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Knigge RP, Vinyard CJ, McNulty KP. Mandibular symphyseal fusion in fossil primates: Insights from correlated patterns of jaw shape and masticatory function in living primates. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 173:322-336. [PMID: 32167167 DOI: 10.1002/ajpa.24048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/27/2020] [Accepted: 02/24/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Variation in primate masticatory form and function has been extensively researched through both morphological and experimental studies. As a result, symphyseal fusion in different primate clades has been linked to either the recruitment of vertically directed balancing-side muscle force, the timing and recruitment of transversely directed forces, or both. This study investigates the relationship between jaw muscle activity patterns and morphology in extant primates to make inferences about masticatory function in extinct primates, with implications for understanding the evolution of symphyseal fusion. MATERIALS AND METHODS Three-dimensional mandibular landmark data were collected for 31 extant primates and nine fossil anthropoids and subfossil lemur species. Published electromyography (EMG) data were available for nine of the extant primate species. Partial least squares analysis and phylogenetic partial least squares analysis were used to identify relationships between EMG and jaw shape data and evaluate variation in jaw morphology. RESULTS Primates with partial and complete symphyseal fusion exhibit shape-function patterns associated with the wishboning motor pattern and loading regime, in contrast to shape-function patterns of primates with unfused jaws. All fossil primates examined (except Apidium) exhibit jaw morphologies suggestive of the wishboning motor pattern demonstrated in living anthropoids and indriids. DISCUSSION Partial fusion in Catopithecus, similar to indriids and some subfossil lemurs, may be sufficient to resist, or transfer, some amounts of transversely directed balancing-side muscle force at the symphysis, representing a transition to greater reliance on transverse jaw movement during mastication. Furthermore, possible functional convergences in physiological patterns during chewing (i.e., Archaeolemur) are identified.
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Affiliation(s)
- Ryan P Knigge
- Evolutionary Anthropology Lab, Department of Anthropology, University of Minnesota, Minneapolis, Minnesota.,Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri.,Department of Orthopaedic Surgery, University of Missouri, Columbia, Missouri
| | - Christopher J Vinyard
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio
| | - Kieran P McNulty
- Evolutionary Anthropology Lab, Department of Anthropology, University of Minnesota, Minneapolis, Minnesota
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McGraw WS, Daegling DJ. Diet, feeding behavior, and jaw architecture of Taï monkeys: Congruence and chaos in the realm of functional morphology. Evol Anthropol 2019; 29:14-28. [PMID: 31580522 DOI: 10.1002/evan.21799] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/13/2019] [Accepted: 08/13/2019] [Indexed: 11/08/2022]
Abstract
We review feeding and mandibular anatomy in a community of West African monkeys. We use field observations, food material property data, and skeletal specimens from the Ivory Coast's Taï Forest to explore the factors that shape mandibular architecture in colobines and cercopithecines. Despite excellent geographic control across our sample, the fit between bone form (as conventionally described) and functional activity (as we perceive it) is not spectacular. We present a thought experiment to assess how well we could reconstruct diet in the Taï monkeys if we only had skeletons and teeth to study. This exercise indicated that we would be correct about half the time. Our analyses reinforce the notion that diet is anything but a monolithic variable and that better success at relating mandibular form to food must incorporate information on ingestive and processing behavior, geometric and material properties of foods, and both material and structural data on jaws themselves.
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Affiliation(s)
- W Scott McGraw
- Smith Laboratory, Department of Anthropology, The Ohio State University, Columbus, Ohio
| | - David J Daegling
- Department of Anthropology, University of Florida, Gainesville, Florida
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Monson TA, Hlusko LJ. Breaking the rules: Phylogeny, not life history, explains dental eruption sequence in primates. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 167:217-233. [DOI: 10.1002/ajpa.23618] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 05/07/2018] [Accepted: 05/09/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Tesla A. Monson
- Department of Integrative Biology; University of California; Berkeley California 94720
- Museum of Vertebrate Zoology, Department of Integrative Biology; University of California; Berkeley California 94720
- Human Evolution Research Center, Department of Integrative Biology; University of California; Berkeley California 94720
| | - Leslea J. Hlusko
- Department of Integrative Biology; University of California; Berkeley California 94720
- Museum of Vertebrate Zoology, Department of Integrative Biology; University of California; Berkeley California 94720
- Human Evolution Research Center, Department of Integrative Biology; University of California; Berkeley California 94720
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Godfrey LR, Muldoon KM. Elwyn Simons: Opening windows into Madagascar's past. Evol Anthropol 2017. [PMID: 28627783 DOI: 10.1002/evan.21518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Laurie R Godfrey
- Department of Anthropology, University of Massachusetts, Amherst, MA, 01003
| | - Kathleen M Muldoon
- Department of Anatomy, Arizona College of Osteopathic Medicine, Midwestern University, 19555 N. 59th Avenue, Glendale, AZ, 85308
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Thompson KD, Weiss-Bilka HE, McGough EB, Ravosa MJ. Bone up: craniomandibular development and hard-tissue biomineralization in neonate mice. ZOOLOGY 2017; 124:51-60. [PMID: 28807504 DOI: 10.1016/j.zool.2017.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/11/2017] [Accepted: 01/24/2017] [Indexed: 10/20/2022]
