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Massé L, d’Incau E, Souron A, Vanderesse N, Santos F, Maureille B, Le Cabec A. Unraveling the Life History of Past Populations through Hypercementosis: Insights into Cementum Apposition Patterns and Possible Etiologies Using Micro-CT and Confocal Microscopy. BIOLOGY 2024; 13:43. [PMID: 38248474 PMCID: PMC10813066 DOI: 10.3390/biology13010043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/23/2024]
Abstract
The "teeth-as-tools" hypothesis posits that Neanderthals used their anterior teeth as a tool or a third hand for non-dietary purposes. These non- or para-masticatory activities (e.g., tool-making or food preparation prior to ingestion) have also been described in other past and extant human populations, and other Primates. Cementum is the mineralized tissue that covers the tooth root surface and anchors it to the alveolar bone. Under certain conditions (e.g., mechanical stress, infection), its production becomes excessive (i.e., beyond the physiological state) and is called 'hypercementosis'. Several studies in dental anthropology have established a correlation between the teeth-as-tools and hypercementosis. The present work aims to characterize the different patterns of cementum apposition on archeological teeth and discuss their supposed etiology. Using microtomography and confocal microscopy, the patterns of cementum apposition (i.e., thickness, location, and surface characteristics) were analyzed in 35 hypercementotic teeth (Sains-en-Gohelle, France; 7th-17th c. A.D.). Four groups were identified with distinct hypercementosis patterns: (1) impacted, (2) infected, (3) hypofunctional, and (4) hyperfunctional teeth. Characterizing hypercementosis can contribute to documenting the oral health status (paleopathology) and/or masticatory activity of individuals, even from isolated teeth. This has implications for the study of fossil hominins, particularly Neanderthals, known for their use of anterior teeth as tools and frequent and substantial occurrence of hypercementosis.
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Affiliation(s)
- Léa Massé
- Univ. Bordeaux, CNRS, Ministère de la Culture, PACEA, UMR 5199, F-33600 Pessac, France; (A.S.); (N.V.); (F.S.); (B.M.); (A.L.C.)
- UFR des Sciences Odontologiques de Bordeaux, Univ. Bordeaux, F-33076 Bordeaux, France;
- University Hospital, F-33076 Bordeaux, France
| | - Emmanuel d’Incau
- UFR des Sciences Odontologiques de Bordeaux, Univ. Bordeaux, F-33076 Bordeaux, France;
- University Hospital, F-33076 Bordeaux, France
- Univ. Bordeaux, CNRS, SANPSY, UMR 6033, F-33000 Bordeaux, France
| | - Antoine Souron
- Univ. Bordeaux, CNRS, Ministère de la Culture, PACEA, UMR 5199, F-33600 Pessac, France; (A.S.); (N.V.); (F.S.); (B.M.); (A.L.C.)
| | - Nicolas Vanderesse
- Univ. Bordeaux, CNRS, Ministère de la Culture, PACEA, UMR 5199, F-33600 Pessac, France; (A.S.); (N.V.); (F.S.); (B.M.); (A.L.C.)
| | - Frédéric Santos
- Univ. Bordeaux, CNRS, Ministère de la Culture, PACEA, UMR 5199, F-33600 Pessac, France; (A.S.); (N.V.); (F.S.); (B.M.); (A.L.C.)
| | - Bruno Maureille
- Univ. Bordeaux, CNRS, Ministère de la Culture, PACEA, UMR 5199, F-33600 Pessac, France; (A.S.); (N.V.); (F.S.); (B.M.); (A.L.C.)
| | - Adeline Le Cabec
- Univ. Bordeaux, CNRS, Ministère de la Culture, PACEA, UMR 5199, F-33600 Pessac, France; (A.S.); (N.V.); (F.S.); (B.M.); (A.L.C.)
