Diagnosis.—Synodontis woleuensis can be distinguished from all congeners by the combination of well developed serrations on the anterior margin of the dorsal spine and a distinctive pigmentation pattern. Its unique pigmentation is characterized by: 1) a variable pattern and number of light, cream colored spots—irregular in size and shape, but always smaller than the orbit diameter—distributed over a largely uniform dark brown upper body and over a more lightly pigmented ventral surface, and 2) a narrow, depigmented, curved band along the entire anterior margin of the caudal fin. While the position and number of light spots on the body is variable, one spot always occurs on the dorsum at the origin of the adipose fin and another at the terminus of this fin. Synodontis woleuensis differs markedly in its pigmentation from the two other species of Synodontis in West Central Africa that possess an anteriorly serrated dorsal spine: S. batesii Boulenger 1907 and S. albolineata Pellegrin 1924. In these species, pigmentation on the ventral surface is as dark or darker than the sides and dorsal surface of the body, not lighter as in S. woleuensis. Synodontis albolineata has a prominent white band overlaying the lateral line and head and flanks are characterized by irregular small dark brown spots and blotches over a lighter brown background. Synodontis batesii in contrast has three broad, irregular dark brown bands along its flanks: the first below the dorsal fin, the second below the adipose fin and the third in advance of the caudal fin and elsewhere irregular dark brown blotches superimposed over a light brown background. Synodontis batesii and S. albolineata have neither the spotted pattern of S. woleuensis, nor the depigmented curved band at the anter- ior margin of the caudal fin.