Zavacephale
From Greek zava meaning 'origin' or 'beginning' and kephale meaning 'head'; translates as 'origin head,' referring to its status as the oldest known pachycephalosaur
Zavacephale 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.
Diagnosis
- Premaxilla and maxilla devoid of lateral ornamentations (autapomorphy)
- Large prefrontal approximately as long as and twice as high as the anterior supraorbital (autapomorphy)
- Absence of a parietosquamosal (posterior) node row (autapomorphy)
- Ventrally deflected anterior end of the dentary with mesialmost dentary tooth reduced in size compared with remaining buccal dentition (autapomorphy)
- Long, slender, occasionally bifurcating ossified myorhabdoid tendons (autapomorphy)
- Medial shelf of ilium extends the length of the postacetabular process (autapomorphy)
Species
Zavacephale rinpoche Chinzorig et al., 2025
Type species
From the Tibetan 'rinpoche' meaning 'precious one', alluding to the domed skull found exposed in the rock outcrop, reminiscent of a cabochon gemstone.
- Holotype
- MPC-D 100/1209 , Paleontological Center, Mongolian Academy of Sciences
- Material
- Partial skull roof
- Horizon
- lower Khuren Dukh Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
- Locality
- Khuren Dukh, Dundgovi, Mongolia
References
- Chinzorig, T.; Takasaki, R.; Yoshida, J.; Tucker, R. T.; Buyantegsh, B.; Mainbayar, B.; Tsogtbaatar, K.; Zanno, L. E. (2025). A domed pachycephalosaur from the early Cretaceous of Mongolia. Nature 646(8087): 1138-1145. Springer Science and Business Media LLC. doi:10.1038/s41586-025-09213-6 chinzorig2025a