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Grine FE, Mongle CS, Kollmer W, Romanos G, du Plessis A, Maureille B, Braga J. Hypercementosis in Late Pleistocene Homo sapiens fossils from Klasies River Main Site, South Africa. Arch Oral Biol 2023; 149:105664. [PMID: 36889227 DOI: 10.1016/j.archoralbio.2023.105664] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 02/23/2023] [Accepted: 02/26/2023] [Indexed: 03/06/2023]
Abstract
OBJECTIVE To examine early Homo sapiens fossils from the Late Pleistocene site of Klasies River Main Site, South Africa for evidence of hypercementosis. The specimens represent seven adult individuals dated to between 119,000 and 58,000 years ago. These observations are contextualized in relation to the incidences of hypercementosis among recent human populations and fossil human samples and the potential etiologies of hypercementosis. DESIGN The fossils were investigated utilizing micro-CT and nano-CT scanning to visualize and measure cementum apposition on permanent incisor, premolar and molar roots. Cementum thickness was measured at mid-root level, and the volume of the cementum sleeve was calculated for the two fossil specimens that display marked hypercementosis. RESULTS Two of the fossils display no evidence of cementum hypertrophy. Three exhibit moderate cementum thickening, barely attaining the quantitative threshold for hypercementosis. Two evince marked hypercementosis. One of the Klasies specimens with marked hypercementosis is judged to be an older individual with periapical abscessing. The second specimen is a younger adult, and seemingly similar in age to other Klasies fossils that exhibit only minimal cementum apposition. However, this second specimen exhibits dento-alveolar ankylosis of the premolar and molars. CONCLUSIONS These two fossils from Klasies River Main Site provide the earliest manifestation of hypercementosis in Homo sapiens.
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Affiliation(s)
- Frederick E Grine
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Carrie S Mongle
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA; Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794, USA
| | - William Kollmer
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA; Department of Periodontology, Stony Brook University School of Dental Medicine, Stony Brook, NY 11794, USA
| | - Georgios Romanos
- Department of Periodontology, Stony Brook University School of Dental Medicine, Stony Brook, NY 11794, USA
| | - Anton du Plessis
- Department of Physics, Stellenbosch University, Stellenbosch 7602, South Africa; Object Research Systems, 460 Saint-Catherine St. W, Montreal, Quebec H3B 1A7, Canada
| | - Bruno Maureille
- Université de Bordeaux, CNRS, Ministère de la Culture, PACEA, UMR5199, F-33600 Pessac, France
| | - José Braga
- Center for Anthrobiology & Genomics Institute of Toulouse, CNRS UMR 5288, Université de Toulouse, Université Paul Sabatier, 37 allées Jules Guesde, Toulouse 31000, France
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Insights into the aetiologies of hypercementosis: A systematic review and a scoring system. Arch Oral Biol 2023; 146:105599. [PMID: 36495812 DOI: 10.1016/j.archoralbio.2022.105599] [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: 09/08/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/11/2022]
Abstract
OBJECTIVES This paper aims to better define hypercementosis, investigate its described potential aetiologies, and determine whether there are different patterns of cementum apposition and if they are a function of their supposed aetiology. DESIGN A literature review was undertaken using the Medline, DOSS, Scopus and Cochrane Library electronic databases. Two co-authors selected the published works independently, extracted the data in accordance with the PRISMA statement. RESULTS Among 546 articles, 75 articles were finally selected. Eight different supposed aetiologies were identified: (1) intensive masticatory effort, (2) systemic disease, (3) carious lesion and apical periodontitis, (4) impaction, (5) periodontal disease, (6) concrescence, (7) super-eruption, and (8) drugs. Some of these aetiologies can be combined in the same tooth. Hypercementosis manifestations are various in nature and extent with different patterns that may be aetiology-specific. To improve the description and associated consistency in the characterisation of hypercementosis, in this review but also in future studies, we propose a new qualitative scoring system to quickly characterise hypercementosis and determine its most relevant aetiology. CONCLUSIONS This systematic review demonstrates that hypercementosis is a complex and not yet well-defined condition. Some forms of apposition are specific to a given aetiology. The hypercementosis characterisation may contribute to document the oral condition and/or the individuals masticatory activity.
