Shells of L . fragilis from the extreme south (A-D) and extreme north (E-F) parts of the studied region. (A, B) Nor-Zaisan Lake, Eastern Kazakhstan, 48° 40′ N (ZMMU). (C, D) An oxbow of the Nura River, Central Kazakhstan, 50° 40′ N, juvenile shells (MSAM). (E, F) A small waterbody in the floodplain of the Ob' River near Labytnangi Town, 66° 39′ N (MSAM). Scale bars, 5 mm.