Mousersaurus Rex

The Mousersaurus Rex, stomping through a jungle.

Mousersaurus Rex is a giant red dinosaur that appeared in the animated segment of The Super Mario Bros. Super Show! episode "Quest for Pizza / The Painting". This dinosaur has sunglasses like Mouser and resembles him. He helps Alley Koop throughout the episode. Although he is big and powerful, he is unable to speak. Additionally, his foot keeps getting hurt.

It's very, very possible they are a species; however, only one was seen in the cartoon.