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Pablos A, Arsuaga JL. Tarsals from the Sima de los Huesos Middle Pleistocene site (Atapuerca, Burgos, Spain). Anat Rec (Hoboken) 2024. [PMID: 38477186 DOI: 10.1002/ar.25425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Here, we provide a complete, updated, and illustrated inventory, as well as a comprehensive study, of the tarsals (rearfoot) recovered from the Middle Pleistocene site of Sima de los Huesos (SH, Atapuerca, Spain) in comparison to other Homo comparative samples, both extant and fossil. The minimum number of individuals (MNI) estimated from the tarsals has been established as 15, which represents 51.7% of the 29 dental individuals identified within the SH sample. Within the SH hominin foot sample, an exclusive combination of primitive or plesiomorphic and derived or autapomorphic traits can be observed when compared with other Homo individuals/populations. Other characters are shared among SH hominins and Neandertals that might represent shared derived or autapomorphic traits for this evolutionary line, and most are likely related to robusticity (e.g., rectangular-like trochlea of the talus, broad calcanei, broad naviculars, and short lateral cuneiforms). Additionally, we observed some exclusive autapomorphic traits in the SH tarsal sample (e.g., narrow head of the talus and short intermediate cuneiforms). A few exclusive traits in SH tarsal remains are even more robust than in Neandertals (e.g., broad lateral malleolar facet in talus, more projected sustentaculum tali, and broad medial cuneiform). These traits could suggest a slightly higher level of gracilization in the tarsal bones of Neandertals compared to the SH sample that is also supported by other anatomical postcranial skeleton elements. Additionally, some paleobiological inferences are made in relation to body size (stature and body mass) and some associations are proposed within the SH sample. In conclusion, the morphology of the SH tarsi confirms an evolutionary relationship of sister groups between this population and Neandertals, probably representing a morphotype similar to the Neandertal ancestors.
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Affiliation(s)
- Adrián Pablos
- Departamento de Geodinámica, Estratigrafía y Paleontología, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Prehistoria y Arqueología, Universidad de Sevilla, Sevilla, Spain
- Centro Mixto UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Madrid, Spain
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
| | - Juan Luis Arsuaga
- Departamento de Geodinámica, Estratigrafía y Paleontología, Universidad Complutense de Madrid, Madrid, Spain
- Centro Mixto UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Madrid, Spain
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2
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Vilos GA, Vilos AG, Burbank F. Bipedalism and the dawn of uterine fibroids. Hum Reprod 2024; 39:454-463. [PMID: 38300232 DOI: 10.1093/humrep/deae005] [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: 03/13/2023] [Revised: 01/03/2024] [Indexed: 02/02/2024] Open
Abstract
The high prevalence and burden of uterine fibroids in women raises questions about the origin of these benign growths. Here, we propose that fibroids should be understood in the context of human evolution, specifically the advent of bipedal locomotion in the hominin lineage. Over the ≥7 million years since our arboreal ancestors left their trees, skeletal adaptations ensued, affecting the pelvis, limbs, hands, and feet. By 3.2 million years ago, our ancestors were fully bipedal. A key evolutionary advantage of bipedalism was the freedom to use hands to carry and prepare food and create and use tools which, in turn, led to further evolutionary changes such as brain enlargement (encephalization), including a dramatic increase in the size of the neocortex. Pelvic realignment resulted in narrowing and transformation of the birth canal from a simple cylinder to a convoluted structure with misaligned pelvic inlet, mid-pelvis, and pelvic outlet planes. Neonatal head circumference has increased, greatly complicating parturition in early and modern humans, up to and including our own species. To overcome the so-called obstetric dilemma provoked by bipedal locomotion and encephalization, various compensatory adaptations have occurred affecting human neonatal development. These include adaptations limiting neonatal size, namely altricial birth (delivery of infants at an early neurodevelopmental stage, relative to other primates) and mid-gestation skeletal growth deceleration. Another key adaptation was hyperplasia of the myometrium, specifically the neomyometrium (the outer two-thirds of the myometrium, corresponding to 90% of the uterine musculature), allowing the uterus to more forcefully push the baby through the pelvis during a lengthy parturition. We propose that this hyperplasia of smooth muscle tissue set the stage for highly prevalent uterine fibroids. These fibroids are therefore a consequence of the obstetric dilemma and, ultimately, of the evolution of bipedalism in our hominin ancestors.
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Affiliation(s)
- George A Vilos
- Department of Obstetrics and Gynecology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Angelos G Vilos
- Department of Obstetrics and Gynecology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Fred Burbank
- Salt Creek International Women's Health Foundation, San Clemente, CA, USA
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3
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Mitteroecker P, Fischer B. Evolution of the human birth canal. Am J Obstet Gynecol 2024; 230:S841-S855. [PMID: 38462258 DOI: 10.1016/j.ajog.2022.09.010] [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: 05/02/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 03/12/2024]
Abstract
It seems puzzling why humans have evolved such a small and rigid birth canal that entails a relatively complex process of labor compared with the birth canal of our closest relatives, the great apes. This study reviewed insights into the evolution of the human birth canal from recent theoretical and empirical studies and discussed connections to obstetrics, gynecology, and orthopedics. Originating from the evolution of bipedality and the large human brain million years ago, the evolution of the human birth canal has been characterized by complex trade-off dynamics among multiple biological, environmental, and sociocultural factors. The long-held notion that a wider pelvis has not evolved because it would be disadvantageous for bipedal locomotion has not yet been empirically verified. However, recent clinical and biomechanical studies suggest that a larger birth canal would compromise pelvic floor stability and increase the risk of incontinence and pelvic organ prolapse. Several mammals have neonates that are equally large or even larger than human neonates compared to the size of the maternal birth canal. In these species, the pubic symphysis opens widely to allow successful delivery. Biomechanical and developmental constraints imposed by bipedality have hindered this evolutionary solution in humans and led to the comparatively rigid pelvic girdle in pregnant women. Mathematical models have shown why the evolutionary compromise to these antagonistic selective factors inevitably involves a certain rate of fetopelvic disproportion. In addition, these models predict that cesarean deliveries have disrupted the evolutionary equilibrium and led to new and ongoing evolutionary changes. Different forms of assisted birth have existed since the stone age and have become an integral part of human reproduction. Paradoxically, by buffering selection, they may also have hindered the evolution of a larger birth canal. Many of the biological, environmental, and sociocultural factors that have influenced the evolution of the human birth canal vary globally and are subject to ongoing transitions. These differences may have contributed to the global variation in the form of the birth canal and the difficulty of labor, and they likely continue to change human reproductive anatomy.
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Affiliation(s)
- Philipp Mitteroecker
- Unit for Theoretical Biology, Department of Evolutionary Biology, University of Vienna, Vienna, Austria.
| | - Barbara Fischer
- Unit for Theoretical Biology, Department of Evolutionary Biology, University of Vienna, Vienna, Austria
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4
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Pablos A, Arsuaga JL. Metatarsals and foot phalanges from the Sima de los Huesos Middle Pleistocene site (Atapuerca, Burgos, Spain). Anat Rec (Hoboken) 2024. [PMID: 38380556 DOI: 10.1002/ar.25412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/22/2024]
Abstract
This study provides a complete, updated and illustrated inventory, as well as a comprehensive study, of the metatarsals and foot phalanges (forefoot) recovered from the Middle Pleistocene site of Sima de los Huesos (SH, Atapuerca, Spain) in comparison to other Homo comparative samples, both extant and fossils. This current updated review has established a minimum number of individuals (MNI) of 17, which represent 58.6% of the 29 dental individuals identified within the SH sample. An exclusive or autoapomorphic combination of traits can be recognized within the SH hominin foot sample. A few traits appear primitive or plesiomorphic when compared with earlier Homo individuals and other recent modern humans. There are other metrical and morphological traits that SH hominins and Neandertals have in common that sometimes represent shared derived traits in this evolutionary line, most of which are probably related to robusticity. Furthermore, some exclusive autoapomorphic traits are observed in the SH sample: a very broad first metatarsal, long and broad hallucal proximal foot phalanges and possibly extremely robust lateral distal foot phalanges compared to those of Neandertals and modern humans. In these last traits, the SH metatarsals and pedal phalanges are even more robust than in Neandertals. They are herein named as "hyper-Neandertal" traits, which could suggest a slight gracilization process in this evolutionary line, at least in the hallux toe. Finally, some paleobiological inferences are made in relation to body size (stature and body mass) and some associations are proposed within the SH sample.
