Morphological and morphometric variations of the water frogs (genus Pelophylax) in Iran

Despitethe efforts conducted on the identification of species of the genus Pelophylaxfrom Iran, recent studies revealed that the taxonomy and identification of localpopulations within this genus havebeen still unresolved. Here, the morphological and morphometricvariations of waterfrog populations (Pelophylax) from different localitiesof Iran were studied.To assess suitable morphological andmorphometric diagnosis for taxonomic identification of the genus, 13morphological and 23morphometric charactersof 160 specimens were analyzed. Our result indicated P.cf. bedriagaeand Pelophylax sp.show cryptic variation in morphology and melanistic diversity.In water frogs, this characteris much more influenced by compatibility to special habitat, so its value is less to be considered as a taxonomic trait or key characterfor identification.However, the morphometricvariables of Pelophylax sp. are larger than P.cf. bedriagaefrom the west of Iran. Followinggeneralized Gloger's rule, a comparison of character states of 12 biological variables revealed that dorsal coloration of waterfrog populations become paler from north to south in eastern Iran,while the ventral part shows low variation in color.This pattern indicates the low selective value of ventral coloration in the viability of waterfrogsin eastern Iran. Moreover, natural selection stabilized olive coloration on the populations of waterfrogsliving in the green habitats of north Iran while compromisinglight grey and dark brown in contrasting ecosystems through the semi-desert and humid oases of south Iran viaa disruptive selection mechanism.