Tianyulong

Lore & Background

Tianyulong confucius was first named and described in 2006 by Xiao-Ting Zheng and colleagues based on a single fossil (holotype STMN 26-3) consisting of most of the skull and skeleton. Despite being privately collected with uncertain stratigraphic and geographic origins, it was initially placed as coming from the Early Cretaceous Jehol Group. The species name honors Confucius, the founder of Confucianism. The specimen was prepared by Y.-Q. Zhang at the Shandong Tianyu Museum of Nature. Five additional specimens are known, all privately collected; four are undescribed at the STMN, and a fifth (IVPP V17090) was described in 2009 by Zheng et al. Evaluation of the locality Yaolugou questioned the Early Cretaceous age; uranium-lead dating of volcanic rocks overlying the Tianyulong horizon gave an age of 158.5 ± 1.6 million years, placing it in the Late Jurassic (Oxfordian) and correlating it with the Daohugou Biota and Tiaojishan Formation.

Reader's Guide

Tianyulong is significant primarily for its filamentous integumentary structures, preserved on the back, tail, and neck. These hollow, unbranched filaments are similar to protofeathers found in theropods like Sinosauropteryx and Beipiaosaurus, but also resemble structures on the tail of the ornithischian Psittacosaurus. The discovery extends the presence of such dermal structures beyond theropods into ornithischians, raising the possibility that the common ancestor of all dinosaurs may have been covered in feather-like structures. However, homology between ornithischian filaments and theropod protofeathers is not obvious; they may have evolved independently. A study in Biology Letters tested the hypothesis and supported that scales are plesiomorphic to dinosaurs, not protofeathers. Tianyulong also provides insight into heterodontosaurid diversity, being one of the youngest and only Asian members of the group, and its re-dated Middle Jurassic age places it among the Daohugou Biota alongside Anchiornis and Darwinopterus.

Did You Know?

• Tianyulong is named after the Shandong Tianyu Museum of Nature, where the holotype is housed.
• The species name confucius honors Confucius, the founder of Confucianism.
• The holotype specimen is missing the rear portion of the skull, middle to end of the tail, and parts of the forelimb and hindlimb.
• Uranium-lead dating of volcanic rocks above the Tianyulong horizon gave an age of 158.5 ± 1.6 million years, re-dating it from the Early Cretaceous to the Late Jurassic (Oxfordian).