The tall and narrow body shape of anatomically modern humans (Homo sapiens) evolved via changes in the thorax, pelvis and limbs. It is debated, however, whether these modifications first evolved together in African Homo erectus, or whether H. erectus had a more primitive body shape that was distinct from both the more ape-like Australopithecus species and H. sapiens. Here we present the first quantitative three-dimensional reconstruction of the thorax of the juvenile H. erectus skeleton, KNM-WT 15000, from Nariokotome, Kenya, along with its estimated adult rib cage, for comparison with H. sapiens and the Kebara 2 Neanderthal. Our three-dimensional reconstruction demonstrates a short, mediolaterally wide and anteroposteriorly deep thorax in KNM-WT 15000 that differs considerably from the much shallower thorax of H. sapiens, pointing to a recent evolutionary origin of fully modern human body shape. The large respiratory capacity of KNM-WT 15000 is compatible with the relatively stocky, more primitive, body shape of H. erectus.
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Computed tomography scans of fossil material from the KNM-WT 15000 skeleton and the 3D models derived from them are the property of the National Museums of Kenya, to whom application must be made for access. The CT data for modern human thoraces cannot be shared, for ethical and legal reasons related to the protocols of the hospitals and hosting institutions. Interested readers should contact the authors, who will assist in getting in touch with the relevant institutions. All other data and linear measurements of fossil reconstructions are provided within the manuscript and Supplementary information.
Walker, A. & Leakey, R. in The Nariokotome Homo erectus Skeleton (eds Walker, A. & Leakey, R.) 95–160 (Harvard Univ. Press, 1993).
Ruff, C. & Walker, A. in The Nariokotome Homo erectus Skeleton (eds Walker, A. & Leakey, R.) 234–265 (Harvard Univ. Press, 1993).
Jellema, L. M., Latimer, B. & Walker, A. in The Nariokotome Homo erectus Skeleton (eds Walker, A. & Leakey, R.) 294–325 (Harvard Univ. Press, 1993).
Holliday, T. W. Body size, body shape, and the circumscription of the genus Homo. Curr. Anthropol. 53, S330–S345 (2012).
Antón, S. C., Leonard, W. R. & Robertson, M. L. An ecomorphological model of the initial hominid dispersal from Africa. J. Hum. Evol. 43, 773–785 (2002).
Bramble, D. M. & Lieberman, D. E. Endurance running and the evolution of Homo. Nature 432, 345–352 (2004).
Pontzer, H. Economy and endurance in human evolution. Curr. Biol. 27, R613–R621 (2017).
Carrier, D. R. et al. The energetic paradox of human running and hominid evolution [and Comments and Reply]. Curr. Anthropol. 25, 483–495 (1984).
Lordkipanidze, D. et al. Postcranial evidence from early Homo from Dmanisi, Georgia. Nature 449, 305–310 (2007).
Braun, D. R. et al. Oldowan behavior and raw material transport: perspectives from the Kanjera Formation. J. Archaeol. Sci. 35, 2329–2345 (2008).
Arsuaga, J. L. et al. A complete human pelvis from the middle Pleistocene of Spain. Nature 399, 255–258 (1999).
Simpson, S. W. et al. A female Homo erectus pelvis from Gona, Ethiopia. Science 322, 1089–1092 (2008).
Rosenberg, K. R., Zuné, L. & Ruff, C. B. Body size, body proportions, and encephalization in a Middle Pleistocene archaic human from northern China. Proc. Natl Acad. Sci. USA 103, 3552–3556 (2006).
Bonmatí, A. et al. Middle Pleistocene lower back and pelvis from an aged human individual from the Sima de los Huesos site, Spain. Proc. Natl Acad. Sci. USA 107, 18386–18391 (2010).
Arsuaga, J. L. et al. Postcranial morphology of the Middle Pleistocene humans from Sima de los Huesos, Spain. Proc. Natl Acad. Sci. USA 112, 11524–11529 (2015).
Franciscus, R. G. & Churchill, S. E. The costal skeleton of Shanidar 3 and a reappraisal of Neandertal thoracic morphology. J. Hum. Evol. 42, 303–356 (2002).
