1
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Hurst SD, Holloway RL, Balzeau A, Garvin HM, Vanti WB, Berger LR, Hawks J. The endocast morphology of LES1, Homo naledi. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24983. [PMID: 38864146 DOI: 10.1002/ajpa.24983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 05/27/2024] [Accepted: 06/02/2024] [Indexed: 06/13/2024]
Abstract
OBJECTIVES Homo naledi is near the extreme of small brain size within Homo but is easily recognized as Homo in other aspects of endocast morphology. This study adds new evidence of the endocast morphology of H. naledi by describing the Lesedi Hominin 1 (LES1) endocranium from the Lesedi Chamber and compares it to the previously known H. naledi individual Dinaledi Hominin 3 (DH3) as well as other hominin taxa. MATERIALS AND METHODS We examined interlandmark distances with both univariate and multivariate methods in multiple hominin taxa and both species of Pan. For each distance, we compared groups using adjusted Z-scores (Azs). Our multivariate analyses included both principal component analyses (PCA) and linear discriminant analyses (LDA). RESULTS DH3 and LES1 each have absolute third frontal convolution measures that enter the upper half of the variation for Homo sapiens, Homo erectus, and Homo neanderthalensis. Examined relative to the cube root of endocranial volume, H. naledi ranks among the highest values in these samples of Homo. Both absolute and relative values for H. naledi specimens are far above Pan, Australopithecus, and Paranthropus, suggesting an expanded Broca's area. CONCLUSIONS Both qualitative and quantitative analyses show consistency between LES1 and other H. naledi endocasts and confirm the shared morphology of H. naledi with H. sapiens, H. neanderthalensis, and some specimens of H. erectus.
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Affiliation(s)
- Shawn D Hurst
- Department of Biology, University of Indianapolis, Indianapolis, USA
| | | | - Antoine Balzeau
- Département Homme et Environnement, Muséum National d'Histoire Naturelle, PaleoFED team, Paris, France
- Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium
| | - Heather M Garvin
- Department of Anatomy, Des Moines University, Des Moines, USA
- Centre for the Exploration of the Deep Human Journey, University of Witwatersrand, Johannesburg, South Africa
| | - William B Vanti
- Science and Engineering Library, Columbia University, New York, USA
| | - Lee R Berger
- Centre for the Exploration of the Deep Human Journey, University of Witwatersrand, Johannesburg, South Africa
- The National Geographic Society, Washington, DC, USA
- The Carnegie Institution for Science, Washington, DC, USA
| | - John Hawks
- Centre for the Exploration of the Deep Human Journey, University of Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Wisconsin-Madison, Madison, USA
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2
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González-Forero M. Evolutionary-developmental (evo-devo) dynamics of hominin brain size. Nat Hum Behav 2024; 8:1321-1333. [PMID: 38802541 PMCID: PMC11272587 DOI: 10.1038/s41562-024-01887-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 04/11/2024] [Indexed: 05/29/2024]
Abstract
Brain size tripled in the human lineage over four million years, but why this occurred remains uncertain. Here, to study what caused this brain expansion, I mathematically model the evolutionary and developmental (evo-devo) dynamics of hominin brain size. The model recovers (1) the evolution of brain and body sizes of seven hominin species starting from brain and body sizes of the australopithecine scale, (2) the evolution of the hominin brain-body allometry and (3) major patterns of human development and evolution. I show that the brain expansion recovered is not caused by direct selection for brain size but by its genetic correlation with developmentally late preovulatory ovarian follicles. This correlation is generated over development if individuals experience a challenging ecology and seemingly cumulative culture, among other conditions. These findings show that the evolution of exceptionally adaptive traits may not be primarily caused by selection for them but by developmental constraints that divert selection.
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3
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Mahon S. Variation and convergence in the morpho-functional properties of the mammalian neocortex. Front Syst Neurosci 2024; 18:1413780. [PMID: 38966330 PMCID: PMC11222651 DOI: 10.3389/fnsys.2024.1413780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 06/03/2024] [Indexed: 07/06/2024] Open
Abstract
Man's natural inclination to classify and hierarchize the living world has prompted neurophysiologists to explore possible differences in brain organisation between mammals, with the aim of understanding the diversity of their behavioural repertoires. But what really distinguishes the human brain from that of a platypus, an opossum or a rodent? In this review, we compare the structural and electrical properties of neocortical neurons in the main mammalian radiations and examine their impact on the functioning of the networks they form. We discuss variations in overall brain size, number of neurons, length of their dendritic trees and density of spines, acknowledging their increase in humans as in most large-brained species. Our comparative analysis also highlights a remarkable consistency, particularly pronounced in marsupial and placental mammals, in the cell typology, intrinsic and synaptic electrical properties of pyramidal neuron subtypes, and in their organisation into functional circuits. These shared cellular and network characteristics contribute to the emergence of strikingly similar large-scale physiological and pathological brain dynamics across a wide range of species. These findings support the existence of a core set of neural principles and processes conserved throughout mammalian evolution, from which a number of species-specific adaptations appear, likely allowing distinct functional needs to be met in a variety of environmental contexts.
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Affiliation(s)
- Séverine Mahon
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
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4
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Mahoney P, McFarlane G, Taurozzi AJ, Madupe PP, O'Hara MC, Molopyane K, Cappellini E, Hawks J, Skinner MM, Berger L. Human-like enamel growth in Homo naledi. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24893. [PMID: 38180115 DOI: 10.1002/ajpa.24893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/12/2023] [Accepted: 12/14/2023] [Indexed: 01/06/2024]
Abstract
OBJECTIVES A modern pattern (rate and duration) of dental development occurs relatively recently during human evolution. Given the temporal overlap of Homo naledi with the first appearance of fossil Homo sapiens in Africa, this small-bodied and small-brained hominin presents an opportunity to elucidate the evolution of enamel growth in the hominin clade. Here we conduct the first histological study of two permanent mandibular canines and one permanent maxillary first molar, representing three individuals attributed to H. naledi. We reconstruct the rate and duration of enamel growth and compare these findings to those reported for other fossil hominins and recent humans. MATERIALS AND METHODS Thin sections of each tooth were produced using standard histological methods. Daily and longer period incremental markings were measured to reconstruct enamel secretion and extension rates, Retzius periodicity, canine crown and molar cusp formation time. RESULTS Daily enamel secretion rates overlapped with those from recent hominins. Canine crown formation time is similar to that observed in recent Europeans but is longer than canine formation times reported for most other hominins including Australopithecus and H. neanderthalensis. The extended period of canine formation appears to be due to a relatively tall enamel crown and a sustained slow rate of enamel extension in the cervical portion of the crown. A Retzius periodicity of 11 days for the canines, and nine days for the molar, in H. naledi parallel results found in recent humans. An 11-day periodicity has not been reported for Late Pleistocene Homo (H. erectus, H. neanderthalensis) and is rarely found in Australopithecus and Paranthropus species. DISCUSSION Enamel growth of H. naledi is most similar to recent humans though comparative data are limited for most fossil hominin species. The high Retzius periodicity values do not follow expectations for a small-brained hominin.
