Statistical comparison of morphometrical data and study of external characters of an important series of specimens allow to confirm the validity of Ptychadena pujoli and Ptychadena arnei. The two species are compared to Ptychadena stenocephala, Ptychadena ingeri and Ptychadena tournieri, three species with which they form a group of Ptychadena with small webbing, sacral folds on the back and tubercles on the feet, the Ptychadena stenocephala group. Intraspecific variation of Ptychadena tournieri is studied and a key is proposed for this group of sibling species.
Ptychadena arnei, Ptychadena pujoli, Ptychadena tournieri, Ptychadena stenocephala, geographic variation, morphometry, western Africa.