#453 - Horse to Dinosaur

Super Mario Bros. 3 developers wanted Mario to ride a horse, but the NES limitations made it impossible. The idea of a rideable partner was brought back when they were designing the world map of Super Mario World: Dinosaur Land... and Yoshi was created.

SOURCE: https://www.nintendo.co.uk/News/2017/October/Nintendo-Classic-Mini-SNES-developer-interview-Volume-5-Super-Mario-World-and-Super-Mario-World-2-Yoshi-s-Island-1290850.html