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Affiliation(s)
- Patrick Mahoney
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Gina McFarlane
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Alberto J Taurozzi
- Section for GeoGenetics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Palesa P Madupe
- Section for GeoGenetics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
- Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
| | - Mackie C O'Hara
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Keneiloe Molopyane
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- The National Geographic Society, Washington, District of Columbia, USA
| | - Enrico Cappellini
- Section for GeoGenetics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - John Hawks
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Wisconsin-Madison, USA
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Lee Berger
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- The National Geographic Society, Washington, District of Columbia, USA
- The Carnegie Institution for Science, Washington, District of Columbia, USA
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5
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Delezene LK, Scott JE, Irish JD, Villaseñor A, Skinner MM, Hawks J, Berger LR. Sex-biased sampling may influence Homo naledi tooth size variation. J Hum Evol 2024; 187:103490. [PMID: 38266614 DOI: 10.1016/j.jhevol.2023.103490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/26/2024]
Abstract
A frequent source of debate in paleoanthropology concerns the taxonomic unity of fossil assemblages, with many hominin samples exhibiting elevated levels of variation that can be interpreted as indicating the presence of multiple species. By contrast, the large assemblage of hominin fossils from the Rising Star cave system, assigned to Homo naledi, exhibits a remarkably low degree of variation for most skeletal elements. Many factors can contribute to low sample variation, including genetic drift, strong natural selection, biased sex ratios, and sampling of closely related individuals. In this study, we tested for potential sex-biased sampling in the Rising Star dental sample. We compared coefficients of variation for the H. naledi teeth to those for eight extant hominoid samples. We used a resampling procedure that generated samples from the extant taxa that matched the sample size of the fossil sample for each possible Rising Star dental sex ratio. We found that variation at four H. naledi tooth positions-I2, M1, P4, M1-is so low that the possibility that one sex is represented by few or no individuals in the sample cannot be excluded. Additional evidence is needed to corroborate this inference, such as ancient DNA or enamel proteome data, and our study design does not address other potential factors that would account for low sample variation. Nevertheless, our results highlight the importance of considering the taphonomic history of a hominin assemblage and suggest that sex-biased sampling is a plausible explanation for the low level of phenotypic variation found in some aspects of the current H. naledi assemblage.
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Affiliation(s)
- Lucas K Delezene
- Department of Anthropology, University of Arkansas, Fayetteville, AR, 72701, USA; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS, 2050, South Africa.
| | - Jeremiah E Scott
- Department of Medical Anatomical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, 91766, USA
| | - Joel D Irish
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS, 2050, South Africa; School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Amelia Villaseñor
- Department of Anthropology, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Matthew M Skinner
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS, 2050, South Africa; Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
| | - John Hawks
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS, 2050, South Africa; Department of Anthropology, University of Wisconsin-Madison. Madison, WI, 53706, USA
| | - Lee R Berger
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS, 2050, South Africa; National Geographic Society, 1145 17th Street NW, Washington DC, 20036, USA
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6
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Brophy JK, Bolter DR, Elliott M, Hawks J, Berger LR. An examination of Homo naledi early juveniles recovered from the Rising Star cave system, South Africa. Ann Hum Biol 2024; 51:2321128. [PMID: 38509686 DOI: 10.1080/03014460.2024.2321128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 02/06/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND Six Homo naledi early juveniles were recovered from U.W. 101 (Dinaledi Chamber), U.W. 102 (Lesedi Chamber), and U.W. 110 in the Rising Star cave system. AIM This paper develops the information for the H. naledi early juvenile life stage, as defined by a combination of deciduous and permanent dentition, and the eruption of the first permanent molar. SUBJECTS AND METHODS The growing number of young individuals recovered from the Rising Star cave system allows us to gain a better understanding of their variation, or lack thereof, and provides a basis to estimate broad ranges for age at death of the individuals. The individuals are identified and described through craniodental remains and spatial associations. RESULTS AND CONCLUSION Our results show that the teeth are remarkably consistent across the localities in their metric and non-metric traits, and our analyses refine previous estimations on dental eruptions with the first permanent molar erupting first in the sequence among permanent teeth.
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Affiliation(s)
- Juliet K Brophy
- Department of Geography and Anthropology, LA State University, Baton Rouge, LA, USA
- The Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - Debra R Bolter
- The Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Modesto Junior College, Modesto, CA, USA
- Department of Anthropology, CA State University Stanislaus, Turlock, CA, USA
| | - Marina Elliott
- The Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- Department of Archaeology, Simon Fraser University, Burnaby, BC, Canada
| | - John Hawks
- The Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of WI-Madison, Madison, WI, USA
| | - Lee R Berger
- The Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
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7
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Ruff CB, Wood BA. The estimation and evolution of hominin body mass. Evol Anthropol 2023; 32:223-237. [PMID: 37335778 DOI: 10.1002/evan.21988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 03/15/2023] [Accepted: 05/29/2023] [Indexed: 06/21/2023]
Abstract
Body mass is a critical variable in many hominin evolutionary studies, with implications for reconstructing relative brain size, diet, locomotion, subsistence strategy, and social organization. We review methods that have been proposed for estimating body mass from true and trace fossils, consider their applicability in different contexts, and the appropriateness of different modern reference samples. Recently developed techniques based on a wider range of modern populations hold promise for providing more accurate estimates in earlier hominins, although uncertainties remain, particularly in non-Homo taxa. When these methods are applied to almost 300 Late Miocene through Late Pleistocene specimens, the resulting body mass estimates fall within a 25-60 kg range for early non-Homo taxa, increase in early Homo to about 50-90 kg, then remain constant until the Terminal Pleistocene, when they decline.
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Affiliation(s)
- Christopher B Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Bernard A Wood
- Center for the Advanced Study of Human Paleobiology, George Washington University, Washington, District of Columbia, USA
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8
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Tattersall I. Endocranial volumes and human evolution. F1000Res 2023; 12:565. [PMID: 37744765 PMCID: PMC10517302 DOI: 10.12688/f1000research.131636.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/05/2023] [Indexed: 09/26/2023] Open
Abstract
Enlarging brains have been held up as the classic (if not the only) example of a consistent long-term trend in human evolution. And hominin endocranial volumes certainly expanded four-fold over the subfamily's seven-million-year history, while on a very coarse scale later hominids showed a strong tendency to have larger brains than earlier ones. However, closer scrutiny of this apparent trend reveals that it was extremely episodic and irregular, a fact that argues against the notion that it was driven by social interactions internal to the hominin clade. In addition, an overall tendency to brain volume increase was expressed independently and concurrently within at least three separate lineages of the genus Homo - suggesting that, whatever the exact influences were that promoted this global trend, they need to be sought among stimuli that acted comprehensively over the entire vast range of periods, geographies and environments that members of our subfamily occupied. Significantly, though, the dramatic recent shrinkage of the brain within the species Homo sapiens implies that the emergence of modern human cognition (via the adoption of the symbolic information processing mode, likely driven by the spontaneous invention of language in an exaptively enabled brain) was not the culmination of the overall hominin trend towards brain enlargement, but rather a departure from it.
