A biosystematic study of new records of the marsh frog Pelophylax ridibundus (Pallas, 1771) (Amphibia: Ranidae) from the southeast of Iran

The marsh frog, Pelophylax ridibundus, is reported from all over Iran except from the southeast and central deserts. This study provides records of 12 specimens of Pelophylax ridibundus from the easternmost extent of its range in Iran, Zabol, Sistan, and Baluchestan Province. Morphological, morphometric, and karyological characteristics of the specimens were investigated and compared with populations from other parts of Iran. Zabol specimens demonstrated 2n = 26, comprising one pair of metacentric, six pairs of submetacentric, and six pairs of subtelocentric chromosomes. Karyological results indicated Zabol specimens are the same as specimens from the central north of Iran. In addition, specimens from the southeast of Iran demonstrated a lower than average size except for tympanum and inter naris length compared with that of specimens from the north, and the northeast of Iran which may be the result of implications of Bergmann's rule due to the higher temperatures of the region.