Scientific name for the Ursus maritimus tyrannus?

I am not sure but I can give you the size. It was much larger than the Short Faced Bear. Even though it was 2000 lb(909 kg)it rarely exceeded 1200 lb(545 kg),stood 6 feet tall(but 5.6 feet at shoulder), and was 10.5 feet long even modern day Polar Bear was longer and a bit heavier(besides 2000 lb).Ursus Maritimus Tyrannus was 6 feet tall and the shoulder,was 13 feet long and a weigh of up to 3300 lb(1 ton 500 kg). It was the Largest Mammal Carnivore to walk earth