Zavacephale

Zavacephale (meaning "origin head") is an extinct genus of pachycephalosaurian dinosaurs known from the Early Cretaceous Khuren Dukh Formation of Mongolia. The genus contains a single species, Zavacephale rinpoche, known from a partial articulated skeleton including a nearly complete skull. It is both the oldest definitive pachycephalosaur known, as well as the most complete. Its skull bears a well-developed dome structure, as seen in most members of the clade.

== Discovery and naming == The Zavacephale holotype specimen, MPC-D 100/1209, was discovered in 2019 outcrops of the Khuren Dukh Formation in the Eastern Gobi Basin in Dundgobi Province, Mongolia. It was subsequently accessioned at the Institute of Paleontology (Mongolian Academy of Sciences) where it was prepared over the following years. The skeleton, which was found in partial articulation, is 54% complete based on element count, making it the most complete pachycephalosaur described. The specimen includes regions of the body not scientifically described in any other pachycephalosaur, including bones of the hand, a gastrolith mass, and a complete tail covered in . The skeleton also includes a complete skull and mandible, a , , the , and most of the and hindlimbs. The fossil material was reported in conference abstracts in 2023 before its formal description.