1a.Dorsal spine 9-1 , soft dorsal raye 23-26: depth 2.5-2.7; Striped in young, spotted or uniform in old Specinens......P.pictus 1b.Dorsal spines 11-15, soft dorsal 15-22..........2
2a. Dorsal spines.14, soft dorsal 15-16;depth 1.9-2.2; scales in lateral line 51-53.........P.crassispina. 2b. Dorsal spinos 11-13; soft dorsal 18-22, dopth 2.5-3.0..3 3a. Body uniform grey or olive-grey; D. XI-XII, 18-21...P.griseus 3b. Body with white patches or light longitudinal bands. .......4 4a. Scales in lateral line 58-69; body with white patches and irregular dark bands in young, brown spots in adult. ..................................I.chaetodonoides 4b. Scales in lateral line 85-90; body with light longitudinal banda, 4 in young, 6 or moro in adults; caudal striped or spotted. ...................P. linentus