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Tague RG. Lumbarization and sacralization: Domains of their co-occurrence with other costal-vertebral transformations are not identical. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024:e25012. [PMID: 39165071 DOI: 10.1002/ajpa.25012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 06/20/2024] [Accepted: 07/29/2024] [Indexed: 08/22/2024]
Abstract
OBJECTIVES This study evaluates whether sacralization of a lumbar vertebra and lumbarization of a sacral vertebra are a paired duality but with opposite expressions; the former is associated with 23 presacral vertebrae (PSV) and the latter with 25 PSV. Are sacralization and lumbarization local phenomena, involving only vertebra (V) 24 and V25, or are they associated with other costal-vertebral transformations? MATERIALS AND METHODS Study sample is of skeletonized humans, 431 females and 1405 males, who were 20-49 years of age-at-death and who died in the United States in the 20th and 21st centuries. Data collected are numbers of PSV and sacral vertebrae, presence of rib of V7, position of diaphragmatic vertebra, and transverse process and rib lengths of V5-V9, V18-V19, and V21-V22. RESULTS Females and males differ significantly in numbers of PSV. Both sexes show significant differences among individuals with 23 PSV, 24 PSV, and 25 PSV: (1) individuals with 23 PSV have the shortest ribs, whereas those with 25 PSV have the longest ribs, of V18 and V19; and (2) individuals with 23 PSV have the highest frequency of 6 sacral vertebrae, whereas those with 25 PSV have the highest frequency of 5 sacral vertebrae. DISCUSSION Individuals with 23 PSV and 25 PSV show posterior and anterior homeotic transformation, respectively, of the thoracic-lumbar and lumbar-sacral boundaries, but only individuals with 25 PSV show transformation of the sacral-coccygeal boundary. As co-occurring costal-vertebral transformations differ between sacralization and lumbarization, inferentially the set of genes that influences these vertebrae also differs.
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Affiliation(s)
- Robert G Tague
- Department of Geography and Anthropology, Louisiana State University, Baton Rouge, Louisiana, USA
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2
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Müller JA, Krenn VA, Böni T, Haeusler M. The influence of lumbosacral transitional vertebrae on lumbar lordosis and the angle of pelvic incidence. J Anat 2024; 244:594-600. [PMID: 38030157 PMCID: PMC10941542 DOI: 10.1111/joa.13985] [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: 07/20/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 12/01/2023] Open
Abstract
Pelvic incidence and lumbar lordosis have only normative values for spines comprising five lumbar and five sacral vertebrae. However, it is unclear how pelvic incidence and lumbar lordosis are affected by the common segmentation anomalies at the lumbo-sacral border leading to lumbosacral transitional vertebrae, including lumbarisations and sacralisations. In lumbosacral transitional vertebrae it is not trivial to identify the correct vertebral endplates to measure pelvic incidence and lumbar lordosis because ontogenetically the first sacral vertebra represents the first non-mobile sacral segment in lumbarisations, but the second segment in sacralisations. We therefore assessed pelvic incidence and lumbar lordosis with respect to both of these vertebral endplates. The type of segmentation anomaly was differentiated using spinal counts, spatial relationship with the iliac crest and morphological features. We found significant differences in pelvic incidence and lumbar lordosis between lumbarisations, sacralisations and the control group. The pelvic incidence in the sacralised group was mostly below the range of the lubarisation group and the control group when measured the traditional way at the first non-mobile segment (30.2°). However, the ranges of the sacralisation and lubarisation groups were completely encompassed by the control group when measured at the ontogenetically true first sacral vertebra. The mean pelvic incidence of the sacraliation group thus increased from 30.2° to 58.6°, and the mean pelvic incidence of the total sample increased from 45.6° to 51.2°, making it statistically indistinguishable from the control sample, whose pelvic incidence was 50.2°. Our results demonstrate that it is crucial to differentiate sacralisations from lumbarisation in order to assess the reference vertebra for pelvic incidence measurement. Due to their significant impact on spino-pelvic parameters, lumbosacral transitional vertebrae should be evaluated separately when examining pelvic incidence and lumbar lordosis.
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Affiliation(s)
- Jonas A Müller
- Institute of Evolutionary Medicine, University of Zürich, Zürich, Switzerland
| | - Viktoria A Krenn
- Institute of Evolutionary Medicine, University of Zürich, Zürich, Switzerland
- Department of Evolutionary Anthropology, University of Vienna, Vienna, Austria
- Frauenhofer Innovation Center for Digitization and Artificial Intelligence - KI4LIFE, Frauenhofer Austria Research, Klagenfurt, Austria
| | - Thomas Böni
- Institute of Evolutionary Medicine, University of Zürich, Zürich, Switzerland
- Balgrist University Hospital, Zürich, Switzerland
| | - Martin Haeusler
- Institute of Evolutionary Medicine, University of Zürich, Zürich, Switzerland
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3
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Spear JK, Grabowski M, Sekhavati Y, Costa CE, Goldstein DM, Petrullo LA, Peterson AL, Lee AB, Shattuck MR, Gómez-Olivencia A, Williams SA. Evolution of vertebral numbers in primates, with a focus on hominoids and the last common ancestor of hominins and panins. J Hum Evol 2023; 179:103359. [PMID: 37099927 DOI: 10.1016/j.jhevol.2023.103359] [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: 10/12/2022] [Revised: 03/14/2023] [Accepted: 03/14/2023] [Indexed: 04/28/2023]
Abstract
The primate vertebral column has been extensively studied, with a particular focus on hominoid primates and the last common ancestor of humans and chimpanzees. The number of vertebrae in hominoids-up to and including the last common ancestor of humans and chimpanzees-is subject to considerable debate. However, few formal ancestral state reconstructions exist, and none include a broad sample of primates or account for the correlated evolution of the vertebral column. Here, we conduct an ancestral state reconstruction using a model of evolution that accounts for both homeotic (changes of one type of vertebra to another) and meristic (addition or loss of a vertebra) changes. Our results suggest that ancestral primates were characterized by 29 precaudal vertebrae, with the most common formula being seven cervical, 13 thoracic, six lumbar, and three sacral vertebrae. Extant hominoids evolved tail loss and a reduced lumbar column via sacralization (homeotic transition at the last lumbar vertebra). Our results also indicate that the ancestral hylobatid had seven cervical, 13 thoracic, five lumbar, and four sacral vertebrae, and the ancestral hominid had seven cervical, 13 thoracic, four lumbar, and five sacral vertebrae. The last common ancestor of humans and chimpanzees likely either retained this ancestral hominid formula or was characterized by an additional sacral vertebra, possibly acquired through a homeotic shift at the sacrococcygeal border. Our results support the 'short-back' model of hominin vertebral evolution, which postulates that hominins evolved from an ancestor with an African ape-like numerical composition of the vertebral column.
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Affiliation(s)
- Jeffrey K Spear
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA.
