Super Mario World marked the point at which “Mario games” were no longer really one series, though this didn’t become obvious until much later in retrospect.
Still, the fact that its sequel was called Super Mario World 2: Yoshi’s Island rather than Super Mario Bros. 5: Yoshi’s Island should have tipped you off a bit… and if that didn’t work, then the fact that you didn’t actually play Super Mario would definitely do the job.
The “rebranding” that Yoshi’s Island ultimately underwent was a good idea though, because although having elements in common with its predecessor, it’s a distinct type of experience in its own right. And one of the best platformers on the SNES.