Rachel, welcome to you and Jack; I looked at you photos and the first one where Jack was resting looked just like our Sergeant, whom we have just lost to Meningitis (in September).
I don't think he is a new kind of breed as all of the Boxers that we have had seemed to have different shaped muzzles, Winston our first Boxer had a very short muzzle and it was quite difficult to keep the creases clean, then Brenin had a short muzzle but not as many creases, then Sergeant had a bit longer face.