Gómez-Olivencia, A., Eaves-Johnson, K. L., Franciscus, R. G., Carretero, J. M. & Arsuaga, J. L. Kebara 2: new insights regarding the most complete Neandertal thorax. J. Hum. Evol. 57, 75–90 (2009).
Gómez-Olivencia, A. et al. 3D virtual reconstruction of the Kebara 2 Neandertal thorax. Nat. Comm. 9, 4387 (2018).
Ohman, J. C. et al. Stature at death of KNM-WT 15000. J. Hum. Evol. 17, 129–142 (2002).
Graves, R. R., Lupo, A. C., McCarthy, R. C., Wescott, D. J. & Cunningham, D. L. Just how strapping was KNM-WT 15000? J. Hum. Evol. 59, 542–554 (2010).
Ruff, C. B. & Burgess, M. L. How much more would KNM-WT 15000 have grown? J. Hum. Evol. 80, 74–82 (2015).
Antón, S., Potts, R. & Aiello, L. Human evolution. Evolution of early Homo: an integrated biological perspective. Science 345, 1236828 (2014).
Torres-Tamayo, N. et al. The torso integration hypothesis revisited in Homo sapiens: contributions to the understanding of hominin body shape evolution. Am. J. Phys. Anthropol. 167, 777–790 (2018).
Williams, S. A. et al. The vertebrae and ribs of Homo naledi. J. Hum. Evol. 104, 136–154 (2017).
Latimer, B., Lovejoy, C. O., Spurlock, L. & Haile-Selassie, Y. in The Postcranial Anatomy of Australopithecus afarensis: New Insights from KSD-VP-1/1 (eds Haile-Selassie, Y. & Su, D. F.) 143–153 (Springer, 2016).
Schmid, P. et al. Mosaic morphology in the thorax of Australopithecus sediba. Science 340, 1234598 (2013).
Bastir, M. et al. 3D geometric morphometrics of thorax variation and allometry in Hominoidea. J. Hum. Evol. 113, 10–23 (2017).
De Troyer, A., Kirkwood, P. A. & Wilson, T. A. Respiratory action of the intercostal muscles. Phys. Rev. 85, 717–756 (2005).
García-Martínez, D. et al. Over 100 years of Krapina: new insights into the Neanderthal thorax from the study of rib cross-sectional morphology. J. Hum. Evol. 122, 124–132 (2018).
Openshaw, P., Edwards, S. & Helms, P. Changes in rib cage geometry during childhood. Thorax 39, 624–627 (1984).
LoMauro, A. & Aliverti, A. Sex differences in respiratory function. Breathe 14, 131–140 (2018).
Bastir, M. et al. In vivo 3D analysis of thoracic kinematics: changes in size and shape during breathing and their implications for respiratory function in recent humans and fossil hominins. Anat. Rec. 300, 255–264 (2017).
Callison, W. É., Holowka, N. B. & Lieberman, D. E. Thoracic adaptations for ventilation during locomotion in humans and other mammals. J. Exp. Biol. 222, jeb189357 (2019).
Latimer, B. & Ward, C. V. in The Nariokotome Homo erectus Skeleton (eds Walker, A. & Leakey, R.) 266–293 (Harvard Univ. Press, 1993).
Haeusler, M., Schiess, R. & Boeni, T. New vertebral and rib material point to modern bauplan of the Nariokotome Homo erectus skeleton. J. Hum. Evol. 61, 575–582 (2011).
Bastir, M. et al. Differential growth and development of the upper and lower human thorax. PLoS ONE 8, e75128 (2013).
Haeusler, M. et al. Morphology, pathology, and the vertebral posture of the La Chapelle-aux-Saints Neandertal. Proc. Natl Acad. Sci. USA 116, 4923–4927 (2019).
Schiess, R. & Haeusler, M. No skeletal dysplasia in the Nariokotome boy KNM-WT 15000 (Homo erectus)—a reassessment of congenital pathologies of the vertebral column. Am. J. Phys. Anthropol. 150, 365–374 (2013).
Warrener, A. G., Lewton, K. L., Pontzer, H. & Lieberman, D. E. A wider pelvis does not increase locomotor cost in humans, with implications for the evolution of childbirth. PLoS ONE 10, e0118903 (2015).
Beyer, B. et al. In vivo thorax 3D modelling from costovertebral joint complex kinematics. Clin. Biomech. 29, 434–438 (2014).
