Tiaojishan Formation
Liaoning, Hebei, China
Why It Matters
The Tiaojishan Formation is renowned for preserving exceptional feathered dinosaurs and early paravians, including Yi qi with its unique bat-like membranous wings. It provides critical evidence for the diversity of flight-related experiments among Mesozoic theropods and documents the Jurassic Daohugou Biota.
How Fossils Survived
The formation consists of pyroclastic rocks, tuffs, and volcanic sediments deposited in a environment with frequent volcanic activity. The fine-grained ash deposits created exceptional preservation conditions for soft tissues, feathers, and delicate skeletal elements. Silicified layers interbedded with mudstones characterize much of the sequence.
Discovery History
The formation has been extensively studied since the early 2000s following discoveries in the Daohugou locality. Major excavations have yielded numerous specimens of pterosaurs, early mammals, and feathered dinosaurs. The discovery of scansoriopterygids including Yi qi in 2015 brought international attention to this formation.
Dinosaurs in the Vault
2 species in our database · sorted by size
Yi qi from this formation possessed a styliform bone and membrane wing structure unique among all known dinosaurs