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Paleoecology, Liverpool John Moores University, Liverpool, UK; Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway
| | - Yeganeh Sekhavati
- Department of Anthropology, Washington University in St. Louis, St. Louis, MO, USA
| | - Christina E Costa
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA
| | - Deanna M Goldstein
- Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Lauren A Petrullo
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Amy L Peterson
- Smithsonian Institution, National Museum of Natural History, Washington DC, USA
| | - Amanda B Lee
- Data Scientist, Jellyfish, Suite 3033, 220 N Green St, Chicago, IL, USA
| | | | - Asier Gómez-Olivencia
- Departamento de Geología, Facultad de Ciencia y Tecnología, Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Barrio Sarriena S/n, 48940 Bilbao, Spain; Sociedad de Ciencias Aranzadi, Zorroagagaina 11, 20014 Donostia-San Sebastián, Spain; Centro UCM-ISCIII de Investigación Sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos 5 (Pabellón 14), 28029 Madrid, Spain
| | - Scott A Williams
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA
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4
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Marino FE, Sibson BE, Lieberman DE. The evolution of human fatigue resistance. J Comp Physiol B 2022; 192:411-422. [PMID: 35552490 PMCID: PMC9197885 DOI: 10.1007/s00360-022-01439-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/28/2022] [Accepted: 04/20/2022] [Indexed: 11/26/2022]
Abstract
Humans differ from African great apes in numerous respects, but the chief initial difference setting hominins on their unique evolutionary trajectory was habitual bipedalism. The two most widely supported selective forces for this adaptation are increased efficiency of locomotion and improved ability to feed in upright contexts. By 4 million years ago, hominins had evolved the ability to walk long distances but extreme selection for endurance capabilities likely occurred later in the genus Homo to help them forage, power scavenge and persistence hunt in hot, arid conditions. In this review we explore the hypothesis that to be effective long-distance walkers and especially runners, there would also have been a strong selective benefit among Homo to resist fatigue. Our hypothesis is that since fatigue is an important factor that limits the ability to perform endurance-based activities, fatigue resistance was likely an important target for selection during human evolution for improved endurance capabilities. We review the trade-offs between strength, power, and stamina in apes and Homo and discuss three biological systems that we hypothesize humans evolved adaptations for fatigue resistance: neurological, metabolic and thermoregulatory. We conclude that the evolution of endurance at the cost of strength and power likely also involved the evolution of mechanisms to resist fatigue.
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Affiliation(s)
- Frank E Marino
- School of Allied Health, Exercise and Sport Science, Charles Sturt University, Bathurst, NSW, 2795, Australia.
| | - Benjamin E Sibson
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Ave, Cambridge, MA, 02138, USA
| | - Daniel E Lieberman
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Ave, Cambridge, MA, 02138, USA
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Krenn VA, Fornai C, Webb NM, Woodert MA, Prosch H, Haeusler M. The morphological consequences of segmentation anomalies in the human sacrum. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:690-707. [PMID: 36787761 PMCID: PMC9303760 DOI: 10.1002/ajpa.24466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/25/2021] [Accepted: 12/07/2021] [Indexed: 04/27/2023]
Abstract
OBJECTIVES Despite the high frequency of segmentation anomalies in the human sacrum, their evolutionary and clinical implications remain controversial. Specifically, inconsistencies involving the classification and counting methods obscure accurate assessment of lumbosacral transitional vertebrae. Therefore, we aim to establish more reliable morphological and morphometric methods for differentiating between sacralizations and lumbarizations in clinical and paleontological contexts. MATERIALS AND METHODS Using clinical CT data from 145 individuals aged 14-47 years, vertebral counts and the spatial relationship between the sacrum and adjoining bony structures were assessed, while the morphological variation of the sacrum was assessed using geometric morphometrics based on varied landmark configurations. RESULTS The prevalence of lumbosacral and sacrococcygeal segmentation anomalies was 40%. Lumbarizations and sacralizations were reliably distinguishable based on the spatial relationship between the iliac crest and the upward or downward trajectory of the linea terminalis on the sacrum. Different craniocaudal orientations of the alae relative to the corpus of the first sacral vertebra were also reflected in the geometric morphometric analyses. The fusion of the coccyx (32%) was frequently coupled with lumbarizations, suggesting that the six-element sacra more often incorporate the coccyx rather than the fifth lumbar vertebra. CONCLUSIONS Our approach allowed the consistent identification of segmentation anomalies even in isolated sacra. Additionally, our outcomes either suggest that homeotic border shifts often affect multiple spinal regions in a unidirectional way, or that sacrum length is highly conserved perhaps due to functional constraints. Our results elucidate the potential clinical, biomechanical, and evolutionary significance of lumbosacral transitional vertebrae.
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Affiliation(s)
- Viktoria A Krenn
- Institute of Evolutionary Medicine, University of Zurich, Zürich, Switzerland
- Department of Evolutionary Anthropology, University of Vienna, Vienna, Austria
| | - Cinzia Fornai
- Institute of Evolutionary Medicine, University of Zurich, Zürich, Switzerland
- Department of Evolutionary Anthropology, University of Vienna, Vienna, Austria
- VieSID, Vienna School of Interdisciplinary Dentistry, Klosterneuburg, Austria
| | - Nicole M Webb
- Institute of Evolutionary Medicine, University of Zurich, Zürich, Switzerland
- Department of Palaeoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt, Germany
- Institute of Archaeological Sciences, Senckenberg Centre for Human Evolution and Palaeoenvironment, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Mirella A Woodert
- Institute of Evolutionary Medicine, University of Zurich, Zürich, Switzerland
| | - Helmut Prosch
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Martin Haeusler
- Institute of Evolutionary Medicine, University of Zurich, Zürich, Switzerland
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6
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Relationship between the lumbosacral plexus deviation and 12th rib length in Japanese macaques (Macaca fuscata). Anat Sci Int 2022; 97:391-398. [PMID: 35303248 DOI: 10.1007/s12565-022-00657-8] [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: 06/16/2021] [Accepted: 03/02/2022] [Indexed: 11/01/2022]
Abstract
The relationship between the lumbosacral plexus (LSP) origin and the 12th rib length was recently determined in humans; cranial and caudal deviations of the plexus origin are related to shortening and elongation of the 12th rib, respectively. However, it remains unclear whether such anatomical correlations are also observed in non-human mammals. To address this issue, in the present study, we evaluated the LSP origin and the 12th rib length in Japanese macaques (Macaca fuscata). In typical cases, the femoral and obturator nerves were derived from both the 4th and 5th lumbar nerves, and the lumbosacral trunk was from the 5th to 7th lumbar nerves. Some of the LSPs exhibited a caudal deviation of their origins; the femoral and obturator nerves were also derived from the 6th lumbar nerve, in addition to the 4th and 5th lumbar nerves; the lumbosacral trunk lost the 5th lumbar nerve origin and arose from the 6th and 7th lumbar nerves. Individuals with the caudal deviation of LSP origin exhibited significant elongation of the 12th ribs, in comparison with individuals with the typical plexus. The present findings indicate that the caudal deviation of LSP origin was correlated to the 12th rib elongation in Japanese macaques, similar to humans. As a future studies, we need to clarify which mammalian groups exhibit such correlation between the deviation of the LSP origin and the lowest rib length, and further to provide evolutionary implications of this correlation.
