Whoa - I've seen the golden ones and golden-headed ones, but I did not know there is a black lion tamarin. That is beautiful.
There is a fourth as well - Black-faced (L. caissara) - sort of an inverted Golden-headed but not kept anywhere outside South America that I'm aware of. Black Lion Tamarins are one of my favourites; they're also kept at Chester, Belfast and Jersey, and a scattering of places across the rest of Europe. Also called Golden-rumped - they have a variable amount of golden fur on their backside!