New Mega Evolved Pokémon have been revealed for Pokémon Omega Ruby and Alpha Sapphire in recent magazine reports from Japan. (Thanks, Serebii.net)
The magazine confirms Mega Evolutions for Gallade, Sharpedo and Camerupt. Mega Sharpedo has the Strong Jaw ability, while Mega Camerupt has Sheer Force.
Additionally, Primal Kyogre has a new ability called Sea of Beginnings, while Primal Groudon’s new ability is Land of Endings. They activate something called Strong Rain and Strong Sunlight respectively.
More details can be found at the Serebii link above.