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7
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Rosen KH, Jones CE, DeSilva JM. Bipedal locomotion in zoo apes: Revisiting the hylobatian model for bipedal origins. EVOLUTIONARY HUMAN SCIENCES 2022; 4:e12. [PMID: 37588936 PMCID: PMC10426021 DOI: 10.1017/ehs.2022.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bipedal locomotion is a hallmark of being human. Yet the body form from which bipedalism evolved remains unclear. Specifically, the positional behaviour (i.e. orthograde vs. pronograde) and the length of the lumbar spine (i.e. long and mobile vs. short and stiff) of the last common ancestor (LCA) of the African great apes and humans require further investigation. While fossil evidence would be the most conclusive, the paucity of hominid fossils from 5-10 million years ago makes this field of research challenging. In their absence, extant primate anatomy and behaviour may offer some insight into the ancestral body form from which bipedalism could most easily evolve. Here, we quantify the frequency of bipedalism in a large sample (N = 496) of zoo-housed hominoids and cercopithecines. Our results show that while each studied species of ape and monkey can move bipedally, hylobatids are significantly more bipedal and engage in bipedal locomotion more frequently and for greater distances than any other primate sampled. These data support hypotheses of an orthograde, long-backed and arboreal LCA, which is consistent with hominoid fossils from the middle-to-late Miocene. If true, knuckle-walking evolved in parallel in Pan and Gorilla, and the human body form, particularly the long lower back and orthograde posture, is conserved.
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Affiliation(s)
- Kyle H. Rosen
- Department of Anthropology, Dartmouth College, 6047 Silsby Hall, Hanover, NH, USA
| | - Caroline E. Jones
- Department of Psychology, University of Georgia, 125 Baldwin Street, Athens, GA, USA
| | - Jeremy M. DeSilva
- Department of Anthropology, Dartmouth College, 6047 Silsby Hall, Hanover, NH, USA
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8
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Ruff CB, Junno JA, Burgess ML, Canington SL, Harper C, Mudakikwa A, McFarlin SC. Body proportions and environmental adaptation in gorillas. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:501-529. [PMID: 36787793 DOI: 10.1002/ajpa.24443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/22/2021] [Accepted: 10/19/2021] [Indexed: 11/07/2022]
Abstract
OBJECTIVES Limb length and trunk proportions are determined in a large, taxonomically and environmentally diverse sample of gorillas and related to variation in locomotion, climate, altitude, and diet. MATERIALS AND METHODS The sample includes 299 gorilla skeletons, 115 of which are infants and juveniles, distributed between western lowland (G. gorilla gorilla), low and high elevation grauer (G. beringei graueri), and Virunga mountain gorillas (G. b. beringei). Limb bone and vertebral column lengths scaled to body mass are compared between subgroups by age group. RESULTS All G. beringei have relatively short 3rd metapodials and manual proximal phalanges compared to G. gorilla, and this difference is apparent in infancy. All G. beringei also have shortened total limb lengths relative to either body mass or vertebral column length, although patterns of variation in individual skeletal elements are more complex, and infants do not display the same patterns as adults. Mountain gorillas have relatively long clavicles, present in infancy, and a relatively long thoracic (but not lumbosacral) vertebral column. DISCUSSION A variety of environmental factors likely contributed to observed patterns of morphological variation among extant gorillas. We interpret the short hand and foot bones of all G. beringei as genetic adaptations to greater terrestriality in the last common ancestor of G. beringei; variation in other limb lengths to climatic adaptation, both genetic and developmental; and the larger thorax of G. b. beringei to adaptation to reduced oxygen pressure at high altitudes, again as a product of both genetic differences and environmental influences during development.
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Affiliation(s)
- Christopher B Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - M Loring Burgess
- Peabody Museum of Archaeology and Ethnology, Harvard University, Cambridge, Massachusetts, USA
| | - Stephanie L Canington
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christine Harper
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Antoine Mudakikwa
- Rwanda Development Board, Department of Tourism and Conservation, Kigali, Rwanda
| | - Shannon C McFarlin
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA.,Human Origins Program, Smithsonian's National Museum of Natural History, Washington, District of Columbia, USA
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9
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Tarrega-Saunders ELR, King C, Roberts AM, Thorpe SKS. Knuckle-walking and behavioural flexibility in great apes. REVUE DE PRIMATOLOGIE 2021. [DOI: 10.4000/primatologie.10855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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10
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Hofmann R, Lehmann T, Warren DL, Ruf I. The squirrel is in the detail: Anatomy and morphometry of the tail in Sciuromorpha (Rodentia, Mammalia). J Morphol 2021; 282:1659-1682. [PMID: 34549832 DOI: 10.1002/jmor.21412] [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: 01/02/2021] [Revised: 09/09/2021] [Accepted: 09/15/2021] [Indexed: 11/07/2022]
Abstract
In mammals, the caudal vertebrae are certainly among the least studied elements of their skeleton. However, the tail plays an important role in locomotion (e.g., balance, prehensility) and behavior (e.g., signaling). Previous studies largely focused on prehensile tails in Primates and Carnivora, in which certain osteological features were selected and used to define tail regions (proximal, transitional, distal). Interestingly, the distribution pattern of these anatomical characters and the relative proportions of the tail regions were similar in both orders. In order to test if such tail regionalization can be applied to Rodentia, we investigated the caudal vertebrae of 20 Sciuridae and six Gliridae species. Furthermore, we examined relationships between tail anatomy/morphometry and locomotion. The position of selected characters along the tail was recorded and their distribution was compared statistically using Spearman rank correlation. Vertebral body length (VBL) was measured to calculate the proportions of each tail region and to perform procrustes analysis on the shape of relative vertebral body length (rVBL) progressions. Our results show that tail regionalization, as defined for Primates and Carnivora, can be applied to almost all investigated squirrels, regardless of their locomotor category. Moreover, major locomotor categories can be distinguished by rVBL progression and tail region proportions. In particular, the small flying squirrels Glaucomys volans and Hylopetes sagitta show an extremely short transitional region. Likewise, several semifossorial taxa can be distinguished by their short distal region. Moreover, among flying squirrels, Petaurista petaurista shows differences with the small flying squirrels, mirroring previous observations on locomotory adaptations based on their inner ear morphometry. Our results show furthermore that the tail region proportions of P. petaurista, phylogenetically more basal than the small flying squirrels, are similar to those of bauplan-conservative arboreal squirrels.