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Affiliation(s)
- Ian Tattersall
- Anthropology, American Museum of Natural History, New York, NY, 10014, USA
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9
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Delezene LK, Skinner MM, Bailey SE, Brophy JK, Elliott MC, Gurtov A, Irish JD, Moggi-Cecchi J, de Ruiter DJ, Hawks J, Berger LR. Descriptive catalog of Homo naledi dental remains from the 2013 to 2015 excavations of the Dinaledi Chamber, site U.W. 101, within the Rising Star cave system, South Africa. J Hum Evol 2023; 180:103372. [PMID: 37229947 DOI: 10.1016/j.jhevol.2023.103372] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 03/31/2023] [Accepted: 03/31/2023] [Indexed: 05/27/2023]
Abstract
More than 150 hominin teeth, dated to ∼330-241 thousand years ago, were recovered during the 2013-2015 excavations of the Dinaledi Chamber of the Rising Star cave system, South Africa. These fossils comprise the first large single-site sample of hominin teeth from the Middle Pleistocene of Africa. Though scattered remains attributable to Homo sapiens, or their possible lineal ancestors, are known from older and younger sites across the continent, the distinctive morphological feature set of the Dinaledi teeth supports the recognition of a novel hominin species, Homo naledi. This material provides evidence of African Homo lineage diversity that lasts until at least the Middle Pleistocene. Here, a catalog, anatomical descriptions, and details of preservation and taphonomic alteration are provided for the Dinaledi teeth. Where possible, provisional associations among teeth are also proposed. To facilitate future research, we also provide access to a catalog of surface files of the Rising Star jaws and teeth.
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Affiliation(s)
- Lucas K Delezene
- Department of Anthropology, University of Arkansas, Fayetteville, AR 72701, USA; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa.
| | - Matthew M Skinner
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa; School of Anthropology and Conservation, University of Kent, Marlowe Building, Canterbury CT2 7NR, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Shara E Bailey
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany; Department of Anthropology, Center for the Study of Human Origins, New York University, New York, NY 10003, USA
| | - Juliet K Brophy
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa; Department of Geography and Anthropology, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Marina C Elliott
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa; Department of Archaeology, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, USA
| | - Alia Gurtov
- Stripe, Inc., 199 Water Street, 30th Floor, New York, NY 10038, USA
| | - Joel D Irish
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa; School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Jacopo Moggi-Cecchi
- Laboratory of Anthropology, Department of Biology, University of Florence, Via del Proconsolo 12, Firenze 50122, Italy
| | - Darryl J de Ruiter
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa; Department of Anthropology, Texas A&M University, College Station, TX 77843, USA
| | - John Hawks
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa; Department of Anthropology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Lee R Berger
- National Geographic Society, 1145 17th Street NW, Washington, DC 20036, USA; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa
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10
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Antón SC, Middleton ER. Making meaning from fragmentary fossils: Early Homo in the Early to early Middle Pleistocene. J Hum Evol 2023; 179:103307. [PMID: 37030994 DOI: 10.1016/j.jhevol.2022.103307] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 11/16/2022] [Accepted: 11/27/2022] [Indexed: 04/10/2023]
Abstract
In celebration of the 50th anniversary of the Journal of Human Evolution, we re-evaluate the fossil record for early Homo (principally Homo erectus, Homo habilis, and Homo rudolfensis) from early diversification and dispersal in the Early Pleistocene to the ultimate demise of H. erectus in the early Middle Pleistocene. The mid-1990s marked an important historical turning point in our understanding of early Homo with the redating of key H. erectus localities, the discovery of small H. erectus in Asia, and the recovery of an even earlier presence of early Homo in Africa. As such, we compare our understanding of early Homo before and after this time and discuss how the order of fossil discovery and a focus on anchor specimens has shaped, and in many ways biased, our interpretations of early Homo species and the fossils allocated to them. Fragmentary specimens may counter conventional wisdom but are often overlooked in broad narratives. We recognize at least three different cranial and two or three pelvic morphotypes of early Homo. Just one postcranial morph aligns with any certainty to a cranial species, highlighting the importance of explicitly identifying how we link specimens together and to species; we offer two ways of visualizing these connections. Chronologically and morphologically H. erectus is a member of early Homo, not a temporally more recent species necessarily evolved from either H. habilis or H. rudolfensis. Nonetheless, an ancestral-descendant notion of their evolution influences expectations around the anatomy of missing elements, especially the foot. Weak support for long-held notions of postcranial modernity in H. erectus raises the possibility of alternative drivers of dispersal. New observations suggest that the dearth of faces in later H. erectus may mask taxonomic diversity in Asia and suggest various later mid-Pleistocene populations could derive from either Asia or Africa. Future advances will rest on the development of nuanced ways to affiliate fossils, greater transparency of implicit assumptions, and attention to detailed life history information for comparative collections; all critical pursuits for future research given the great potential they have to enrich our evolutionary reconstructions for the next fifty years and beyond.
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Affiliation(s)
- Susan C Antón
- Center for the Study of Human Origins, Department of Anthropology, New York University, NY, NY 10003, USA.
| | - Emily R Middleton
- Department of Anthropology, University of Wisconsin-Milwaukee, WI 53211, USA
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11
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Two Late Pleistocene human femora from Trinil, Indonesia: Implications for body size and behavior in Southeast Asia. J Hum Evol 2022; 172:103252. [PMID: 36162353 DOI: 10.1016/j.jhevol.2022.103252] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/15/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022]
Abstract
Late Pleistocene hominin postcranial specimens from Southeast Asia are relatively rare. Here we describe and place into temporal and geographic context two partial femora from the site of Trinil, Indonesia, which are dated stratigraphically and via Uranium-series direct dating to ca. 37-32 ka. The specimens, designated Trinil 9 and 10, include most of the diaphysis, with Trinil 9 being much better preserved. Microcomputed tomography is used to determine cross-sectional diaphyseal properties, with an emphasis on midshaft anteroposterior to mediolateral bending rigidity (Ix/Iy), which has been shown to relate to both body shape and activity level in modern humans. The body mass of Trinil 9 is estimated from cortical area and reconstructed length using new equations based on a Pleistocene reference sample. Comparisons are carried out with a large sample of Pleistocene and Holocene East Asian, African, and European/West Asian femora. Our results show that Trinil 9 has a high Ix/Iy ratio, most consistent with a relatively narrow-bodied male from a mobile hunting-gathering population. It has an estimated body mass of 55.4 kg and a stature of 156 cm, which are small relative to Late Pleistocene males worldwide, but larger than the penecontemporaneous Deep Skull femur from Niah Cave, Malaysia, which is very likely female. This suggests the presence of small-bodied active hunter-gatherers in Southeast Asia during the later Late Pleistocene. Trinil 9 also contrasts strongly in morphology with earlier partial femora from Trinil dating to the late Early-early Middle Pleistocene (Femora II-V), and to a lesser extent with the well-known complete Femur I, most likely dating to the terminal Middle-early Late Pleistocene. Temporal changes in morphology among femoral specimens from Trinil parallel those observed in Homo throughout the Old World during the Pleistocene and document these differences within a single site.
