The limestone spheroids of 'Ubeidiya: intentional imposition of symmetric geometry by early hominins?

Antoine Muller*, Deborah Barsky, Robert Sala-Ramos, Gonen Sharon, Stefania Titton, Josep Maria Vergès, Leore Grosman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Spheroids are one of the least understood lithic items yet are one of the most enduring, spanning from the Oldowan to the Middle Palaeolithic. Why and how they were made remains highly debated. We seek to address whether spheroids represent unintentional by-products of percussive tasks or if they were intentionally knapped tools with specific manufacturing goals. We apply novel three-dimensional analysis methods, including spherical harmonics and surface curvature, to 150 limestone spheroids from 'Ubeidiya (ca 1.4 Ma), presently the earliest Acheulean occurrence outside of Africa, to bring a new perspective to these enigmatic artefacts. We reconstruct the spheroid reduction sequence based on trends in their scar facets and geometry, finding that the spheroid makers at 'Ubeidiya followed a premeditated reduction strategy. During their manufacture, the spheroids do not become smoother, but they become markedly more spherical. They approach an ideal sphere, a feat that likely required skilful knapping and a preconceived goal. Acheulean bifaces are currently thought to represent the earliest evidence of hominins imposing a premeditated, symmetrical shape on stone. The intentional production of sphere-like objects at 'Ubeidiya similarly shows evidence of Acheulean hominins desiring and achieving intentional geometry and symmetry in stone.

Original languageAmerican English
Article number230671
JournalRoyal Society Open Science
Issue number9
StatePublished - 6 Sep 2023

Bibliographical note

Funding Information:
The authors are grateful for support from the Gerda Henkel Foundation (AZ 32/V/19), Lower Paleolithic Spheroids Project (LPSP). This research was supported by the Spanish Ministry of Science and Innovation through the ‘María de Maeztu’ excellence accreditation (CEX2019-000945-M), by grant no. PID2021-123092NB-C21 funded by MCIN/AEI/10.13039/501100011033 and by ‘ERDF A way of making Europe’, and the Generalitat de Catalunya Research Group ‘Human Paleoecology of the Plio-Pleistocene’ (SGR: 2021 SGR 01238 (AGAUR)). We are also grateful to the Robert W. Wilson Charitable Trust and Yad Hanadiv Foundation for their significant contributions given to L.G., without which these scientific developments would not have been possible. A.M. was funded via the Asian Sphere Program of the Hebrew University and the University of Haifa and scholarships from the Computational Archaeology Laboratory and the Institute of Archaeology of the Hebrew University. S.T. is a beneficiary of a Margarita Salas contract (Spanish System of Science, Technology and Innovation) at Universitat Rovira i Virgili (2021URV-MS-03) funded by the European Union–NextGenerationEU, the Ministry of Universities and Recovery, Transformation and Resilience Plan. Acknowledgements

Publisher Copyright:
© 2023 The Authors.


  • 'Ubeidiya‌
  • Lower Palaeolithic
  • spherical harmonics
  • spheroids
  • stone balls
  • three-dimensional lithic analysis


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