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Taverne M, Lalieve L, Persohn S, Khonsari RH, Paternoster G, James S, Blauwblomme T, Benichi S, Laporte S. Anatomy and mobility in the adult cadaveric craniocervical junction. J Morphol 2024; 285:e21748. [PMID: 38938002 DOI: 10.1002/jmor.21748] [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: 02/01/2024] [Revised: 06/12/2024] [Accepted: 06/14/2024] [Indexed: 06/29/2024]
Abstract
Genetic diseases with craniofacial malformations can be associated with anomalies of the craniocervical joint (CCJ). The functions of the CCJ are thus impaired, as mobility may be either limited by abnormal bone fusion causing headaches, or exaggerated in the case of hypermobility, which may cause irreparable damage to the spinal cord. Restoring the balance between mobility and stability requires surgical correction in children. The anatomy and biomechanics of the CCJ are quite unique, yet have been overlooked in the past decades. Pediatric evidence is so scarce, that investigating the adult CCJ is our best shot to disentangle the form-function relationships of this anatomical region. The motivation of the present study was to understand the morphological and functional basis of motion in the CCJ, in the hope to find morphological features accessible from medical imaging able to predict mobility. To do so, we have quantified the in-vitro kinematics of the CCJ in nine cadaveric asymptomatic adults, and estimated a wide range of mobility variables covering the complexity of spinal motion. We compared these variables with the shape of the occipital, the atlas and the axis, obtained using a dense geometric morphometric approach. Morphological joint congruence was also quantified. Our results suggest a strong relationship between bone shape and motion, with the overall geometry predicting best the primary movements, and the joint facets predicting best the secondary movements. We propose a functional hypothesis stating that the musculoligamental system determines movements of great amplitude, while the shape and congruence of joint facets determine the secondary and coupled movements, especially by varying the geometry of bone stops and the way ligaments are tensioned. We believe this work will provide valuable insights in understanding the biomechanics of the CCJ. Furthermore, it should help surgeons treating CCJ anomalies by enabling them to translate objectives of functional and clinical outcome into clear objectives of morphological outcome.
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Affiliation(s)
- Maxime Taverne
- Craniofacial Growth and Form Laboratory, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Laura Lalieve
- Craniofacial Growth and Form Laboratory, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Sylvain Persohn
- Arts et Métiers - Institute of Technology, Institut de Biomécanique Humaine Georges Charpak, Paris, France
| | - Roman Hossein Khonsari
- Craniofacial Growth and Form Laboratory, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
- Department of Pediatric Maxillofacial Surgery and Plastic surgery, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
- UFR de Médecine, Université Paris Cité, Paris, France
| | - Giovanna Paternoster
- UFR de Médecine, Université Paris Cité, Paris, France
- Department of Pediatric Neurosurgery, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
- CRMR CRANIOST, Filière TeteCou, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Syril James
- UFR de Médecine, Université Paris Cité, Paris, France
- Department of Pediatric Neurosurgery, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Thomas Blauwblomme
- UFR de Médecine, Université Paris Cité, Paris, France
- Department of Pediatric Neurosurgery, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
- CRMR C-MAVEM, Filière NeuroSphinx, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Sandro Benichi
- UFR de Médecine, Université Paris Cité, Paris, France
- Department of Pediatric Neurosurgery, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
- CRMR C-MAVEM, Filière NeuroSphinx, Necker-Enfants Malades Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Sébastien Laporte
- Arts et Métiers - Institute of Technology, Institut de Biomécanique Humaine Georges Charpak, Paris, France
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Taewcharoen N, Norris R, Sherratt E. Small- to medium-sized mammals show greater morphological disparity in cervical than lumbar vertebrae across different terrestrial modes of locomotion. Ecol Evol 2024; 14:e11478. [PMID: 38835523 PMCID: PMC11148397 DOI: 10.1002/ece3.11478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/08/2024] [Accepted: 05/10/2024] [Indexed: 06/06/2024] Open
Abstract
During mammalian terrestrial locomotion, body flexibility facilitated by the vertebral column is expected to be correlated with observed modes of locomotion, known as gait (e.g., sprawl, trot, hop, bound, gallop). In small- to medium-sized mammals (average weight up to 5 kg), the relationship between locomotive mode and vertebral morphology is largely unexplored. Here we studied the vertebral column from 46 small- to medium-sized mammals. Nine vertebrae across cervical, thoracic, and lumbar regions were chosen to represent the whole vertebral column. Vertebra shape was analysed using three-dimensional geometric morphometrics with the phylogenetic comparative method. We also applied the multi-block method, which can consider all vertebrae as a single structure for analysis. We calculated morphological disparity, phylogenetic signal, and evaluated the effects of allometry and gait on vertebral shape. We also investigated the pattern of integration in the column. We found the cervical vertebrae show the highest degree of morphological disparity, and the first thoracic vertebra shows the highest phylogenetic signal. A significant effect of gait type on vertebrae shape was found, with the lumbar vertebrae having the strongest correlation; but this effect was not significant after taking phylogeny into account. On the other hand, allometry has a significant effect on all vertebrae regardless of the contribution from phylogeny. The regions showed differing degrees of integration, with cervical vertebrae most strongly correlated. With these results, we have revealed novel information that cannot be captured from study of a single vertebra alone: although the lumbar vertebrae are the most correlated with gait, the cervical vertebrae are more morphologically diverse and drive the diversity among species when considering whole column shape.
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Affiliation(s)
- Nuttakorn Taewcharoen
- School of Biological Sciences The University of Adelaide Adelaide South Australia Australia
| | - Rachel Norris
- School of Animal and Veterinary Sciences The University of Adelaide Roseworthy South Australia Australia
| | - Emma Sherratt
- School of Biological Sciences The University of Adelaide Adelaide South Australia Australia
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Villamil CI, Middleton ER. Conserved patterns and locomotor-related evolutionary constraints in the hominoid vertebral column. J Hum Evol 2024; 190:103528. [PMID: 38579429 DOI: 10.1016/j.jhevol.2024.103528] [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: 06/20/2023] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 04/07/2024]
Abstract
The evolution of the hominoid lineage is characterized by pervasive homoplasy, notably in regions such as the vertebral column, which plays a central role in body support and locomotion. Few isolated and fewer associated vertebrae are known for most fossil hominoid taxa, but identified specimens indicate potentially high levels of convergence in terms of both form and number. Homoplasy thus complicates attempts to identify the anatomy of the last common ancestor of hominins and other taxa and stymies reconstructions of evolutionary scenarios. One way to clarify the role of homoplasy is by investigating constraints via phenotypic integration, which assesses covariation among traits, shapes evolutionary pathways, and itself evolves in response to selection. We assessed phenotypic integration and evolvability across the subaxial (cervical, thoracic, lumbar, sacral) vertebral column of macaques (n = 96), gibbons (n = 77), chimpanzees (n = 92), and modern humans (n = 151). We found a mid-cervical cluster that may have shifted cranially in hominoids, a persistent thoracic cluster that is most marked in chimpanzees, and an expanded lumbosacral cluster in hominoids that is most expanded in gibbons. Our results highlight the highly conserved nature of the vertebral column. Taxa appear to exploit existing patterns of integration and ontogenetic processes to shift, expand, or reduce cluster boundaries. Gibbons appear to be the most highly derived taxon in our sample, possibly in response to their highly specialized locomotion.