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12
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Cofran Z, VanSickle C, Valenzuela R, García‐Martínez D, Walker CS, Hawks J, Zipfel B, Williams SA, Berger LR. The immature
Homo naledi
ilium from the Lesedi Chamber, Rising Star Cave, South Africa. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022. [PMCID: PMC9546141 DOI: 10.1002/ajpa.24522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Objectives Homo naledi is represented by abundant remains from the Dinaledi Chamber of the Rising Star Cave system in South Africa. While pelvic elements from the Dinaledi Chamber of the cave are fragmentary, a relatively complete ilium (U.W. 102a–138) was recovered from the Lesedi Chamber. We reconstructed and analyzed the Lesedi ilium, providing qualitative descriptions and quantitative assessment of its morphology and developmental state. Materials and Methods We compared the Lesedi ilium to remains from the Dinaledi Chamber, other South African hominin fossils, and an ontogenetic series of human ilia. We used the Dinaledi adults as a guide for reconstructing the Lesedi ilium. To assess development of the Lesedi ilium, we compared immature/mature proportional ilium height for fossils and humans. We used 3D geometric morphometrics (GMs) to examine size and shape variation among this sample. Results The Lesedi ilium showed incipient development of features expressed in adult H. naledi ilia. The proportional height of the Lesedi ilium was within the range of human juveniles between 4–11 years of age. GM analyses showed that the Lesedi ilium had an iliac blade shape similar to those of australopiths and an expanded auricular surface more similar to humans. Conclusions The reconstructed Lesedi specimen represents the best preserved ilium of H. naledi, confirming the australopith‐like iliac blade morphology first hypothesized in adult specimens, and establishing that this anatomy was present early in this species' ontogeny. In contrast to australopiths, the Lesedi ilium displays an enlarged sacroiliac joint, the significance of which requires further investigation.
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Affiliation(s)
- Zachary Cofran
- Anthropology Department, Vassar College Poughkeepsie New York USA
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
| | - Caroline VanSickle
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
- Department of Anatomy A.T. Still University, Kirksville College of Osteopathic Medicine Kirksville Missouri USA
| | | | - Daniel García‐Martínez
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
- Physical Anthropology Unit, Department of Biodiversity, Ecology, and Evolution, Faculty of Biological Sciences Complutense University of Madrid Madrid Spain
- Centro Nacional de Investigación sobre la Evolución Humana Burgos Spain
| | - Christopher S. Walker
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine North Carolina State University Raleigh North Carolina USA
| | - John Hawks
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
- Department of Anthropology University of Wisconsin Madison Wisconsin USA
| | - Bernhard Zipfel
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
- Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
| | - Scott A. Williams
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
- Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
- Center for the Study of Human Origins, Department of Anthropology New York University New York New York USA
- New York Consortium in Evolutionary Primatology New York New York USA
| | - Lee R. Berger
- Centre for the Exploration of the Deep Human Journey University of the Witwatersrand Johannesburg South Africa
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13
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The relative limb size of Homonaledi. J Hum Evol 2022; 170:103235. [PMID: 35994845 DOI: 10.1016/j.jhevol.2022.103235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/03/2022] [Accepted: 07/03/2022] [Indexed: 11/20/2022]
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14
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Everett MC, Elliott MC, Gaynor D, Hill AC, Syeda SM, Casana J, Zipfel B, DeSilva JM, Dominy NJ. Mechanical loading of primate fingers on vertical rock surfaces. S AFR J SCI 2021. [DOI: 10.17159/sajs.2021/10409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Mechanical loading of finger bones (phalanges) can induce angular curvature, which benefits arboreal primates by dissipating forces and economising the recruitment of muscles during climbing. The recent discovery of extremely curved phalanges in a hominin, Homo naledi, is puzzling, for it suggests life in an arboreal milieu, or, alternatively, habitual climbing on vertical rock surfaces. The importance of climbing rock walls is attested by several populations of baboons, one of which uses a 7-m vertical surface to enter and exit Dronkvlei Cave, De Hoop Nature Reserve, South Africa. This rock surface is an attractive model for estimating the probability of extreme mechanical loading on the phalanges of rock-climbing primates. Here we use three-dimensional photogrammetry to show that 82–91% of the climbable surface would generate high forces on the flexor tendon pulley system and severely load the phalanges of baboons and H. naledi. If such proportions are representative of vertical rock surfaces elsewhere, it may be sufficient to induce stress-mitigating curvature in the phalanges of primates.
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Affiliation(s)
- Michael C. Everett
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
| | - Marina C. Elliott
- Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - David Gaynor
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Austin C. Hill
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Samar M. Syeda
- Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jesse Casana
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
| | - Bernhard Zipfel
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeremy M. DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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15
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Bowland LA, Scott JE, Kivell TL, Patel BA, Tocheri MW, Orr CM. Homo naledi pollical metacarpal shaft morphology is distinctive and intermediate between that of australopiths and other members of the genus Homo. J Hum Evol 2021; 158:103048. [PMID: 34340120 DOI: 10.1016/j.jhevol.2021.103048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 10/20/2022]
Abstract
Homo naledi fossils from the Rising Star cave system provide important insights into the diversity of hand morphology within the genus Homo. Notably, the pollical (thumb) metacarpal (Mc1) displays an unusual suite of characteristics including a median longitudinal crest, a narrow proximal base, and broad flaring intrinsic muscle flanges. The present study evaluates the affinities of H. naledi Mc1 morphology via 3D geometric morphometric analysis of shaft shape using a broader comparative sample (n = 337) of fossil hominins, recent humans, apes, and cercopithecoid monkeys than in prior work. Results confirm that the H. naledi Mc1 is distinctive from most other hominins in being narrow at the proximal end but surmounted by flaring muscle flanges distally. Only StW 418 (Australopithecus cf. africanus) is similar in these aspects of shape. The gracile proximal shaft is most similar to cercopithecoids, Pan, Pongo, Australopithecus afarensis, and Australopithecus sediba, suggesting that H. naledi retains the condition primitive for the genus Homo. In contrast, Neandertal Mc1s are characterized by wide proximal bases and shafts, pinched midshafts, and broad distal flanges, while those of recent humans generally have straight shafts, less robust muscle flanges, and wide proximal shafts/bases. Although uncertainties remain regarding character polarity, the morphology of the H. naledi thumb might be interpreted as a retained intermediate state in a transformation series between the overall gracility of the shaft and the robust shafts of later hominins. Such a model suggests that the addition of broad medial and lateral muscle flanges to a primitively slender shaft was the first modification in transforming the Mc1 into the overall more robust structure exhibited by other Homo taxa including Neandertals and recent Homo sapiens in whose shared lineage the bases and proximal shafts became expanded, possibly as an adaptation to the repeated recruitment of powerful intrinsic pollical muscles.