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Affiliation(s)
- Rebecca Hofmann
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Frankfurt am Main, Germany.,Institut für Geowissenschaften, Goethe-Universität, Frankfurt am Main, Germany
| | - Thomas Lehmann
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Frankfurt am Main, Germany
| | - Dan L Warren
- Senckenberg Biodiversität und Klima Forschungszentrum, Frankfurt am Main, Germany.,Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Irina Ruf
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Frankfurt am Main, Germany.,Institut für Geowissenschaften, Goethe-Universität, Frankfurt am Main, Germany
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11
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Williams SA, Pilbeam D. Homeotic change in segment identity derives the human vertebral formula from a chimpanzee-like one. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 176:283-294. [PMID: 34227681 DOI: 10.1002/ajpa.24356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 02/12/2021] [Accepted: 06/07/2021] [Indexed: 01/10/2023]
Abstract
OBJECTIVES One of the most contentious issues in paleoanthropology is the nature of the last common ancestor of humans and our closest living relatives, chimpanzees and bonobos (panins). The numerical composition of the vertebral column has featured prominently, with multiple models predicting distinct patterns of evolution and contexts from which bipedalism evolved. Here, we study total numbers of vertebrae from a large sample of hominoids to quantify variation in and patterns of regional and total numbers of vertebrae in hominoids. MATERIALS AND METHODS We compile and study a large sample (N = 893) of hominoid vertebral formulae (numbers of cervical, thoracic, lumbar, sacral, caudal segments in each specimen) and analyze full vertebral formulae, total numbers of vertebrae, and super-regional numbers of vertebrae: presacral (cervical, thoracic, lumbar) vertebrae and sacrococcygeal vertebrae. We quantify within- and between-taxon variation using heterogeneity and similarity measures derived from population genetics. RESULTS We find that humans are most similar to African apes in total and super-regional numbers of vertebrae. Additionally, our analyses demonstrate that selection for bipedalism reduced variation in numbers of vertebrae relative to other hominoids. DISCUSSION The only proposed ancestral vertebral configuration for the last common ancestor of hominins and panins that is consistent with our results is the modal formula demonstrated by chimpanzees and bonobos (7 cervical-13 thoracic-4 lumbar-6 sacral-3 coccygeal). Hox gene expression boundaries suggest that a rostral shift in Hox10/Hox11-mediated complexes could produce the human modal formula from the proposal ancestral and panin modal formula.
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Affiliation(s)
- Scott A Williams
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, USA.,New York Consortium in Evolutionary Primatology, New York, USA
| | - David Pilbeam
- Department of Human Evolutionary Biology, Harvard University, Cambridge, USA
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12
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Machnicki AL, Reno PL. Great apes and humans evolved from a long-backed ancestor. J Hum Evol 2020; 144:102791. [DOI: 10.1016/j.jhevol.2020.102791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 03/20/2020] [Accepted: 03/23/2020] [Indexed: 12/20/2022]
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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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14
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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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Böhme M, Spassov N, Fuss J, Tröscher A, Deane AS, Prieto J, Kirscher U, Lechner T, Begun DR. A new Miocene ape and locomotion in the ancestor of great apes and humans. Nature 2019; 575:489-493. [DOI: 10.1038/s41586-019-1731-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/27/2019] [Indexed: 01/26/2023]
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16
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A late Miocene hominid partial pelvis from Hungary. J Hum Evol 2019; 136:102645. [DOI: 10.1016/j.jhevol.2019.102645] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 07/28/2019] [Accepted: 07/29/2019] [Indexed: 11/22/2022]
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17
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Arlegi M, Veschambre‐Couture C, Gómez‐Olivencia A. Evolutionary selection and morphological integration in the vertebral column of modern humans. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 171:17-36. [DOI: 10.1002/ajpa.23950] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 07/03/2019] [Accepted: 09/26/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Mikel Arlegi
- Departamento de Estratigrafía y Paleontología, Facultad de Ciencia y TecnologíaUniversidad del País Vasco‐Euskal Herriko Unibertsitatea (UPV/EHU) Leioa Spain
- Université de Bordeaux, PACEA UMR 5199 Pessac France
| | | | - Asier Gómez‐Olivencia
- Departamento de Estratigrafía y Paleontología, Facultad de Ciencia y TecnologíaUniversidad del País Vasco‐Euskal Herriko Unibertsitatea (UPV/EHU) Leioa Spain
- IKERBASQUE. Basque Foundation for Science Bizkaia Spain
- Centro UCM‐ISCIII de Investigación sobre Evolución y Comportamiento Humanos Madrid Spain
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Selby MS, Gillette A, Raval Y, Taufiq M, Sampson MJ. Modern Medical Consequences of the Ancient Evolution of a Long, Flexible Lumbar Spine. J Osteopath Med 2019; 119:622-630. [PMID: 31449308 DOI: 10.7556/jaoa.2019.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Modern human bipedality is unique and requires lumbar lordosis, whereas chimpanzees, our closest relatives, have short lumbar spines rendering them incapable of lordosis. To facilitate lordosis, humans have longer lumbar spines, greater lumbosacral angle, dorsally wedged lumbar vertebral bodies, and lumbar zygapophyseal joints with both increasingly coronal orientation and further caudal interfacet distances. These features limit modern lower lumbar spine and lumbosacral joint ailments, albeit imperfectly. The more coronal zygapophyseal orientation limits spondylolisthesis, while increasing interfacet distance may limit spondylolysis. Common back pain, particularly in people who are obese or pregnant, may result from increased lumbar lordosis, causing additional mass transfer through the zygapophyseal joints rather than vertebral bodies. Reduction in lumbar lordosis, such as in flatback syndrome from decreased lumbosacral angle, can also cause back pain. Human lumbar lordosis is necessary for placing the trunk atop the pelvis and presents a balancing act not required of our closest primate relatives.
