No, they weren't, and there's no evidence whatsoever saying they are fertile even if it actually did ever happen. They are so far apart genetically then they would almost certainly be sterile. And even if your far fetched theory happened to be right, there's no documented cases of black puma, only stories, as is the case with a lot of big cat rumours. So, seeing as there's no black pumas, how do you explain all these cats being black when melanism is recessive, meaning both cats need to carry that gene.