First European record of Paramecium septaurelia and the discovery of new European habitats of P. pentaurelia and P. sexaurelia in Russia (Astrakhan and Volgograd regions).

The presence of several species of the P. aurelia complex was revealed in the studied regions. In the Volgograd region P. primaurelia, P. biaurelia, P. triaurelia, and P. novaurelia were recorded. In the Astrakhan Nature Reserve P. primaurelia, P. pentaurelia, P. sexaurelia, and P. septaurelia were identified. Among these species, P. septaurelia was recorded for the first time in Europe, known before only from the territory of the USA, P. pentaurelia and P. sexaurelia are species rare in Europe. The studied regions are very rich in species of the P. aurelia complex and worthy of future studies.