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Nalley TK, Scott JE, Ward CV, Alemseged Z. Comparative morphology and ontogeny of the thoracolumbar transition in great apes, humans, and fossil hominins. J Hum Evol 2019; 134:102632. [DOI: 10.1016/j.jhevol.2019.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 01/01/2023]
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20
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Williams SA, Spear JK, Petrullo L, Goldstein DM, Lee AB, Peterson AL, Miano DA, Kaczmarek EB, Shattuck MR. Increased variation in numbers of presacral vertebrae in suspensory mammals. Nat Ecol Evol 2019; 3:949-956. [DOI: 10.1038/s41559-019-0894-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 04/08/2019] [Indexed: 11/09/2022]
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21
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Bergmann PJ, Morinaga G. The convergent evolution of snake‐like forms by divergent evolutionary pathways in squamate reptiles*. Evolution 2018; 73:481-496. [DOI: 10.1111/evo.13651] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 11/08/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Philip J. Bergmann
- Department of Biology Clark University 950 Main Street Worcester Massachusetts 01610
| | - Gen Morinaga
- Department of Biology Clark University 950 Main Street Worcester Massachusetts 01610
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22
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Shapiro LJ, Kemp AD. Functional and developmental influences on intraspecific variation in catarrhine vertebrae. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 168:131-144. [DOI: 10.1002/ajpa.23730] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/13/2018] [Accepted: 09/26/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Liza J. Shapiro
- Department of Anthropology University of Texas at Austin Austin Texas
| | - Addison D. Kemp
- Department of Anthropology University of Texas at Austin Austin Texas
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Arlegi M, Gómez‐Robles A, Gómez‐Olivencia A. Morphological integration in the gorilla, chimpanzee, and human neck. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:408-416. [DOI: 10.1002/ajpa.23441] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Mikel Arlegi
- Department of Estratigrafía y Paleontología, Facultad de Ciencia y TecnologíaEuskal Herriko Unibertsitatea (UPV/EHU), Barrio Sarriena s/nLeioa, 48940 Spain
- Université de Bordeaux, PACEA UMR 5199, Bâtiment B8, Allée Geoffroy Saint‐HilairePessac 33615 France
| | - Aida Gómez‐Robles
- Department of Genetics, Evolution, and EnvironmentUniversity College LondonLondon WC1E 6BT United Kingdom
- Department of Life SciencesNatural History MuseumLondon SW7 5BD United Kingdom
| | - Asier Gómez‐Olivencia
- Department of Estratigrafía y Paleontología, Facultad de Ciencia y TecnologíaEuskal Herriko Unibertsitatea (UPV/EHU), Barrio Sarriena s/nLeioa, 48940 Spain
- IKERBASQUE. Basque Foundation for Science Spain
- Centro UCM‐ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos 5 (Pabellón 14)Madrid 28029 Spain
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25
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Ward CV, Maddux SD, Middleton ER. Three‐dimensional anatomy of the anthropoid bony pelvis. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:3-25. [DOI: 10.1002/ajpa.23425] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/11/2017] [Accepted: 01/12/2018] [Indexed: 01/27/2023]
Affiliation(s)
- Carol V. Ward
- Department of Pathology and Anatomical Sciences, M263 Medical Sciences BuildingUniversity of MissouriColumbia Missouri 65212
| | - Scott D. Maddux
- Center for Anatomical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie BoulevardFt. Worth Texas 76107
| | - Emily R. Middleton
- Department of Pathology and Anatomical Sciences, M263 Medical Sciences BuildingUniversity of MissouriColumbia Missouri 65212
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26
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3D geometric morphometrics of thorax variation and allometry in Hominoidea. J Hum Evol 2017; 113:10-23. [DOI: 10.1016/j.jhevol.2017.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/31/2017] [Accepted: 08/02/2017] [Indexed: 12/29/2022]
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27
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Tague RG. Proximate cause, anatomical correlates, and obstetrical implication of a supernumerary lumbar vertebra in humans. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 165:444-456. [PMID: 29159938 DOI: 10.1002/ajpa.23361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 10/28/2017] [Accepted: 10/30/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Three issues are considered on variation in number of presacral vertebrae (PSV) in humans: (1) sexual difference in number of PSV, (2) inactivation of Hoxd-11 gene as etiology for a supernumerary lumbar vertebra, and (3) anatomical correlates of a supernumerary lumbar vertebra, including lumbar-sacral nearthrosis, and pelvic size. MATERIALS AND METHODS Sample was 407 skeletonized females and 1,318 males from United States; ages at death were 20 to 49 years. Two subsamples of males were used: (1) 98 with modal numbers of cervical, thoracic, lumbar, and sacral vertebrae (PSV = 24) and (2) 45 with a supernumerary lumbar vertebra but modal numbers for other vertebral segments (PSV = 25). Measurements were taken of ulna, second metacarpal, vertebrae, femur, and pelvis; presence of lumbar-sacral nearthrosis was observed. RESULTS Although 90% of females and males have 24 PSV, females have higher frequency of 23 PSV and males have higher frequency of 25 PSV. Compared to males with 24 PSV, males with 25 PSV and supernumerary lumbar vertebra show (1) no difference in anatomies associated with inactivation of Hoxd-11, and (2) higher frequency of lumbar-sacral nearthrosis and smaller pelvic inlet circumference. DISCUSSION Sexual difference in number of PSV may be due to tempo of somite formation and Hox gene activation. Hypothesis is not supported that a supernumerary lumbar vertebra is due to inactivation of Hoxd-11. The presence of a supernumerary lumbar vertebra is associated with small pelvic inlet circumference, which can be obstetrically disadvantageous.
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Affiliation(s)
- Robert G Tague
- Department of Geography and Anthropology, Louisiana State University, Baton Rouge, Louisiana, 70803
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Thompson NE, Almécija S. The evolution of vertebral formulae in Hominoidea. J Hum Evol 2017; 110:18-36. [DOI: 10.1016/j.jhevol.2017.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/24/2017] [Accepted: 05/27/2017] [Indexed: 01/06/2023]
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Thoracic vertebral count and thoracolumbar transition in Australopithecus afarensis. Proc Natl Acad Sci U S A 2017; 114:6000-6004. [PMID: 28533391 DOI: 10.1073/pnas.1702229114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The evolution of the human pattern of axial segmentation has been the focus of considerable discussion in paleoanthropology. Although several complete lumbar vertebral columns are known for early hominins, to date, no complete cervical or thoracic series has been recovered. Several partial skeletons have revealed that the thoracolumbar transition in early hominins differed from that of most extant apes and humans. Australopithecus africanus, Australopithecus sediba, and Homo erectus all had zygapophyseal facets that shift from thoracic-like to lumbar-like at the penultimate rib-bearing level, rather than the ultimate rib-bearing level, as in most humans and extant African apes. What has not been clear is whether Australopithecus had 12 thoracic vertebrae as in most humans, or 13 as in most African apes, and where the position of the thoracolumbar transitional element was. The discovery, preparation, and synchrotron scanning of the Australopithecus afarensis partial skeleton DIK-1-1, from Dikika, Ethiopia, provides the only known complete hominin cervical and thoracic vertebral column before 60,000 years ago. DIK-1-1 is the only known Australopithecus skeleton to preserve all seven cervical vertebrae and provides evidence for 12 thoracic vertebrae with a transition in facet morphology at the 11th thoracic level. The location of this transition, one segment cranial to the ultimate rib-bearing vertebra, also occurs in all other early hominins and is higher than in most humans or extant apes. At 3.3 million years ago, the DIK-1-1 skeleton is the earliest example of this distinctive and unusual pattern of axial segmentation.
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30
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Tague RG. Sacral Variability in Tailless Species: Homo sapiens
and Ochotona princeps. Anat Rec (Hoboken) 2017; 300:798-809. [DOI: 10.1002/ar.23555] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 10/05/2016] [Accepted: 11/26/2016] [Indexed: 12/29/2022]
Affiliation(s)
- Robert G. Tague
- Department of Geography and Anthropology; Louisiana State University; Baton Rouge Louisiana
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31
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Arlegi M, Gómez-Olivencia A, Albessard L, Martínez I, Balzeau A, Arsuaga JL, Been E. The role of allometry and posture in the evolution of the hominin subaxial cervical spine. J Hum Evol 2017; 104:80-99. [PMID: 28317557 DOI: 10.1016/j.jhevol.2017.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 01/02/2017] [Accepted: 01/04/2017] [Indexed: 12/01/2022]
Abstract
Cervical vertebrae not only protect the spinal cord but also are the insertion and origin points for muscles related to the movement of the head, upper limb, and trunk, among others, and are thus important elements in primate evolution. While previous work has been undertaken on the first two cervical vertebrae, there is a dearth of studies on the subaxial cervical spine in hominines. In this paper, we provide detailed morphological information on two important aspects of the subaxial cervical vertebrae (C3 - C7): mid-sagittal morphology and superior facet orientation. We studied large samples of African apes including modern humans and the most complete fossil hominin subaxial cervical vertebrae using both traditional and geometric morphometrics. There are significant differences between extant hominoids related to the relative length and orientation of the spinous process as well as to the orientation of the articular facets, which are related to size, locomotion, and neck posture. In fact, fossil hominins do not completely conform to any of the extant groups. Our assessment of mid-sagittal morphology and superior articular facet orientation shows that australopiths have more Homo-like upper subaxial cervical vertebrae coupled with more "primitive" lower cervical vertebrae. Based on these results, we hypothesize that those changes, maybe related to postural changes derived from bipedalism, did not affect the entire subaxial cervical spine at once. From a methodological point of view, the combination of traditional and geometric morphometric data provides a more integrative perspective of morphological change and evolution, which is certainly useful in human evolutionary studies.