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Affiliation(s)
- Adrián Pablos
- Departamento de Geodinámica, Estratigrafía y Paleontología, Universidad Complutense de Madrid, Madrid, Spain
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
- Departamento de Prehistoria y Arqueología, Universidad de Sevilla, Sevilla, Spain
- Centro Mixto UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Madrid, Spain
| | - Juan Luis Arsuaga
- Departamento de Geodinámica, Estratigrafía y Paleontología, Universidad Complutense de Madrid, Madrid, Spain
- Centro Mixto UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Madrid, Spain
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 4: evolution, thermal adaptation and unsupported theories of thermoregulation. Eur J Appl Physiol 2024; 124:147-218. [PMID: 37796290 DOI: 10.1007/s00421-023-05262-9] [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: 02/06/2023] [Accepted: 06/13/2023] [Indexed: 10/06/2023]
Abstract
This review is the final contribution to a four-part, historical series on human exercise physiology in thermally stressful conditions. The series opened with reminders of the principles governing heat exchange and an overview of our contemporary understanding of thermoregulation (Part 1). We then reviewed the development of physiological measurements (Part 2) used to reveal the autonomic processes at work during heat and cold stresses. Next, we re-examined thermal-stress tolerance and intolerance, and critiqued the indices of thermal stress and strain (Part 3). Herein, we describe the evolutionary steps that endowed humans with a unique potential to tolerate endurance activity in the heat, and we examine how those attributes can be enhanced during thermal adaptation. The first of our ancestors to qualify as an athlete was Homo erectus, who were hairless, sweating specialists with eccrine sweat glands covering almost their entire body surface. Homo sapiens were skilful behavioural thermoregulators, which preserved their resource-wasteful, autonomic thermoeffectors (shivering and sweating) for more stressful encounters. Following emigration, they regularly experienced heat and cold stress, to which they acclimatised and developed less powerful (habituated) effector responses when those stresses were re-encountered. We critique hypotheses that linked thermoregulatory differences to ancestry. By exploring short-term heat and cold acclimation, we reveal sweat hypersecretion and powerful shivering to be protective, transitional stages en route to more complete thermal adaptation (habituation). To conclude this historical series, we examine some of the concepts and hypotheses of thermoregulation during exercise that did not withstand the tests of time.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Aramendi J, Mabulla A, Baquedano E, Domínguez-Rodrigo M. Biomechanical and taxonomic diversity in the Early Pleistocene in East Africa: Structural analysis of a recently discovered femur shaft from Olduvai Gorge (bed I). J Hum Evol 2024; 186:103469. [PMID: 38071888 DOI: 10.1016/j.jhevol.2023.103469] [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: 04/28/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 12/30/2023]
Abstract
Recent Plio-Pleistocene hominin findings have revealed the complexity of human evolutionary history and the difficulties involved in its interpretation. Moreover, the study of hominin long bone remains is particularly problematic, since it commonly depends on the analysis of fragmentary skeletal elements that in many cases are merely represented by small diaphyseal portions and appear in an isolated fashion in the fossil record. Nevertheless, the study of the postcranial skeleton is particularly important to ascertain locomotor patterns. Here we report on the discovery of a robust hominin femoral fragment (OH 84) at the site of Amin Mturi Korongo dated to 1.84 Ma (Olduvai Bed I). External anatomy and internal bone structure of OH 84 were analyzed and compared with previously published data for modern humans and chimpanzees, as well as for Australopithecus, Paranthropus and Homo specimens ranging from the Late Pliocene to Late Pleistocene. Biomechanical analyses based on transverse cross-sections and the comparison of OH 84 with another robust Olduvai specimen (OH 80) suggest that OH 84 might be tentatively allocated to Paranthropus boisei. More importantly, the identification of a unique combination of traits in OH 84 could indicate both terrestrial bipedalism and an arboreal component in the locomotor repertoire of this individual. If interpreted correctly, OH 84 could thus add to the already mounting evidence of substantial locomotor diversity among Early Pleistocene hominins. Likewise, our results also highlight the difficulties in accurately interpreting the link between form and function in the human fossil record based on fragmentary remains, and ultimately in distinguishing between coeval hominin groups due to the heterogeneous pattern of inter- and intraspecific morphological variability detected among fossil femora.
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Affiliation(s)
- Julia Aramendi
- McDonald Institute for Archaeological Research, University of Cambridge, CB2 1TN, UK.
| | - Audax Mabulla
- Department of Archaeology and Heritage Studies, University of Dar Es Salaam, P.O. Box 35050, Dar Es Salaam, Tanzania
| | - Enrique Baquedano
- Archaeological and Paleontological Museum of the Community of Madrid, Plaza de Las Bernardas s/n, 28801, Alcalá de Henares, Spain; Institute of Evolution in Africa (IDEA), University of Alcalá and Archaeological and Paleontological Museum of the Community of Madrid, C/Covarrubias 36, 28010, Madrid, Spain
| | - Manuel Domínguez-Rodrigo
- Institute of Evolution in Africa (IDEA), University of Alcalá and Archaeological and Paleontological Museum of the Community of Madrid, C/Covarrubias 36, 28010, Madrid, Spain; University of Alcalá, Department of History and Philosophy, Area of Prehistory, C/Colegios 2, 28801, Alcalá de Henares, Spain; Rice University, Department of Anthropology, 6100 Main St., Houston, TX, 77005 1827, USA
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7
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Torres-Tamayo N, Rae TC, Hirasaki E, Betti L. Testing the reliability of the rearticulation of osteological primate pelves in comparative morphological studies. Anat Rec (Hoboken) 2023. [PMID: 38112056 DOI: 10.1002/ar.25366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/20/2023]
Abstract
The evolution of human pelvic form is primarily studied using disarticulated osteological material of living and fossil primates that need rearticulation to approximate anatomical position. To test whether this technique introduces errors that impact biological signals, virtual rearticulations of the pelvis in anatomical position from computed tomography scans were compared with rearticulated models from the same individuals for one female and one male of Homo sapiens, Pan troglodytes, Macaca mulatta, Lepilemur mustelinus, Galago senegalensis, and Nycticebus pygmaeus. "Cadaveric" pelvic bones were first analyzed in anatomical position, then the three bones were segmented individually, intentionally scattered, and "rearticulated" to test for rearticulation error. Three-dimensional landmarks and linear measurements were used to characterize the overall pelvis shape. Cadaveric and rearticulated pelves were not identical, but inter-specific and intra-specific shape differences were higher than the landmarking error in the cadaveric individuals and the landmarking/rearticulation error in the rearticulated pelves, demonstrating that the biological signal is stronger than the noise introduced by landmarking and rearticulation. The rearticulation process, however, underestimates the medio-lateral pelvic measurements in species with a substantial pubic gap (e.g., G. senegalensis, N. pygmaeus) possibly because the greater contribution of soft tissue to the pelvic girdle introduces higher uncertainty during rearticulation. Nevertheless, this discrepancy affects only the caudal-most part of the pelvis. This study demonstrates that the rearticulation of pelvic bones does not substantially affect the biological signal in comparative 3D morphological studies but suggests that anatomically connected pelves of species with wide pubic gaps should be preferentially included in these studies.
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Affiliation(s)
| | - Todd C Rae
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Eishi Hirasaki
- Centre for Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Japan
| | - Lia Betti
- Department of Anthropology, University College London, London, UK
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8
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Rodríguez L, García-González R, Arsuaga JL, Carretero JM. Exploring the morphology of adult tibia and fibula from Sima de los Huesos site in sierra de Atapuerca, Burgos, Spain. Anat Rec (Hoboken) 2023. [PMID: 37792425 DOI: 10.1002/ar.25336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 10/05/2023]
Abstract
The analysis of the locomotor anatomy of Late Pleistocene Homo has largely focused on changes in proximal femur and pelvic morphologies, with much attention centered on the emergence of modern humans. Although much of the focus has been on changes in the proximal femur, some research has also been conducted on tibiae and, to a lesser extent, fibulae. With this in mind, we present one of the largest samples of the same population of human tibiae and fibulae from the Middle Pleistocene to determine their main characteristic traits and establish similarities and differences, primarily with those of Neanderthals and modern humans, but also with other Middle Pleistocene specimens in the fossil record. Through this study, we established that the Middle Pleistocene population from the Sima de los Huesos (Atapuerca, Burgos, Spain) had lower leg long bones similar to those of Neanderthals, although there were some important differences, such as bone length, which this fossil individuals resembled those of modern humans and not to Neanderthals. This fact is related to the crural index and leg length, even though we do not have any true association between femora and tibiae yet, it has implications for establishing locomotor efficiency and climate adaptation.
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Affiliation(s)
- Laura Rodríguez
- Area de Antropología Física. Departamento de Biodiversidad y Gestión Ambiental, Universidad de León. Facultad de Ciencias Biológicas y Ambientales. Campus De Vegazana, León, España
- Laboratorio de Evolución Humana, Universidad de Burgos, Burgos, España
| | | | - Juan Luis Arsuaga
- Departamento de Geodinámica, Estratigrafía y Paleontología, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid, Madrid, Spain
- Centro UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Madrid, Spain
| | - José-Miguel Carretero
- Laboratorio de Evolución Humana, Universidad de Burgos, Burgos, España
- Centro UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Madrid, Spain
- Unidad Asociada de I+D+i al CSIC Vidrio y Materiales del Patrimonio Cultural (VIMPAC), Universidad de Burgos, Burgos, España
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9
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Warrener A. The multifactor pelvis: An alternative to the adaptationist approach of the obstetrical dilemma. Evol Anthropol 2023; 32:260-274. [PMID: 37527355 DOI: 10.1002/evan.21997] [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: 07/31/2022] [Revised: 02/23/2023] [Accepted: 07/08/2023] [Indexed: 08/03/2023]
Abstract
The obstetrical dilemma describes the competing demands that a bipedally adapted pelvis and a large-brained neonate place on human childbirth and is the predominant model within which hypotheses about the evolution of the pelvis are framed. I argue the obstetrical dilemma follows the adaptationist program outlined by Gould and Lewontin in 1979 and should be replaced with a new model, the multifactor pelvis. This change will allow thorough consideration of nonadaptive explanations for the evolution of the human pelvis and avoid negative social impacts from considering human childbirth inherently dangerous. First, the atomization of the pelvis into discrete traits is discussed, after which current evidence for both adaptive and nonadaptive hypotheses is evaluated, including childbirth, locomotion, shared genetics with other traits under selection, evolutionary history, genetic drift, and environmental and epigenetic influences on the pelvis.
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Affiliation(s)
- Anna Warrener
- Department of Anthropology, University of Colorado Denver, Denver, Colorado, USA
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10
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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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11
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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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12
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Teeth, prenatal growth rates, and the evolution of human-like pregnancy in later Homo. Proc Natl Acad Sci U S A 2022; 119:e2200689119. [PMID: 36191229 PMCID: PMC9564099 DOI: 10.1073/pnas.2200689119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Evidence of how gestational parameters evolved is essential to understanding this fundamental stage of human life. Until now, these data seemed elusive given the skeletal bias of the fossil record. We demonstrate that dentition provides a window into the life of neonates. Teeth begin to form in utero and are intimately associated with gestational development. We measured the molar dentition for 608 catarrhine primates and collected data on prenatal growth rate (PGR) and endocranial volume (ECV) for 19 primate genera from the literature. We found that PGR and ECV are highly correlated (R2 = 0.93, P < 0.001). Additionally, we demonstrated that molar proportions are significantly correlated with PGR (P = 0.004) and log-transformed ECV (P = 0.001). From these correlations, we developed two methods for reconstructing PGR in the fossil record, one using ECV and one using molar proportions. Dental proportions reconstruct hominid ECV (R2 = 0.81, P < 0.001), a result that can be extrapolated to PGR. As teeth dominate fossil assemblages, our findings greatly expand our ability to investigate life history in the fossil record. Fossil ECVs and dental measurements from 13 hominid species both support significantly increasing PGR throughout the terminal Miocene and Plio-Pleistocene, reflecting known evolutionary changes. Together with pelvic and endocranial morphology, reconstructed PGRs indicate the need for increasing maternal energetics during pregnancy over the last 6 million years, reaching a human-like PGR (i.e., more similar to humans than to other extant apes) and ECV in later Homo less than 1 million years ago.
