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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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2
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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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3
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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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4
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Grine FE, Mongle CS, Fleagle JG, Hammond AS. The taxonomic attribution of African hominin postcrania from the Miocene through the Pleistocene: Associations and assumptions. J Hum Evol 2022; 173:103255. [PMID: 36375243 DOI: 10.1016/j.jhevol.2022.103255] [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: 09/15/2021] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 11/06/2022]
Abstract
Postcranial bones may provide valuable information about fossil taxa relating to their locomotor habits, manipulative abilities and body sizes. Distinctive features of the postcranial skeleton are sometimes noted in species diagnoses. Although numerous isolated postcranial fossils have become accepted by many workers as belonging to a particular species, it is worthwhile revisiting the evidence for each attribution before including them in comparative samples in relation to the descriptions of new fossils, functional analyses in relation to particular taxa, or in evolutionary contexts. Although some workers eschew the taxonomic attribution of postcranial fossils as being less important (or interesting) than interpreting their functional morphology, it is impossible to consider the evolution of functional anatomy in a taxonomic and phylogenetic vacuum. There are 21 widely recognized hominin taxa that have been described from sites in Africa dated from the Late Miocene to the Middle Pleistocene; postcranial elements have been attributed to 17 of these. The bones that have been thus assigned range from many parts of a skeleton to isolated elements. However, the extent to which postcranial material can be reliably attributed to a specific taxon varies considerably from site to site and species to species, and is often the subject of considerable debate. Here, we review the postcranial remains attributed to African hominin taxa from the Late Miocene to the Middle and Late Pleistocene and place these assignations into categories of reliability. The catalog of attributions presented here may serve as a guide for making taxonomic decisions in the future.
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Affiliation(s)
- Frederick E Grine
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA.
| | - Carrie S Mongle
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA; Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - John G Fleagle
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - Ashley S Hammond
- Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA; New York Consortium of Evolutionary Primatology (NYCEP), New York, NY 10024, USA
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5
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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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6
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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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7
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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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8
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Distinct mandibular premolar crown morphology in Homo naledi and its implications for the evolution of Homo species in southern Africa. Sci Rep 2020; 10:13196. [PMID: 32764597 PMCID: PMC7413389 DOI: 10.1038/s41598-020-69993-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/22/2020] [Indexed: 01/13/2023] Open
Abstract
Homo naledi displays a combination of features across the skeleton not found in any other hominin taxon, which has hindered attempts to determine its placement within the hominin clade. Using geometric morphometrics, we assess the morphology of the mandibular premolars of the species at the enamel-dentine junction (EDJ). Comparing with specimens of Paranthropus, Australopithecus and Homo (n = 97), we find that the H. naledi premolars from the Dinaledi chamber consistently display a suite of traits (e.g., tall crown, well-developed P3 and P4 metaconid, strongly developed P3 mesial marginal ridge, and a P3 > P4 size relationship) that distinguish them from known hominin groups. Premolars from a second locality, the Lesedi Chamber, are consistent with this morphology. We also find that two specimens from South Africa, SK 96 (usually attributed to Paranthropus) and Stw 80 (Homo sp.), show similarities to the species, and we discuss a potential evolutionary link between H. naledi and hominins from Sterkfontein and Swartkrans.
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9
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Uy J, Hawks J, VanSickle C. Sexual dimorphism of the relationship between the gut and pelvis in humans. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 173:130-140. [PMID: 32519366 DOI: 10.1002/ajpa.24084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 02/04/2020] [Accepted: 05/06/2020] [Indexed: 01/12/2023]
Abstract
OBJECTIVES Obstetric demands have long been considered in the evolution of the pelvis, yet consideration of the interaction of pregnancy, the pelvis, and the gastrointestinal tract (gut) is lacking. Here, we explore sex differences in the relationship of gut volume with body size and pelvic dimensions. MATERIALS AND METHODS Computed tomography (CT) scans of living adult Homo sapiens (46 females and 42 males) were obtained to measure in vivo gut volume (GV) and to extract 3D models of the pelvis. We collected 19 3D landmarks from each pelvis model to acquire pelvic measurements. We used ordinary least squares regression to explore relationships between GV and body weight, stature, and linear pelvic dimensions. RESULTS The gut-pelvis relationship differs between males and females. Females do not exhibit significant statistical correlations between GV and any variable tested. GV correlates with body size and pelvic outlet size in males. GV scales with negative allometry relative to body weight, stature, maximum bi-iliac breadth, inferior transverse outlet breadth, and bispinous distance in males. DISCUSSION The lack of association between GV and body size in females may be due to limits imposed by the anticipation of accommodating a gravid uterus and/or the increased plasticity of the pelvis. The pattern of relationship between GV and the pelvic outlet suggests the role of the bony pelvis in supporting the adominal viscera in females may be small relative to its role in childbirth. We conclude that gut size inference in fossil hominins from skeletal proxies is limited and confounded by sexual dimorphism.
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Affiliation(s)
- Jeanelle Uy
- Department of Anthropology, California State University, Long Beach, California, USA
| | - John Hawks
- Department of Anthropology, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, South Africa
| | - Caroline VanSickle
- Department of Anatomy, A.T. Still University Kirksville College of Osteopathic Medicine, 800 W. Jefferson St., Kirksville, Missouri, USA
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10
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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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11
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Moving Beyond the Obstetrical Dilemma Hypothesis: Birth, Weaning and Infant Care in the Plio-Pleistocene. THE MOTHER-INFANT NEXUS IN ANTHROPOLOGY 2020. [DOI: 10.1007/978-3-030-27393-4_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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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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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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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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