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Affiliation(s)
- Catalina I Villamil
- School of Chiropractic, Universidad Central del Caribe, Puerto Rico, PO Box 60327, Bayamón, USA.
| | - Emily R Middleton
- Department of Anthropology, University of Wisconsin-Milwaukee, 3413 N. Downer Ave., Sabin Hall 390, Milwaukee, WI, USA
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Nalley TK, Scott JE, McGechie F, Grider-Potter N. Comparative ontogeny of functional aspects of human cervical vertebrae. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:e24788. [PMID: 37283367 DOI: 10.1002/ajpa.24788] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 05/15/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023]
Abstract
OBJECTIVES Differences between adult humans and great apes in cervical vertebral morphology are well documented, but the ontogeny of this variation is still largely unexplored. This study examines patterns of growth in functionally relevant features of C1, C2, C4, and C6 in extant humans and apes to understand the development of their disparate morphologies. MATERIALS AND METHODS Linear and angular measurements were taken from 530 cervical vertebrae representing 146 individual humans, chimpanzees, gorillas, and orangutans. Specimens were divided into three age-categories based on dental eruption: juvenile, adolescent, and adult. Inter- and intraspecific comparisons were evaluated using resampling methods. RESULTS Of the eighteen variables examined here, seven distinguish humans from apes at the adult stage. Human-ape differences in features related to atlantoaxial joint function tend to be established by the juvenile stage, whereas differences in features related to the nuchal musculature and movement of the subaxial elements do not fully emerge until adolescence or later. The orientation of the odontoid process-often cited as a feature that distinguishes humans from apes-is similar in adult humans and adult chimpanzees, but the developmental patterns are distinct, with human adultlike morphology being achieved much earlier. DISCUSSION The biomechanical consequences of the variation observed here is poorly understood. Whether the differences in growth patterns represent functional links to cranial development or postural changes, or both, requires additional investigation. Determining when humanlike ontogenetic patterns evolved in hominins may provide insight into the functional basis driving the morphological divergence between extant humans and apes.
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Affiliation(s)
- Thierra K Nalley
- Medical Anatomical Sciences Department, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California, USA
| | - Jeremiah E Scott
- Medical Anatomical Sciences Department, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California, USA
| | - Faye McGechie
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA
| | - Neysa Grider-Potter
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas, USA
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Rader JA, Hedrick TL. Morphological evolution of bird wings follows a mechanical sensitivity gradient determined by the aerodynamics of flapping flight. Nat Commun 2023; 14:7494. [PMID: 37980422 PMCID: PMC10657351 DOI: 10.1038/s41467-023-43108-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 10/31/2023] [Indexed: 11/20/2023] Open
Abstract
The physical principles that govern the function of biological structures also mediate their evolution, but the evolutionary drivers of morphological traits within complex structures can be difficult to predict. Here, we use morphological traits measured from 1096 3-dimensional bird wing scans from 178 species to test the interaction of two frameworks for relating morphology to evolution. We examine whether the evolutionary rate (σ2) and mode is dominated by the modular organization of the wing into handwing and armwing regions, and/or the relationship between trait morphology and functional output (i.e. mechanical sensitivity, driven here by flapping flight aerodynamics). Our results support discretization of the armwing and handwing as morphological modules, but morphological disparity and σ2 varied continuously with the mechanical sensitivity gradient and were not modular. Thus, mechanical sensitivity should be considered an independent and fundamental driver of evolutionary dynamics in biomechanical traits, distinct from morphological modularity.
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Affiliation(s)
- Jonathan A Rader
- Dept. of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Tyson L Hedrick
- Dept. of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Urošević A, Ajduković M, Vučić T, Scholtes SJ, Arntzen JW, Ivanović A. Regionalization and morphological integration in the vertebral column of Eurasian small-bodied newts (Salamandridae: Lissotriton). JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:403-413. [PMID: 37272301 DOI: 10.1002/jez.b.23205] [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: 07/20/2022] [Revised: 03/30/2023] [Accepted: 05/11/2023] [Indexed: 06/06/2023]
Abstract
Serially homologous structures may have complex patterns of regionalization and morphological integration, influenced by developmental Hox gene expression and functional constraints. The vertebral column, consisting of a number of repeated, developmentally constrained, and highly integrated units-vertebrae-is such a complex serially homologous structure. Functional diversification increases regionalization and modularity of the vertebral column, particularly in mammals. For salamanders, three concepts of regionalization of the vertebral column have been proposed, recognizing one, two, or three presacral regions. Using three-dimensional geometric morphometrics on vertebra models acquired with microcomputerized tomography scanning, we explored the covariation of vertebrae in four closely related taxa of small-bodied newts in the genus Lissotriton. The data were analyzed by segmented linear regression to explore patterns of vertebral regionalization and by a two-block partial least squares method to test for morphological integration. All taxa show a morphological shift posterior to the fifth trunk vertebra, which corresponds to the two-region concept. However, morphological integration is found to be strongest in the mid-trunk. Taken jointly, these results indicate a highly integrated presacral vertebral column with a subtle two-region differentiation. The results are discussed in relation to specific functional requirements, developmental and phylogenetic constraints, and specific requirements posed by a biphasic life cycle and different locomotor modes (swimming vs. walking). Further research should be conducted on different ontogenetic stages and closely related but ecologically differentiated species.
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Affiliation(s)
- Aleksandar Urošević
- Department of Evolutionary Biology, Institute for Biological Research "Siniša Stanković," National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Maja Ajduković
- Department of Evolutionary Biology, Institute for Biological Research "Siniša Stanković," National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Tijana Vučić
- Institute of Zoology, Faculty of Biology, University of Belgrade, Belgrade, Serbia
- Animal Sciences, Institute of Biology, Leiden University, Leiden, The Netherlands
- Naturalis Biodiversity Center, Leiden, The Netherland
| | | | - Jan W Arntzen
- Animal Sciences, Institute of Biology, Leiden University, Leiden, The Netherlands
- Naturalis Biodiversity Center, Leiden, The Netherland
| | - Ana Ivanović
- Institute of Zoology, Faculty of Biology, University of Belgrade, Belgrade, Serbia
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May-Davis S, Dzingle D, Saber E, Blades Eckelbarger P. Characterization of the Caudal Ventral Tubercle in the Sixth Cervical Vertebra in Modern Equus ferus caballus. Animals (Basel) 2023; 13:2384. [PMID: 37508161 PMCID: PMC10376820 DOI: 10.3390/ani13142384] [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: 06/01/2023] [Revised: 07/10/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
This study examined the anomalous variations of the ventral process of C6 in modern E. ferus caballus. The aim was to provide an incremental grading protocol measuring the absence of the caudal ventral tubercle (CVT) in this ventral process. The findings revealed the most prevalent absent CVT (aCVT) was left unilateral (n = 35), with bilateral (n = 29) and right unilateral (n = 12). Grading was determined in equal increments of absence 1/4, 2/4, 3/4, with 4/4 representing a complete aCVT in 56/76, with a significance of p = 0.0013. This also applied to bilateral specimens. In those C6 osseous specimens displaying a 4/4 grade aCVT, 41/56 had a partial absence of the caudal aspect of the cranial ventral tubercle (CrVT). Here, grading absent CrVTs (aCrVT) followed similarly to aCVTs, though 4/4 was not observed. The significance between 4/4 grade aCVTs and the presentation of an aCrVT was left p = 0.00001 and right p = 0.00018. In bilateral specimens, C6 morphologically resembled C5, implying a homeotic transformation that limited the attachment sites for the cranial and thoracal longus colli muscle. This potentially diminishes function and caudal cervical stability. Therefore, it is recommended that further studies examine the morphological extent of this equine complex vertebral malformation (ECVM) as well as its interrelationships and genetic code/blueprint.