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13
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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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14
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Bastir M, González Ruíz JM, Rueda J, Garrido López G, Gómez-Recio M, Beyer B, San Juan AF, Navarro E. Variation in human 3D trunk shape and its functional implications in hominin evolution. Sci Rep 2022; 12:11762. [PMID: 35817835 PMCID: PMC9273616 DOI: 10.1038/s41598-022-15344-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 06/22/2022] [Indexed: 11/25/2022] Open
Abstract
This study investigates the contribution of external trunk morphology and posture to running performance in an evolutionary framework. It has been proposed that the evolution from primitive to derived features of torso shape involved changes from a mediolaterally wider into a narrower, and antero-posteriorly deeper into a shallower, more lightly built external trunk configuration, possibly in relation to habitat-related changes in locomotor and running behaviour. In this context we produced experimental data to address the hypothesis that medio-laterally narrow and antero-posteriorly shallow torso morphologies favour endurance running capacities. We used 3D geometric morphometrics to relate external 3D trunk shape of trained, young male volunteers (N = 27) to variation in running velocities during different workloads determined at 45–50%, 70% and 85% of heart rate reserve (HRR) and maximum velocity. Below 85% HRR no relationship existed between torso shape and running velocity. However, at 85% HRR and, more clearly, at maximum velocity, we found highly statistically significant relations between external torso shape and running performance. Among all trained subjects those with a relatively narrow, flat torso, a small thoracic kyphosis and a more pronounced lumbar lordosis achieved significantly higher running velocities. These results support the hypothesis that external trunk morphology relates to running performance. Low thoracic kyphosis with a flatter ribcage may affect positively respiratory biomechanics, while increased lordosis affects trunk posture and may be beneficial for lower limb biomechanics related to leg return. Assuming that running workload at 45–50% HRR occurs within aerobic metabolism, our results may imply that external torso shape is unrelated to the evolution of endurance running performance.
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Affiliation(s)
- Markus Bastir
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales, CSIC, J.G. Abascal 2, 28006, Madrid, Spain.
| | - José María González Ruíz
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales, CSIC, J.G. Abascal 2, 28006, Madrid, Spain
| | - Javier Rueda
- Department of Health and Human Performance, Faculty of Physical Activity and Sports Sciences-INEF, Universidad Politécnica de Madrid, 28040, Madrid, Spain
| | - Gonzalo Garrido López
- Department of Health and Human Performance, Faculty of Physical Activity and Sports Sciences-INEF, Universidad Politécnica de Madrid, 28040, Madrid, Spain
| | - Marta Gómez-Recio
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales, CSIC, J.G. Abascal 2, 28006, Madrid, Spain
| | - Benoit Beyer
- Laboratory of Functional Anatomy (LAF), Faculty of Motor Skills Sciences, Université Libre de Bruxelles, Brussels, Belgium
| | - Alejandro F San Juan
- Department of Health and Human Performance, Faculty of Physical Activity and Sports Sciences-INEF, Universidad Politécnica de Madrid, 28040, Madrid, Spain
| | - Enrique Navarro
- Department of Health and Human Performance, Faculty of Physical Activity and Sports Sciences-INEF, Universidad Politécnica de Madrid, 28040, Madrid, Spain
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15
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Terrace HS, Bigelow AE, Beebe B. Intersubjectivity and the Emergence of Words. Front Psychol 2022; 13:693139. [PMID: 35602746 PMCID: PMC9116197 DOI: 10.3389/fpsyg.2022.693139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 03/23/2022] [Indexed: 11/13/2022] Open
Abstract
Intersubjectivity refers to two non-verbal intersubjective relations infants experience during their first year that are precursors to the emergence of words. Trevarthen, a pioneer in the study of intersubjectivity, referred to those relations as primary and secondary intersubjectivity. The former, a dyadic coordination between the infant and her caregiver, begins at birth. The latter, a triadic coordination that develops around 9 months, allows the infant and a caregiver to share attention to particular features of the environment. Secondary intersubjectivity is crucial for an infant’s ability to begin to produce words, at around 12 months. Much research on the social and cognitive origins of language has focused on secondary intersubjectivity. That is unfortunate because it neglects the fact that secondary intersubjectivity and the emergence of words are built on a foundation of primary intersubjectivity. It also ignores the evolutionary origins of intersubjectivity and its uniquely human status. That unique status explains why only humans learn words. This article seeks to address these issues by relating the literature on primary intersubjectivity, particularly research on bi-directional and contingent communication between infants and mothers, to joint attention and ultimately to words. In that context, we also discuss Hrdy’s hypothesis about the influence of alloparents on the evolution of intersubjectivity.
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Affiliation(s)
- Herbert S Terrace
- Departments of Psychology and Psychiatry, Columbia University, New York, NY, United States
| | - Ann E Bigelow
- Department of Psychology, St. Francis Xavier University, Antigonish, NS, Canada
| | - Beatrice Beebe
- New York State Psychiatric Institute, Columbia University Medical Center, New York City, NY, United States
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16
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Lassek WD, Gaulin SJC. Substantial but Misunderstood Human Sexual Dimorphism Results Mainly From Sexual Selection on Males and Natural Selection on Females. Front Psychol 2022; 13:859931. [PMID: 35664212 PMCID: PMC9156798 DOI: 10.3389/fpsyg.2022.859931] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/28/2022] [Indexed: 01/05/2023] Open
Abstract
Human sexual dimorphism has been widely misunderstood. A large literature has underestimated the effect of differences in body composition and the role of male contest competition for mates. It is often assumed that sexually dimorphic traits reflect a history of sexual selection, but natural selection frequently builds different phenotypes in males and females. The relatively small sex difference in stature (∼7%) and its decrease during human evolution have been widely presumed to indicate decreased male contest competition for mates. However, females likely increased in stature relative to males in order to successfully deliver large-brained neonates through a bipedally-adapted pelvis. Despite the relatively small differences in stature and body mass (∼16%), there are marked sex differences in body composition. Across multiple samples from groups with different nutrition, males typically have 36% more lean body mass, 65% more muscle mass, and 72% more arm muscle than women, yielding parallel sex differences in strength. These sex differences in muscle and strength are comparable to those seen in primates where sexual selection, arising from aggressive male mating competition, has produced high levels of dimorphism. Body fat percentage shows a reverse pattern, with females having ∼1.6 times more than males and depositing that fat in different body regions than males. We argue that these sex differences in adipose arise mainly from natural selection on women to accumulate neurodevelopmental resources.
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Affiliation(s)
| | - Steven J. C. Gaulin
- Department of Anthropology, University of California, Santa Barbara, Santa Barbara, CA, United States
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17
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Childbirth and Infant Care in Early Human Ancestors: What the Bones Tell Us. EVOLUTIONARY PSYCHOLOGY 2022. [DOI: 10.1007/978-3-030-76000-7_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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18
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Abstract
Humans have a prolonged childhood, which begins with an immature developmental state at birth. We take care of these helpless infants through a variety of cultural adaptations, including material culture, provisioning of food, and shared child care. Our species has long been characterized as having secondary altriciality, but an examination of human life history shows that we are fundamentally precocial, despite seeming helpless at birth. Human babies are also relatively large and overall require substantial attention and energy from caregivers. Previous work has focused on how culture permits us to give birth to helpless young and how our cultural adaptation solves problems stemming from encephalization. The birth of these dependent, costly creatures poses challenges but also creates opportunities by enhancing the development of social and emotional relationships with caregivers as well as language acquisition and enculturation.
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Affiliation(s)
- Karen R. Rosenberg
- Department of Anthropology, University of Delaware, Newark, Delaware 19716, USA
- Philosophical Faculty, University of Hradec Králové, 500 03 Hradec Králové, Czech Republic
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19
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Moffett EA. Sexual dimorphism in the size and shape of the non-obstetric pelvis across anthropoids. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 176:402-421. [PMID: 34453450 DOI: 10.1002/ajpa.24398] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 04/26/2021] [Accepted: 07/20/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVES The presence of sexual dimorphism in the birth canals of anthropoid primates is well documented, and birth canal dimorphism tends to be especially robust among species that give birth to relatively large neonates. However, it is less clear whether birth canal dimorphism is accompanied by dimorphism in parts of the pelvis not directly under selection for birth, particularly including bi-iliac breadth, biactetabular breadth, lengths of the ischium and ilium, and 3D shape. This study investigates the patterns of dimorphism among anthropoid primates in those parts of the pelvis which do not directly contribute to the bony birth canal, here termed the non-obstetric pelvis. METHODS 3D landmark data were collected on the bony pelves of 899 anthropoid primates. Specifically, landmark data were collected on parts of the pelvis not thought to be directly involved in selection for parturition, including portions of the posterior and superior ilium, acetabulum, and lateral ischium. Principal components analysis and Euclidean distance matrix analysis were used to ascertain sexual dimorphism in pelvic sizes and shapes within each species. RESULTS Results show that dimorphism in non-obstetric pelvic size and shape exists across anthropoids, just as is seen in the birth canal. However, the magnitude of dimorphism in non-obstetric pelvic shape tends to be greater among anthropoid species that give birth to relatively large neonates compared with those birthing smaller neonates relative to maternal pelvic size. CONCLUSIONS Though all anthropoids included in the study show some degree of sexual dimorphism in non-obstetric pelvic size and/or shape, species which give birth to large neonates relative to maternal pelvic size have the highest levels of dimorphism in pelvic shape. Moreover, the magnitude of dimorphism in certain parts of the non-obstetric pelvis mirrors patterns seen in the birth canal. The results of this study are promising for ascertaining pelvic dimorphism and relative neonate size in fossil primates, particularly in fragmentary remains which do not preserve a complete bony birth canal.
