Diagnosis: It differs from other known species of the genus Salmo from Morocco, except Salmo pallaryi, by the absence of spots or marks on the body; it has a lesser number of anal pterygophores, 10-11 than Salmo pallaryi, 12-14, and shorter orbital length; horizontal orbital length with respect to the head length is 16-23% of head length in Salmo viridis vs. 25-31% of head length in Salmo pallaryi (Ref. 107622). The following combination of characters are also diagnostic to Salmo viridis: vomer teeth in one row, premaxilla extended laterally, supramaxilla short and deep, dorsal fin pterygophores from 11 to 13; and one molecular autapomorphy in the MT-CYTB gene in the nucleotide position 508 (Ref. 107622).
Description: It is a large-sized species that reaches 500 mm of standard length; the caudal peduncle is more elongated, in comparison to other trout populations, and the proportion of body to least depth, with respect to caudal peduncle length, is 25.3-26.0% of caudal peduncle length in females and 23.5-27.1% of caudal peduncle length in males; the head is small, relative to the body, with head length 21.7-24.4% of standard length in females and 21.4-24.8% of standard length in males; the skull is narrow with a pointed snout; the preorbital distance is large and the proportion, with respect to head length, is 26.0-31.0% of head length in females and 21.6-34.0% of head length in males; the fourth and fifth infraorbitals are wide and extended over the hyomandibular bone (Ref. 107622). The supramaxilla is short and deep; the length of the maxilla is variable in this species and usually reaches the edge of the posterior eye orbit; the length of the maxilla, in proportion and with respect to head length is 44.4-56.3% of standard length in females and 46.5-52.8% of standard length in males; the upper jaw is narrow; the maximum height of the upper jaw, in proportion to its length, is 28.4-33.1% of upper jaw length in females and 24.6-32.2% of upper jaw length in males; the eye orbit is small, in proportion to head length, the horizontal diameter being 17.5-19.4% of head length in females and 15.6-22.8% of head length in males, and the vertical diameter being 16.4-19.8% of head length in females and 13.8-20.0% of head length in males; the vomer teeth are placed in one row and are small and thin (Ref. 107622).
Colouration: The colouration is uniformly grayish with some greenish iridizations, paler in the ventra region; the pectoral fins are slightly yellow and caudal, adipose and anal fins are greenish; no spot or marks are found, only some traces in caudal fin and dorsal skull (Ref. 107622).