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Affiliation(s)
- Lucyna A Bowland
- Department of Anthropology, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Jill E Scott
- Department of Sociology and Anthropology, Metropolitan State University of Denver, Denver, CO, 80217, USA; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa
| | - Tracy L Kivell
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa; School of Anthropology and Conservation, University of Kent, Canterbury, CT2 7NR, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany
| | - Biren A Patel
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA; Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, ON, P7K 1L8, Canada; Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington DC, 20560, USA; Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - Caley M Orr
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, 80045, USA; Department of Anthropology, University of Colorado Denver, Denver, CO, 80217, USA.
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16
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Irish JD, Grabowski M. Relative tooth size, Bayesian inference, and Homo naledi. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 176:262-282. [PMID: 34190335 DOI: 10.1002/ajpa.24353] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 05/04/2021] [Accepted: 06/08/2021] [Indexed: 01/29/2023]
Abstract
OBJECTIVES Size-corrected tooth crown measurements were used to estimate phenetic affinities among Homo naledi (~335-236 ka) and 11 other Plio-Pleistocene and recent species. To assess further their efficacy, and identify dental evolutionary trends, the data were then quantitatively coded for phylogenetic analyses. Results from both methods contribute additional characterization of H. naledi relative to other hominins. MATERIALS AND METHODS After division by their geometric mean, scaled mesiodistal and buccolingual dimensions were used in tooth size apportionment analysis to compare H. naledi with Australopithecus africanus, A. afarensis, Paranthropus robustus, P. boisei, H. habilis, H. ergaster, H. erectus, H. heidelbergensis, H. neanderthalensis, H. sapiens, and Pan troglodytes. These data produce equivalently scaled samples unaffected by interspecific size differences. The data were then gap-weighted for Bayesian inference. RESULTS Congruence in interspecific relationships is evident between methods, and with many inferred from earlier systematic studies. However, the present results place H. naledi as a sister taxon to H. habilis, based on a symplesiomorphic pattern of relative tooth size. In the preferred Bayesian phylogram, H. naledi is nested within a clade comprising all Homo species, but it shares some characteristics with australopiths and, particularly, early Homo. DISCUSSION Phylogenetic analyses of relative tooth size yield information about evolutionary dental trends not previously reported in H. naledi and the other hominins. Moreover, with an appropriate model these data recovered plausible evolutionary relationships. Together, the findings support recent study suggesting H. naledi originated long before the geological date of the Dinaledi Chamber, from which the specimens under study were recovered.
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Affiliation(s)
- Joel D Irish
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK.,The Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK.,Centre for Ecology and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Oslo, Norway
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17
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Divergence-time estimates for hominins provide insight into encephalization and body mass trends in human evolution. Nat Ecol Evol 2021; 5:808-819. [PMID: 33795855 DOI: 10.1038/s41559-021-01431-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 02/25/2021] [Indexed: 12/18/2022]
Abstract
Quantifying speciation times during human evolution is fundamental as it provides a timescale to test for the correlation between key evolutionary transitions and extrinsic factors such as climatic or environmental change. Here, we applied a total evidence dating approach to a hominin phylogeny to estimate divergence times under different topological hypotheses. The time-scaled phylogenies were subsequently used to perform ancestral state reconstructions of body mass and phylogenetic encephalization quotient (PEQ). Our divergence-time estimates are consistent with other recent studies that analysed extant species. We show that the origin of the genus Homo probably occurred between 4.30 and 2.56 million years ago. The ancestral state reconstructions show a general trend towards a smaller body mass before the emergence of Homo, followed by a trend towards a greater body mass. PEQ estimations display a general trend of gradual but accelerating encephalization evolution. The obtained results provide a rigorous temporal framework for human evolution.
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18
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Prang TC, Ramirez K, Grabowski M, Williams SA. Ardipithecus hand provides evidence that humans and chimpanzees evolved from an ancestor with suspensory adaptations. SCIENCE ADVANCES 2021; 7:eabf2474. [PMID: 33627435 PMCID: PMC7904256 DOI: 10.1126/sciadv.abf2474] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 01/12/2021] [Indexed: 05/08/2023]
Abstract
The morphology and positional behavior of the last common ancestor of humans and chimpanzees are critical for understanding the evolution of bipedalism. Early 20th century anatomical research supported the view that humans evolved from a suspensory ancestor bearing some resemblance to apes. However, the hand of the 4.4-million-year-old hominin Ardipithecus ramidus purportedly provides evidence that the hominin hand was derived from a more generalized form. Here, we use morphometric and phylogenetic comparative methods to show that Ardipithecus retains suspensory adapted hand morphologies shared with chimpanzees and bonobos. We identify an evolutionary shift in hand morphology between Ardipithecus and Australopithecus that renews questions about the coevolution of hominin manipulative capabilities and obligate bipedalism initially proposed by Darwin. Overall, our results suggest that early hominins evolved from an ancestor with a varied positional repertoire including suspension and vertical climbing, directly affecting the viable range of hypotheses for the origin of our lineage.
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Affiliation(s)
- Thomas C Prang
- Department of Anthropology, Texas A&M University, College Station, TX 77843, USA.
| | - Kristen Ramirez
- New York Consortium in Evolutionary Primatology, New York, NY 10024, USA
- Department of Anthropology, CUNY Graduate Center, New York, NY 10016, USA
- Office of Medical Education, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, UK
- Centre for Ecology and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Scott A Williams
- New York Consortium in Evolutionary Primatology, New York, NY 10024, USA
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
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19
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Brophy JK, Moggi-Cecchi J, Matthews GJ, Bailey SE. Comparative morphometric analyses of the deciduous molars of Homo naledi from the Dinaledi Chamber, South Africa. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 174:299-314. [PMID: 33290582 DOI: 10.1002/ajpa.24190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/12/2020] [Accepted: 11/09/2020] [Indexed: 11/08/2022]
Abstract
OBJECTIVES The purpose of this study is to help elucidate the taxonomic relationship between Homo naledi and other hominins. MATERIALS AND METHODS Homo naledi deciduous maxillary and mandibular molars from the Dinaledi Chamber, South Africa were compared to those of Australopithecus africanus, Australopithecus afarensis, Paranthropus robustus, Paranthropus boisei, early Homo sp., Homo erectus, early Homo sapiens, Upper Paleolithic H. sapiens, recent southern African H. sapiens, and Neanderthals by means of morphometric analyses of crown outlines and relative cusp areas. The crown shapes were analyzed using elliptical Fourier analyses followed by principal component analyses (PCA). The absolute and relative cusp areas were obtained in ImageJ and compared using PCA and cluster analyses. RESULTS PCA suggests that the crown shapes and relative cusp areas of mandibular molars are more diagnostic than the maxillary molars. The H. naledi deciduous mandibular first and second molar (dm1 and dm2 ) do not have a strong affinity to any taxon in the comparative sample in all analyses. While the H. naledi dm2 plots as an outlier in the relative cusp analysis, the H. naledi specimen fall closest to Australopithecus due to their relatively large metaconid, a primitive trait for the genus Homo. Although useful for differentiating Neanderthals from recent southern African H. sapiens and UP H. sapiens, the PCA of the relative cusp areas suggests that the deciduous maxillary second molars (dm2 ) do not differentiate other groups. The three H. naledi dm2 cuspal areas are variable and fall within the ranges of other Homo, as well as Australopithecus, and Paranthropus suggesting weak diagnostic utility. DISCUSSION This research provides another perspective on the morphology of, and variation within, H. naledi. The H. naledi deciduous molars do not consistently align with any genus or species in the comparative sample in either the crown shape or relative cusp analyses. This line of inquiry is consistent with other cranial and postcranial studies suggesting that H. naledi is unique.