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Affiliation(s)
- Sharon May-Davis
- Canine and Equine Research Group, University of New England, Armidale, NSW 2351, Australia
| | - Diane Dzingle
- Equus Soma-Equine Osteology and Anatomy Learning Center, Aiken, SC 29805, USA
| | - Elle Saber
- Biological Data Science Institute, Australian National University, Canberra, ACT 2601, Australia
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May-Davis S, Hunter R, White R. Morphology of the Ventral Process of the Sixth Cervical Vertebra in Extinct and Extant Equus: Functional Implications. Animals (Basel) 2023; 13:ani13101672. [PMID: 37238101 DOI: 10.3390/ani13101672] [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: 04/10/2023] [Revised: 05/07/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
In this study, we examined the ventral process of C6 in extinct and extant Equus (sister taxa to Equus ferus caballus only) with the purpose of describing normal morphology and identifying anomalous variations relevant to recent studies describing a congenital malformation in E. ferus caballus. Overall, 83 specimens from 9 museums and 3 research/educational facilities were examined, totalling 71 extinct specimens from 12 species and 12 extant specimens from 5 species. The lateral view revealed that a large convexity exists in the ventral process between the cranial ventral tubercle (CrVT) and the caudal ventral tubercle (CVT) in the earliest ancestor, Hyracotherium grangeri, from 55 mya, which receded throughout the millennia to become a smaller convexity in E. ferus caballus and the sister taxa. The CrVT is visibly shorter and narrower than the CVT, with a constricted section directly ventral to the transverse process, essentially demarcating the CrVT and CVT. No congenital malformations were evident. As the ventral process of C6 is an integral component for muscle attachment in supporting the head/neck during posture and locomotion, this would indicate that the caudal module in the cervical column might be compromised when a partial or complete absence of the CVT is detected via radiographs in modern E. ferus caballus.
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Affiliation(s)
- Sharon May-Davis
- Canine and Equine Research Group, University of New England, Armidale, NSW 2351, Australia
| | - Robert Hunter
- Canine and Equine Research Group, University of New England, Armidale, NSW 2351, Australia
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Figueirido B, Pérez-Ramos A, Martín-Serra A. Intravertebral vs. intervertebral integration and modularity in the vertebral column of mammalian carnivorans. J Anat 2023; 242:642-656. [PMID: 36584354 PMCID: PMC10008293 DOI: 10.1111/joa.13811] [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: 08/20/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/31/2022] Open
Abstract
The vertebral column is a multicomponent structure whose organization results from developmental and functional demands. According to their distinct somitic origins, individual vertebrae exhibit intravertebral modularity between the centrum and neural spine. However, vertebrae are also organized into larger units called intervertebral modules that result from integration between adjacent vertebrae due to locomotory demands or from common developmental origins due to resegmentation. A previous hypothesis suggested that the boundaries of intervertebral modules coincide with changes in the patterns of intravertebral integration. Here, we explicitly test whether the patterns of modularity and integration between the centrum and neural spine (i.e., intravertebral) in the boundary vertebrae among previously defined intervertebral modules change with respect to those in the vertebrae within intervertebral modules. We quantified intravertebral modularity patterns and quantified the strength of intravertebral integration for each vertebra of the presacral region in 41 species of carnivoran mammals using 3D geometric morphometrics. Our results demonstrate a significant intravertebral modular signal between the centrum and neural spine in all post-cervical vertebrae, including the boundary vertebrae among intervertebral modules. However, the strength of intravertebral integration decreases at the boundary vertebrae. We also found a significant correlation between the degree of intravertebral integration and intervertebral integration. Following our results, we hypothesize that natural selection does not override the integration between the centrum and neural spine at the boundary vertebrae, a pattern that should be influenced by their distinct somitic origins and separate ossification centers during early development. However, natural selection has probably influenced (albeit indirectly) the integration between the centrum and neural spine in the vertebrae that compose the intervertebral modules.
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Affiliation(s)
- Borja Figueirido
- Facultad de Ciencias, Departamento de Ecología y Geología, Universidad de Málaga, Málaga, Spain
| | - Alejandro Pérez-Ramos
- Facultad de Ciencias, Departamento de Ecología y Geología, Universidad de Málaga, Málaga, Spain
| | - Alberto Martín-Serra
- Facultad de Ciencias, Departamento de Ecología y Geología, Universidad de Málaga, Málaga, Spain
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Ferreira-Cardoso S, Claude J, Goswami A, Delsuc F, Hautier L. Flexible conservatism in the skull modularity of convergently evolved myrmecophagous placental mammals. BMC Ecol Evol 2022; 22:87. [PMID: 35773630 PMCID: PMC9248141 DOI: 10.1186/s12862-022-02030-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/06/2022] [Indexed: 12/05/2022] Open
Abstract
Background The skull of placental mammals constitutes one of the best studied systems for phenotypic modularity. Several studies have found strong evidence for the conserved presence of two- and six-module architectures, while the strength of trait correlations (integration) has been associated with major developmental processes such as somatic growth, muscle-bone interactions, and tooth eruption. Among placentals, ant- and termite-eating (myrmecophagy) represents an exemplar case of dietary convergence, accompanied by the selection of several cranial morphofunctional traits such as rostrum elongation, tooth loss, and mastication loss. Despite such drastic functional modifications, the covariance patterns of the skull of convergently evolved myrmecophagous placentals are yet to be studied in order to assess the potential consequences of this dietary shift on cranial modularity. Results Here, we performed a landmark-based morphometric analysis of cranial covariance patterns in 13 species of myrmecophagous placentals. Our analyses reveal that most myrmecophagous species present skulls divided into six to seven modules (depending on the confirmatory method used), with architectures similar to those of non-myrmecophagous placentals (therian six modules). Within-module integration is also similar to what was previously described for other placentals, suggesting that most covariance-generating processes are conserved across the clade. Nevertheless, we show that extreme rostrum elongation and tooth loss in myrmecophagid anteaters have resulted in a shift in intermodule correlations in the proximal region of the rostrum. Namely, the naso-frontal and maxillo-palatine regions are strongly correlated with the oro-nasal module, suggesting an integrated rostrum conserved from pre-natal developmental processes. In contrast, the similarly toothless pangolins show a weaker correlation between the anterior rostral modules, resembling the pattern of toothed placentals. Conclusions These results reveal that despite some integration shifts related to extreme functional and morphological features of myrmecophagous skulls, cranial modular architectures have conserved the typical mammalian scheme. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-02030-9.
