Final answer:
Staurikosaurus was a theropod, a subcategory of saurischian dinosaurs, and not related to ornithischian, or “bird-hipped”, dinosaurs despite common misconceptions based on pelvic structures.
Step-by-step explanation:
Staurikosaurus is classified as a theropod dinosaur which is a subcategory of the larger group known as saurischians. Theropods are known for their bipedal stance and are best known in today’s world as the ancestors of modern birds. However, it is a common misconception that birds evolved from the ornithischian, or “bird-hipped”, dinosaurs due to the similarity in pelvic structure.
The saurischian “lizard-hipped” dinosaurs, which include theropods like Staurikosaurus, are the actual ancestors of birds. Notable for walking upright on two legs, Staurikosaurus was considered one of the first dinosaurs to exhibit this characteristic that is common among theropods, maintaining legs positioned directly under the pelvic region.