He's cute. He looks purebred to me. A lot of the time with Berners, and other breeds really, they can be below or above the accepted weight and size range. It simply means they will be a tad smaller than average. Most of the time, they are perfectly healthy in every other way. With a giant breed like Berners, being on the smaller side is not a bad thing. Less food
. For reference, I know a purebred female Great Dane who is 100 pounds healthy weight.