Tianyulong

Tianyulong was a small, bipedal dinosaur discovered in the Late Jurassic Tiaojishan Formation of Liaoning, China. Measuring less than a metre in length, it belonged to the Heterodontosauridae, an archaic family of ornithischians previously known almost exclusively from much older Early Jurassic strata elsewhere. Tianyulong's discovery astonished palaeontologists because its beautifully preserved skeleton bore long, unbranched filamentous integumentary structures along its neck, back, and tail. These stiff filaments closely resembled the primitive feathers found on theropod dinosaurs, providing compelling evidence that feather-like skin coverings may have originated at the base of the dinosaur family tree before the split between saurischians and ornithischians. Equipped with distinctive tusks and grinding teeth, Tianyulong was an agile runner that likely fed on seeds, low vegetation, and possibly occasional invertebrates.

It proved that filamentous, feather-like integument was present in ornithischian dinosaurs as well as theropods.

Where and when

Tianyulong lived in the Late Jurassic, from 161 to 158 million years ago (Oxfordian age). Its remains come from China, in the Tiaojishan Formation.

The numbers

Length 0.8 m (estimates run from 0.7 to 0.8 m). Mass about 1.6 kg. Hip height about 0.25 m. That is 0.5 human-lengths, or 0.07 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Tianyulong with a bus Place on the timeline