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An ancient cranium from Dmanisi: Evidence for interpersonal violence, disease, and possible predation by carnivores on Early Pleistocene Homo. J Hum Evol 2022; 166:103180. [DOI: 10.1016/j.jhevol.2022.103180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 12/11/2022]
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Towle I, Irish JD, Sabbi KH, Loch C. Dental caries in wild primates: Interproximal cavities on anterior teeth. Am J Primatol 2021; 84:e23349. [PMID: 34855230 DOI: 10.1002/ajp.23349] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/13/2021] [Accepted: 11/11/2021] [Indexed: 11/10/2022]
Abstract
Dental caries has been reported in a variety of primates, although it is still considered rare in wild populations. In this study, 11 catarrhine primate taxa (n = 339 individuals; 7946 teeth) were studied for the presence of caries. A differential diagnosis of lesions in interproximal regions of anterior teeth was undertaken, since they had been previously described as both carious and non-carious in origin. Each permanent tooth was examined macroscopically, with severity and position of lesions recorded. Two specimens were examined further, using micro-CT scans to assess demineralization. Differential diagnosis confirmed the cariogenic nature of interproximal cavities on anterior teeth (ICATs). Overall results show 3.3% of all teeth (i.e., anterior and posterior teeth combined) were carious (n = 262), with prevalence varying among species from 0% to >7% of teeth affected. Those with the highest prevalence of ICATs include Pan troglodytes verus (9.8% of anterior teeth), Gorilla gorilla gorilla (2.6%), Cercopithecus denti (22.4%), Presbytis femoralis (19.5%), and Cercopithecus mitis (18.3%). ICATs make up 87.9% of carious lesions on anterior teeth. These results likely reflect dietary and food processing differences among species, but also between the sexes (e.g., 9.3% of all female P. troglodytes verus teeth were carious vs. 1.8% in males). Processing cariogenic fruits and seeds with the anterior dentition (e.g., wadging) likely contributes to ICAT formation. Further research is needed in living primate populations to ascertain behavioral/dietary influences on caries occurrence. Given the presence of ICATs in frugivorous primates, their diagnosis in archaeological and paleontological specimens may shed light on diet and food processing behaviors in fossil primates.
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Affiliation(s)
- Ian Towle
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - 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
| | - Kris H Sabbi
- Department of Anthropology and Department of Biology, Tufts University, Medford, MA, USA
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
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Towle I, Irish JD, De Groote I, Fernée C, Loch C. Dental caries in South African fossil hominins. S AFR J SCI 2021. [DOI: 10.17159/sajs.2021/8705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Once considered rare in fossil hominins, caries has recently been reported in several hominin species, requiring a new assessment of this condition during human evolution. Caries prevalence and location on the teeth of South African fossil hominins were observed and compared with published data from other hominin samples. Teeth were viewed macroscopically, with lesion position and severity noted and described. For all South African fossil hominin specimens studied to date, a total of 10 carious teeth (14 lesions), including 4 described for the first time here, have been observed. These carious teeth were found in a minimum of seven individuals, including five Paranthropus robustus, one early Homo, and one Homo naledi. All 14 lesions affected posterior teeth. The results suggest cariogenic biofilms and foods may have been present in the oral environment of a wide variety of hominins. Caries prevalence in studied fossil hominins is similar to those in pre-agricultural human groups, in which 1–5% of teeth are typically affected.
