White-shouldered whiptail

Dorsal spines (total): 10; Dorsal soft rays (total): 9; Anal spines: 3; Anal soft rays: 7. Head scales reaching forward to between level of posterior and anterior nostrils. Suborbital naked. Lower limb of preopercle with 2 or 3 scale rows. Pelvic fins moderately long, reaching to or almost to level of anus. Axillary scale present. Color: Upper body brown, white on ventral surface. This species is easily distinguished from P. trivittatus by the head scales extending forward to the nostrils, the absence of scales on the suborbital, and presence of a white bar on the upper margin of the opercle.