Nanger dama dama looks quite like ruficollis (and as such lacks the red mask typical to mhorr like is the case in this picture), except that the rufous area extends to the leg and that the shape of the white spot on their neck is different and smaller than on ruficollis. (see Klaus Rudloff's pictures on zootierliste or one of the drawings in the very interesting papers written by Royal Zoological Society of Scotland which I can't find anything about anymore except for a preview where you can see said drawing in the this link: speech bubbles)
This is definitely a beautiful individual though with odd face markings.