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Affiliation(s)
- Elizabeth A Moffett
- Department of Clinical Anatomy and Osteopathic Principles, Rocky Vista University, Parker, Colorado, USA
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20
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Sylvester AD, Lautzenheiser SG, Kramer PA. Muscle forces and the demands of human walking. Biol Open 2021; 10:270958. [PMID: 34279576 PMCID: PMC8325943 DOI: 10.1242/bio.058595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/20/2021] [Indexed: 12/22/2022] Open
Abstract
Reconstructing the locomotor behavior of extinct animals depends on elucidating the principles that link behavior, function, and morphology, which can only be done using extant animals. Within the human lineage, the evolution of bipedalism represents a critical transition, and evaluating fossil hominins depends on understanding the relationship between lower limb forces and skeletal morphology in living humans. As a step toward that goal, here we use a musculoskeletal model to estimate forces in the lower limb muscles of ten individuals during walking. The purpose is to quantify the consistency, timing, and magnitude of these muscle forces during the stance phase of walking. We find that muscles which act to support or propel the body during walking demonstrate the greatest force magnitudes as well as the highest consistency in the shape of force curves among individuals. Muscles that generate moments in the same direction as, or orthogonal to, the ground reaction force show lower forces of greater variability. These data can be used to define the envelope of load cases that need to be examined in order to understand human lower limb skeletal load bearing. Summary: A musculoskeletal model of human walking reveals the consistency, timing, and magnitude of lower limb muscle forces across the stance phase.
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Affiliation(s)
- Adam D Sylvester
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, 1830 E. Monument Street, Baltimore, MD 21205, USA
| | - Steven G Lautzenheiser
- Department of Anthropology, University of Washington, Denny Hall, Seattle, WA 98195, USA.,Department of Anthropology, The University of Tennessee, Knoxville, Strong Hall, Knoxville, TN 37996, USA
| | - Patricia Ann Kramer
- Department of Anthropology, University of Washington, Denny Hall, Seattle, WA 98195, USA
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21
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Prabhat AM, Miller CK, Prang TC, Spear J, Williams SA, DeSilva JM. Homoplasy in the evolution of modern human-like joint proportions in Australopithecus afarensis. eLife 2021; 10:65897. [PMID: 33978569 PMCID: PMC8116054 DOI: 10.7554/elife.65897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/19/2021] [Indexed: 11/22/2022] Open
Abstract
The evolution of bipedalism and reduced reliance on arboreality in hominins resulted in larger lower limb joints relative to the joints of the upper limb. The pattern and timing of this transition, however, remains unresolved. Here, we find the limb joint proportions of Australopithecus afarensis, Homo erectus, and Homo naledi to resemble those of modern humans, whereas those of A. africanus, Australopithecus sediba, Paranthropus robustus, Paranthropus boisei, Homo habilis, and Homo floresiensis are more ape-like. The homology of limb joint proportions in A. afarensis and modern humans can only be explained by a series of evolutionary reversals irrespective of differing phylogenetic hypotheses. Thus, the independent evolution of modern human-like limb joint proportions in A. afarensis is a more parsimonious explanation. Overall, these results support an emerging perspective in hominin paleobiology that A. afarensis was the most terrestrially adapted australopith despite the importance of arboreality throughout much of early hominin evolution.
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Affiliation(s)
| | - Catherine K Miller
- Anthropology, Dartmouth College, Hanover, United States.,Ecology, Evolution, Ecosystems, and Society, Dartmouth College, Hanover, United States
| | - Thomas Cody Prang
- Department of Anthropology, Texas A&M University, College Station, United States
| | - Jeffrey Spear
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, United States.,New York Consortium in Evolutionary Primatology, New York, United States
| | - Scott A Williams
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, United States.,New York Consortium in Evolutionary Primatology, New York, United States
| | - Jeremy M DeSilva
- Anthropology, Dartmouth College, Hanover, United States.,Ecology, Evolution, Ecosystems, and Society, Dartmouth College, Hanover, United States
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22
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Hammond AS, Mavuso SS, Biernat M, Braun DR, Jinnah Z, Kuo S, Melaku S, Wemanya SN, Ndiema EK, Patterson DB, Uno KT, Palcu DV. New hominin remains and revised context from the earliest Homo erectus locality in East Turkana, Kenya. Nat Commun 2021; 12:1939. [PMID: 33850143 PMCID: PMC8044126 DOI: 10.1038/s41467-021-22208-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 03/05/2021] [Indexed: 02/01/2023] Open
Abstract
The KNM-ER 2598 occipital is among the oldest fossils attributed to Homo erectus but questions have been raised about whether it may derive from a younger horizon. Here we report on efforts to relocate the KNM-ER 2598 locality and investigate its paleontological and geological context. Although located in a different East Turkana collection area (Area 13) than initially reported, the locality is stratigraphically positioned below the KBS Tuff and the outcrops show no evidence of deflation of a younger unit, supporting an age of >1.855 Ma. Newly recovered faunal material consists primarily of C4 grazers, further confirmed by enamel isotope data. A hominin proximal 3rd metatarsal and partial ilium were discovered <50 m from the reconstructed location where KNM-ER 2598 was originally found but these cannot be associated directly with the occipital. The postcrania are consistent with fossil Homo and may represent the earliest postcrania attributable to Homo erectus.
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Affiliation(s)
- Ashley S Hammond
- Division of Anthropology, American Museum of Natural History, New York, NY, USA.
- New York Consortium of Evolutionary Primatology (NYCEP), New York, NY, USA.
| | | | - Maryse Biernat
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA
| | - David R Braun
- Department of Anthropology and Center for Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Zubair Jinnah
- School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Sharon Kuo
- Department of Anthropology, Pennsylvania State University, University Park, PA, USA
| | - Sahleselasie Melaku
- Authority for Research and Conservation of Cultural Heritage (ARCCH), National Museum of Ethiopia, Addis Ababa, Ethiopia
- Paleoanthropology and Paleoenvironment Program, Addis Ababa University, Addis Ababa, Ethiopia
| | - Sylvia N Wemanya
- Archaeology Section, Department of Earth Sciences, National Museums of Kenya, Nairobi, Kenya
- Department of Archaeology and History, University of Nairobi, Nairobi, Kenya
| | - Emmanuel K Ndiema
- Archaeology Section, Department of Earth Sciences, National Museums of Kenya, Nairobi, Kenya
| | - David B Patterson
- Department of Biology, University of North Georgia, Dahlonega, GA, USA
| | - Kevin T Uno
- Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA
| | - Dan V Palcu
- Paleomagnetic Laboratory 'Fort Hoofddijk', Utrecht University, Utrecht, Netherlands
- Instituto Oceanográfico, Universidade de São Paulo, São Paulo, Brazil
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23
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Adegboyega MT, Stamos PA, Hublin JJ, Weaver TD. Virtual reconstruction of the Kebara 2 Neanderthal pelvis. J Hum Evol 2020; 151:102922. [PMID: 33360685 DOI: 10.1016/j.jhevol.2020.102922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/01/2022]
Abstract
The paucity of well-preserved pelvises in the hominin fossil record has hindered robust analyses of shifts in critical biological processes throughout human evolution. The Kebara 2 pelvis remains one of the best preserved hominin pelvises, providing a rare opportunity to assess Neanderthal pelvic morphology and function. Here, we present two new reconstructions of the Kebara 2 pelvis created from CT scans of the right hip bone and sacrum. For both reconstructions, we proceeded as follows. First, we virtually reconstructed the right hip bone and the sacrum by repositioning the fragments of the hip bone and sacrum. Then, we created a mirrored copy of the right hip bone to act as the left hip bone. Next, we 3D printed the three bones and physically articulated them. Finally, we used fiducial points collected from the physically articulated models to articulate the hip bones and sacrum in virtual space. Our objectives were to (1) reposition misaligned fragments, particularly the ischiopubic ramus; (2) create a 3D model of a complete pelvis; and (3) assess interobserver reconstruction variation. These new reconstructions show that, in comparison with previous measurements, Kebara 2 possessed a higher shape index (maximum anteroposterior length/maximum mediolateral width) for the pelvic inlet and perhaps the outlet and a more anteriorly positioned sacral promontory and pubic symphysis relative to the acetabula. The latter differences result in a lower ratio between the distances anterior and posterior to the anterior margins of the acetabula. Generally, the new reconstructions tend to accentuate features of the Kebara 2 pelvis--the long superior pubic ramus and anteriorly positioned pelvic inlet--that have already been discussed for Kebara 2 and other Neanderthals.
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Affiliation(s)
- Mayowa T Adegboyega
- Department of Anthropology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA.
| | - Peter A Stamos
- Department of Anthropology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA; Department of Organismal Biology and Anatomy, University of Chicago, 1027 E. 57th Street / Anatomy 201, Chicago, IL, 60637, USA
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
| | - Timothy D Weaver
- Department of Anthropology, University of California, 1 Shields Avenue, Davis, CA, 95616, USA; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
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24
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Abstract
Aging occurs in all sexually reproducing organisms. That is, physical degradation over time occurs from conception until death. While the life span of a species is often viewed as a benchmark of aging, the pace and intensity of physical degradation over time varies owing to environmental influences, genetics, allocation of energetic investment, and phylogenetic history. Significant variation in aging within mammals, primates, and great apes, including humans, is therefore common across species. The evolution of aging in the hominin lineage is poorly known; however, clues can be derived from the fossil record. Ongoing advances continue to shed light on the interactions between life-history variables such as reproductive effort and aging. This review presents our current understanding of the evolution of aging in humans, drawing on population variation, comparative research, trade-offs, and sex differences, as well as tissue-specific patterns of physical degradation. Implications for contemporary health challenges and the future of human evolutionary anthropology research are also discussed.
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25
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García-Martínez D, Bastir M, Gómez-Olivencia A, Maureille B, Golovanova L, Doronichev V, Akazawa T, Kondo O, Ishida H, Gascho D, Zollikofer CPE, de León MP, Heuzé Y. Early development of the Neanderthal ribcage reveals a different body shape at birth compared to modern humans. SCIENCE ADVANCES 2020; 6:6/41/eabb4377. [PMID: 33028520 PMCID: PMC7541074 DOI: 10.1126/sciadv.abb4377] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 08/25/2020] [Indexed: 05/12/2023]
Abstract
Ontogenetic studies provide clues for understanding important paleobiological aspects of extinct species. When compared to that of modern humans, the adult Neanderthal thorax was shorter, deeper, and wider. This is related to the wide Neanderthal body and is consistent with their hypothetical large requirements for energy and oxygen. Whether these differences were already established at birth or appeared later during development is unknown. To delve into this question, we use virtual reconstruction tools and geometric morphometrics to recover the 3D morphology of the ribcages of four Neanderthal individuals from birth to around 3 years old: Mezmaiskaya 1, Le Moustier 2, Dederiyeh 1, and Roc de Marsal. Our results indicate that the comparatively deep and short ribcage of the Neanderthals was already present at birth, as were other skeletal species-specific traits. This morphology possibly represents the plesiomorphic condition shared with Homo erectus, and it is likely linked to large energetic requirements.