Beyer, B. et al. Effect of anatomical landmark perturbation on mean helical axis parameters of in vivo upper costovertebral joints. J. Biomech. 48, 534–538 (2015).
De Troyer, A., Kelly, S., Macklem, P. T. & Zin, W. A. Mechanics of intercostal space and actions of external and internal intercostal muscles. J. Clin. Invest. 75, 850–857 (1985).
Wilson, T. A. & De Troyer, A. The two mechanisms of intercostal muscle action on the lung. J. Appl Physiol. 96, 483–488 (2004).
Gehr, P. et al. Design of the mammalian respiratory system. V. Scaling morphometric pulmonary diffusing capacity to body mass: wild and domestic mammals. Respir. Physiol. 44, 61–86 (1981).
Stahl, W. R. Scaling of respiratory variables in mammals. J. Appl. Physiol. 22, 453–460 (1967).
Jones, R. L. & Nzekwu, M. M. U. The effects of body mass index on lung volumes. Chest 130, 827–833 (2006).
Ruff, C. Body size and body shape in early hominins – implications of the Gona Pelvis. J. Hum. Evol. 58, 166–178 (2010).
Ruff, C. B., Burgess, M. L., Squyres, N., Junno, J. A. & Trinkaus, E. Lower limb articular scaling and body mass estimation in Pliocene and Pleistocene hominins. J. Hum. Evol. 115, 85–111 (2018).
Raichlen, D. A., Armstrong, H. & Lieberman, D. E. Calcaneus length determines running economy: implications for endurance running performance in modern humans and Neandertals. J. Hum. Evol. 60, 299–308 (2011).
Schmidt-Nielsen, K. Desert Animals: Physiological Problems of Heat and Water (Clarendon Press, 1964)
Hora, M., Pontzer, H., Wall-Scheffler, C. M. & Sládek, V. Dehydration and persistence hunting in Homo erectus. J. Hum. Evol. 138, 102682 (2020).
Stewart, J. R. et al. Palaeoecological and genetic evidence for Neanderthal power locomotion as an adaptation to a woodland environment. Quat. Sci. Rev. 217, 310–315 (2019).
Ahmetov, I. I., Egorova, E. S., Gabdrakhmanova, L. J. & Fedotovskaya, O. N. Genes and athletic performance: an update. Genet. Sports 61, 41–54 (2016).
García-Martínez, D. et al. Ribcage measurements indicate greater lung capacity in Neanderthals and Lower Pleistocene hominins compared to modern humans. Commun. Biol. 1, 117 (2018).
Churchill, S. E. in Neanderthals Revisited (eds Harvati, K. & Harrison, T.) 113–156 (Springer Verlag, 2006).
Churchill, S. E. Thin on the Ground: Neandertal Biology, Archeology and Ecology (Wiley Blackwell, 2014).
Lieberman, D. E., Bramble, D. M., Raichlen, D. A. & Shea, J. J. in The First Humans: Origin and Early Evolution of the Genus Homo (eds Grine, F. E. et al.) 77–92 (Springer, 2009).
García-Martínez, D., Riesco, A. & Bastir, M. in Geometric Morphometrics Trends in Biology, Paleobiology and Archaeology (eds Carme Rissech, L. L. et al.) 93–97 (Seminari d’Estudis i Recerques Preshistoriques, Universitat de Barcelona, Societat Catalana d’Arqueologia, 2018).
Mitteroecker, P. & Gunz, P. Advances in geometric morphometrics. J. Evol. Biol. 36, 235–247 (2009).
Gunz, P. & Mitteroecker, P. Semilandmarks: a method for quantifying curves and surfaces. Hystrix 24, 103–109 (2013).
García-Martínez, D. et al. 3D growth changes in ribs during late ontogeny in hominids and its importance for the thorax of KNM-WT 15000: a preliminary approach. Proc. Eur. Soc. Study Hum. Evol. 6, 72 (2017).
Bastir, M., García-Martínez, D., Spoor, F. & Williams, S. A. Thoracic vertebral morphology of KNM-WT 15000. Proc. Eur. Soc. Study Hum. Evol. 8, 11 (2018).
Bastir, M. et al. Workflows in a virtual morphology lab: 3D scanning, measuring, and printing. J. Anthropol. Sci. 97, 1–28 (2019).
