Skeletal muscle was investigated by SDS-PAGE protein electrophoresis for western versus eastern Turkish populations of the newt Ommatotriton ophryticus. The number of protein bands resolved was 25 in the west and 26 in the east. The modal number of trunk vertebrae was also compared among 10 populations of the eastern group (Artvin, Trabzon, Giresun, and Ordu) and 3 populations of the western group (Zonguldak, Bartin, and Karabuk). The eastern group had 13 vertebrae except Sinik (Trabzon) specimens, which had 14 vertebrae, whereas the western group had 12 vertebrae. These data supported the recognition of 2 taxa that would correspond to O. o. nesterovi in the west O. o. ophryticus in the east.