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Adler KA, De Nault DL, Cardoza CM, Womack M. Evolutionary rates and shape variation along the anuran vertebral column with attention to phylogeny, body size, and ecology. Evolution 2022; 76:2724-2738. [PMID: 36117276 DOI: 10.1111/evo.14614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 07/31/2022] [Accepted: 08/08/2022] [Indexed: 01/22/2023]
Abstract
The vertebral column is critical to a vertebrate species' flexibility and skeletal support, making vertebrae a clear target for selection. Anurans (frogs and toads) have a unique, truncated vertebral column that appears constrained to provide axial rigidity for efficient jumping. However, no study has examined how presacral vertebrae shape varies among anuran species at the macroevolutionary scale nor how intrinsic (developmental and phylogenetic) and extrinsic (ecological) factors may have influenced vertebrae shape evolution. We used microCT scans and phylogenetic comparative methods to examine the vertebrae of hundreds of anuran species that vary in body size as well as adult and larval ecology. We found variation in shape and evolutionary rates among anuran vertebrae, dispelling any notion that trunk vertebrae evolve uniformly. We discovered the highest evolutionary rates in the cervical vertebrae and in the more caudal trunk vertebrae. We found little evidence for selection pressures related to adult or larval ecology affecting vertebrae evolution, but we did find body size was highly associated with vertebrae shape and microhabitat (mainly burrowing) affected those allometric relationships. Our results provide an interesting comparison to vertebrae evolution in other clades and a jumping-off point for studies of anuran vertebrae evolution and development.
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Affiliation(s)
- Katie A Adler
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California, 94720
| | - Diego L De Nault
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California, 94720
| | - Cassandra M Cardoza
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California, 94720
| | - Molly Womack
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California, 94720.,Department of Biology, Utah State University, Logan, Utah, 84322
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12
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Jung H, von Cramon-Taubadel N. Morphological modularity in the anthropoid axial skeleton. J Hum Evol 2022; 172:103256. [PMID: 36156434 DOI: 10.1016/j.jhevol.2022.103256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 01/31/2023]
Abstract
Previous research has found that hominoids have stronger modularity between limb elements than other anthropoids, suggesting that there is less constraint on morphological diversification (e.g., limb proportions) in hominoids in terms of evolutionary independence. However, degrees of modularity in the axial skeleton have not been investigated across a broad range of anthropoid taxa. Thus, it is unknown whether hominoids also have stronger modularity in the axial skeleton than other anthropoids, which has implications for the evolution of diverse torso morphologies in Miocene apes as well as the evolution of novel characteristics in the skull and vertebrae of fossil hominins. In this study, 12 anthropoid genera were sampled to examine degrees of modularity between axial skeletal elements (i.e., cranium, mandible, vertebrae, and sacrum). Covariance ratio coefficients were calculated using variance/covariance matrices of interlandmark distances for each axial skeletal element to evaluate degrees of modularity. The results showed that Alouatta, Hylobates, Gorilla, Pan, and Homo showed generally stronger modularity than other anthropoid taxa when considering all axial skeletal elements. When only considering the vertebral elements (i.e., vertebrae and sacrum), Alouatta, Hylobates, Gorilla, and Pan showed generally stronger modularity than other anthropoid taxa. Humans showed stronger modularity between the skull and vertebrae than other hominoids. Thus, the evolution of novel characteristics in the skull and vertebral column may have been less constrained in fossil hominins due to the dissociation of trait covariation between axial skeletal elements in hominoid ancestors, thus fostering more evolutionary independence between the skull and vertebral column.
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Affiliation(s)
- Hyunwoo Jung
- Buffalo Human Evolutionary Morphology Lab, Department of Anthropology, University at Buffalo, SUNY, 380 Academic Center, Ellicott Complex, Buffalo, NY 14261, USA; Department of Anatomy, College of Graduate Studies, Midwestern University, 19555 N 59th Ave, Glendale, AZ 85308, USA.
| | - Noreen von Cramon-Taubadel
- Buffalo Human Evolutionary Morphology Lab, Department of Anthropology, University at Buffalo, SUNY, 380 Academic Center, Ellicott Complex, Buffalo, NY 14261, USA
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13
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High-Density Three-Dimensional Morphometric Analyses Reveal Predation-Based Disparity and Evolutionary Modularity in Spider ‘Jaws’. Evol Biol 2022. [DOI: 10.1007/s11692-022-09576-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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14
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Smith SM, Angielczyk KD. A shrewd inspection of vertebral regionalization in large shrews (Soricidae: Crocidurinae). Integr Org Biol 2022; 4:obac006. [PMID: 35291671 PMCID: PMC8915212 DOI: 10.1093/iob/obac006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
The regionalization of the mammalian spinal column is an important evolutionary, developmental, and functional hallmark of the clade. Vertebral column regions are usually defined using transitions in external bone morphology, such as the presence of transverse foraminae or rib facets, or measurements of vertebral shape. Yet the internal structure of vertebrae, specifically the trabecular (spongy) bone, plays an important role in vertebral function, and is subject to the same variety of selective, functional, and developmental influences as external bone morphology. Here we investigated regionalization of external and trabecular bone morphology in the vertebral column of a group of shrews (family Soricidae). The primary goals of this study were to: 1) determine if vertebral trabecular bone morphology is regionalized in large shrews, and if so, in what configuration relative to external morphology; 2) assess correlations between trabecular bone regionalization and functional or developmental influences; and 3) determine if external and trabecular bone regionalization patterns provide clues about the function of the highly modified spinal column of the hero shrew Scutisorex.
Trabecular bone is regionalized along the soricid vertebral column, but the configuration of trabecular bone regions does not match that of the external vertebral morphology, and is less consistent across individuals and species. The cervical region has the most distinct and consistent trabecular bone morphology, with dense trabeculae indicative of the ability to withstand forces in a variety of directions. Scutisorex exhibits an additional external morphology region compared to unmodified shrews, but this region does not correspond to a change in trabecular architecture.
Although trabecular bone architecture is regionalized along the soricid vertebral column, and this regionalization is potentially related to bone functional adaptation, there are likely aspects of vertebral functional regionalization that are not detectable using trabecular bone morphology. For example, the external morphology of the Scutisorex lumbar spine shows signs of an extra functional region that is not apparent in trabecular bone analyses. It is possible that body size and locomotor mode affect the degree to which function is manifest in trabecular bone, and broader study across mammalian size and ecology is warranted to understand the relationship between trabecular bone morphology and other measures of vertebral function such as intervertebral range of motion.