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Affiliation(s)
- Mikel Arlegi
- Dept. Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Euskal Herriko Unibertsitatea, UPV-EHU. Apdo. 644, 48080 Bilbao, Spain.
| | - Asier Gómez-Olivencia
- Dept. Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Euskal Herriko Unibertsitatea, UPV-EHU. Apdo. 644, 48080 Bilbao, Spain; IKERBASQUE, Basque Foundation for Science, 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 UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos 5 (Pabellón 14), 28029 Madrid, Spain.
| | - Lou Albessard
- 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
| | - Ignacio Martínez
- Área de Antropología Física, Depto. de Ciencias de la Vida, Universidad de Alcalá, Alcalá de Henares 28871, Spain; Centro UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos 5 (Pabellón 14), 28029 Madrid, Spain
| | - Antoine Balzeau
- 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; Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium
| | - Juan Luis Arsuaga
- Dpto. de Paleontología, Fac. Ciencias Geológicas, Universidad Complutense de Madrid, Avda. Complutense s/n, Madrid 28040, 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
| | - Ella Been
- Physical Therapy Department, Faculty of Health Professions, Ono Academic College, Kiryat Ono 5545173, Israel; Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 39040 Tel Aviv, Israel
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Gómez-Olivencia A, Arlegi M, Barash A, Stock JT, Been E. The Neandertal vertebral column 2: The lumbar spine. J Hum Evol 2017; 106:84-101. [PMID: 28434542 DOI: 10.1016/j.jhevol.2017.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 12/26/2016] [Accepted: 01/20/2017] [Indexed: 12/26/2022]
Abstract
Here we provide the most extensive metric and morphological analysis performed to date on the Neandertal lumbar spine. Neandertal lumbar vertebrae show differences from modern humans in both the vertebral body and in the neural arch, although not all Neandertal lumbar vertebrae differ from modern humans in the same way. Differences in the vertebral foramen are restricted to the lowermost lumbar vertebrae (L4 and L5), differences in the orientation of the upper articular facets appear in the uppermost lumbar vertebrae (probably in L1 and L2-L3), and differences in the horizontal angle of the transverse process appear in L2-L4. Neandertals, when compared to modern humans, show a smaller degree of lumbar lordosis. Based on a still limited fossil sample, early hominins (australopiths and Homo erectus) had a lumbar lordosis that was similar to but below the mean of modern humans. Here, we hypothesize that from this ancestral degree of lumbar lordosis, the Neandertal lineage decreased their lumbar lordosis and Homo sapiens slightly increased theirs. From a postural point of view, the lower degree of lordosis is related to a more vertical position of the sacrum, which is also positioned more ventrally with respect to the dorsal end of the pelvis. This results in a spino-pelvic alignment that, though different from modern humans, maintained an economic postural equilibrium. Some features, such as a lower degree of lumbar lordosis, were already present in the middle Pleistocene populations ancestral to Neandertals. However, these middle Pleistocene populations do not show the full suite of Neandertal lumbar morphologies, which probably means that the characteristic features of the Neandertal lumbar spine did not arise all at once.
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Affiliation(s)
- Asier Gómez-Olivencia
- Dept. Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Euskal Herriko Unibertsitatea, UPV-EHU. Apdo. 644, 48080 Bilbao, Spain; IKERBASQUE, Basque Foundation for Science, 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 UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos 5 (Pabellón 14), 28029 Madrid, Spain.
| | - Mikel Arlegi
- Dept. Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Euskal Herriko Unibertsitatea, UPV-EHU. Apdo. 644, 48080 Bilbao, Spain
| | - Alon Barash
- Faculty of Medicine in the Galilee, Bar Ilan University, Zefat 1311502, Israel
| | - Jay T Stock
- PAVE Research Group, Department of Archaeology and Anthropology, University of Cambridge, Pembroke Street, Cambridge CB2 3DZ, UK
| | - Ella Been
- Physical Therapy Department, Faculty of Health Professions, Ono Academic College, Kiryat Ono 5545173, Israel; Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 39040 Tel Aviv, Israel
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Castillo ER, Hsu C, Mair RW, Lieberman DE. Testing biomechanical models of human lumbar lordosis variability. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 163:110-121. [DOI: 10.1002/ajpa.23189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/16/2016] [Accepted: 01/29/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Eric R. Castillo
- Department of Human Evolutionary Biology; Harvard University; Cambridge Massachusetts 02138
| | - Connie Hsu
- Department of Human Evolutionary Biology; Harvard University; Cambridge Massachusetts 02138
| | - Ross W. Mair
- Department of Human Evolutionary Biology; Harvard University; Cambridge Massachusetts 02138
| | - Daniel E. Lieberman
- Department of Human Evolutionary Biology; Harvard University; Cambridge Massachusetts 02138
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Sacral vertebral remains of the Middle Miocene hominoid Nacholapithecus kerioi from northern Kenya. J Hum Evol 2016; 94:117-25. [DOI: 10.1016/j.jhevol.2016.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 11/21/2022]
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35
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Machnicki AL, Lovejoy CO, Reno PL. Developmental identity versus typology: Lucy has only four sacral segments. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 160:729-39. [DOI: 10.1002/ajpa.22997] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 02/25/2016] [Accepted: 03/31/2016] [Indexed: 12/28/2022]
Affiliation(s)
| | - C. Owen Lovejoy
- Department of Anthropology and School of Biomedical SciencesKent State UniversityKent OH
| | - Philip L. Reno
- Department of AnthropologyPennsylvania State UniversityUniversity Park PA
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36
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Williams SA, Middleton ER, Villamil CI, Shattuck MR. Vertebral numbers and human evolution. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 159:S19-36. [DOI: 10.1002/ajpa.22901] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Scott A. Williams
- Department of Anthropology; Center for the Study of Human Origins, New York University; New York NY 10003
- New York Consortium in Evolutionary Primatology; New York NY
| | - Emily R. Middleton
- Department of Anthropology; Center for the Study of Human Origins, New York University; New York NY 10003
- New York Consortium in Evolutionary Primatology; New York NY
| | - Catalina I. Villamil
- Department of Anthropology; Center for the Study of Human Origins, New York University; New York NY 10003
- New York Consortium in Evolutionary Primatology; New York NY
| | - Milena R. Shattuck
- Department of Anthropology; Center for the Study of Human Origins, New York University; New York NY 10003
- New York Consortium in Evolutionary Primatology; New York NY
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Machnicki AL, Spurlock LB, Strier KB, Reno PL, Lovejoy CO. First steps of bipedality in hominids: evidence from the atelid and proconsulid pelvis. PeerJ 2016; 4:e1521. [PMID: 26793418 PMCID: PMC4715437 DOI: 10.7717/peerj.1521] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/29/2015] [Indexed: 11/20/2022] Open
Abstract
Upright walking absent a bent-hip-bent-knee gait requires lumbar lordosis, a ubiquitous feature in all hominids for which it can be observed. Its first appearance is therefore a central problem in human evolution. Atelids, which use the tail during suspension, exhibit demonstrable lordosis and can achieve full extension of their hind limbs during terrestrial upright stance. Although obviously homoplastic with hominids, the pelvic mechanisms facilitating lordosis appear largely similar in both taxa with respect to abbreviation of upper iliac height coupled with broad sacral alae. Both provide spatial separation of the most caudal lumbar(s) from the iliac blades. A broad sacrum is therefore a likely facet of earliest hominid bipedality. All tailed monkeys have broad alae. By contrast all extant apes have very narrow sacra, which promote “trapping” of their most caudal lumbars to achieve lower trunk rigidity during suspension. The alae in the tailless proconsul Ekembo nyanzae appear to have been quite broad, a character state that may have been primitive in Miocene hominoids not yet adapted to suspension and, by extension, exaptive for earliest bipedality in the hominid/panid last common ancestor. This hypothesis receives strong support from other anatomical systems preserved in Ardipithecus ramidus.
