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Research Article
Postcranial evidence of late Miocene hominin bipedalism in Chad
Franck Guy
Université de Poitiers / CNRS UMR 7262 - PALEVOPRIM Paléontologie, Evolution, Paléo-écosytèmes, Paléoprimatologie
Corresponding Author
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Terrestrial bipedal locomotion is one of the key adaptations defining the hominin clade. Evidences of undisputed bipedalism are known from postcranial remains of late Miocene hominins as soon as 6 Ma in eastern Africa. Bipedality of Sahelanthropus tchadensis was hitherto documented at 7 Ma in central Africa (Chad) by cranial evidence. Here, we present the first postcranial evidence of the locomotor behavior of the Chadian hominin with new insights on bipedalism at the early stage of our evolutionary history. The original material was discovered at locality TM 266 (Toros-Menalla fossiliferous area), and consists in one left femur and two antimeric ulnae. These new findings confirm that hominins were already terrestrial biped relatively soon after the human-chimpanzee divergence but also suggest that careful climbing arboreal behaviors was still a significant part of their locomotor repertoire.
Keywords
Terrestrial bipedal, Miocene hominins, postcranial remains
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This is a list of supplementary files associated with this preprint. Click to download.
- ExtData1.tif
Extended Data 1: Schematic Map of the Republic of Chad and localization of TM 266 locality.
- ExtData2.tif
Extended Data 2: . Illustration of the postcranial original material from Toros-Menalla, Chad. TM 266-01-063 femur: a, anterior view; b, posterior view; c, lateral view; d, medial view. TM 266-01-358 ulna: e, anterior view; f, posterior view; g, lateral view; h, medial view. TM 266- 01-050 ulna: i, anterior view; j, posterior view; k, lateral view; l, medial view.
- ExtData3.tif
Extended Data 3: Illustration and estimation of the femoral anteversion. a. view of the femur showing proximal plan; b view of the femur showing the distal plan; c, micro-CT slice showing the major axis of the diaphyseal proximal cross section; d, micro-CT slice showing the major axis of the diaphyseal distal cross section; e, superimposition of the medial and distal axes forming an angle of about 26°.
- ExtData4.tif
Extended Data 4: Comparative CSGP data for TM 266 femur and ulnae. Comparisons of the TM 266-01-50 ulna and extant hominoid values for a, Imax/Imin and b, Ix/Iy. Comparisons of the TM 266-01-063 femur and extant hominoid values for c, Imax/Imin; d, Ix/Iy and e, %CA (see methods). Circles are for means and whiskers for standard deviations.
- Supplementarynotes.docx
Supplementary Information
- SupplementaryTable1.xlsx
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This preprint is under consideration at a Nature Portfolio Journal. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Nature journals have partnered with Research Square to offer In Review, a journal-integrated preprint deposition service.
Research Article
Postcranial evidence of late Miocene hominin bipedalism in Chad
Franck Guy
Université de Poitiers / CNRS UMR 7262 - PALEVOPRIM Paléontologie, Evolution, Paléo-écosytèmes, Paléoprimatologie
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 1
Posted 10 Sep, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Terrestrial bipedal locomotion is one of the key adaptations defining the hominin clade. Evidences of undisputed bipedalism are known from postcranial remains of late Miocene hominins as soon as 6 Ma in eastern Africa. Bipedality of Sahelanthropus tchadensis was hitherto documented at 7 Ma in central Africa (Chad) by cranial evidence. Here, we present the first postcranial evidence of the locomotor behavior of the Chadian hominin with new insights on bipedalism at the early stage of our evolutionary history. The original material was discovered at locality TM 266 (Toros-Menalla fossiliferous area), and consists in one left femur and two antimeric ulnae. These new findings confirm that hominins were already terrestrial biped relatively soon after the human-chimpanzee divergence but also suggest that careful climbing arboreal behaviors was still a significant part of their locomotor repertoire.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5