According to genetic typing, Melvin is 75% Bernese mountain dog and 25% Great Pyrenees… (edit: nope, see below) bearing in mind that those tests often have a very tenuous connection to reality. According to me, Melvin is 35% goofball 110% great foofly snorghound. He looks just like a Berner except he’s only bi-color instead of tri-color, everywhere he should have black instead being red. I will say that I can’t identify anything that looks particularly Great Pyrenees-like in Melvin.
Edit: After extensive research, our merry band of giant-dog-ologists has determined that Melvin is most likely a purebred Bernese Mountain Dog, whose parents were both carriers of the (very unusual in Berners) ‘recessive red‘ gene. (The top part of the linked page talks about masks… scroll down to the bottom to see the discussion of ‘recessive red’). If so, this must be a vanishingly rare condition, since google does not appear to know of any other purebred Berners that look like Melvin. Pretty neat!