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Affiliation(s)
- Allison L Machnicki
- Department of Anthropology, Pennsylvania State University , University Park, PA , United States
| | - Linda B Spurlock
- Department of Anthropology, Kent State University , Kent, OH , United States
| | - Karen B Strier
- Department of Anthropology, University of Wisconsin-Madison , Madison, WI , United States
| | - Philip L Reno
- Department of Anthropology, Pennsylvania State University , University Park, PA , United States
| | - C Owen Lovejoy
- Department of Anthropology, Kent State University , Kent, OH , United States
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Meyer MR, Haeusler M. Spinal cord evolution in early Homo. J Hum Evol 2015; 88:43-53. [DOI: 10.1016/j.jhevol.2015.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 10/22/2022]
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Püschel TA, Sellers WI. Standing on the shoulders of apes: Analyzing the form and function of the hominoid scapula using geometric morphometrics and finite element analysis. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2015; 159:325-41. [DOI: 10.1002/ajpa.22882] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 09/02/2015] [Accepted: 10/01/2015] [Indexed: 12/30/2022]
Affiliation(s)
- Thomas A. Püschel
- Computational and Evolutionary Biology Group, Faculty of Life Sciences; University of Manchester; Manchester M13 9PT UK
| | - William I. Sellers
- Computational and Evolutionary Biology Group, Faculty of Life Sciences; University of Manchester; Manchester M13 9PT UK
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Russo GA, Williams SA. Giant pandas (Carnivora: Ailuropoda melanoleuca) and living hominoids converge on lumbar vertebral adaptations to orthograde trunk posture. J Hum Evol 2015; 88:160-179. [PMID: 26341032 DOI: 10.1016/j.jhevol.2015.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 06/06/2015] [Accepted: 06/28/2015] [Indexed: 01/11/2023]
Abstract
Living hominoids share a common body plan characterized by a gradient of derived postcranial features that distinguish them from their closest living relatives, cercopithecoid monkeys. However, the evolutionary scenario(s) that led to the derived postcranial features of hominoids are uncertain. Explanations are complicated by the fact that living hominoids vary considerably in positional behaviors, and some Miocene hominoids are morphologically, and therefore probably behaviorally, distinct from modern hominoids. Comparative studies that aim to identify morphologies associated with specific components of positional behavioral repertoires are an important avenue of research that can improve our understanding of the evolution and adaptive significance of the hominoid postcranium. Here, we employ a comparative approach to offer additional insight into the evolution of the hominoid lumbar vertebral column. Specifically, we tested whether giant pandas (Carnivora: Ailuropoda melanoleuca) converge with living hominoids on lumbar vertebral adaptations to the single component of their respective positional behavioral repertoires that they share--orthograde (i.e., upright) trunk posture. We compare lumbar vertebral morphologies of Ailuropoda to those of other living ursids and caniform outgroups (northern raccoons and gray wolves). Mirroring known differences between living hominoids and cercopithecoids, Ailuropoda generally exhibits fewer, craniocaudally shorter lumbar vertebrae with more dorsally positioned transverse processes that are more dorsally oriented and laterally directed, and taller, more caudally directed spinous processes than other caniforms in the sample. Our comparative evidence lends support to a potential evolutionary scenario in which the acquisition of hominoid-like lumbar vertebral morphologies may have evolved for generalized orthograde behaviors and could have been exapted for suspensory behavior in crown hominoids and for other locomotor specializations (e.g., brachiation) in extant lineages.
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Affiliation(s)
- Gabrielle A Russo
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Scott A Williams
- Center for the Study of Human Origins, Department of Anthropology, New York University, 25 Waverly Place, New York, NY 10003, USA; New York Consortium in Evolutionary Primatology, New York, NY 10024, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.
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Reno PL. Genetic and developmental basis for parallel evolution and its significance for hominoid evolution. Evol Anthropol 2015; 23:188-200. [PMID: 25347977 DOI: 10.1002/evan.21417] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Greater understanding of ape comparative anatomy and evolutionary history has brought a general appreciation that the hominoid radiation is characterized by substantial homoplasy.(1-4) However, little consensus has been reached regarding which features result from repeated evolution. This has important implications for reconstructing ancestral states throughout hominoid evolution, including the nature of the Pan-Homo last common ancestor (LCA). Advances from evolutionary developmental biology (evo-devo) have expanded the diversity of model organisms available for uncovering the morphogenetic mechanisms underlying instances of repeated phenotypic change. Of particular relevance to hominoids are data from adaptive radiations of birds, fish, and even flies demonstrating that parallel phenotypic changes often use similar genetic and developmental mechanisms. The frequent reuse of a limited set of genes and pathways underlying phenotypic homoplasy suggests that the conserved nature of the genetic and developmental architecture of animals can influence evolutionary outcomes. Such biases are particularly likely to be shared by closely related taxa that reside in similar ecological niches and face common selective pressures. Consideration of these developmental and ecological factors provides a strong theoretical justification for the substantial homoplasy observed in the evolution of complex characters and the remarkable parallel similarities that can occur in closely related taxa. Thus, as in other branches of the hominoid radiation, repeated phenotypic evolution within African apes is also a distinct possibility. If so, the availability of complete genomes for each of the hominoid genera makes them another model to explore the genetic basis of repeated evolution.