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Affiliation(s)
- Stephanie M Smith
- Field Museum of Natural History, Negaunee Integrative Research Center, 1400 S DuSable Lake Shore Drive, Chicago, IL 60605
| | - Kenneth D Angielczyk
- Field Museum of Natural History, Negaunee Integrative Research Center, 1400 S DuSable Lake Shore Drive, Chicago, IL 60605
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15
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Berio F, Bayle Y, Riley C, Larouche O, Cloutier R. Phenotypic regionalization of the vertebral column in the thorny skate Amblyraja radiata: Stability and variation. J Anat 2022; 240:253-267. [PMID: 34542171 PMCID: PMC8742970 DOI: 10.1111/joa.13551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 01/14/2023] Open
Abstract
Regionalization of the vertebral column occurred early during vertebrate evolution and has been extensively investigated in mammals. However, less data are available on vertebral regions of crown gnathostomes. This is particularly true for batoids (skates, sawfishes, guitarfishes, and rays) whose vertebral column has long been considered to be composed of the same two regions as in teleost fishes despite the presence of a synarcual. However, the numerous vertebral units in chondrichthyans may display a more complex regionalization pattern than previously assumed and the intraspecific variation of such pattern deserves a thorough investigation. In this study, we use micro-computed tomography (µCT) scans of vertebral columns of a growth series of thorny skates Amblyraja radiata to provide the first fine-scale morphological description of vertebral units in a batoids species. We further investigate axial regionalization using a replicable clustering analysis on presence/absence of vertebral elements to decipher the regionalization of the vertebral column of A. radiata. We identify four vertebral regions in this species. The two anteriormost regions, named synarcual and thoracic, may undergo strong developmental or functional constraints because they display stable patterns of shapes and numbers of vertebral units across all growth stages. The third region, named hemal transitional, is characterized by high inter-individual morphological variation and displays a transition between the monospondylous (one centrum per somite) to diplospondylous (two centra per somite) conditions. The posteriormost region, named caudal, is subdivided into three sub-regions with shapes changing gradually along the anteroposterior axis. These regionalized patterns are discussed in light of ecological habits of skates.
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Affiliation(s)
- Fidji Berio
- Laboratoire de Paléontologie et Biologie ÉvolutiveUniversité du Québec à RimouskiRimouskiQuébecCanada
| | - Yann Bayle
- Université de BordeauxBordeaux INPCNRSLaBRIUMR5800TalenceFrance
| | - Cyrena Riley
- Laboratoire de Paléontologie et Biologie ÉvolutiveUniversité du Québec à RimouskiRimouskiQuébecCanada
| | - Olivier Larouche
- Laboratoire de Paléontologie et Biologie ÉvolutiveUniversité du Québec à RimouskiRimouskiQuébecCanada
- Department of BioSciencesRice UniversityHoustonTexasUSA
| | - Richard Cloutier
- Laboratoire de Paléontologie et Biologie ÉvolutiveUniversité du Québec à RimouskiRimouskiQuébecCanada
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16
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Oliver JD, Jones KE, Pierce SE, Hautier L. Size and shape regional differentiation during the development of the spine in the nine-banded armadillo (Dasypus novemcinctus). Evol Dev 2021; 23:496-512. [PMID: 34813149 DOI: 10.1111/ede.12393] [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: 03/17/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 11/28/2022]
Abstract
Xenarthrans (armadillos, anteaters, sloths, and their extinct relatives) are unique among mammals in displaying a distinctive specialization of the posterior trunk vertebrae-supernumerary vertebral xenarthrous articulations. This study seeks to understand how xenarthry develops through ontogeny and if it may be constrained to appear within pre-existing vertebral regions. Using three-dimensional geometric morphometrics on the neural arches of vertebrae, we explore phenotypic, allometric, and disparity patterns of the different axial morphotypes during the ontogeny of nine-banded armadillos. Shape-based regionalization analyses showed that the adult thoracolumbar column is divided into three regions according to the presence or absence of ribs and the presence or absence of xenarthrous articulations. A three-region division was retrieved in almost all specimens through development, although younger stages (e.g., fetuses, neonates) have more region boundary variability. In size-based regionalization analyses, thoracolumbar vertebrae are separated into two regions: a prediaphragmatic, prexenarthrous region, and a postdiaphragmatic xenarthrous region. We show that posterior thoracic vertebrae grow at a slower rate, while anterior thoracics and lumbars grow at a faster rate relatively, with rates decreasing anteroposteriorly in the former and increasing anteroposteriorly in the latter. We propose that different proportions between vertebrae and vertebral regions might result from differences in growth pattern and timing of ossification.
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Affiliation(s)
- Jillian D Oliver
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Katrina E Jones
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Stephanie E Pierce
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Lionel Hautier
- Institut des Sciences de l'Évolution, Université Montpellier, CNRS, IRD, EPHE, Montpellier, France
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17
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Zelditch ML, Goswami A. What does modularity mean? Evol Dev 2021; 23:377-403. [PMID: 34464501 DOI: 10.1111/ede.12390] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 06/25/2021] [Accepted: 08/09/2021] [Indexed: 01/03/2023]
Abstract
Modularity is now generally recognized as a fundamental feature of organisms, one that may have profound consequences for evolution. Modularity has recently become a major focus of research in organismal biology across multiple disciplines including genetics, developmental biology, functional morphology, population and evolutionary biology. While the wealth of new data, and also new theory, has provided exciting and novel insights, the concept of modularity has become increasingly ambiguous. That ambiguity is underlain by diverse intuitions about what modularity means, and the ambiguity is not merely about the meaning of the word-the metrics of modularity are measuring different properties and the methods for delimiting modules delimit them by different, sometimes conflicting criteria. The many definitions, metrics and methods can lead to substantial confusion not just about what modularity means as a word but also about what it means for evolution. Here we review various concepts, using graphical depictions of modules. We then review some of the metrics and methods for analyzing modularity at different levels. To place these in theoretical context, we briefly review theories about the origins and evolutionary consequences of modularity. Finally, we show how mismatches between concepts, metrics and methods can produce theoretical confusion, and how potentially illogical interpretations can be made sensible by a better match between definitions, metrics, and methods.
