Appearance
Scorpaena jacksoniensis has 12 spines and 9 soft rays in its dorsal fin, the 4th (occasionally the 3rd) spine being the longest, There are 16–18, normally 17, fin rays in the pectoral fin. The pelvic fin base is covered in embedded cycloid scales and these are also found on the rear of the underside which has a thick skin. The lateral lacrimal spine has 2, occasionally 3, points; the forward lacrimal spine has, 1 or 2, small spiny points on its rear edge and the rear lacrimal spine has a single point and us directed forwards and downwards in juveniles and young with a standard length of less than 100 mm (3.9 in) but it is pointed either straight down or diagonally rearwards in adults. There is a ridge in the middle of the interorbital space which has no spines but there is an occipital pit and a supplementary spine on the preoperculum.

