He looks like a Presa they are one of 4 breeds that don't have a DNA profile http://en.wikipedia.org/wiki/Presa_Canario They have been revived since the 70's with foreign blood the 12% would probable be the parent breed the Majorero here is the profile on this site http://molosserdogs.com/e107_plugins/content/content.php?content.857. Looks like a fine dog with training he should work out I'd keep them separate for the first few hours let everybody cool off a kennel would be good they can sniff with little worry of the big dog stepping on the little one, I did this when we got a small puppy I locked the big pup up to mellow her first they are great together. I would take the Presa for a good walk near your house and in your yard first best of luck.