F.W. is supported by a Marie Skłodowska Curie Individual Fellowship (no. 795569). E. Cappellini was supported by VILLUM FONDEN (no. 17649). E.W. is supported by the Lundbeck Foundation, the Danish National Research Foundation, the Novo Nordisk Foundation, the Carlsberg Foundation, KU2016 and the Wellcome Trust. Without the effort of the members of the Atapuerca research team during fieldwork, this work would have not been possible; we make a special mention of J. Rosell, who supervises the excavation of the TD6 level. The research of the Atapuerca project has been supported by the Dirección General de Investigación of the Ministerio de Ciencia, Innovación y Universidades (grant numbers PGC2018-093925-B-C31, C32, and C33); field seasons are supported by the Consejería de Cultura y Turismo of the Junta de Castilla y León and the Fundación Atapuerca. We acknowledge The Leakey Foundation through the personal support of G. Getty (2013) and D. Crook (2014–2016, 2018, and 2019) to M.M.-T., as well as F.W. (2017). Restoration and conservation work on the material have been carried out by P. Fernández-Colón and E. Lacasa from the Conservation and Restoration Area of CENIEH-ICTS and L. López-Polín from IPHES. The picture of the specimen ATD6-92 was made by M. Modesto-Mata. E. Cappellini, J.C., J.V.O. and P. Gutenbrunner are supported by the Marie Skłodowska-Curie European Training Network (ETN) TEMPERA, a project funded by the European Union’s Framework Program for Research and Innovation Horizon 2020 (grant agreement no. 722606). Amino acid analyses were undertaken thanks to the Leverhulme Trust (PLP-2012-116) and NERC (NE/K500987/1). T.M.-B. is supported by BFU2017-86471-P (MINECO/FEDER, UE), U01 MH106874 grant, Howard Hughes International Early Career, Obra Social ‘La Caixa’ and Secretaria d’Universitats i Recerca and CERCA Programme del Departament d’Economia i Coneixement de la Generalitat de Catalunya (GRC 2017 SGR 880). C.L.-F. is supported by a FEDER-MINECO grant (PGC2018-095931-B-100). M.K. was supported by the Postdoctoral Junior Leader Fellowship Programme from ‘la Caixa’ Banking Foundation (LCF/BQ/PR19/11700002). M.M. is supported by the Danish National Research Foundation award PROTEIOS (DNRF128). Work at the Novo Nordisk Foundation Center for Protein Research is funded in part by a donation from the Novo Nordisk Foundation (grant number NNF14CC0001). The CRG/UPF Proteomics Unit is part of the Spanish Infrastructure for Omics Technologies (ICTS OmicsTech) and it is a member of the ProteoRed PRB3 consortium, which is supported by grant PT17/0019 of the PE I+D+i 2013-2016 from the Instituto de Salud Carlos III (ISCIII) and ERDF. We acknowledge support from the Spanish Ministry of Science, Innovation and Universities, ‘Centro de Excelencia Severo Ochoa 2013-2017’, SEV-2012-0208, and ‘Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya’ (2017SGR595). D.L. and A.M. are supported by the John Templeton Foundation (no. 52935) and by the Shota Rustaveli National Science Foundation of Georgia (no. FR-18-27262). We thank M. L. Schjellerup Jørkov for providing specimen Ø1952.