The Tianyulong is known from one partial fossil that was found in Jianchang Country, China. The name Tianyulong comes from the Shandong Tianyu Museum of Nature where the partial fossil is currently on show. The partial fossil of the Tianyulong shows most of the skull and some of the spine and limbs and is believed to date back to the Late Jurassic Period.
The Tianyulong is classed as part of the heterodontosaurid family which is part of the ornithischia. This family is made of of small, slender dinosaurs with very long tails and prominent teeth that almost resemble tusks.
The discovery of the Tianyulong as a breakthrough as up until its discovery the only members of the heterodontosaurid family were dated back to the Early Jurassic periods in South Africa and North America.The Tianyulong is the first to be found from the Late Jurassic period and also the first to be found in China.
The partial fossil of the Tianyulong also shows what are believed to be very early, primitive ‘feathers’. The indication of primitive ‘feathers’ comes from the long rows that span the back, neck and tail of the Tianyulong, these filament structures are similar to those found on other dinosaurs that are believed to have had feathers at some point.
The ares where the primitive feathers are believed to have been are shown on the fossil above the tail, a patch at the base of the neck and a patch on the back. It is believed that had the fossil been in better condition you would be able to see that the feathers span the entire length.
The feathers of the Tianyulong are shown on the fossil as around 60mm in length and are straight and hollow.