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Affiliation(s)
- Daniel García-Martínez
- University of Bordeaux, CNRS, MCC, PACEA, UMR5199, Pessac, France.
- Paleobiology Department, Museo Nacional de Ciencias Naturales (MNCN-CSIC), c/ José Gutiérrez Abascal 2, 28006 Madrid, Spain
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Pso. Sierra de Atapuerca 3, 09002 Burgos, Spain
| | - Markus Bastir
- Paleobiology Department, Museo Nacional de Ciencias Naturales (MNCN-CSIC), c/ José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - Asier Gómez-Olivencia
- Departamento de Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Universidad del País Vasco-Euskal Herriko Unibertsitatea (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
- Sociedad de Ciencias Aranzadi, Zorroagagaina 11, 20014 Donostia-San Sebastián, Spain
- Centro Mixto UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, c/ Avda. Monforte de Lemos 5 (Pabellón 14), 28029 Madrid, Spain
| | - Bruno Maureille
- University of Bordeaux, CNRS, MCC, PACEA, UMR5199, Pessac, France
| | | | | | | | - Osamu Kondo
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Hajime Ishida
- Department of Human Biology and Anatomy, Graduate School of Medicine, University of the Ryukyus Nishihara, Okinawa 903-0215, Japan
| | - Dominic Gascho
- Institute of Forensic Medicine, University of Zurich, CH-8057 Zurich, Switzerland
| | | | | | - Yann Heuzé
- University of Bordeaux, CNRS, MCC, PACEA, UMR5199, Pessac, France
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Halcrow S, Warren R, Kushnick G, Nowell A. Care of Infants in the Past: Bridging evolutionary anthropological and bioarchaeological approaches. EVOLUTIONARY HUMAN SCIENCES 2020; 2:e47. [PMID: 37588386 PMCID: PMC10427473 DOI: 10.1017/ehs.2020.46] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The importance of care of infants and children in palaeoanthropological and human behavioural ecological research on the evolution of our species is evident in the diversity of research on human development, alloparental care, and learning and social interaction. There has been a recent surge of interest in modelling the social implications of care provision for people with serious disabilities in bioarchaeology. However, there is a lack of acknowledgement of infant and child care in bioarchaeology, despite the significant labour and resources that are required, and the implications this has for health outcomes within societies. Drawing on the recent proliferation of studies on infancy and childhood in evolutionary anthropology and bioarchaeology, this paper presents ways the subdisciplines may draw on research developments from each field to advance a more holistic understanding of the evolutionary, social and health significance of infant and children care in the past.
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Affiliation(s)
- Siân Halcrow
- Department of Anatomy, University of Otago, New Zealand
| | - Ruth Warren
- Department of Anatomy, University of Otago, New Zealand
| | - Geoff Kushnick
- School of Archaeology and Anthropology, Research School of Humanities and the Arts, ANU College of Arts and Social Sciences, Australian National University, Australia
| | - April Nowell
- Department of Anthropology, University of Victoria, Canada
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Torres-Tamayo N, Schlager S, García-Martínez D, Sanchis-Gimeno JA, Nalla S, Ogihara N, Oishi M, Martelli S, Bastir M. Three-dimensional geometric morphometrics of thorax-pelvis covariation and its potential for predicting the thorax morphology: A case study on Kebara 2 Neandertal. J Hum Evol 2020; 147:102854. [PMID: 32805525 DOI: 10.1016/j.jhevol.2020.102854] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 07/04/2020] [Accepted: 07/04/2020] [Indexed: 11/18/2022]
Abstract
The skeletal torso is a complex structure of outstanding importance in understanding human body shape evolution, but reconstruction usually entails an element of subjectivity as researchers apply their own anatomical expertise to the process. Among different fossil reconstruction methods, 3D geometric morphometric techniques have been increasingly used in the last decades. Two-block partial least squares analysis has shown great potential for predicting missing elements by exploiting the covariation between two structures (blocks) in a reference sample: one block can be predicted from the other one based on the strength of covariation between blocks. The first aim of this study is to test whether this predictive approach can be used for predicting thorax morphologies from pelvis morphologies within adult Homo sapiens reference samples with known covariation between the thorax and the pelvis. The second aim is to apply this method to Kebara 2 Neandertal (Israel, ∼60 ka) to predict its thorax morphology using two different pelvis reconstructions as predictors. We measured 134 true landmarks, 720 curve semilandmarks, and 160 surface semilandmarks on 60 3D virtual torso models segmented from CT scans. We conducted three two-block partial least squares analyses between the thorax (block 1) and the pelvis (block 2) based on the H. sapiens reference samples after performing generalized Procrustes superimposition on each block separately. Comparisons of these predictions in full shape space by means of Procrustes distances show that the male-only predictive model yields the most reliable predictions within modern humans. In addition, Kebara 2 thorax predictions based on this model concur with the thorax morphology proposed for Neandertals. The method presented here does not aim to replace other techniques, but to rather complement them through quantitative prediction of a virtual 'scaffold' to articulate the thoracic fossil elements, thus extending the potential of missing data estimation beyond the methods proposed in previous works.
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Affiliation(s)
- Nicole Torres-Tamayo
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J.G. Abascal 2, 28006, Madrid, Spain; GIAVAL Research Group, Department of Anatomy and Human Embryology, University of Valencia, Av. Blasco Ibanez, 15, E-46010, Valencia, Spain.
| | - Stefan Schlager
- Biological Anthropology, Faculty of Medicine, University of Freiburg, Hebelstr 29, D-79104, Freiburg, Germany
| | - Daniel García-Martínez
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J.G. Abascal 2, 28006, Madrid, Spain; Centro Nacional de Investigación Sobre La Evolución Humana (CENIEH), Avenida de La Sierra de Atapuerca 3, 09002, Burgos, Spain
| | - Juan Alberto Sanchis-Gimeno
- GIAVAL Research Group, Department of Anatomy and Human Embryology, University of Valencia, Av. Blasco Ibanez, 15, E-46010, Valencia, Spain
| | - Shahed Nalla
- Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, P.O. Box 524, Auckland Park, Johannesburg, 2006, Gauteng, South Africa
| | - Naomichi Ogihara
- Department of Biological Science, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Motoharu Oishi
- Laboratory of Anatomy 1, School of Veterinary Medicine, Azabu University, Kanagawa, 252-5201, Japan
| | - Sandra Martelli
- UCL Centre for Integrative Anatomy (CIA), Department of Cell and Developmental Biology, Faculty of Life Sciences, Gower Street, WC1E 6BT, London, UK
| | - Markus Bastir
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J.G. Abascal 2, 28006, Madrid, Spain
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Rib cage anatomy in Homo erectus suggests a recent evolutionary origin of modern human body shape. Nat Ecol Evol 2020; 4:1178-1187. [PMID: 32632258 DOI: 10.1038/s41559-020-1240-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 06/04/2020] [Indexed: 01/13/2023]
Abstract
The tall and narrow body shape of anatomically modern humans (Homo sapiens) evolved via changes in the thorax, pelvis and limbs. It is debated, however, whether these modifications first evolved together in African Homo erectus, or whether H. erectus had a more primitive body shape that was distinct from both the more ape-like Australopithecus species and H. sapiens. Here we present the first quantitative three-dimensional reconstruction of the thorax of the juvenile H. erectus skeleton, KNM-WT 15000, from Nariokotome, Kenya, along with its estimated adult rib cage, for comparison with H. sapiens and the Kebara 2 Neanderthal. Our three-dimensional reconstruction demonstrates a short, mediolaterally wide and anteroposteriorly deep thorax in KNM-WT 15000 that differs considerably from the much shallower thorax of H. sapiens, pointing to a recent evolutionary origin of fully modern human body shape. The large respiratory capacity of KNM-WT 15000 is compatible with the relatively stocky, more primitive, body shape of H. erectus.
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Berecz B, Cyrille M, Casselbrant U, Oleksak S, Norholt H. Carrying human infants - An evolutionary heritage. Infant Behav Dev 2020; 60:101460. [PMID: 32569907 DOI: 10.1016/j.infbeh.2020.101460] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 05/21/2020] [Accepted: 06/03/2020] [Indexed: 02/08/2023]
Abstract
We propose that infant carrying is a biological norm for human caregiving, given that human infants have evolved a capacity to cling onto an upright caregiver whose body co-evolved to enable offspring carrying. The origins of this mutual adaptation may date back 4 million years, with the emergence of bipedalism, which precluded the infant horizontal and gravity-supported position on the back of a quadrupedal caregiver. We describe infant cooperative reflexes and behaviors, including the carrying-induced calming response and discuss hypotheses for the invention of infant carrier tools. Carrying involves several physiological and behavioral parent-infant co-adaptations that imply it is an evolutionarily conserved strategy. Epigenetic transmission of reproductive behavior through generations affects the development of the offspring, as well as the mental health of the parent. Carrying might have contributed to the evolution of Hominidae, potentially aiding dexterity, handedness, language acquisition, and social interactions. We review the evolutionary milestones and time points where the infant-caregiver interactions might have changed, exploring infant carrying as it intersects with biological and cultural evolution. We briefly summarize the effects of infant carrying on physiological, epigenetic, and socio-emotional outcomes.
