Mario jumped from 8-bit to 16-bit with the debut of Super Mario World . His art reflected this change by actually showing off his blue overalls. The sharp lines and blocky colors of erlier generations are replaced by sublte shading. His is also given more dimension by slightly tilting he face towards the player, revealing both of his eyes.
Miyamoto had wanted to let Mario ride a dinosaur in the first game and kept the concept art taped up in his cubical for 5 years. With the hardware of the Super Nintendo Yoshi was finally able to carry mario to the goal.