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Affiliation(s)
- Juliet K Brophy
- Department of Geography and Anthropology, Louisiana State University, Baton Rouge, Louisiana, USA.,Evolutionary Studies Institute, University of the Witwatersrand, WITS, South Africa
| | - Jacopo Moggi-Cecchi
- Laboratori di Antropologia, Dipartimento di Biologia, Università degli Studi di Firenze, Florence, Italy
| | - Gregory J Matthews
- Department of Mathematics and Statistics, Loyola University Chicago, Chicago, Illinois, USA
| | - Shara E Bailey
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, New York, USA.,New York Consortium in Evolutionary Primatology, New York, New York, USA.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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20
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Bolter DR, Cameron N. Utilizing auxology to understand ontogeny of extinct hominins: A case study on Homo naledi. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 173:368-380. [PMID: 32537780 DOI: 10.1002/ajpa.24088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 02/03/2020] [Accepted: 05/10/2020] [Indexed: 02/05/2023]
Abstract
The methods used to study human growth and development (auxology) have not previously been applied within the setting of hominin maturation (ontogeny). Ontogeny is defined here as the pattern of biological change into an adult form, both at the individual and species level. The hominin fossil record has a lack of recovered immature materials, due to such factors as taphonomic processes that destroy pre-adults; the fragility of immature compared to adult bone; and the lower mortality rates of juveniles compared to adults. The recent discovery of pre-adult hominin skeletal material from a single, homogeneous Homo naledi species from the Rising Star cave system in South Africa provides the opportunity for a broader application of auxology methods and thus the need to understand their use in a modern context. Human auxology studies benefit from a robust database, across multiple populations, and with longitudinal studies in order to assess the patterns and variations in typical growth, development and life history stages. Here, we review the approach, vocabulary, and methods of these human studies, investigate commonalities in data with the fossil record, and then advance the reconstruction of ontogeny for the extinct hominin species H. naledi. To this end, we apply an auxology model into the paleontological context to broadly predict H. naledi birthweight of the offspring at 2.06 kg with a range (±1 SD) of 1.89 to 2.24 kg, with a length at birth 45.5 cm. We estimate a H. naledi juvenile partial skeleton DH7 to be a height of 111-125 cm at death.
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Affiliation(s)
- Debra R Bolter
- Department of Anthropology, Modesto Junior College, Modesto, California, USA
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Noel Cameron
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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21
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Bolter DR, Elliott MC, Hawks J, Berger LR. Immature remains and the first partial skeleton of a juvenile Homo naledi, a late Middle Pleistocene hominin from South Africa. PLoS One 2020; 15:e0230440. [PMID: 32236122 PMCID: PMC7112188 DOI: 10.1371/journal.pone.0230440] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 02/29/2020] [Indexed: 11/18/2022] Open
Abstract
Immature remains are critical for understanding maturational processes in hominin species as well as for interpreting changes in ontogenetic development in hominin evolution. The study of these subjects is hindered by the fact that associated juvenile remains are extremely rare in the hominin fossil record. Here we describe an assemblage of immature remains of Homo naledi recovered from the 2013–2014 excavation season. From this assemblage, we attribute 16 postcranial elements and a partial mandible with some dentition to a single juvenile Homo naledi individual. The find includes postcranial elements never before discovered as immature elements in the sub-equatorial early hominin fossil record, and contributes new data to the field of hominin ontogeny.
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Affiliation(s)
- Debra R. Bolter
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Modesto Junior College, Modesto, California, United States of America
- * E-mail:
| | - Marina C. Elliott
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - John Hawks
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Lee R. Berger
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
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22
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White S, Soligo C, Pope M, Hillson S. Taxonomic variation in the supraorbital region of catarrhine primates. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 171:198-218. [PMID: 31762014 DOI: 10.1002/ajpa.23975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 10/28/2019] [Accepted: 11/04/2019] [Indexed: 11/07/2022]
Abstract
OBJECTIVES This study aimed to test the taxonomic utility of the catarrhine supraorbital region using 3D geometric morphometrics, with the aim of establishing its potential use in elucidating the position of more debated hominin groups. MATERIALS AND METHODS 230 3D coordinates were used to record the supraorbital morphology of two datasets: one containing 460 non-hominin catarrhine primates from species and subspecies of Gorilla, Pan, Papio, and Macaca; and the other containing 55 Pleistocene hominins from Homo, Australopithecus, and Paranthropus. Principal component analyses in tangent, form, and allometry-free shape space were used to assess differentiation of taxa, with biological distinctiveness of taxa being established using step-wise discriminant analysis with subsampling. RESULTS Results indicated that the recorded supraorbital morphology could be used to separate non-hominin catarrhine primate genera, species, and subspecies, although accuracy was found to decrease with decreasing Linnaean rank. In addition, analyses in tangent space were found to produce the highest accuracy when classifying primates of known taxonomy. Biological distinctiveness of the middle and later Homo species was comparable to or higher than that of the non-hominin primates, and relatively lower for the earlier groups of Homo. DISCUSSION This study indicates that the supraorbital region preserves taxonomic information that can be used to delineate between closely related groups, both within hominins and wider catarrhine primates. Therefore, this region may be used to provide insight when assessing the taxonomic affiliation of disputed hominin specimens.
