerlund, 1881)

(Table 6; fig. 7 F)

Regional distribution. In collectionS examined by uS, Gyraulus stroemi waS preSent in SeVeral SampleS obtained from floodplain waterbodieS and Small lakeS of the weStern, central, and eaStern partS of the country. ThiS SpecieS haS hitherto not been recorded aS a member of the Recent malacofauna of Mongolia (See Table 1) though PopoVa (1981) found it in the Pliocene and the early PleiStocene depoSitS of WeStern Mongolia.

Extra-limital distribution. Glöer & VinarSki (2009) publiShed the re-deScription of thiS planorbid SpecieS widely diStributed in Northern ASia, northern partS of European RuSSia, and ScandinaVia. ThiS Snail iS Very common in Siberia, though there are no recordS of it from the waterbodieS of Mongolia (See Table 1).

Morphology. The preSence of wide fringe or Soft keel on the Shell periphery iS the moSt apparent diagnoStic feature of thiS planorbid (Glöer & VinarSki 2009).