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Affiliation(s)
- Miriam L Zelditch
- Museum of Paleontology, University of Michigan, Ann Arbor, Michigan, USA
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18
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Figueirido B, Martín-Serra A, Pérez-Ramos A, Velasco D, Pastor FJ, Benson RJ. Serial disparity in the carnivoran backbone unveils a complex adaptive role in metameric evolution. Commun Biol 2021; 4:863. [PMID: 34267313 PMCID: PMC8282787 DOI: 10.1038/s42003-021-02346-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 05/20/2021] [Indexed: 11/09/2022] Open
Abstract
Organisms comprise multiple interacting parts, but few quantitative studies have analysed multi-element systems, limiting understanding of phenotypic evolution. We investigate how disparity of vertebral morphology varies along the axial column of mammalian carnivores — a chain of 27 subunits — and the extent to which morphological variation have been structured by evolutionary constraints and locomotory adaptation. We find that lumbars and posterior thoracics exhibit high individual disparity but low serial differentiation. They are pervasively recruited into locomotory functions and exhibit relaxed evolutionary constraint. More anterior vertebrae also show signals of locomotory adaptation, but nevertheless have low individual disparity and constrained patterns of evolution, characterised by low-dimensional shape changes. Our findings demonstrate the importance of the thoracolumbar region as an innovation enabling evolutionary versatility of mammalian locomotion. Moreover, they underscore the complexity of phenotypic macroevolution of multi-element systems and that the strength of ecomorphological signal does not have a predictable influence on macroevolutionary outcomes. Figueirido et al. use a 3D geometric morphometric approach to study functional among-species disparity in the vertebral column of Carnivora, as well as assessing the effect of different sampling methods on homology. Disparity is generally higher in more caudal regions, compared to more cranial regions, but recruitment for locomotor function is pervasive throughout the whole studied column.
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Affiliation(s)
- Borja Figueirido
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.
| | - Alberto Martín-Serra
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Alejandro Pérez-Ramos
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - David Velasco
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Francisco J Pastor
- Departamento de Anatomía y Radiología, Museo de Anatomía, Universidad de Valladolid, Valladolid, Spain
| | - Roger J Benson
- Department of Earth Sciences, University of Oxford, Oxford, UK
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19
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Martín-Serra A, Pérez-Ramos A, Pastor FJ, Velasco D, Figueirido B. Phenotypic integration in the carnivoran backbone and the evolution of functional differentiation in metameric structures. Evol Lett 2021; 5:251-264. [PMID: 34136273 DOI: 10.1002/evl3.224] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 02/10/2021] [Accepted: 02/23/2021] [Indexed: 11/06/2022] Open
Abstract
Explaining the origin and evolution of a vertebral column with anatomically distinct regions that characterizes the tetrapod body plan provides understanding of how metameric structures become repeated and how they acquire the ability to perform different functions. However, despite many decades of inquiry, the advantages and costs of vertebral column regionalization in anatomically distinct blocks, their functional specialization, and how they channel new evolutionary outcomes are poorly understood. Here, we investigate morphological integration (and how this integration is structured [modularity]) between all the presacral vertebrae of mammalian carnivorans to provide a better understanding of how regionalization in metameric structures evolves. Our results demonstrate that the subunits of the presacral column are highly integrated. However, underlying to this general pattern, three sets of vertebrae are recognized as presacral modules-the cervical module, the anterodorsal module, and the posterodorsal module-as well as one weakly integrated vertebra (diaphragmatic) that forms a transition between both dorsal modules. We hypothesize that the strength of integration organizing the axial system into modules may be associated with motion capability. The highly integrated anterior dorsal module coincides with a region with motion constraints to avoid compromising ventilation, whereas for the posterior dorsal region motion constraints avoid exceeding extension of the posterior back. On the other hand, the weakly integrated diaphragmatic vertebra belongs to the "Diaphragmatic joint complex"-a key region of the mammalian column of exceedingly permissive motion. Our results also demonstrate that these modules do not match with the traditional morphological regions, and we propose natural selection as the main factor shaping this pattern to stabilize some regions and to allow coordinate movements in others.
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Affiliation(s)
- Alberto Martín-Serra
- Departamento de Ecología y Geología, Facultad de Ciencias Universidad de Málaga Málaga 29071 Spain
| | - Alejandro Pérez-Ramos
- Departamento de Ecología y Geología, Facultad de Ciencias Universidad de Málaga Málaga 29071 Spain
| | - Francisco J Pastor
- Departmento de Anatomía y Radiología, Museo de Anatomía Universidad de Valladolid Valladolid 47002 Spain
| | - David Velasco
- Departamento de Ecología y Geología, Facultad de Ciencias Universidad de Málaga Málaga 29071 Spain
| | - Borja Figueirido
- Departamento de Ecología y Geología, Facultad de Ciencias Universidad de Málaga Málaga 29071 Spain
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20
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Rhoda D, Polly PD, Raxworthy C, Segall M. Morphological integration and modularity in the hyperkinetic feeding system of aquatic-foraging snakes. Evolution 2020; 75:56-72. [PMID: 33226114 DOI: 10.1111/evo.14130] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/05/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022]
Abstract
The kinetic skull is a key innovation that allowed snakes to capture, manipulate, and swallow prey exclusively using their heads using the coordinated movement of eight bones. Despite these unique feeding behaviors, patterns of evolutionary integration and modularity within the feeding bones of snakes in a phylogenetic framework have yet to be addressed. Here, we use a dataset of 60 μCT-scanned skulls and high-density geometric morphometric methods to address the origin and patterns of variation and integration in the feeding bones of aquatic-foraging snakes. By comparing alternate superimposition protocols allowing us to analyze the entire kinetic feeding system simultaneously, we find that the feeding bones are highly integrated, driven predominantly by functional selective pressures. The most supported pattern of modularity contains four modules, each associated with distinct functional roles: the mandible, the palatopterygoid arch, the maxilla, and the suspensorium. Further, the morphological disparity of each bone is not linked to its magnitude of integration, indicating that integration within the feeding system does not strongly constrain morphological evolution, and that adequate biomechanical solutions to a wide range of feeding ecologies and behaviors are readily evolvable within the constraint due to integration in the snake feeding system.
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Affiliation(s)
- Daniel Rhoda
- Department of Herpetology, American Museum of Natural History, New York, New York, 10024.,Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois, 60637
| | - P David Polly
- Department of Geological Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Christopher Raxworthy
- Department of Herpetology, American Museum of Natural History, New York, New York, 10024
| | - Marion Segall
- Department of Herpetology, American Museum of Natural History, New York, New York, 10024
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21
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Michaud M, Veron G, Fabre AC. Phenotypic integration in feliform carnivores: Covariation patterns and disparity in hypercarnivores versus generalists. Evolution 2020; 74:2681-2702. [PMID: 33085081 DOI: 10.1111/evo.14112] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 08/01/2020] [Accepted: 10/03/2020] [Indexed: 01/01/2023]
Abstract
The skeleton is a complex arrangement of anatomical structures that covary to various degrees depending on both intrinsic and extrinsic factors. Among the Feliformia, many species are characterized by predator lifestyles providing a unique opportunity to investigate the impact of highly specialized hypercarnivorous diet on phenotypic integration and shape diversity. To do so, we compared the shape of the skull, mandible, humerus, and femur of species in relation to their feeding strategies (hypercarnivorous vs. generalist species) and prey preference (predators of small vs. large prey) using three-dimensional geometric morphometric techniques. Our results highlight different degrees of morphological integration in the Feliformia depending on the functional implication of the anatomical structure, with an overall higher covariation of structures in hypercarnivorous species. The skull and the forelimb are not integrated in generalist species, whereas they are integrated in hypercarnivores. These results can potentially be explained by the different feeding strategies of these species. Contrary to our expectations, hypercarnivores display a higher disparity for the skull than generalist species. This is probably due to the fact that a specialization toward high-meat diet could be achieved through various phenotypes. Finally, humeri and femora display shape variations depending on relative prey size preference. Large species feeding on large prey tend to have robust long bones due to higher biomechanical constraints.