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Affiliation(s)
- Suzanna White
- Department of Anthropology, University College London, London, UK
| | | | - Matt Pope
- Institute of Archaeology, University College London, London, UK
| | - Simon Hillson
- Institute of Archaeology, University College London, London, UK
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23
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Friedl L, Claxton AG, Walker CS, Churchill SE, Holliday TW, Hawks J, Berger LR, DeSilva JM, Marchi D. Femoral neck and shaft structure in Homo naledi from the Dinaledi Chamber (Rising Star System, South Africa). J Hum Evol 2019; 133:61-77. [PMID: 31358184 DOI: 10.1016/j.jhevol.2019.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 01/27/2023]
Abstract
The abundant femoral assemblage of Homo naledi found in the Dinaledi Chamber provides a unique opportunity to test hypotheses regarding the taxonomy, locomotion, and loading patterns of this species. Here we describe neck and shaft cross-sectional structure of all the femoral fossils recovered in the Dinaledi Chamber and compare them to a broad sample of fossil hominins, recent humans, and extant apes. Cross-sectional geometric (CSG) properties from the femoral neck (base of neck and midneck) and diaphysis (subtrochanteric region and midshaft) were obtained through CT scans for H. naledi and through CT scans or from the literature for the comparative sample. The comparison of CSG properties of H. naledi and the comparative samples shows that H. naledi femoral neck is quite derived with low superoinferior cortical thickness ratio and high relative cortical area. The neck appears superoinferiorly elongated because of two bony pilasters on its superior surface. Homo naledi femoral shaft shows a relatively thick cortex compared to the other hominins. The subtrochanteric region of the diaphysis is mediolaterally elongated resembling early hominins while the midshaft is anteroposteriorly elongated, indicating high mobility levels. In term of diaphyseal robusticity, the H. naledi femur is more gracile that other hominins and most apes. Homo naledi shows a unique combination of characteristics in its femur that undoubtedly indicate a species committed to terrestrial bipedalism but with a unique loading pattern of the femur possibly consequence of the unique postcranial anatomy of the species.
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Affiliation(s)
- Lukas Friedl
- Department of Anthropology, University of West Bohemia, Plzeň, Czech Republic
| | - Alex G Claxton
- Department of Anthropology, Dartmouth College, 409 Silsby, HB 6047, Hanover, USA
| | - Christopher S Walker
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa; Department of Evolutionary Anthropology, Duke University, 04 Bio Sci Bldg, Durham, NC, 27708, USA
| | - Steven E Churchill
- Department of Evolutionary Anthropology, Duke University, 04 Bio Sci Bldg, Durham, NC, 27708, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Trenton W Holliday
- Department of Anthropology, Tulane University, 417 Dinwiddie Hall, New Orleans, LA, 70118, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - John Hawks
- Department of Anthropology, University of Wisconsin, 5325 Sewell Social Science Building, Madison, WI, 53706, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Lee R Berger
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, 409 Silsby, HB 6047, Hanover, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Damiano Marchi
- Department of Biology, University of Pisa, vis Derna 1, Pisa, 56126, Italy; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa.
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24
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Walker CS, Cofran ZD, Grabowski M, Marchi D, Cook RW, Churchill SE, Tommy KA, Throckmorton Z, Ross AH, Hawks J, Yapuncich GS, Van Arsdale AP, Rentzeperis FI, Berger LR, DeSilva JM. Morphology of the Homo naledi femora from Lesedi. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 170:5-23. [PMID: 31228254 DOI: 10.1002/ajpa.23877] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 05/26/2019] [Accepted: 05/27/2019] [Indexed: 11/07/2022]
Abstract
OBJECTIVES The femoral remains recovered from the Lesedi Chamber are among the most complete South African fossil hominin femora discovered to date and offer new and valuable insights into the anatomy and variation of the bone in Homo naledi. While the femur is one of the best represented postcranial elements in the H. naledi assemblage from the Dinaledi Chamber, the fragmentary and commingled nature of the Dinaledi femoral remains has impeded the assessment of this element in its complete state. MATERIALS AND METHODS Here we analyze and provide descriptions of three new relatively well-preserved femoral specimens of H. naledi from the Lesedi Chamber: U.W. 102a-001, U.W. 102a-003, and U.W. 102a-004. These femora are quantitatively and qualitatively compared to multiple extinct hominin femoral specimens, extant hominid taxa, and, where possible, each other. RESULTS The Lesedi femora are morphologically similar to the Dinaledi femora for all overlapping regions, with differences limited to few traits of presently unknown significance. The Lesedi distal femur and mid-diaphysis preserve anatomy previously unidentified or unconfirmed in the species, including an anteroposteriorly expanded midshaft and anteriorly expanded patellar surface. The hypothesis that the Lesedi femoral sample may represent two individuals is supported. DISCUSSION The Lesedi femora increase the range of variation of femoral morphology in H. naledi. Newly described features of the diaphysis and distal femur are either taxonomically uninformative or Homo-like. Overall, these three new femora are consistent with previous functional interpretations of the H. naledi lower limb as belonging to a species adapted for long distance walking and, possibly, running.
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Affiliation(s)
- Christopher S Walker
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.,Department of Evolutionary Anthropology, Duke University, Durham, North Carolina.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Zachary D Cofran
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Anthropology Department, Vassar College, Poughkeepsie, New York
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Damiano Marchi
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Biology, University of Pisa, Pisa, Italy
| | - Rebecca W Cook
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.,Department of Evolutionary Anthropology, Duke University, Durham, North Carolina
| | - Steven E Churchill
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Kimberleigh A Tommy
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Human Variation and Identification Research Unit, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Zachary Throckmorton
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anatomy, Arkansas College of Osteopathic Medicine, Fort Smith, Arkansas
| | - Ann H Ross
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina
| | - John Hawks
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anthropology, University of Wisconsin, Madison, Wisconsin
| | - Gabriel S Yapuncich
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.,Department of Evolutionary Anthropology, Duke University, Durham, North Carolina
| | | | | | - Lee R Berger
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeremy M DeSilva
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anthropology, Dartmouth College, Hanover, New Hampshire
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25
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Kupczik K, Delezene LK, Skinner MM. Mandibular molar root and pulp cavity morphology in Homo naledi and other Plio-Pleistocene hominins. J Hum Evol 2019; 130:83-95. [PMID: 31010546 DOI: 10.1016/j.jhevol.2019.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 12/31/2022]
Abstract
The craniomandibular morphology of Homo naledi shows variable resemblances with species across Homo, which confounds an easy assessment of its phylogenetic position. In terms of skull shape, H. naledi has its closest affinities with Homo erectus, while mandibular shape places it closer to early Homo. From a tooth crown perspective, the smaller molars of H. naledi make it distinct from early Homo and H. erectus. Here, we compare the mandibular molar root morphology of six H. naledi individuals from the Dinaledi Chamber to those of African and Eurasian Plio-Pleistocene fossil hominins (totalling 183 mandibular first, second and third molars). The analysis of five root metric variables (cervical plane area, root length, root cervix volume, root branch volume, and root surface area) derived from microCT reconstructions reveals that the molar roots of H. naledi are smaller than those of Homo habilis, Homo rudolfensis, and H. erectus, but that they resemble those of three Homo sp. specimens from Swartkrans and Koobi Fora in size and overall appearance. Moreover, though H. naledi molar roots are similar in absolute size to Pleistocene Homo sapiens, they differ from H. sapiens in having a larger root volume for a given cervical plane area and less taurodont roots; the root cervix-to-branch proportions of H. naledi are comparable to those of Australopithecus africanus and species of Paranthropus. H. naledi also shares a metameric root volume pattern (M2 > M3 > M1) with Australopithecus and Paranthropus but not with any of the other Homo species (M2 > M1 > M3). Our findings therefore concur with previous studies that found that H. naledi shares plesiomorphic features with early Homo, Australopithecus, and Paranthropus. While absolute molar root size aligns H. naledi with Homo from North and South Africa, it is distinguishable from these in terms of root volumetric proportions.