Mallison, H. The digital Plateosaurus II: an assessment of the range of motion of the limbs and vertebral column and of previous reconstructions using a digital skeletal mount. Acta Paleontol. Pol. 55, 433–458 (2010).
Been, E., Gómez-Olivencia, A., Kramer, P. A. & Barash, A. in Human Paleontology and Prehistory (eds Marom, A. & Hovers, E.) 239–251 (Springer Verlag, 2017).
Bastir, M. et al. in The Human Spine (eds Been, E., Gómez-Olivencia, A. & Kramer, P.) 361–386 (Springer Verlag, 2019).
Fletcher, J., Stringer, M., Briggs, C., Davies, T. & Woodley, S. CT morphometry of adult thoracic intervertebral discs. Eur. Spine J. 24, 2321–2329 (2015).
Goh, S., Price, R. I., Leedman, P. J. & Singer, K. P. The relative influence of vertebral body and intervertebral disc shape on thoracic kyphosis. Clin. Biomech. 14, 439–448 (1999).
Schiess, R., Boeni, T., Rühli, F. & Haeusler, M. Revisiting scoliosis in the KNM-WT 15000 Homo erectus skeleton. J. Hum. Evol. 67, 48–59 (2014).
Goodyear, M. D. E., Krleza-Jeric, K. & Lemmens, T. The Declaration of Helsinki. BMJ 335, 624–625 (2007).
Sokal, R. R. & Rohlf, F. J. Biometry 3rd edn (W. H. Freeman and Company, 1998).
Hackx, M. et al. Effect of total lung capacity, gender and height on CT airway measurements. Br. J. Radiol. 90, 20160898 (2017).
Stocks, J. & Quanjer, P. Reference values for residual volume, functional residual capacity and total lung capacity. ATS Workshop on Lung Volume Measurements. Official Statement of The European Respiratory Society. Eur. Resp. J. 8, 492–506 (1995).
Nagesh, K. R. & Pradeep Kumar, G. Estimation of stature from vertebral column length in South Indians. Leg. Med. 8, 269–272 (2006).
Sverzellati, N. et al. Computed tomography measurement of rib cage morphometry in emphysema. PLoS ONE 8, e68546 (2013).
Cassart, M., Gevenois, P. A. & Estenne, M. Rib cage dimensions in hyperinflated patients with severe chronic obstructive pulmonary disease. Am. J. Respir. 154, 800–805 (1996).
García-Martínez, D. et al. 3D analysis of sexual dimorphism in ribcage kinematics of modern humans. Am. J. Phys. Anthropol. 169, 348–355 (2019).
Beyer, B., Van Sint Jan, S., Chèze, L., Sholukha, V. & Feipel, V. Relationship between costovertebral joint kinematics and lung volume in supine humans. Respir. Physiol. Neurobiol. 232, 57–65 (2016).
Chapman, T. et al. How different are the Kebara 2 ribs to modern humans? J. Anthropol. Sci. 95, 183–201 (2017).
Van Sint, J. S. et al. Une plate-forme technologique liée à la paralysie cérébrale. Le projet ICT4Rehab. Med Sci. (Paris) 29, 529–536 (2013).
Hammer, Ø. PAST: Palaeontological Statistics, version 3.25 https://folk.uio.no/ohammer/past/past3manual.pdf (2019).
Klingenberg, C. P. & Marugán-Lobón, J. Evolutionary covariation in geometric morphometric data: analyzing integration, modularity and allometry in a phylogenetic context. Syst. Biol. 62, 591–610 (2013).
We thank the National Museums of Kenya, E. Mbua and F. Kyalo Manthi for permissions to perform CT and surface scanning of the vertebrae and ribs of KNM-WT 15000. H. Pontzer, D. Lieberman and B. Wood provided helpful comments on an earlier draft of this manuscript. We also thank B. Perea-Pérez, D.A. Cáceres-Monllor, A.L. Santos, E. Cunha and M. Almeida for permissions and access to their collections. This research was funded by the Spanish Ministry of Economy and Competitivity (no. CGL 2015-63648-P) to M.B. D.G.-M. was funded by IdEx University of Bordeaux Investments for the Future programme (no. ANR-10-IDEX-03-02) and the European Commission’s Research Infrastructure Action via the Synthesys Projects (nos. SE-TAF-6406, DE-TAF-6404, BE-TAF-5639). Financial support for M.H. was provided by the Swiss National Science Foundation (no. 31003A_176319/1) and the Mäxi Foundation. A.G.-O. received support from the Spanish FEDER/Ministerio de Ciencia e Innovación-AEI (project no. PGC2018-093925-B-C33) and Research Group (no. IT1418-19) from Eusko Jaurlaritza-Gobierno Vasco. A.G.-O. is funded by a Ramón y Cajal fellowship (no. RYC-2017-22558).