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Affiliation(s)
- Ian Towle
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Joel D. Irish
- Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, United Kingdom
- Evolutionary Studies Institute and Centre for Excellence in PaleoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Christianne Fernée
- Department of Anthropology and Archaeology, University of Bristol, Bristol, United Kingdom
- Department of Archaeology, University of Southampton, Southampton, United Kingdom
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
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Towle I, Riga A, Irish JD, Dori I, Menter C, Moggi-Cecchi J. Root caries on a Paranthropus robustus third molar from Drimolen. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 170:319-323. [PMID: 31265762 DOI: 10.1002/ajpa.23891] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/17/2019] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Dental caries is often perceived as a modern human disease. However, their presence is documented in many early human groups, various nonhuman primates and, increasingly, our hominin ancestors and relatives. In this study, we describe an antemortem lesion on the root of a Paranthropus robustus third molar from Drimolen, South Africa, which likely represents another example of caries in fossil hominins. MATERIALS AND METHODS The molar, DNH 40, is dated to 2.0-1.5 Ma and displays a lesion on the mesial root surface, extending from the cementoenamel junction 3 mm down toward the apex. The position and severity of the lesion was macroscopically recorded and micro-CT scanned to determine the extent of dentine involvement. RESULTS A differential diagnosis indicates root caries, as the lesion is indistinguishable from clinical examples. Although necrotic in appearance, external tertiary dentine is evident on a micro CT scan. Gingival recession and/or continuous eruption of the tooth as a result of extensive occlusal wear would have occurred to facilitate caries formation. Therefore, the lesion is likely linked to relative old age of this individual. DISCUSSION This new example increases the total number of carious lesions described in P. robustus teeth to 10, on occlusal, interproximal, and now, root surfaces. Beyond the consumption of caries-causing food, caries formation would have also required the presence of requisite intraoral cariogenic bacteria in this individual and the species. Of interest, the presence of tertiary dentine on the outward surface suggests the DNH 40 lesion may have been arrested, that is, no longer active, perhaps relating to a change in diet or oral microbiome just prior to the individual's death.
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Affiliation(s)
- Ian Towle
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Alessandro Riga
- Department of Biology, University of Florence, Florence, Italy
| | - Joel D Irish
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK.,Evolutionary Studies Institute and Centre for Excellence in PaleoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Irene Dori
- Department of Biology, University of Florence, Florence, Italy
| | - Colin Menter
- Department of Biology, University of Florence, Florence, Italy
| | - Jacopo Moggi-Cecchi
- Department of Biology, University of Florence, Florence, Italy.,Palaeo-Research Institute, University of Johannesburg, Auckland Park, South Africa
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Marklein KE, Torres-Rouff C, King LM, Hubbe M. The Precarious State of Subsistence: Reevaluating Dental Pathological Lesions Associated with Agricultural and Hunter-Gatherer Lifeways. CURRENT ANTHROPOLOGY 2019. [DOI: 10.1086/703376] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Rightmire GP, Margvelashvili A, Lordkipanidze D. Variation among the Dmanisi hominins: Multiple taxa or one species? AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 168:481-495. [PMID: 30578552 DOI: 10.1002/ajpa.23759] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 11/08/2022]
Abstract
OBJECTIVES There is continuing controversy over the number of taxa documented by the Dmanisi hominins. Variation may reflect age and sex differences within a single population. Alternatively, two (or more) distinct species may be present. Our null hypothesis states that just one population is represented at the site. MATERIALS AND METHODS We assess the likely sources of variation in endocranial capacity, craniofacial and mandibular morphology, and the expression of characters related to aging and sex dimorphism. We use the coefficient of variation and a modified version of Levene's test for equal variances to compare trait variation at Dmanisi with that in fossil hominins and modern Homo sapiens from Africa. RESULTS Skull 5 presents a low, massive vault, and a muzzle-like lower face. Other individuals have larger brains and more globular vaults. Despite such variation, the five crania share numerous features. All of the mandibles possess marginal tubercles, mandibular tori, and a distinctive patterning of mental foramina. Relative variation at Dmanisi is comparable to that in selected reference groups. Further growth anticipated in Skull 3, age-related remodeling affecting the D2600 mandible, pathology, and sex dimorphism can account for much of the interindividual variation observed. The preponderance of evidence supports our null hypothesis. DISCUSSION Sources of the variation within ancient Homo assemblages remain poorly understood. Skull 5 is a very robust male, with a brain smaller than that of both a juvenile (Skull 3) and a probable female (Skull 2). Skull 1 has the largest brain, but cranial superstructures do not clearly mark this individual as male or female. It is likely that the Dmanisi hominins represent a single paleospecies of Homo displaying a pattern of sex dimorphism not seen in living hominids.