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Affiliation(s)
- Margot Michaud
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, 75231 cedex 05, France
| | - Géraldine Veron
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, 75231 cedex 05, France
| | - Anne-Claire Fabre
- Department of Life Sciences, The Natural History Museum, London, SW7 5BD, United Kingdom
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22
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Urošević A, Ajduković M, Arntzen JW, Ivanović A. Morphological integration and serial homology: A case study of the cranium and anterior vertebrae in salamanders. J ZOOL SYST EVOL RES 2020. [DOI: 10.1111/jzs.12374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Aleksandar Urošević
- Department of Evolutionary Biology, Institute for Biological Research “Siniša Stanković” National Institute of Republic of Serbia University of Belgrade Belgrade Serbia
| | - Maja Ajduković
- Department of Evolutionary Biology, Institute for Biological Research “Siniša Stanković” National Institute of Republic of Serbia University of Belgrade Belgrade Serbia
| | | | - Ana Ivanović
- Naturalis Biodiversity Center Leiden The Netherlands
- Institute of Zoology Faculty of Biology University of Belgrade Belgrade Serbia
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23
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Examination of Sample Size Determination in Integration Studies Based on the Integration Coefficient of Variation (ICV). Evol Biol 2020. [DOI: 10.1007/s11692-020-09514-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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Evolution of the Mammalian Neck from Developmental, Morpho-Functional, and Paleontological Perspectives. J MAMM EVOL 2020. [DOI: 10.1007/s10914-020-09506-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
AbstractThe mammalian neck adopts a variety of postures during daily life and generates numerous head trajectories. Despite its functional diversity, the neck is constrained to seven cervical vertebrae in (almost) all mammals. Given this low number, an unexpectedly high degree of modularity of the mammalian neck has more recently been uncovered. This work aims to review neck modularity in mammals from a developmental, morpho-functional, and paleontological perspective and how high functional diversity evolved in the mammalian neck after the occurrence of meristic limitations. The fixed number of cervical vertebrae and the developmental modularity of the mammalian neck are closely linked to anterior Hox genes expression and strong developmental integration between the neck and other body regions. In addition, basic neck biomechanics promote morpho-functional modularity due to preferred motion axes in the cranio-cervical and cervico-thoracic junction. These developmental and biomechanical determinants result in the characteristic and highly conserved shape variation among the vertebrae that delimits morphological modules. The step-wise acquisition of these unique cervical traits can be traced in the fossil record. The increasing functional specialization of neck modules, however, did not evolve all at once but started much earlier in the upper than in the lower neck. Overall, the strongly conserved modularity in the mammalian neck represents an evolutionary trade-off between the meristic constraints and functional diversity. Although a morpho-functional partition of the neck is common among amniotes, the degree of modularity and the way neck disparity is realized is unique in mammals.
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25
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Abstract
Abstract
The origin of birds from their terrestrial antecedents was accompanied by a wholesale transformation of their skeleton as they transitioned from a terrestrial to aerial realm. Part of this dramatic transformation is the reduction of separate vertebral elements into regional fusions to limit axial flexibility. This is partially mirrored within the development of the axial column, with regions of the axial column experiencing increasing morphological modularity and the loss of skeletal elements through vertebral fusions. Using a detailed description of the morphological development of the axial column in the model domestic chicken, Gallus gallus domesticus, we present a map of axial ossification based on discrete characters. Delays in ossification are found to occur in conjunction with the formation of fusions. Our study shows that the pattern and sequence of fusion and ossification during development may reflect the presence of independent modules as subsets within the typical regions of the avian axial column. Interestingly, few of these fusion modules correspond to the initial axial Hox expression patterns, suggesting another patterning mechanism is driving axial fusion regionalization. Additionally, two regions of fusion are discovered in the synsacrum. The anterior region of seven fused synsacrals may correspond to the non-ornithuran pygostylian synsacrum of the same number of vertebrae.
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26
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Boonsri B, Buddhachat K, Punyapornwithaya V, Phatsara M, Nganvongpanit K. Determination of whether morphometric analysis of vertebrae in the domestic cat (Felis catus) is related to sex or skull shape. Anat Sci Int 2020; 95:387-398. [PMID: 32125674 DOI: 10.1007/s12565-020-00533-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/17/2020] [Indexed: 11/26/2022]
Abstract
In many mammals, gender and skull shape are related to the bone morphology of the entire body; however, this has not been well established in the domestic cat (Felis catus). This study aims to find a relationship between cervical, thoracic and lumbar vertebrae morphometrics with regard to the sex and skull shape of domestic cats. A total of 79 samples obtained from 92 dried bones of domestic cats were used to determine morphometric measurements for a total of 29 parameters. Hierarchical clustering was used to cluster the vertebral bones found in three groups: C3-T1, T2-T11 and T12-L7. The skull shape identification process employed discriminative analysis and revealed the highest training data accuracy rate at up to 86.20% in T4 followed by L1 (86.04%) Axis (85.71%) and C5 (85.18%). Sex identification employed discriminative analysis and displayed the highest training data accuracy rate at up to 75.58% in L1 followed by, T7 (71.87%) and C6 (71.79%). Moreover, we found that 14% of the samples had one vertebra missing (T13 or L1). In conclusion, domestic cat vertebral morphometrics were found to be more related to skull shape than gender. In addition, bone clustering employed morphometric data and yielded a result that was similar to that of traditional cluster analysis involving body regions.
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Affiliation(s)
- Burin Boonsri
- Animal Bone and Joint Research Laboratory, Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, 50100, Thailand
| | - Kittisak Buddhachat
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, 65000, Thailand
- Excellence Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Veerasak Punyapornwithaya
- Department of Food Animal Clinic, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, 50100, Thailand
| | - Manussabhorn Phatsara
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Korakot Nganvongpanit
- Animal Bone and Joint Research Laboratory, Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, 50100, Thailand.
- Excellence Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai, 50200, Thailand.
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27
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Jones KE, Angielczyk KD, Pierce SE. Stepwise shifts underlie evolutionary trends in morphological complexity of the mammalian vertebral column. Nat Commun 2019; 10:5071. [PMID: 31699978 PMCID: PMC6838112 DOI: 10.1038/s41467-019-13026-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 10/11/2019] [Indexed: 11/09/2022] Open
Abstract
A fundamental concept in evolutionary biology is that life tends to become more complex through geologic time, but empirical examples of this phenomenon are controversial. One debate is whether increasing complexity is the result of random variations, or if there are evolutionary processes which actively drive its acquisition, and if these processes act uniformly across clades. The mammalian vertebral column provides an opportunity to test these hypotheses because it is composed of serially-repeating vertebrae for which complexity can be readily measured. Here we test seven competing hypotheses for the evolution of vertebral complexity by incorporating fossil data from the mammal stem lineage into evolutionary models. Based on these data, we reject Brownian motion (a random walk) and uniform increasing trends in favor of stepwise shifts for explaining increasing complexity. We hypothesize that increased aerobic capacity in non-mammalian cynodonts may have provided impetus for increasing vertebral complexity in mammals.
