Final answer:
Ceratosaurs were not the ancestors of modern birds; that distinction belongs to the maniraptoran theropods. Distinctive fossils like Archaeopteryx provide evidence for the theropod lineage leading to birds.
Step-by-step explanation:
The statement that ceratosaurs are the predators that do not lead to the bird line is true. Ceratosaurs were a group of large predatory dinosaurs that are not directly related to the lineage that gave rise to modern birds. Instead, birds evolved from a different group of theropod dinosaurs known as maniraptoran theropods. Within the vast array of dinosaur diversity, it was specifically the maniraptoran branch of the theropod family that led to the evolution of birds. Notable intermediate fossils that showcase traits indicative of both dinosaurs and modern birds include the famous Archaeopteryx, which possessed both avian and dinosaurian characteristics such as flight feathers and a jaw with teeth respectively.