*5.3. Limitations*

Considering the difficulty in obtaining homologous landmarks on the cerebellum, this is still a very preliminary study. The morphological information obtained is limited, and the uncertainty of the landmarks also introduced errors, especially in the measurement of the horizontal orientation. Further studies with landmark-free methods are suggested to reduce measurement error and extract more information from the whole cerebellar surface. Also, the basilar part of the cranium is rarely well preserved in human fossils and led to the small sample size in the analysis, which also prohibited us from obtaining convincing results.

**Author Contributions:** Conceptualization, Y.Z. and X.W.; methodology, Y.Z.; software, Y.Z. and X.W.; validation, Y.Z. and X.W.; formal analysis, Y.Z.; resources, Y.Z. and X.W., data curation, Y.Z. and X.W.; writing—original draft preparation, Y.Z.; writing—review and editing, Y.Z.; visualization, Y.Z.; funding acquisition, Y.Z. and X.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the Key Laboratory of Vertebrate Evolution and Human Origins, IVPP, CAS (NO. LVEHO20005), the Strategic Priority Research Program of Chinese Academy of the Sciences (XDB26000000), and the Shandong University Humanities and Social Science Major Project (No. 19RWZD08).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data used in the study are available from the authors upon reasonable request.

**Conflicts of Interest:** The authors declare no conflict of interest.