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Affiliation(s)
- Philip L Reno
- Department of Anthropology, The Pennsylvania State University, University Park, PA, 16802
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Williams SA, Russo GA. Evolution of the hominoid vertebral column: The long and the short of it. Evol Anthropol 2015; 24:15-32. [DOI: 10.1002/evan.21437] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Spencer HT, Gold ME, Hresko MT. Abnormal rib count in scoliosis surgery: impact on the reporting of spinal fusion levels. J Child Orthop 2014; 8:497-503. [PMID: 25370702 PMCID: PMC4252269 DOI: 10.1007/s11832-014-0623-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 10/20/2014] [Indexed: 02/03/2023] Open
Abstract
PURPOSE Variation in rib numbering has been noted in adolescent idiopathic scoliosis (AIS), but its effect on the reporting of fusion levels has not been studied. We hypothesized that vertebral numbering variations can lead to differing documentation of fusion levels. METHODS We examined the radiographs of 161 surgical AIS patients and 179 control patients without scoliosis. For AIS patients, the operative report of fusion levels was compared to conventional vertebral labeling from the first thoracic level and proceeding caudal. We defined normal counts as 12 thoracic (rib-bearing) and five lumbar (non-rib-bearing) vertebrae. We compared our counts with data from 181 anatomic specimens. RESULTS Among AIS patients, 22 (14 %) had an abnormal number of ribs and 29 (18 %) had either abnormal rib or lumbar count. In 12/29 (41 %) patients, the operative report differed from conventional labeling by one level, versus 3/132 (2 %) patients with normal numbering (p < 0.001). However, there were no cases seen of wrong fusion levels based on curve pattern. Among controls, 11 % had abnormal rib count (p = 0.41) compared to the rate in AIS. Anatomic specimen data did not differ in abnormal rib count (p = 1.0) or thoracolumbar pattern (p = 0.59). CONCLUSIONS The rate of numerical variations in the thoracolumbar vertebrae of AIS patients is equivalent to that in the general population. When variations in rib count are present, differences in numbering levels can occur. In the treatment of scoliosis, no wrong fusion levels were noted. However, for both scoliosis patients and the general population, we suggest adherence to conventional labeling to enhance clarity.
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Affiliation(s)
- Hillard T Spencer
- Department of Orthopaedic Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Hunnewell 2, Boston, MA, 02115, USA,
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Russo GA, Williams SA. “Lucy” (A.L. 288-1) had five sacral vertebrae. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2014; 156:295-303. [DOI: 10.1002/ajpa.22642] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/10/2014] [Accepted: 10/08/2014] [Indexed: 12/13/2022]
Affiliation(s)
- Gabrielle A. Russo
- Department of Anthropology and IDPAS; Stony Brook University; Stony Brook NY 11794
| | - Scott A. Williams
- Center for the Study of Human Origins, Department of Anthropology; New York University; New York NY 10003
- New York Consortium in Evolutionary Primatology; New York NY 10024
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand; Wits 2050 South Africa
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Pattinson DJ, Thompson RS, Piotrowski AK, Asher RJ. Phylogeny, Paleontology, and Primates: Do Incomplete Fossils Bias the Tree of Life? Syst Biol 2014; 64:169-86. [DOI: 10.1093/sysbio/syu077] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David J. Pattinson
- Department of Zoology, Downing Street, Cambridge, CB2 3EJ; 2Division of Ecology and Evolution, Imperial College London, South Kensington Campus, London, SW7 2AZ; 3Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD; and 4Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
- Department of Zoology, Downing Street, Cambridge, CB2 3EJ; 2Division of Ecology and Evolution, Imperial College London, South Kensington Campus, London, SW7 2AZ; 3Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD; and 4Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
- Department of Zoology, Downing Street, Cambridge, CB2 3EJ; 2Division of Ecology and Evolution, Imperial College London, South Kensington Campus, London, SW7 2AZ; 3Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD; and 4Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Richard S. Thompson
- Department of Zoology, Downing Street, Cambridge, CB2 3EJ; 2Division of Ecology and Evolution, Imperial College London, South Kensington Campus, London, SW7 2AZ; 3Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD; and 4Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Aleks K. Piotrowski
- Department of Zoology, Downing Street, Cambridge, CB2 3EJ; 2Division of Ecology and Evolution, Imperial College London, South Kensington Campus, London, SW7 2AZ; 3Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD; and 4Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Robert J. Asher
- Department of Zoology, Downing Street, Cambridge, CB2 3EJ; 2Division of Ecology and Evolution, Imperial College London, South Kensington Campus, London, SW7 2AZ; 3Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD; and 4Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
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Susanna I, Alba DM, Almécija S, Moyà-Solà S. The vertebral remains of the late Miocene great ape Hispanopithecus laietanus from Can Llobateres 2 (Vallès-Penedès Basin, NE Iberian Peninsula). J Hum Evol 2014; 73:15-34. [DOI: 10.1016/j.jhevol.2014.05.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 02/18/2014] [Accepted: 05/07/2014] [Indexed: 10/25/2022]
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Reevaluation of the lumbosacral region of Oreopithecus bambolii. J Hum Evol 2013; 65:253-65. [DOI: 10.1016/j.jhevol.2013.05.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 05/04/2013] [Accepted: 05/13/2013] [Indexed: 11/23/2022]
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Gómez-Olivencia A, Couture-Veschambre C, Madelaine S, Maureille B. The vertebral column of the Regourdou 1 Neandertal. J Hum Evol 2013; 64:582-607. [DOI: 10.1016/j.jhevol.2013.02.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 02/12/2013] [Accepted: 02/12/2013] [Indexed: 10/27/2022]
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Reno PL, Horton WE, Lovejoy CO. Metapodial or phalanx? An evolutionary and developmental perspective on the homology of the first ray's proximal segment. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:276-85. [PMID: 23640850 DOI: 10.1002/jez.b.22506] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/29/2013] [Accepted: 04/01/2013] [Indexed: 12/30/2022]
Abstract
The first mammalian metapodial (MP1) has periodically been argued to actually be a phalanx, because the first ray has one less element than the four posterior rays, and because the MP1 growth plate is proximal like those of all phalanges, rather than distal as in metapodials 2-5. However, growth plates are formed at both ends in non-therian tetrapod metapodials, and phylogenetic analysis demonstrates that growth plate loss is a therian synapomorphy that postdates the establishment of the mammalian phalangeal formula. These data, along with results of developmental and morphological studies, suggest that the MP1 is not a phalanx. The singular, proximal growth plates in MPs 2-5 are likely to be an adaptation to dynamic erect quadrupedal gait which was characterized by conversion of the posterior metapodials into rigid struts with the carpus/tarsus. While the adaptive significance of the reversed ossification of MP1 is less clear, we present three functional/developmental hypotheses.
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Affiliation(s)
- Philip L Reno
- Department of Anthropology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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Williams SA, Ostrofsky KR, Frater N, Churchill SE, Schmid P, Berger LR. The Vertebral Column of Australopithecus sediba. Science 2013; 340:1232996. [DOI: 10.1126/science.1232996] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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