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended Data Fig. 1 Original scans of the KNM-WT 15000 thoracic vertebrae and virtual 3D models and the reconstructed thoracic spine.
a, S (T1), b,T (T2), c, U (T3), d, CA (T4), e, T5: virtual, quantitative virtual 3D reconstruction, f, W, (T6), g, V (T7), h, T8: quantitative virtual 3D reconstruction. i, BI, (T9 quantitative virtual 3D reconstruction), j, X (T10, quantitative virtual 3D reconstruction), k, Y (T11), l, T12: virtually assembled following Haeusler et al.35; m: ventral view of thoracic spine, n: left lateral view of thoracic spine.
Extended Data Fig. 2 Original scans of the KNM-WT 15000 ribs and virtual 3D models for the rib cage reconstruction.
Cranial view of the individual ribs using the level assessment from Haeusler et al.35. The labels displayed in black are originals whereas the labels displayed in red colour are mirror images. (Rec indicates virtual reconstruction).
Extended Data Fig. 3 Mean comparisons of the juvenile and hypothetical adult KNM-WT 15000 thorax with modern humans and the Kebara 2 Neanderthal.
a, The KNM-WT 15000 thorax (red) superimposed on the modern human juvenile mean in Procrustes registration. b, The hypothetical adult KNM-WT 15000 thorax (red) superimposed on the modern human adult mean in Procrustes registration. c, The hypothetical adult KNM-WT 15000 thorax (red) superimposed on the Kebara 2 Neanderthal thorax reconstruction in Procrustes registration. Note the similar (more horizontal) orientation of the ribs in these two specimens due to reduced rib torsion.
a, Rib landmarks account for height, thickness and the 3D shape of the cranial and caudal curvatures and torsion of the shaft. b, Vertebral landmarks account for the morphology of the vertebral body (outline of endplates, body height, width and lengths), and the neural arches (curvatures, articulations, neural canal) and the thickness, height and orientations of the transverse and spinous processes. (Landmarks: red, semilandmarks of curves and surfaces: blue).
a, Scatterplot of PC1 and PC2 of the four original (stars) and 24 reconstructed thoracic spines (dots: reconstructions carried out by researcher 1; open squares: reconstructions carried out by researcher 2), and the convex hulls of each spine. PC1 shows that all (except one) reconstructions plotted towards more positive PC1 scores relative to their original. Inset 3D shapes illustrate variation along PC1. The experiment indicates a systematic underestimation of the thoracic kyphosis following the standardized reconstruction methods. b, The dendrogram shows the high accuracy of the reconstructions, which is independent of the researcher. All reconstructions fall together only with their original spine.
Supplementary methods, Tables 1–7 and references.
Breathing simulation of the KNM-WT 15000 juvenile rib cage. Kinematic changes in the KNM-WT 15000 thorax are based on computer simulations of modern human axes and ranges of motion applied to the virtual 3D reconstruction of the KNM-WT 15000 thorax. Note the lateral expansion of the rib cage during inspiration. Motion was simulated for true ribs only.
About this article
Cite this article
Bastir, M., García-Martínez, D., Torres-Tamayo, N. et al. Rib cage anatomy in Homo erectus suggests a recent evolutionary origin of modern human body shape. Nat Ecol Evol 4, 1178–1187 (2020). https://doi.org/10.1038/s41559-020-1240-4
Early development of the Neanderthal ribcage reveals a different body shape at birth compared to modern humans
Science Advances (2020)
Three-dimensional geometric morphometrics of thorax-pelvis covariation and its potential for predicting the thorax morphology: A case study on Kebara 2 Neandertal
Journal of Human Evolution (2020)
Journal of Human Evolution (2020)