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Affiliation(s)
- Bernadett Berecz
- Eotvos Lorand University, Institute of Biology, Pazmany Peter stny. 1/C. H-1117, Budapest, Hungary.
| | | | | | - Sarah Oleksak
- University of Maryland Eastern Shore, Lift Me Up, Inc., United States
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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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Frost SR, Simpson SW, Levin NE, Quade J, Rogers MJ, Semaw S. Fossil Cercopithecidae from the Early Pliocene Sagantole Formation at Gona, Ethiopia. J Hum Evol 2020; 144:102789. [PMID: 32485477 DOI: 10.1016/j.jhevol.2020.102789] [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: 07/12/2019] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 10/24/2022]
Abstract
The Early Pliocene Sagantole Fm. in the Gona Project area, Afar State, Ethiopia, is noted for discoveries of the early hominin Ardipithecus ramidus. A large series of fossil cercopithecid primates dated to between 4.8 and 4.3 Ma has also been collected from these sediments. In this paper, we use qualitative analysis and standard dental and postcranial measures to systematically describe the craniodental remains and tentatively allocate postcrania to taxa where we are able to. We then use these data to compare these specimens to fossil assemblages from contemporary sites, interpret their paleobiology, and discuss implications for the paleoecology of the Gona Sagantole Fm. We recognize three cercopithecid species in the Gona Sagantole Fm. Pliopapio alemui makes up approximately two-thirds of the identifiable specimens; nearly all of the rest are allocated to Kuseracolobus aramisi, and a single molar indicates the presence of a second, somewhat larger but morphologically distinct papionin. Among the Early Pliocene cercopithecids from Gona are also a number of postcranial elements. None of the postcranial remains are directly associated with any of the cranial material. Nonetheless, some of the distal humeri and proximal femora can be tentatively allocated to either Pl. alemui or K. aramisi based on a combination of size, as the latter is approximately 50% larger than the former, and morphology. If these assignments are correct, they suggest K. aramisi was primarily arboreal and similar to most extant colobines, whereas Pl. alemui was more mixed in its substrate use, being more terrestrially adapted than K. aramisi, but less so than extant Papio or Theropithecus. Thus, we interpret the predominance of Pl. alemui over K. aramisi is consistent with a somewhat more open environment at Gona than at Aramis.
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Affiliation(s)
- Stephen R Frost
- Department of Anthropology, University of Oregon, Eugene, OR, 97403-1218, USA.
| | - Scott W Simpson
- Department of Anatomy, Case Western Reserve University-School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA; Laboratory of Physical Anthropology, Cleveland Museum of Natural History, Cleveland, OH, 44106, USA
| | - Naomi E Levin
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jay Quade
- Department of Geosciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Michael J Rogers
- Department of Anthropology, Southern Connecticut State University, 501 Crescent Street, New Haven, CT, 06515-1355, USA
| | - Sileshi Semaw
- Centro Nacional de Investigación Sobre La Evolución Humana, Paseo de Atapuerca 3, 09002, Burgos, Spain; Stone Age Institute & CRAFT Research Center, Gosport, IN, 47408, USA
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Rosas A, Losada Agustina B, García-Martínez D, Torres-Tamayo N, García-Tabernero A, Pastor JF, Rasilla MDL, Bastir M. Analyses of the neandertal patellae from El Sidrón (Asturias, Spain) with implications for the evolution of body form in Homo. J Hum Evol 2020; 141:102738. [PMID: 32146203 DOI: 10.1016/j.jhevol.2019.102738] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 01/04/2023]
Abstract
The evolution of the body form in Homo and its potential morphological connection to the arrangement of different skeletal systems is of major interest in human evolution. Patella morphology as part of the knee is potentially influenced by body form. Here, we describe for the first time the patellae remains recovered at El Sidrón Neandertal site and analyze them in a comparative evolutionary framework. We aim to clarify whether morphometric features frequently observed in Neandertal and modern human patellae are retained from a primitive anatomical arrangement or whether they represent derived features (apomorphies). For this purpose, we combine analyses of discrete features, classic anthropological measurements, and 3D geometric morphometrics based on generalized Procrustes analysis, mean size and shape comparisons, and principal components analysis. We found a size increment of the patella in hominin evolution, with large species showing a larger patella. Modern humans and Neandertals exhibit overall larger patellae, with maximum values observed in the latter, likely as a consequence of their broader body shape. Also, some Neandertals display a thicker patella, which has been linked to larger quadriceps muscles. However, Neandertals retain a primitive morphology in their patellar articular surfaces, with similar-sized lateral and medial articular facets, leading to a more symmetrical internal face. This feature is inherited from a primitive Homo ancestor and suggests a different configuration of the knee in Neandertals. Conversely, Homo sapiens exhibits an autoapomorphic patellar anatomy with expanded lateral articular facets. We propose that these distinct configurations of the patella within Homo may be a consequence of different body forms rather than specific functional adaptations of the knee. Thus, the slender body form of modern humans may entail a medial reorientation of the tibial tuberosity (patellar ligament), allowing lateral surface expansion. These anatomical evolutionary variations may involve subtle secondary differences in bipedalism within Homo.
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Affiliation(s)
- Antonio Rosas
- Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain.
| | - Beatriz Losada Agustina
- Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain
| | - Daniel García-Martínez
- Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain; Centro Nacional de Investigación sobre la Evolución Humana, CENIEH, Avenida de La Sierra de Atapuerca 3, 09002, Burgos, Spain
| | - Nicole Torres-Tamayo
- Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain
| | - Antonio García-Tabernero
- Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain
| | - Juan Francisco Pastor
- Museo Anatómico, Departamento de Anatomía Humana, Universidad de Valladolid, C. Ramón y Cajal 7, 47005, Valladolid, Spain
| | - Marco de la Rasilla
- Área de Prehistoria Departamento de Historia, Universidad de Oviedo, Calle Teniente Alfonso Martínez S/n, 33011, Oviedo, Spain
| | - Markus Bastir
- Group of Paleoanthropology MNCN-CSIC, Department of Paleobiology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, Madrid, Spain
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Semaw S, Rogers MJ, Simpson SW, Levin NE, Quade J, Dunbar N, McIntosh WC, Cáceres I, Stinchcomb GE, Holloway RL, Brown FH, Butler RF, Stout D, Everett M. Co-occurrence of Acheulian and Oldowan artifacts with Homo erectus cranial fossils from Gona, Afar, Ethiopia. SCIENCE ADVANCES 2020; 6:eaaw4694. [PMID: 32181331 PMCID: PMC7056306 DOI: 10.1126/sciadv.aaw4694] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Although stone tools generally co-occur with early members of the genus Homo, they are rarely found in direct association with hominins. We report that both Acheulian and Oldowan artifacts and Homo erectus crania were found in close association at 1.26 million years (Ma) ago at Busidima North (BSN12), and ca. 1.6 to 1.5 Ma ago at Dana Aoule North (DAN5) archaeological sites at Gona, Afar, Ethiopia. The BSN12 partial cranium is robust and large, while the DAN5 cranium is smaller and more gracile, suggesting that H. erectus was probably a sexually dimorphic species. The evidence from Gona shows behavioral diversity and flexibility with a lengthy and concurrent use of both stone technologies by H. erectus, confounding a simple "single species/single technology" view of early Homo.
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Affiliation(s)
- Sileshi Semaw
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Sierra de Atapuerca 3, 09002 Burgos, Spain
- Stone Age Institute and CRAFT Research Center, 1392 W. Dittemore Rd., Gosport, IN 47408, USA
| | - Michael J. Rogers
- Department of Anthropology, Southern Connecticut State University, 501 Crescent Street, New Haven, CT 06515, USA
| | - Scott W. Simpson
- Department of Anatomy, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Laboratory of Physical Anthropology, Cleveland Museum of Natural History, Cleveland, OH 44106, USA
| | - Naomi E. Levin
- Department of Earth and Environmental Sciences, University of Michigan, 1100 North University Avenue, Ann Arbor, MI 48109, USA
| | - Jay Quade
- Department of Geosciences/Desert Laboratory, University of Arizona, Tucson, AZ 85721, USA
| | - Nelia Dunbar
- New Mexico Bureau of Geology and Mineral Resources, Earth and Environmental Science Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801-4796, USA
| | - William C. McIntosh
- New Mexico Bureau of Geology and Mineral Resources, Earth and Environmental Science Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801-4796, USA
| | - Isabel Cáceres
- Universitat Rovira i Virgili (URV), Avinguda de Catalunya 35, 43002 Tarragona, Spain
- IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Zona Educacional 4–Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain
| | - Gary E. Stinchcomb
- Watershed Studies Institute and Department of Earth and Environmental Sciences, Murray State University, Murray, KY 42071, USA
| | - Ralph L. Holloway
- Department of Anthropology, Columbia University, 1200 Amsterdam Ave., New York, NY 10027, USA
| | - Francis H. Brown
- The University of Utah, 201 South Presidents Circle Room 201, Salt Lake City, UT 84112, USA
| | - Robert F. Butler
- Department of Physics, University of Portland, Portland, OR 97203, USA
| | - Dietrich Stout
- Department of Anthropology, Emory University, 1557 Dickey Drive, Atlanta, GA 30322, USA
| | - Melanie Everett
- Chevron Energy Technology Company, 1500 Louisiana St., Houston, TX 77002, USA
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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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Abstract
Oreopithecus bambolii (8.3-6.7 million years old) is the latest known hominoid from Europe, dating to approximately the divergence time of the Pan-hominin lineages. Despite being the most complete nonhominin hominoid in the fossil record, the O. bambolii skeleton IGF 11778 has been, for decades, at the center of intense debate regarding the species' locomotor behavior, phylogenetic position, insular paleoenvironment, and utility as a model for early hominin anatomy. Here we investigate features of the IGF 11778 pelvis and lumbar region based on torso preparations and supplemented by other O. bambolii material. We correct several crucial interpretations relating to the IGF 11778 anterior inferior iliac spine and lumbar vertebrae structure and identifications. We find that features of the early hominin Ardipithecus ramidus torso that are argued to have permitted both lordosis and pelvic stabilization during upright walking are not present in O. bambolii However, O. bambolii also lacks the complete reorganization for torso stiffness seen in extant great apes (i.e., living members of the Hominidae), and is more similar to large hylobatids in certain aspects of torso form. We discuss the major implications of the O. bambolii lower torso anatomy and how O. bambolii informs scenarios of hominoid evolution.
