RT Journal Article T1 Fossil ribcages of Homo sapiens provide new insights into modern human evolution A1 López Rey, José M. A1 Crevecoeur, Isabelle A1 May, Hila A1 Nadel, Dani A1 Palancar, Carlos A. A1 Gómez Recio, Marta A1 García Martínez, Daniel A1 Bastir, Markus AB Recent research on the Nariokotome Boy’s ribcage suggests the slender thorax of modern H. sapiens is a derived condition. However, since digital ribcage reconstructions of fossil H. sapiens are not available yet, it is unknown whether these individuals would have had a primitive or derived thorax. To address this issue, we first reconstructed the ribcages of Nazlet Khater 2, Ohalo II H2, Dolní Věstonice 13, and Ötzi. We used geometric morphometrics to compare them to 59 recent H. sapiens and three other Homo fossils (Nariokotome Boy, Kebara 2, Shanidar 3). Fossil H. sapiens ribcages exhibit the typical globular proportions of recent humans. Additionally, size and shape seem to be climate-dependent: smaller, cylindrical ribcages in warmer and more temperate climates (Nazlet Khater 2, Ohalo II H2) contrasted with larger, broader ribcages in colder climates (Dolní Věstonice 13). The ribcage of Ötzi presented mixed features, something that could have been beneficial for seasonal alpine transhumance. This suggests H. sapiens ribcage morphology encompasses both slender and stockier forms, highlighting that human anatomical variation might be more complex and context-dependent than previously thought. PB Springer SN 2399-3642 YR 2025 FD 2025-07 LK https://hdl.handle.net/20.500.14352/123553 UL https://hdl.handle.net/20.500.14352/123553 LA eng NO López-Rey, J.M., Crevecoeur, I., May, H. et al. Fossil ribcages of Homo sapiens provide new insights into modern human evolution. Commun Biol 8, 1038 (2025). https://doi.org/10.1038/s42003-025-08472-3 NO Regarding funding information, grant PRE2021-097584 to JMLR and grant PID2020-115854GB-I00 to MB are funded by MCIN/AEI/10.13039/501100011033 of the Spanish Ministry of Science and Innovation and the European Union. The work of DGM is carried out at the R&D Unit Center for Functional Ecology - Science for People and the Planet (CFE), with reference UIDB/04004/2020, financed by FCT/MCTES through national funds (PIDDAC) (DOI 10.54499/UIDB/04004/2020). NO Ministerio de Ciencia, Innovación y Universidades (España) NO European Commission NO Fundação para a Ciência e Tecnologia (Portugal) DS Docta Complutense RD 7 sept 2025