The primary way to visually distinguish between a black leopard and a jaguar is by their spots. Jaguars have rosettes (spots within spots), whereas leopards have solid spots.
How can you tell the difference between a black leopard and panther?
Black leopards and panthers are not different species. "Panther" is a general term that can refer to any of several large wild cats, including leopards, lions, tigers, and jaguars. When people refer to a "black panther," they are usually talking about a black leopard.