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Affiliation(s)
- Kornelius Kupczik
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
| | - Lucas K Delezene
- Department of Anthropology, University of Arkansas, 330 Old Main, Fayetteville, AR, 72701, USA; Evolutionary Studies Institute and Centre for Excellence in PaleoSciences, University of the Witwatersrand, South Africa
| | - Matthew M Skinner
- Evolutionary Studies Institute and Centre for Excellence in PaleoSciences, University of the Witwatersrand, South Africa; School of Anthropology and Conservation, University of Kent, Canterbury, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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26
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VanSickle C, Cofran Z, García-Martínez D, Williams SA, Churchill SE, Berger LR, Hawks J. Homo naledi pelvic remains from the Dinaledi Chamber, South Africa. J Hum Evol 2018; 125:122-136. [DOI: 10.1016/j.jhevol.2017.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 09/27/2017] [Accepted: 10/03/2017] [Indexed: 11/30/2022]
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27
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Ancient teeth, phenetic affinities, and African hominins: Another look at where Homo naledi fits in. J Hum Evol 2018; 122:108-123. [DOI: 10.1016/j.jhevol.2018.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 05/18/2018] [Accepted: 05/21/2018] [Indexed: 12/25/2022]
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28
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Guatelli-Steinberg D, O'Hara MC, Le Cabec A, Delezene LK, Reid DJ, Skinner MM, Berger LR. Patterns of lateral enamel growth in Homo naledi as assessed through perikymata distribution and number. J Hum Evol 2018; 121:40-54. [DOI: 10.1016/j.jhevol.2018.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 11/24/2022]
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29
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Description and analysis of three Homo naledi incudes from the Dinaledi Chamber, Rising Star cave (South Africa). J Hum Evol 2018; 122:146-155. [PMID: 30001870 DOI: 10.1016/j.jhevol.2018.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/20/2018] [Accepted: 06/21/2018] [Indexed: 11/22/2022]
Abstract
This study describes three incudes recovered from the Dinaledi Chamber in the Rising Star cave system in South Africa. All three bones were recovered during sieving of excavated sediments and likely represent three Homo naledi individuals. Morphologically and metrically, the Dinaledi ossicles resemble those of chimpanzees and Paranthropus robustus more than they do later members of the genus Homo, and fall outside of the modern human range of variation in several dimensions. Despite this, when overall size is considered, the functional lengths in H. naledi and P. robustus are very similar to those predicted for a human with a similar-sized incus. In this sense, both taxa seem to show a relatively elongated functional length, distinguishing them from chimpanzees. The functional length in H. naledi is slightly longer in absolute terms than in P. robustus, suggesting H. naledi may already show a slight increase in functional length compared with early hominins. While H. naledi lacks the more open angle between the long and short processes found in modern humans, considered a derived feature within the genus Homo, the value in H. naledi is similar to that predicted for a hominoid with a similar-sized incus. Principal components analysis of size-standardized variables shows H. naledi falling outside of the recent human range of variation, but within the confidence ellipse for gorillas. Phylogenetic polarity is complicated by the absence of incus data from early members of the genus Homo, but the generally primitive nature of the H. naledi incudes is consistent with other primitive features of the species, such as the very small cranial capacity. These ossicles add significantly to the understanding of incus variation in hominins and provide important new data on the morphology and taxonomic affinities of H. naledi.
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30
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Dental topography and the diet of Homo naledi. J Hum Evol 2018; 118:14-26. [DOI: 10.1016/j.jhevol.2018.02.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 02/05/2018] [Accepted: 02/08/2018] [Indexed: 11/20/2022]
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31
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DUNN JACOBC. Sexual selection and the loss of laryngeal air sacs during the evolution of speech. ANTHROPOL SCI 2018. [DOI: 10.1537/ase.180309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- JACOB C. DUNN
- Behavioural Ecology Research Group, Department of Biology, Anglia Ruskin University, Cambridge
- Division of Biological Anthropology, Department of Archaeology, University of Cambridge, Cambridge
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32
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Will M, Pablos A, Stock JT. Long-term patterns of body mass and stature evolution within the hominin lineage. ROYAL SOCIETY OPEN SCIENCE 2017; 4:171339. [PMID: 29291118 PMCID: PMC5717693 DOI: 10.1098/rsos.171339] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 10/04/2017] [Indexed: 05/20/2023]
Abstract
Body size is a central determinant of a species' biology and adaptive strategy, but the number of reliable estimates of hominin body mass and stature have been insufficient to determine long-term patterns and subtle interactions in these size components within our lineage. Here, we analyse 254 body mass and 204 stature estimates from a total of 311 hominin specimens dating from 4.4 Ma to the Holocene using multi-level chronological and taxonomic analytical categories. The results demonstrate complex temporal patterns of body size variation with phases of relative stasis intermitted by periods of rapid increases. The observed trajectories could result from punctuated increases at speciation events, but also differential proliferation of large-bodied taxa or the extinction of small-bodied populations. Combined taxonomic and temporal analyses show that in relation to australopithecines, early Homo is characterized by significantly larger average body mass and stature but retains considerable diversity, including small body sizes. Within later Homo, stature and body mass evolution follow different trajectories: average modern stature is maintained from ca 1.6 Ma, while consistently higher body masses are not established until the Middle Pleistocene at ca 0.5-0.4 Ma, likely caused by directional selection related to colonizing higher latitudes. Selection against small-bodied individuals (less than 40 kg; less than 140 cm) after 1.4 Ma is associated with a decrease in relative size variability in later Homo species compared with earlier Homo and australopithecines. The isolated small-bodied individuals of Homo naledi (ca 0.3 Ma) and Homo floresiensis (ca 100-60 ka) constitute important exceptions to these general patterns, adding further layers of complexity to the evolution of body size within the genus Homo. At the end of the Late Pleistocene and Holocene, body size in Homo sapiens declines on average, but also extends to lower limits not seen in comparable frequency since early Homo.
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Affiliation(s)
- Manuel Will
- Gonville and Caius College, University of Cambridge, Cambridge CB2 3QG, UK
- PAVE Research Group, Department of Archaeology, University of Cambridge, Cambridge CB2 3QG, UK
- Department of Early Prehistory and Quaternary Ecology, University of Tübingen, Schloss Hohentübingen, 72070 Tübingen, Germany
| | - Adrián Pablos
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Paseo Sierra de Atapuerca 3, 09002 Burgos, Spain
- Grupo de Bioacústica Evolutiva y Paleoantropolgía (BEP), Área de Antropología Física, Departamento de Ciencias de la Vida, Universidad de Alcalá, Alcalá de Henares, 28871 Madrid, Spain
- Centro Mixto UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, c/Monforte de Lemos, 5, 28029 Madrid, Spain
| | - Jay T. Stock
- PAVE Research Group, Department of Archaeology, University of Cambridge, Cambridge CB2 3QG, UK
- Department of Anthropology, Western University, London, Ontario, CanadaN6A 3K7
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