Stokesosaurus

Type Species: Stokesosaurus clevelandi

Classification: Dinosauria – Saurischia – Theropoda – Tetanurae – Coelurosauria – Tyrannosauroidea – Pantyrannosauria - Stokesosauridae

Time Period: Late Jurassic 

Location: North America 

Diet: Carnivore

Stokesosaurus was a medium-sized theropod from the Late Jurassic Morrison Formation of North America. By the Cretaceous Period, tyrannosaurs would be becoming larger-than-life despite austere beginnings in the Jurassic. Stokesosaurus represents the gradual increase of size among the tyrannosaur lineage; while the earliest tyrannosaurs emerged in the Middle Jurassic small and lithe, as the Jurassic progressed they were growing larger. Stokesosaurus graduated from a small-sized predator to a medium-sized one, clocking in at ten to thirteen feet in length. A fleet-footed predator, this tyrannosaur likely hunted Morrison ornithopods such as Camptosaurus and Dryosaurus, perhaps even wrangling with an occasional stegosaur. The larger predators of its environment, such as Allosaurus and Torvosaurus, likely preyed on the much-larger sauropods. 

Aviatyrannis

Type Species: Aviatyrannis jurassica

Classification: Dinosauria – Saurischia – Theropoda – Tetanurae – Coelurosauria – Tyrannosauroidea – Pantyrannosauria 

Time Period: Late Jurassic 

Location: Europe (Portugal)

Diet: Carnivore   

The tyrannosaurs had their genesis in the Jurassic Period – the earliest being the Middle Jurassic Proceratosaurus – but these were a far cry from their giant ancestors. The tyrannosaurs of the Jurassic were small and lithe; Aviatyrannis was the size of a dog, and its name means ‘tyrant’s grandmother.’ Aviatyrannis’ bones were collected at Guimarota, an abandoned coalmine that has become famous for its Jurassic mammal fossils. During the Late Jurassic, this was a warm and dry wooded island. Other dinosaurs in the environment included sauropods, troodontids, and other small theropods such as Compsognathus.