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Fatica LM, Almécija S, McFarlin SC, Hammond AS. Pelvic shape variation among gorilla subspecies: Phylogenetic and ecological signals. J Hum Evol 2019; 137:102684. [DOI: 10.1016/j.jhevol.2019.102684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 01/28/2023]
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Abstract
Hominin birth mechanics have been examined and debated from limited and often fragmentary fossil pelvic material. Some have proposed that birth in the early hominin genus Australopithecus was relatively easy and ape-like, while others have argued for a more complex, human-like birth mechanism in australopiths. Still others have hypothesized a unique birth mechanism, with no known modern equivalent. Preliminary work on the pelvis of the recently discovered 1.98 million-year-old hominin Australopithecus sediba found it to possess a unique combination of Homo and Australopithecus-like features. Here, we create a composite pelvis of Australopithecus sediba to reconstruct the birth process in this early hominin. Consistent with other hominin species, including modern humans, the fetus would enter the pelvic inlet in a transverse direction. However, unlike in modern humans, the fetus would not need additional rotations to traverse the birth canal. Further fetal rotation is unnecessary even with a Homo-like pelvic midplane expansion, not seen in earlier hominin species. With a birth canal shape more closely associated with specimens from the genus Homo and a lack of cephalopelvic or shoulder constraints, we therefore find evidence to support the hypothesis that the pelvic morphology of Australopithecus sediba is a result of locomotor, rather than strictly obstetric constraints.
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Villmoare B, Hatala KG, Jungers W. Sexual dimorphism in Homo erectus inferred from 1.5 Ma footprints near Ileret, Kenya. Sci Rep 2019; 9:7687. [PMID: 31118467 PMCID: PMC6531427 DOI: 10.1038/s41598-019-44060-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/26/2019] [Indexed: 11/09/2022] Open
Abstract
Sexual dimorphism can be one of the most important indicators of social behavior in fossil species, but the effects of time averaging, geographic variation, and differential preservation can complicate attempts to determine this measure from preserved skeletal anatomy. Here we present an alternative, using footprints from near Ileret, Kenya, to assess the sexual dimorphism of presumptive African Homo erectus at 1.5 Ma. Footprint sites have several unique advantages not typically available to fossils: a single surface can sample a population over a very brief time (in this case likely not more than a single day), and the data are geographically constrained. Further, in many cases, the samples can be much larger than those from skeletal fossil assemblages. Our results indicate that East African Homo erectus was more dimorphic than modern Homo sapiens, although less so than highly dimorphic apes, suggesting that the Ileret footprints offer a unique window into an important transitional period in hominin social behavior.
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Affiliation(s)
- Brian Villmoare
- Department of Anthropology, University of Nevada Las Vegas, 89154-5003, Las Vegas, NV, USA.
| | - Kevin G Hatala
- Department of Biology, Chatham University, 15232, Pittsburgh, PA, USA
| | - William Jungers
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, 11794-8081, New York, USA
- Association Vahatra, BP 3972, 101, Antananarivo, Madagascar
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Simpson SW, Levin NE, Quade J, Rogers MJ, Semaw S. Ardipithecus ramidus postcrania from the Gona Project area, Afar Regional State, Ethiopia. J Hum Evol 2019; 129:1-45. [DOI: 10.1016/j.jhevol.2018.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 11/26/2018] [Accepted: 12/05/2018] [Indexed: 11/30/2022]
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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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How Evolutionary Theory Illuminates Radiologic Practice: Bipedalism. Acad Radiol 2018; 25:1667-1668. [PMID: 30190229 DOI: 10.1016/j.acra.2018.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 08/06/2018] [Indexed: 11/20/2022]
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Gómez-Olivencia A, Barash A, García-Martínez D, Arlegi M, Kramer P, Bastir M, Been E. 3D virtual reconstruction of the Kebara 2 Neandertal thorax. Nat Commun 2018; 9:4387. [PMID: 30377294 PMCID: PMC6207772 DOI: 10.1038/s41467-018-06803-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 09/17/2018] [Indexed: 11/17/2022] Open
Abstract
The size and shape of the Neandertal thorax has been debated since the first discovery of Neandertal ribs more than 150 years ago, with workers proposing different interpretations ranging from a Neandertal thoracic morphology that is indistinguishable from modern humans, to one that was significantly different from them. Here, we provide a virtual 3D reconstruction of the thorax of the adult male Kebara 2 Neandertal. Our analyses reveal that the Kebara 2 thorax is significantly different but not larger from that of modern humans, wider in its lower segment, which parallels his wide bi-iliac breadth, and with a more invaginated vertebral column. Kinematic analyses show that rib cages that are wider in their lower segment produce greater overall size increments (respiratory capacity) during inspiration. We hypothesize that Neandertals may have had a subtle, but somewhat different breathing mechanism compared to modern humans.
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Affiliation(s)
- Asier Gómez-Olivencia
- Dept. Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain.
- IKERBASQUE. Basque Foundation for Science, 48013, Bilbao, Spain.
- Équipe de Paléontologie Humaine, UMR 7194, CNRS, Département de Préhistoire, Muséum National d'Histoire naturelle, Musée de l'Homme, 17, Place du Trocadéro, 75016, Paris, France.
- Centro Mixto UCM-ISCIII de Evolución y Comportamiento Humanos, Avda. Monforte de Lemos, 5, Madrid, 28029, Spain.
| | - Alon Barash
- Faculty of Medicine in the Galilee, Bar-Ilan University, Henrietta Szold, 8. P.O.B 1589, 1311502, Zefat, Israel
| | - Daniel García-Martínez
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J. G. Abascal 2, 28006, Madrid, Spain
| | - Mikel Arlegi
- Dept. Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
- Université de Bordeaux, Allée Geoffroy Saint-Hilaire, PACEA UMR 5199, Bâtiment B8, 33615, Pessac, France
| | - Patricia Kramer
- Departments of Anthropology and Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, 98195-3100, USA
| | - Markus Bastir
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J. G. Abascal 2, 28006, Madrid, Spain
| | - Ella Been
- Department of Sports Therapy, Faculty of Health Professions, Ono Academic College, 5545001, Kiryat Ono, Israel
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
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43
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Torres-Tamayo N, García-Martínez D, Nalla S, Barash A, Williams SA, Blanco-Pérez E, Mata Escolano F, Sanchis-Gimeno JA, Bastir M. The torso integration hypothesis revisited in Homo sapiens: Contributions to the understanding of hominin body shape evolution. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 167:777-790. [PMID: 30259957 DOI: 10.1002/ajpa.23705] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/04/2018] [Accepted: 08/09/2018] [Indexed: 01/08/2023]
Abstract
OBJECTIVES Lower thoracic widths and curvatures track upper pelvic widths and iliac blades curvatures in hominins and other primates (torso integration hypothesis). However, recent studies suggest that sexual dimorphism could challenge this assumption in Homo sapiens. We test the torso integration hypothesis in two modern human populations, both considering and excluding the effect of sexual dimorphism. We further assess covariation patterns between different thoracic and pelvic levels, and we explore the allometric effects on torso shape variation. MATERIAL AND METHODS A sex-balanced sample of 50 anatomically connected torsos (25 Mediterraneans, 25 Sub-Saharan Africans) was segmented from computed tomography scans. We compared the maximum medio-lateral width at seventh-ninth rib levels with pelvic bi-iliac breadth in males and females within both populations. We measured 1,030 (semi)landmarks on 3D torso models, and torso shape variation, mean size and shape comparisons, thoraco-pelvic covariation and allometric effects were quantified through 3D geometric morphometrics. RESULTS Females show narrow thoraces and wide pelves and males show wide thoraces and narrow pelves, although this trend is more evident in Mediterraneans than in Sub-Saharans. Equal thoracic and pelvic widths, depths and curvatures were found in absence of sexual dimorphism. The highest strength of covariation was found between the lowest rib levels and the ilia, and allometric analyses showed that smaller torsos were wider than larger torsos. CONCLUSIONS This is the first study testing statistically the torso integration hypothesis in anatomically connected torsos. We propose a new and more complex torso integration model in H. sapiens with sexual dimorphism leading to different thoracic and pelvic widths and curvatures. These findings have important implications in hominin body shape reconstructions.
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Affiliation(s)
| | | | - Shahed Nalla
- Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.,Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Alon Barash
- Faculty of Medicine, Bar-Ilan University, Ramat Gan, Israel
| | - Scott A Williams
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa.,Center for the Study of Human Origins, Department of Anthropology, New York University, New York, New York.,New York Consortium in Evolutionary Primatology, New York, New York
| | | | - Federico Mata Escolano
- CT and MRI Unit, ERESA, Department of Radiology, General University Hospital, Valencia, Spain
| | - Juan Alberto Sanchis-Gimeno
- Department of Radiology, Hospital de La Ribera, Valencia, Spain.,Department of Anatomy and Human Embryology, Faculty of Medicine, University of Valencia, Valencia, Spain
| | - Markus Bastir
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales, Madrid, Spain
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44
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Hammond AS, Almécija S, Libsekal Y, Rook L, Macchiarelli R. A partial Homo pelvis from the Early Pleistocene of Eritrea. J Hum Evol 2018; 123:109-128. [PMID: 30017175 DOI: 10.1016/j.jhevol.2018.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/27/2018] [Accepted: 06/27/2018] [Indexed: 12/15/2022]
Abstract
Here we analyze 1.07-0.99 million-year-old pelvic remains UA 173/405 from Buia, Eritrea. Based on size metrics, UA 173/405 is likely associated with an already described pubic symphysis (UA 466) found nearby. The morphology of UA 173/405 was quantitatively characterized using three-dimensional landmark-based morphometrics and linear data. The Buia specimen falls within the range of variation of modern humans for all metrics investigated, making it unlikely that the shared last common ancestor of Late Pleistocene Homo species would have had an australopith-like pelvis. The discovery of UA 173/405 adds to the increasing number of fossils suggesting that the postcranial morphology of Homo erectus s.l. was variable and, in some cases, nearly indistinguishable from modern human morphology. This Eritrean fossil demonstrates that modern human-like pelvic morphology may have had origins in the Early Pleistocene, potentially within later African H. erectus.
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Affiliation(s)
- Ashley S Hammond
- Division of Anthropology, American Museum of Natural History, New York, NY 10024, USA; Center for Advanced Study of Human Paleobiology, Department of Anthropology, George Washington University, Washington, DC 20052, USA.
| | - Sergio Almécija
- Division of Anthropology, American Museum of Natural History, New York, NY 10024, USA; Center for Advanced Study of Human Paleobiology, Department of Anthropology, George Washington University, Washington, DC 20052, USA; Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/Columnes s/n, Campus de la UAB, 08193 Cerdanyola Del Vallès, Barcelona, Spain
| | | | - Lorenzo Rook
- Dipartimento di Scienze Della Terra, Università di Firenze, Via G. La Pira, 4, 50121 Firenze, Italy
| | - Roberto Macchiarelli
- UMR 7194 CNRS, Muséum National d'Histoire Naturelle, Palais de Chaillot, 17 Place du Trocadero, 75116 Paris, France; Unité de Formation Géosciences, Université de Poitiers, Bât. B35 Sciences Naturelles, 86073 Poitiers, France.
