Why is R35 not a skyline?

Why is R35 not a skyline?

Every Skyline GT-R is wider than each corresponding regular Skyline, and each from R32 to R34 has a different front bumper. ... The R35 GT-R is not based on the Skyline body of the same year, therefore it is not “just” the highest trim level of the Skyline range, and is instead its own model.