The animal that we know as a black panther is actually a leopard! In fact, Wikipedia states that the black panthers found in Asia and Africa belong to the species known Panthera pardus (leopards), while the ones from the Americas are Panthera onca (jaguars).
It’s quite common to find melanism in leopards. 11% of them are black thanks to the presence of melanism, and the distribution is not as random as you may think. Melanism occurs in five subspecies, including Javan leopard, African leopard, Indian leopard, Indochinese leopard and Sri Lankan leopard.
Some leopards are born with pseudo-melanism. They have a normal background color but have denser spots so they look golden-brownish.