The First Record of the Pool Frog (<i>Pelophylax lessonae</i>) in St. Petersburg (Russia)

An isolated population of Pelophylax lessonae was first identified in St. Petersburg. The population occupies a fairly small area (~2.0 × 1.5 km). It is located approximately 100 km north of the species’ range boundary and is one of the northernmost in Russia. The origin of the population is unclear. Apparently, the pool frog was recently introduced from more southern parts of its range. Since the pool frog is very vulnerable here, we recommend adding the species to the Red Data Book of St. Petersburg.