The third pattern, found in B. melanurus, has the caudal fin completely dark. The coloration pattern is useful for separating species, but apparently does not allow inferences about phylogenetic relationships to be safely made, since this character is widespread in this family.
The third pattern, observed in B. melanurus, comprises a completely dark tail fin. The coloration pattern proves helpful in distinguishing species; nonetheless, it fails to provide a sound basis for drawing conclusions regarding evolutionary ties, as this characteristic is widespread within the family.