Diagnosis: width (as percentage of length) of occipital process 75-114% (average 93%); depth (as percentage of width) of premaxillary tooth plate 19-36% (average 26%); vomerine teeth absent or exceptionally present as isolated teeth (mature males have a small vomerine tooth plate), palatine teeth absent (Ref. 81642).

Description: within the subgenus Chrysobagrus, C. longidorsalis has an acute, pointed snout and a relatively small mouth with premaxillary toothband 14-20% (generally 16.6%) HL; occipital process very broad (base length 5-7.5 times in HL); in 60% of specimens examined vomerine dentition was lacking, and in remaining 40% it was represented only by a few isolated teeth; palatine dentition always lacking; species, as its name suggests, also characterized by its high dorsal fin (33-66% SL) and long caudal fin (upper lobe 30-70% SL); remarkably, C. nigrodigitatus of the same locality (middle Sanaga and Nachtigal Falls) show a similar phenotype; anal fin with 4 soft branched rays and 8-9 unbranched rays; the single ripe male examined differs little from immature males but its vomerine dentition is far more developed and is in the form of a small tooth plate (Ref. 81642).

Coloration: rather uniform; in preservation head and dorsum dark brown, ventrum creamy white (Ref. 81642).