Abstract
The lake minnow, Eupallasella percnurus (Pall.), has a vast distribution range which extends from Poland to the Chukchi Peninsula, Sakhalin, Hokkaido, and Korea. This area and its adjacent regions are inhabited by an array of other minnow species which are morphologically close to the lake minnow and are currently included in the genera Phoxinus and Rhynchocypris. However, their systematic relationships remain largely obscure. The vast distribution range of the species, including numerous river systems divided by many mountain ranges that provide it with a very diverse and rich hydrographic and glaciological history, favors the evolution of locally differentiated forms. As a result, five subspecies have been distinguished within the lake minnow: E. p. percnurus; E. p. stagnalis; E. p. ignatowi; E. p. mantschuricus; E. p. sachalinensis. Because of great morphological variation, their status is still the subject of debate. The most recent morphological studies suggest a separate specific status of the Volga minnow E. p. stagnalis.