Is uniquely diagnosed by the W-shaped lateral marks on the body, which are formed by a concentration of melanophores in three scales of the lateral and two adjacent scales of the series situated immediately below. Is also distinguished from other species of Characidium from southern Brazil in having 12 series of scales around the caudal peduncle (14 in C. pterostictum), complete lateral line (incomplete in C. rachovii), 37-38 lateral scales (36 or fewer in C. orientale and C. occidentale); and lack of oblique bars below lateral line (10-14 such bars present in C. serrano).