Abstract
The presence of regional variation in the osteogenic abilities of cranial bones underscores the fact that the mechanobiology of the mammalian skull is more complex than previously recognized. However, the relationship between patterns of cranial bone formation and biomineralization remains incompletely understood. In four strains of mice, micro-computed tomography was used to measure tissue mineral density during perinatal development in three skull regions (calvarium, basicranium, mandible) noted for variation in loading environment, embryological origin, and ossification mode. Biomineralization levels increased during perinatal ontogeny in the mandible and calvarium, but did not increase in the basicranium. Tissue mineral density levels also varied intracranially, with density in the mandible being highest, in the basicranium intermediate, and in the calvarium lowest. Perinatal increases in, and elevated levels of, mandibular biomineralization appear related to the impending postweaning need to resist elevated masticatory stresses. Similarly, perinatal increases in calvarial biomineralization may be linked to ongoing brain expansion, which is known to stimulate sutural bone formation in this region. The lack of perinatal increase in basicranial biomineralization could be a result of earlier developmental maturity in the cranial base relative to other skull regions due to its role in supporting the brain's mass throughout ontogeny. These results suggest that biomineralization levels and age-related trajectories throughout the skull are influenced by the functional environment and ontogenetic processes affecting each region, e.g., onset of masticatory loads in the mandible, whereas variation in embryology and ossification mode may only have secondary effects on patterns of biomineralization. Knowledge of perinatal variation in tissue mineral density, and of normal cranial bone formation early in development, may benefit clinical therapies aiming to correct developmental defects and traumatic injuries in the skull, and more generally characterize loading environments and skeletal adaptations in mammals by highlighting the need for multi-level analyses for evaluating functional performance of cranial bone.
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Affiliation(s)
- Khari D Thompson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Holly E Weiss-Bilka
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Elizabeth B McGough
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Matthew J Ravosa
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA; Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA; Department of Anthropology, University of Notre Dame, Notre Dame, IN 46556, USA.
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Ravosa MJ, Menegaz RA, Scott JE, Daegling DJ, McAbee KR. Limitations of a morphological criterion of adaptive inference in the fossil record. Biol Rev Camb Philos Soc 2015; 91:883-898. [DOI: 10.1111/brv.12199] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 05/08/2015] [Accepted: 05/15/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Matthew J. Ravosa
- Department of Biological Sciences Galvin Life Science Center, University of Notre Dame Notre Dame IN 46556 U.S.A
- Department of Aerospace and Mechanical Engineering University of Notre Dame Notre Dame IN 46556 U.S.A
- Department of Anthropology University of Notre Dame Notre Dame IN 46556 U.S.A
| | - Rachel A. Menegaz
- Department of Biomedical and Applied Sciences Indiana University School of Dentistry Indianapolis IN 46202 U.S.A
| | - Jeremiah E. Scott
- Department of Anthropology Southern Illinois University Carbondale IL 62901 U.S.A
| | - David J. Daegling
- Department of Anthropology University of Florida Gainesville FL 32611 U.S.A
| | - Kevin R. McAbee
- Department of Biological Sciences Galvin Life Science Center, University of Notre Dame Notre Dame IN 46556 U.S.A
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SCOTT JE, HOGUE AS, RAVOSA MJ. The adaptive significance of mandibular symphyseal fusion in mammals. J Evol Biol 2012; 25:661-73. [DOI: 10.1111/j.1420-9101.2012.02457.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Menegaz RA, Sublett SV, Figueroa SD, Hoffman TJ, Ravosa MJ, Aldridge K. Evidence for the Influence of Diet on Cranial Form and Robusticity. Anat Rec (Hoboken) 2010; 293:630-41. [DOI: 10.1002/ar.21134] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Menegaz RA, Sublett SV, Figueroa SD, Hoffman TJ, Ravosa MJ. Phenotypic plasticity and function of the hard palate in growing rabbits. Anat Rec (Hoboken) 2009; 292:277-84. [PMID: 19089904 DOI: 10.1002/ar.20840] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Morphological variation related to differential loading is well known for many craniomandibular elements. Yet, the function of the hard palate, and in particular the manner in which cortical and trabecular bone of the palate respond to masticatory loads, remains more ambiguous. Here, experimental data are presented that address the naturalistic influence of biomechanical loading on the postweaning development and structure of the hard palate. A rabbit model was used to test the hypothesis that variation in the morphology of the hard palate is linked to variation in masticatory stresses. Rabbit siblings were divided as weanlings into soft and hard/tough dietary treatment groups of 10 subjects each and were raised for 15 weeks until subadulthood. MicroCT analyses indicate that rabbits subjected to elevated masticatory loading developed hard palates with significantly greater bone area, greater cortical bone thickness along the oral lamina, and thicker anterior palates. Such diet-induced levels of palatal plasticity are comparable to those for other masticatory elements, which likely reflect osteogenic responses for maintaining the functional integrity of the palate vis-à-vis elevated stresses during unilateral mastication. These data support a role for mechanical loading in the determination of palatal morphology, especially its internal structure, in living and fossil mammals such as the hominin Paranthropus. Furthermore, these findings have potential implications for the evolution of the mammalian secondary hard palate as well as for clinical considerations of human oral pathologies.
