Supposed to be Harlequin Great Dane. Looks like a mastiff might've jumped the fence a generation or two back, though. I actually like his build better than the standard Harlequin.
What the fuck? Why on earth is it only like a third of the wheel?! and why is it on the tire too?! what happens if you get new tires? or the tire spins a little? AND THE LINE ON THE OUTSIDE DOESNT EVEN LINE UP WITH HOW FAR IT GOES DOWN THE SPOKE?!!??!
Harlequin is just a color or marking, same as fawn, brindle, mantle or boston, blue, black, etc. There is a difference between the Europe breed and US, some of the Euros have been re-introduced in the US. This is noted by the droopier jowls and thicker head. The dane is basically a cross between the mastiff and greyhound, as you noted.