3b. Four to six scales between lateral line and median dorsal spines; L1. 44-53..........................4
4a. Dorsal with blotches or spots...........................5
4b. Dorsal without spots or blotches; body uniform, silvery........P. argyreus
5a. Dorsal with black blotches on its spinous part; back ofton with largo transverse bonds........P. maculatus
5b. Dorsal with spots; body with longitudinal rows of spots or transverse bands.........P.hasta