Petalomonas sphagnophila has been found for the first time in Russia from the Shichengskoe raised bog (Vologda Region). Morphology of the species is studied by means of light microscopy and illustrated by original micrographs. The data on its taxonomy, ecology and distribution are given. The name P. sphagnophila was not validly published because no type was indicated in the original publication (Christen, 1962), so we are validating the name by indicating its holotype. P. polytaphrena Skuja, nom. inval. is treated as a synonym of P. sphagnophila. Currently, thirty species of the genus Petalomonas, including P. sphagnophila, are known from Russia.