Guanlongs

Guanlong is a genus of tyrannosauroid dinosaur that lived during the Late Jurassic period. The name Guanlong means "crown dragon" in Chinese, a reference to the prominent bony crest on its skull. Two species are known: Guanlong wucaii and Guanlong paradoxus. These dinosaurs were relatively small for their group, with adults reaching about 12 meters (40 feet) in length.

Fossils of Guanlong have been discovered in the Shishugou Formation of Xinjiang, China. These fossils indicate that Guanlong possessed a distinctive, thin, and hollow crest on its snout. The exact function of this crest is debated among paleontologists, with theories ranging from display purposes to thermoregulation. Guanlong also had long, three-fingered arms, which were more developed than those of later tyrannosaurs like Tyrannosaurus rex. Its teeth were serrated, suggesting it was a carnivore.

The discovery of Guanlong is significant because it represents one of the earliest known tyrannosauroids. Its features, such as the crest and the relatively long arms, provide important clues about the evolutionary development of the tyrannosaur lineage, showing a gradual transition from smaller, more agile ancestors to the giant predators of the Cretaceous period. Guanlong lived alongside other dinosaurs, including stegosaurs and other theropods.