Why A.niger has been replaced by A.brasiliensis in different pharmacopoeias?

In different pharmacopoeias A.niger was mentioned as a challenge microorganisms for used in different testing like Sterility validation, MLT and Disinfectant validation etc. But recently in different pharmacopoeias A.niger has been replaced by A.brasiliensis. ATCC announced that the recent molecular and genotyping testing clearly indicates organism previously designated as A.niger ATCC no. 16404 belongs to the A.brasiliensis species and ATCC no. 16404 will remain same. Hence A.niger has been replaced with A.brasiliensis in pharmacopoeias as well. But it is not possible to differentiate A.niger from A.brasiliensis on the basis of their morphological characteristics. Both colonies look like same but with the help of advance testing at molecular and genotypic level it is possible to differentiate. 

Thanks!