Dental data challenge the ubiquitous presence of Homo in the Cradle of Humankind

Clément Zanolli¹, Thomas W Davies^{2

3}, Renaud Joannes-Boyau^{4

5}, Amélie Beaudet^{6

7

8}, Laurent Bruxelles^{7

9

10}, Frikkie de Beer^{11

12}, Jakobus Hoffman¹¹, Jean-Jacques Hublin², Kudakwashe Jakata¹³, Lazarus Kgasi^{5

14}, Ottmar Kullmer^{15

16}, Roberto Macchiarelli^{17

18}, Lei Pan^{19

20}, Friedemann Schrenk^{15

16}, Frédéric Santos¹, Dominic Stratford⁷, Mirriam Tawane¹⁴, Francis Thackeray¹³, Song Xing^{19

20}, Bernhard Zipfel¹³, Matthew M Skinner^{2

3

21}

Affiliations

¹ Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, F-33600 Pessac, France.
² Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany.
³ School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NZ, United Kingdom.
⁴ Geoarchaeology and Archaeometry Research Group, Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia.
⁵ Palaeo-Research Institute, University of Johannesburg, Auckland Park 2006, South Africa.
⁶ Department of Archaeology, University of Cambridge, Cambridge CB2 1TN, United Kingdom.
⁷ School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg 2000, South Africa.
⁸ Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
⁹ UMR 5608 CNRS, TRACES, Maison de la Recherche, Université Toulouse Jean Jaurès, 31058 Toulouse Cedex 9, France.
¹⁰ INRAP, French Institute for Preventive Archaeological Researches, 30900 Nîmes, France.
¹¹ South African Nuclear Energy Corporation SOC Ltd., Pretoria 0001, South Africa.
¹² Department of Anthropology & Development Studies, University of Johannesburg, Auckland Park 2006, South Africa.
¹³ Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 2000, South Africa.
¹⁴ Ditsong National Museum of Natural History, Pretoria 0001, South Africa.
¹⁵ Department of Paleoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt 60325, Germany.
¹⁶ Department of Paleobiology and Environment, Institute of Ecology, Evolution, and Diversity, Goethe University Frankfurt, 60323 Frankfurt, Germany.
¹⁷ UMR 7194 CNRS, Muséum National d'Histoire Naturelle, 75005 Paris, France.
¹⁸ Département Géosciences, Université de Poitiers, 86000 Poitiers, France.
¹⁹ Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 100044 Beijing, China.
²⁰ Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 100044 Beijing, China.
²¹ Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg 2000, South Africa.

PMID: 35787044
PMCID: PMC9282359
DOI: 10.1073/pnas.2111212119

Dental data challenge the ubiquitous presence of Homo in the Cradle of Humankind

Clément Zanolli et al. Proc Natl Acad Sci U S A. 2022.

. 2022 Jul 12;119(28):e2111212119.

doi: 10.1073/pnas.2111212119. Epub 2022 Jul 5.

Authors

Affiliations

¹ Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, F-33600 Pessac, France.
² Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany.
³ School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NZ, United Kingdom.
⁴ Geoarchaeology and Archaeometry Research Group, Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia.
⁵ Palaeo-Research Institute, University of Johannesburg, Auckland Park 2006, South Africa.
⁶ Department of Archaeology, University of Cambridge, Cambridge CB2 1TN, United Kingdom.
⁷ School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg 2000, South Africa.
⁸ Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
⁹ UMR 5608 CNRS, TRACES, Maison de la Recherche, Université Toulouse Jean Jaurès, 31058 Toulouse Cedex 9, France.
¹⁰ INRAP, French Institute for Preventive Archaeological Researches, 30900 Nîmes, France.
¹¹ South African Nuclear Energy Corporation SOC Ltd., Pretoria 0001, South Africa.
¹² Department of Anthropology & Development Studies, University of Johannesburg, Auckland Park 2006, South Africa.
¹³ Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 2000, South Africa.
¹⁴ Ditsong National Museum of Natural History, Pretoria 0001, South Africa.
¹⁵ Department of Paleoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt 60325, Germany.
¹⁶ Department of Paleobiology and Environment, Institute of Ecology, Evolution, and Diversity, Goethe University Frankfurt, 60323 Frankfurt, Germany.
¹⁷ UMR 7194 CNRS, Muséum National d'Histoire Naturelle, 75005 Paris, France.
¹⁸ Département Géosciences, Université de Poitiers, 86000 Poitiers, France.
¹⁹ Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 100044 Beijing, China.
²⁰ Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 100044 Beijing, China.
²¹ Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg 2000, South Africa.

