Yinlong
| Key | Value |
|---|---|
| Name Meaning | “hidden dragon” |
| Location | China (Xinjiang) |
| Time Period | c. 158 million years ago (Late Jurassic) |
| Length | 4 ft (1.2 m) |
| Weight | 22 lb (10 kg) |
| Locomotion | Biped |
| Diet | Herbivore |
| Described | 2006 (Xu et al.) |
| Geological Formation(s) | Shishugou |
| Valid Species | Yinlong downsi (type) |
Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Cerapoda > Marginocephalia > Ceratopsia > Chaoyangsauridae
Overview: Long before the enormous Triceratops roamed North America in the Late Cretaceous, its tiny ancestors did the same in Asia. Yinlong, while perhaps not a direct ancestor of Triceratops and its kin, is a prime example of an early ceratopsian dinosaur. Ceratopsians first appear in the fossil record only a few million years prior to Yinlong, near the start of the Late Jurassic. At that time, most were only around a meter long. They were bipeds, with quadrupedal locomotion only appearing among the ceratopsians in the Late Cretaceous. Later quadrupedal ceratopsians, such as Triceratops, often had gigantic heads sporting prominent bony frills, spikes and horns. Yinlong had the beginnings of a frill, taking the form of a ridge of bone along the back of its head, but had a tiny skull and entirely lacked horns. Both early and later ceratopsians possessed prominent beaks. Lacking any form of armor or actual horns, the only real defense this dinosaur possessed was said beak.
Phylogenetic studies usually classify Yinlong as a member of the family Chaoyangsauridae, named for the genus Chaoyangsaurus. Chaoyangsaurids are only known from China, with ceratopsians most likely having first evolved in central or eastern Asia. They would remain very successful in the region, though they would also migrate into North America and probably to Europe, though they don’t appear to have found much success in the southern hemisphere. Yinlong was probably a mostly or entirely herbivorous animal, though insects may’ve made up part of its diet. It retained teeth towards the front of its jaws, which the most derived ceratopsian dinosaurs lacked. Remains are known from the Shishugou Formation, in the Xinjiang region of western China. Described as a new genus in 2006, the generic name of Yinlong, meaning “hidden dragon” in Mandarin, refers to it having been discovered near to where the movie Crouching Tiger, Hidden Dragon was filmed.