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Affiliation(s)
- G Philip Rightmire
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts
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Fuss J, Uhlig G, Böhme M. Earliest evidence of caries lesion in hominids reveal sugar-rich diet for a Middle Miocene dryopithecine from Europe. PLoS One 2018; 13:e0203307. [PMID: 30161214 PMCID: PMC6117023 DOI: 10.1371/journal.pone.0203307] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 08/17/2018] [Indexed: 12/13/2022] Open
Abstract
The formation of dental caries is mainly caused by dietary habits and therefore, may contain information for dietary reconstructions of fossil hominids. This study investigates the caries lesion in the 12.5 Ma old type specimen of Dryopithecus carinthiacus Mottl 1957 (Primates, Hominidae) from St. Stefan (Austria). Potential food sources are identified on associated palynological data, which allow conclusions about food quality, sugar availability and the hominid metabolism during the Middle Miocene. Using micro computed tomography (μCT) and scanning electron microscopy (SEM) we provide a detailed analysis and characterization of the individuals' caries type. Its lesion is compared with a dataset of 311 wild chimpanzees, indicating morphological and etiological differences in caries formation between both species. The affected molar of D. carinthiacus reveals features known from severe dental caries in humans: (1) Cavitation with steep walls and smooth surface; (2) Reparative dentine at the roof of the pulp chamber; (3) Sclerotic dentine below the cavitation; (4) Association with dental calculus and (5) Unilateral usage of the healthy right tooth row. Its advanced primary caries, initiating on the intact enamel surface, indicates a frequent intake of highly cariogenic sugar-rich fruits, which likely exceeds the frugivory of extant chimpanzees. This finding corresponds with the associated palynological record, which infers a habitat with nearly year-round supply (9-10 months/year) of high quality foods (>carbohydrates; < fibers). Our conclusions challenge the model of a step-wise increase in dietary quality during hominid evolution and support the uricase hypothesis, which discusses the hominid autapomorphy of a fructose-based fat accumulation for periods of starvation. This model receives further validation by the identification of soft-tissue preservation, interpreted as fossilized white adipose cells, in the articulated hominid skeleton of Oreopithecus bamboli from Italy.
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Affiliation(s)
- Jochen Fuss
- Department of Geoscience, Eberhard-Karls-University Tübingen, Tübingen, Germany
- Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP), Tübingen, Germany
| | - Gregor Uhlig
- Department of Chemistry and Food Chemistry, Technical University Dresden, Dresden, Germany
| | - Madelaine Böhme
- Department of Geoscience, Eberhard-Karls-University Tübingen, Tübingen, Germany
- Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP), Tübingen, Germany
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Grine FE, Marean CW, Faith JT, Black W, Mongle CS, Trinkaus E, le Roux SG, du Plessis A. Further human fossils from the Middle Stone Age deposits of Die Kelders Cave 1, Western Cape Province, South Africa. J Hum Evol 2017; 109:70-78. [DOI: 10.1016/j.jhevol.2017.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/21/2017] [Accepted: 05/22/2017] [Indexed: 10/19/2022]
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Skull 5 from Dmanisi: Descriptive anatomy, comparative studies, and evolutionary significance. J Hum Evol 2017; 104:50-79. [PMID: 28317556 DOI: 10.1016/j.jhevol.2017.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 11/21/2022]
Abstract
A fifth hominin skull (cranium D4500 and mandible D2600) from Dmanisi is massively constructed, with a large face and a very small brain. Traits documented for the first time in a basal member of the Homo clade include the uniquely low ratio of endocranial volume to basicranial width, reduced vertex height, angular vault profile, smooth nasal sill coupled with a long and sloping maxillary clivus, elongated palate, and tall mandibular corpus. The convex clivus and receding symphysis of skull 5 produce a muzzle-like form similar to that of Australopithecus afarensis. While the Dmanisi cranium is very robust, differing from OH 13, OH 24, and KNM-ER 1813, it resembles Homo habilis specimens in the "squared off" outline of its maxilla in facial view, maxillary sulcus, rounded and