PMID: 35787044
PMCID: PMC9282359
DOI: 10.1073/pnas.2111212119

Abstract

The origins of Homo, as well as the diversity and biogeographic distribution of early Homo species, remain critical outstanding issues in paleoanthropology. Debates about the recognition of early Homo, first appearance dates, and taxonomic diversity within Homo are particularly important for determining the role that southern African taxa may have played in the origins of the genus. The correct identification of Homo remains also has implications for reconstructing phylogenetic relationships between species of Australopithecus and Paranthropus, and the links between early Homo species and Homo erectus. We use microcomputed tomography and landmark-free deformation-based three-dimensional geometric morphometrics to extract taxonomically informative data from the internal structure of postcanine teeth attributed to Early Pleistocene Homo in the southern African hominin-bearing sites of Sterkfontein, Swartkrans, Drimolen, and Kromdraai B. Our results indicate that, from our sample of 23 specimens, only 4 are unambiguously attributed to Homo, 3 of them coming from Swartkrans member 1 (SK 27, SK 847, and SKX 21204) and 1 from Sterkfontein (Sts 9). Three other specimens from Sterkfontein (StW 80 and 81, SE 1508, and StW 669) approximate the Homo condition in terms of overall enamel-dentine junction shape, but retain Australopithecus-like dental traits, and their generic status remains unclear. The other specimens, including SK 15, present a dominant australopith dental signature. In light of these results, previous dietary and ecological interpretations can be reevaluated, showing that the geochemical signal of one tooth from Kromdraai (KB 5223) and two from Swartkrans (SK 96 and SKX 268) is consistent with that of australopiths.

Keywords: dental structure; early Homo; geometric morphometrics; taxonomic assessment.

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Conflict of interest statement

The authors declare no competing interest.

Figures

**Fig. 1.**
The EDJ of the postcanine teeth of the purported *Homo* specimens from Swartkrans compared with those of Early Pleistocene *Homo* (KNM-ER 1590 M¹ and M², Sangiran 4 M³, and KNM-ER 992 lower postcanine teeth), *Australopithecus* (Taung M¹ and M₁, StW 183 M², StW 128 M³, StW 498 P₃, StW 104 P₄, StW 133 M₂, and StW 312 M₃), and *Paranthropus* (TM 1517 upper molars and P₃, P₄, M₁, and M₃, and SK 1 M₂). Specimens belonging to the same individual are encased by a plain line, and specimens that likely belong to the same individual are enclosed by a dotted line.

**Fig. 2.**
Bivariate plot of the bgPCA scores based on the DSM deformation fields for the M¹ (A), M² (B), and M³ (C). The totality of the variance refers to between-group variation. Symbols highlighted in bold represent the holotype specimens of *Australopithecus* (Taung) and *Paranthropus* (TM 1517). Filled triangles indicate African *Homo*, while open triangles represent Asian *Homo*.

**Fig. 3.**
Bivariate plot of the between-group principal component analysis (bgPCA) scores based on the DSM deformation fields for the P₃ (A), P₄ (B), M₁ (C), M₂ (D), and M₃ (E). The totality of the variance refers to between-group variation. Symbols highlighted in bold represent the holotype specimens of *Australopithecus* (Taung) and *Paranthropus* (TM 1517). Filled triangles indicate African *Homo*, while open triangles represent Asian *Homo*.

**Fig. 4.**
Chronostratigraphic distribution of the investigated purported *Homo* remains. In light of the results of the present study, only four specimens are likely to represent *Homo* (green ticks), four are possibly *Homo* (light green question marks), and the others more likely belong to *Australopithecus* or *Paranthropus* (red crosses).

**Fig. 5.**
Ba/Ca (A) and Sr/CA (B) ratios and elemental mapping of SK 96, KB 5223, and SKX 268 compared with the distributions of *Australopithecus* and *Paranthropus*. Asterisks denote that data for taxa distribution were calculated using a combination of new data and a previously published datasets (80, 81), with the average values of KB 5223 (triangles) and SKX 268 (crosses) extracted from Balter et al. (76). SK 96 profile analysis was realized on the enamel for this study, as well as the geochemical maps of KB 5223 and SKX 268. All error bars are 2 sigma.

See this image and copyright information in PMC

References

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Dental data challenge the ubiquitous presence of Homo in the Cradle of Humankind

Affiliations

Dental data challenge the ubiquitous presence of Homo in the Cradle of Humankind

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

Publication types

MeSH terms

LinkOut - more resources

Full Text Sources