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Affiliation(s)
- Rachel A Menegaz
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, One Hospital Drive, Columbia, MO 65212, USA
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Ravosa MJ, Kunwar R, Stock SR, Stack MS. Pushing the limit: masticatory stress and adaptive plasticity in mammalian craniomandibular joints. ACTA ACUST UNITED AC 2007; 210:628-41. [PMID: 17267649 DOI: 10.1242/jeb.02683] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Excessive, repetitive and altered loading have been implicated in the initiation of a series of soft- and hard-tissue responses or ;functional adaptations' of masticatory and locomotor elements. Such adaptive plasticity in tissue types appears designed to maintain a sufficient safety factor, and thus the integrity of given element or system, for a predominant loading environment(s). Employing a mammalian species for which considerable in vivo data on masticatory behaviors are available, genetically similar domestic white rabbits were raised on diets of different mechanical properties so as to develop an experimental model of joint function in a normal range of physiological loads. These integrative experiments are used to unravel the dynamic inter-relationships among mechanical loading, tissue adaptive plasticity, norms of reaction and performance in two cranial joint systems: the mandibular symphysis and temporomandibular joint (TMJ). Here, we argue that a critical component of current and future research on adaptive plasticity in the skull, and especially cranial joints, should employ a multifaceted characterization of a functional system, one that incorporates data on myriad tissues so as to evaluate the role of altered load versus differential tissue response on the anatomical, cellular and molecular processes that contribute to the strength of such composite structures. Our study also suggests that the short-term duration of earlier analyses of cranial joint tissues may offer a limited notion of the complex process of developmental plasticity, especially as it relates to the effects of long-term variation in mechanical loads, when a joint is increasingly characterized by adaptive and degradative changes in tissue structure and composition. Indeed, it is likely that a component of the adaptive increases in rabbit TMJ and symphyseal proportions and biomineralization represent a compensatory mechanism to cartilage degradation that serves to maintain the overall functional integrity of each joint system. Therefore, while variation in cranial joint anatomy and performance among sister taxa is, in part, an epiphenomenon of interspecific differences in diet-induced masticatory stresses characterizing the individual ontogenies of the members of a species, this behavioral signal may be increasingly mitigated in over-loaded and perhaps older organisms by the interplay between adaptive and degradative tissue responses.
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Affiliation(s)
- Matthew J Ravosa
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, M263 Medical Sciences Building, One Hospital Drive DC055.07, Columbia, MO 65212, USA.
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Ravosa MJ, Klopp EB, Pinchoff J, Stock SR, Hamrick MW. Plasticity of mandibular biomineralization in myostatin-deficient mice. J Morphol 2007; 268:275-82. [PMID: 17299778 DOI: 10.1002/jmor.10517] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Compared with the normal or wild-type condition, knockout mice lacking myostatin (Mstn), a negative regulator of skeletal muscle growth, develop significant increases in relative masticatory muscle mass as well as the ability to generate higher maximal muscle forces. Wild-type and myostatin-deficient mice were compared to assess the postweaning influence of elevated masticatory loads because of increased jaw-adductor muscle and bite forces on the biomineralization of mandibular cortical bone and dental tissues. Microcomputed tomography (microCT) was used to quantify bone density at a series of equidistant external and internal sites in coronal sections for two symphysis and two corpus locations. Discriminant function analyses and nonparametric ANOVAs were used to characterize variation in biomineralization within and between loading cohorts. Multivariate analyses indicated that 95% of the myostatin-deficient mice and 95% of the normal mice could be distinguished based on biomineralization values at both symphysis and corpus sections. At the corpus, ANOVAs suggest that between-group differences are due to the tendency for cortical bone mineralization to be higher in myostatin-deficient mice, coupled with higher levels of dental biomineralization in normal mice. At the symphysis, ANOVAs indicate that between-group differences are related to significantly elevated bone-density levels along the articular surface and external cortical bone in the knockout mice. Both patterns, especially those for the symphysis, appear because of the postweaning effects of increased masticatory stresses in the knockout mice versus normal mice. The greater number of symphyseal differences suggest that bone along this jaw joint may be characterized by elevated plasticity. Significant differences in bone-density levels between normal and myostatin-deficient mice, coupled with the multivariate differences in patterns of plasticity between the corpus and symphysis, underscore the need for a comprehensive analysis of the plasticity of masticatory tissues vis-à-vis altered mechanical loads.
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Affiliation(s)
- Matthew J Ravosa
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri 65212, USA.
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