Family Valvatidae Gray, 1840

The diVerSity of ValVatid SnailS in Mongolia iS rather low. On the baSiS of their conchological featureS, they may be placed into two Separate groupS. One of them includeS SpecieS with prominent radial ribS on Shell Surface. ThiS group correSpondS to the SubgenuS Valvata ( Sibirovalvata StarobogatoV et Streletzkaja, 1967) widely diStributed in Northern ASia and the RuSSian Far EaSt (ProzoroVa & StarobogatoV 1998; SitnikoVa et al. 2015). The Second group includeS ValVatidS with almoSt Smooth or weakly Sculptured Shell Surface. TheSe SnailS demonStrate clear affinity with a European-WeSt-Siberian group of SpecieS that iS uSually treated aS a large polymorphic SpecieS Valvata piscinalis (O.F. Müller, 1774) S. lato (Glöer 2002) or aS a complex of nearly 10 cloSely allied SpecieS (StarobogatoV et al. 2004).