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45
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Cunningham DL, Graves RR, Wescott DJ, McCarthy RC. The effect of ontogeny on estimates of KNM-WT 15000's adult body size. J Hum Evol 2018; 121:119-127. [PMID: 29754743 DOI: 10.1016/j.jhevol.2018.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 03/30/2018] [Accepted: 04/02/2018] [Indexed: 02/04/2023]
Abstract
The Homo erectus specimen KNM-WT 15000 has played a critical role in our understanding of body size evolution. New interpretations suggest that KNM-WT 15000 had a younger age-at-death and a more rapid ontogenetic trajectory than previously suggested. Recent fossil discoveries and new interpretations suggest a wide range of body size and shape variation in H. erectus. Based on these new insights, we argue that KNM-WT 15000's adult stature and body mass could have been much smaller than has been traditionally presented in the literature. Using chimpanzee and modern human growth trajectories, we bracketed the range of possibilities for KNM-WT 15000's adult body size between 160.0 and 177.7 cm (5'3″-5'10″) for stature and 60.0 and 82.7 kg (132-182 lbs.) for body mass. These estimates put KNM-WT 15000 near the mean rather than among the largest known H. erectus specimens.
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Affiliation(s)
| | - Ronda R Graves
- Grunley Construction Company, Inc., Rockville, MD 20850, USA
| | - Daniel J Wescott
- Texas State University, Department of Anthropology, San Marcos, TX 78666, USA
| | - Robert C McCarthy
- Benedictine University, Department of Biological Sciences, Lisle, IL 60532, USA
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46
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Sylvester AD, Kramer PA. Young's Modulus and Load Complexity: Modeling Their Effects on Proximal Femur Strain. Anat Rec (Hoboken) 2018; 301:1189-1202. [PMID: 29451371 DOI: 10.1002/ar.23796] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/23/2017] [Accepted: 11/27/2017] [Indexed: 01/22/2023]
Abstract
Finite element analysis (FEA) is a powerful tool for evaluating questions of functional morphology, but the application of FEA to extant or extinct creatures is a non-trivial task. Three categories of input data are needed to appropriately implement FEA: geometry, material properties, and boundary conditions. Geometric data are relatively easily obtained from imaging techniques, but often material properties and boundary conditions must be estimated. Here we conduct sensitivity analyses of the effect of the choice of Young's Modulus for elements representing trabecular bone and muscle loading complexity on the proximal femur using a finite element mesh of a modern human femur. We found that finite element meshes that used a Young's Modulus between 500 and 1,500 MPa best matched experimental strains. Loading scenarios that approximated the insertion sites of hip musculature produced strain patterns in the region of the greater trochanter that were different from scenarios that grouped muscle forces to the superior greater trochanter, with changes in strain values of 40% or more for 20% of elements. The femoral head, neck, and proximal shaft were less affected (e.g. approximately 50% of elements changed by 10% or less) by changes in the location of application of muscle forces. From our sensitivity analysis, we recommend the use of a Young's Modulus for the trabecular elements of 1,000 MPa for the proximal femur (range 500-1,500 MPa) and that the muscular loading complexity be dependent on whether or not strains in the greater trochanter are the focus of the analytical question. Anat Rec, 301:1189-1202, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Adam D Sylvester
- The John Hopkins University School of Medicine, Center for Functional Anatomy and Evolution, 1830 E. Monument Street, Baltimore, Maryland
| | - Patricia A Kramer
- Department of Anthropology, University of Washington, 314 Denny Hall, Seattle, Washington
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47
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García-Martínez D, Nalla S, Ferreira MT, Guichón RA, D'Angelo Del Campo MD, Bastir M. Eco-geographic adaptations in the human ribcage throughout a 3D geometric morphometric approach. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:323-336. [PMID: 29417988 DOI: 10.1002/ajpa.23433] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 11/11/2022]
Abstract
OBJECTIVES According to eco-geographic rules, humans from high latitude areas present larger and wider trunks than their low-latitude areas counterparts. This issue has been traditionally addressed on the pelvis but information on the thorax is largely lacking. We test whether ribcages are larger in individuals inhabiting high latitudes than in those from low latitudes and explored the correlation of rib size with latitude. We also test whether a common morphological pattern is exhibited in the thorax of different cold-adapted populations, contributing to their hypothetical widening of the trunk. MATERIALS AND METHODS We used 3D geometric morphometrics to quantify rib morphology of three hypothetically cold-adapted populations, viz. Greenland (11 individuals), Alaskan Inuit (8 individuals) and people from Tierra del Fuego (8 individuals), in a comparative framework with European (Spain, Portugal and Austria; 24 individuals) and African populations (South African and sub-Saharan African; 20 individuals). RESULTS Populations inhabiting high latitudes present longer ribs than individuals inhabiting areas closer to the equator, but a correlation (p < 0.05) between costal size and latitude is only found in ribs 7-11. Regarding shape, the only cold adapted population that was different from the non-cold-adapted populations were the Greenland Inuit, who presented ribs with less curvature and torsion. CONCLUSIONS Size results from the lower ribcage are consistent with the hypothesis of larger trunks in cold-adapted populations. The fact that only Greenland Inuit present a differential morphological pattern, linked to a widening of their ribcage, could be caused by differences in latitude. However, other factors such as genetic drift or specific cultural adaptations cannot be excluded and should be tested in future studies.
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Affiliation(s)
| | - Shahed Nalla
- Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.,Evolutionary Studies Institute (ESI) and Center of Excellence in Palaeosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Maria Teresa Ferreira
- Laboratory of Forensic Anthropology, Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ricardo A Guichón
- Núcleo de Estudios Interdisciplinarios de Poblaciones Humanas de Patagonia Austral, Laboratorio de Ecología Evolutiva Humana, Facultad de Ciencias Sociales, Universidad del Centro de la Provincia de Buenos Aires, Argentina (CONICET)
| | - Manuel D D'Angelo Del Campo
- Núcleo de Estudios Interdisciplinarios de Poblaciones Humanas de Patagonia Austral, Laboratorio de Ecología Evolutiva Humana, Facultad de Ciencias Sociales, Universidad del Centro de la Provincia de Buenos Aires, Argentina (CONICET).,Laboratorio de Poblaciones de Pasado, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, España
| | - Markus Bastir
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales, Madrid, Spain
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48
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Evaluating morphometric body mass prediction equations with a juvenile human test sample: accuracy and applicability to small-bodied hominins. J Hum Evol 2018; 115:65-77. [DOI: 10.1016/j.jhevol.2017.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 11/18/2022]
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49
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Ruff CB, Burgess ML, Squyres N, Junno JA, Trinkaus E. Lower limb articular scaling and body mass estimation in Pliocene and Pleistocene hominins. J Hum Evol 2018; 115:85-111. [PMID: 29331230 DOI: 10.1016/j.jhevol.2017.10.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 10/11/2017] [Accepted: 10/14/2017] [Indexed: 01/02/2023]
Abstract
Previous attempts to estimate body mass in pre-Holocene hominins have relied on prediction equations derived from relatively limited extant samples. Here we derive new equations to predict body mass from femoral head breadth and proximal tibial plateau breadth based on a large and diverse sample of modern humans (avoiding the problems associated with using diaphyseal dimensions and/or cadaveric reference samples). In addition, an adjustment for the relatively small femoral heads of non-Homo taxa is developed based on observed differences in hip to knee joint scaling. Body mass is then estimated for 214 terminal Miocene through Pleistocene hominin specimens. Mean body masses for non-Homo taxa range between 39 and 49 kg (39-45 kg if sex-specific means are averaged), with no consistent temporal trend (6-1.85 Ma). Mean body mass increases in early Homo (2.04-1.77 Ma) to 55-59 kg, and then again dramatically in Homo erectus and later archaic middle Pleistocene Homo, to about 70 kg. The same average body mass is maintained in late Pleistocene archaic Homo and early anatomically modern humans through the early/middle Upper Paleolithic (0.024 Ma), only declining in the late Upper Paleolithic, with regional variation. Sexual dimorphism in body mass is greatest in Australopithecus afarensis (log[male/female] = 1.54), declines in Australopithecus africanus and Paranthropus robustus (log ratio 1.36), and then again in early Homo and middle and late Pleistocene archaic Homo (log ratio 1.20-1.27), although it remains somewhat elevated above that of living and middle/late Pleistocene anatomically modern humans (log ratio about 1.15).
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Affiliation(s)
- Christopher B Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, 1830 E. Monument St., Baltimore, MD 21205, USA.
| | - M Loring Burgess
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, 1830 E. Monument St., Baltimore, MD 21205, USA
| | - Nicole Squyres
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, 1830 E. Monument St., Baltimore, MD 21205, USA
| | - Juho-Antti Junno
- Department of Archeology, University of Oulu, Oulu 90014, Finland
| | - Erik Trinkaus
- Department of Anthropology, Washington University, St. Louis, MO 63130, USA
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50
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Abstract
Abstract
Evolution acts through a combination of four different drivers: (1) mutation, (2) selection, (3) genetic drift, and (4) developmental constraints. There is a tendency among some biologists to frame evolution as the sole result of natural selection, and this tendency is reinforced by many popular texts. “The Naked Ape” by Desmond Morris, published 50 years ago, is no exception. In this paper I argue that evolutionary biology is much richer than natural selection alone. I illustrate this by reconstructing the evolutionary history of five different organs of the human body: foot, pelvis, scrotum, hand and brain. Factors like developmental tinkering, by-product evolution, exaptation and heterochrony are powerful forces for body-plan innovations and the appearance of such innovations in human ancestors does not always require an adaptive explanation. While Morris explained the lack of body hair in the human species by sexual selection, I argue that molecular tinkering of regulatory genes expressed in the brain, followed by positive selection for neotenic features, may have been the driving factor, with loss of body hair as a secondary consequence.
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Affiliation(s)
- Nico M. van Straalen
- Department of Ecological Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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