receding zygomatic arch, and flexed zygomaticoalveolar pillar. These characters distinguish early Homo from species of Australopithecus and Paranthropus. Skull 5 is unlike Homo rudolfensis cranium KNM-ER 1470. Although it appears generally primitive, skull 5 possesses a bar-like supraorbital torus, elongated temporal squama, occipital transverse torus, and petrotympanic traits considered to be derived for Homo erectus. As a group, the Dmanisi crania and mandibles display substantial anatomical and metric variation. A key question is whether the fossils document age-related growth and sex dimorphism within a single population, or whether two (or more) distinct taxa may be present at the site. We use the coefficient of variation to compare Dmanisi with Paranthropus boisei, H. erectus, and recent Homo sapiens, finding few signals that the Dmanisi sample is excessively variable in comparison to these reference taxa. Using cranial measurements and principal components analysis, we explore the proposal that the Dmanisi skulls can be grouped within a regionally diverse hypodigm for H. erectus. Our results provide only weak support for this hypothesis. Finally, we consider all available morphological and paleobiological evidence in an attempt to clarify the phyletic relationship of Dmanisi to Homo species evolving >2.0 to 1.0 Ma.
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Antón SC, Taboada HG, Middleton ER, Rainwater CW, Taylor AB, Turner TR, Turnquist JE, Weinstein KJ, Williams SA. Morphological variation in Homo erectus and the origins of developmental plasticity. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150236. [PMID: 27298467 PMCID: PMC4920293 DOI: 10.1098/rstb.2015.0236] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2016] [Indexed: 11/12/2022] Open
Abstract
Homo erectus was the first hominin to exhibit extensive range expansion. This extraordinary departure from Africa, especially into more temperate climates of Eurasia, has been variously related to technological, energetic and foraging shifts. The temporal and regional anatomical variation in H. erectus suggests that a high level of developmental plasticity, a key factor in the ability of H. sapiens to occupy a variety of habitats, may also have been present in H. erectus. Developmental plasticity, the ability to modify development in response to environmental conditions, results in differences in size, shape and dimorphism across populations that relate in part to levels of resource sufficiency and extrinsic mortality. These differences predict not only regional variations but also overall smaller adult sizes and lower levels of dimorphism in instances of resource scarcity and high predator load. We consider the metric variation in 35 human and non-human primate 'populations' from known environmental contexts and 14 time- and space-restricted paleodemes of H. erectus and other fossil Homo Human and non-human primates exhibit more similar patterns of variation than expected, with plasticity evident, but in differing patterns by sex across populations. The fossil samples show less evidence of variation than expected, although H. erectus varies more than Neandertals.This article is part of the themed issue 'Major transitions in human evolution'.
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Affiliation(s)
- Susan C Antón
- Department of Anthropology, New York University, New York, NY 10003, USA
| | - Hannah G Taboada
- Department of Anthropology, New York University, New York, NY 10003, USA
| | - Emily R Middleton
- Department of Anthropology, New York University, New York, NY 10003, USA Department of Pathology and Anatomical Sciences, University of Missouri, M263 Medical Science Building, Columbia, MO 65212, USA
| | | | - Andrea B Taylor
- Department of Orthopaedics, Duke University School of Medicine, Durham, NC 27708, USA Department of Evolutionary Anthropology, Duke University School of Medicine, Durham, NC 27708, USA
| | - Trudy R Turner
- Department of Anthropology, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA University of the Free State, Bloemfontein, South Africa
| | - Jean E Turnquist
- Caribbean Primate Research Center and Department of Anatomy and Neurobiology (Retired), University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico, USA
| | - Karen J Weinstein
- Department of Anthropology and Archaeology, Dickinson College, Carlisle, PA 17013, USA
| | - Scott A Williams
- Department of Anthropology, New York University, New York, NY 10003, USA
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