Theropods are the third largest dinosaurs although there were small ones. Only Ornithopod family and the Sauropodomorpha members were even bigger. The smallest theropod ever is the Bee Humming Bird but the smallest nonavian known was said to be Anchiornis which grew 13 inches although recently smaller theropods have been found. While this Spinosaurus Giganotosaurus, and a few other gigantic theropods. were the largest for now. However we might never known which was the smallest or which was the largest theropod. There were some giant theropods. For example in Argentina a giant Femur belonging to a Carnosaurian was found. However, an exact estimate was not said.