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Affiliation(s)
- Katrina E Jones
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA.
| | - Kenneth D Angielczyk
- Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL, 60605-2496, USA
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA.
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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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29
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Abstract
Morphological integration and modularity are important for understanding phenotypic evolution because they constrain variation subjected to selection and enable independent evolution of functional and developmental units. We report dental integration and modularity in representative otariid (Eumetopias jubatus, Callorhinus ursinus) and phocid (Phoca largha, Histriophoca fasciata) species of Pinnipedia. This is the first study of integration and modularity in a secondarily simplified dentition with simple occlusion. Integration was stronger in both otariid species than in either phocid species and related positively to dental occlusion and negatively to both modularity and tooth-size variability across all the species. The canines and third upper incisor were most strongly integrated, comprising a module that likely serves as occlusal guides for the postcanines. There was no or weak modularity among tooth classes. The reported integration is stronger than or similar to that in mammals with complex dentition and refined occlusion. We hypothesise that this strong integration is driven by dental occlusion, and that it is enabled by reduction of modularity that constrains overall integration in complex dentitions. We propose that modularity was reduced in pinnipeds during the transition to aquatic life in association with the origin of pierce-feeding and loss of mastication caused by underwater feeding.
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30
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Kelly EM, Marcot JD, Selwood L, Sears KE. The Development of Integration in Marsupial and Placental Limbs. Integr Org Biol 2019; 1:oby013. [PMID: 33791518 PMCID: PMC7671123 DOI: 10.1093/iob/oby013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The morphological interdependence of traits, or their integration, is commonly thought to influence their evolution. As such, study of morphological integration and the factors responsible for its generation form an important branch of the field of morphological evolution. However, most research to date on post-cranial morphological integration has focused on adult patterns of integration. This study investigates patterns of correlation (i.e., morphological integration) among skeletal elements of the fore- and hind limbs of developing marsupial and placental mammals. The goals of this study are to establish how patterns of limb integration vary over development in marsupials and placentals, and identify factors that are likely responsible for their generation. Our results indicate that although the overall pattern of correlation among limb elements is consistent with adult integration throughout mammalian development, correlations vary at the level of the individual element and stage. As a result, the relative integration among fore- and hind limb elements varies dynamically between stages during development in both marsupial and placental mammals. Therefore, adult integration studies of the limbs may not be indicative of developmental integration. Results are also consistent with integration during early limb development being more heavily influenced by genetic and developmental factors, and later by function. Additionally, results are generally consistent with a constraint on marsupial forelimb evolution caused by the functional requirements of the crawl to the teat that operates by limiting morphological variation before and at the time of birth, and not after.
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Affiliation(s)
- E M Kelly
- School of Integrative Biology, University of Illinois, Urbana, IL61801, USA
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - J D Marcot
- Department of Ecology and Evolutionary Biology, University of California at Los Angeles, Los Angeles, CA90095, USA
| | - L Selwood
- Department of Zoology, University of Melbourne, Melbourne, Australia
| | - K E Sears
- Department of Ecology and Evolutionary Biology, University of California at Los Angeles, Los Angeles, CA90095, USA
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31
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Bardua C, Wilkinson M, Gower DJ, Sherratt E, Goswami A. Morphological evolution and modularity of the caecilian skull. BMC Evol Biol 2019; 19:30. [PMID: 30669965 PMCID: PMC6343317 DOI: 10.1186/s12862-018-1342-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 12/21/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Caecilians (Gymnophiona) are the least speciose extant lissamphibian order, yet living forms capture approximately 250 million years of evolution since their earliest divergences. This long history is reflected in the broad range of skull morphologies exhibited by this largely fossorial, but developmentally diverse, clade. However, this diversity of form makes quantification of caecilian cranial morphology challenging, with highly variable presence or absence of many structures. Consequently, few studies have examined morphological evolution across caecilians. This extensive variation also raises the question of degree of conservation of cranial modules (semi-autonomous subsets of highly-integrated traits) within this clade, allowing us to assess the importance of modular organisation in shaping morphological evolution. We used an intensive surface geometric morphometric approach to quantify cranial morphological variation across all 32 extant caecilian genera. We defined 16 cranial regions using 53 landmarks and 687 curve and 729 surface sliding semilandmarks. With these unprecedented high-dimensional data, we analysed cranial shape and modularity across caecilians assessing phylogenetic, allometric and ecological influences on cranial evolution, as well as investigating the relationships among integration, evolutionary rate, and morphological disparity. RESULTS We found highest support for a ten-module model, with greater integration of the posterior skull. Phylogenetic signal was significant (Kmult = 0.87, p < 0.01), but stronger in anterior modules, while allometric influences were also significant (R2 = 0.16, p < 0.01), but stronger posteriorly. Reproductive strategy and degree of fossoriality were small but significant influences on cranial morphology (R2 = 0.03-0.05), after phylogenetic (p < 0.03) and multiple-test (p < 0.05) corrections. The quadrate-squamosal 'cheek' module was the fastest evolving module, perhaps due to its pivotal role in the unique dual jaw-closing mechanism of caecilians. Highly integrated modules exhibited both high and low disparities, and no relationship was evident between integration and evolutionary rate. CONCLUSIONS Our high-dimensional approach robustly characterises caecilian cranial evolution and demonstrates that caecilian crania are highly modular and that cranial modules are shaped by differential phylogenetic, allometric, and ecological effects. More broadly, and in contrast to recent studies, this work suggests that there is no simple relationship between integration and evolutionary rate or disparity.
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Affiliation(s)
- Carla Bardua
- Department of Life Sciences, Natural History Museum, London, UK. .,Department of Genetics, Evolution and Environment, UCL, London, UK.
| | - Mark Wilkinson
- Department of Life Sciences, Natural History Museum, London, UK
| | - David J Gower
- Department of Life Sciences, Natural History Museum, London, UK
| | - Emma Sherratt
- School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Anjali Goswami
- Department of Life Sciences, Natural History Museum, London, UK.,Department of Genetics, Evolution and Environment, UCL, London, UK
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32
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Jones KE, Benitez L, Angielczyk KD, Pierce SE. Adaptation and constraint in the evolution of the mammalian backbone. BMC Evol Biol 2018; 18:172. [PMID: 30445907 PMCID: PMC6240174 DOI: 10.1186/s12862-018-1282-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/30/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The axial skeleton consists of repeating units (vertebrae) that are integrated through their development and evolution. Unlike most tetrapods, vertebrae in the mammalian trunk are subdivided into distinct thoracic and lumbar modules, resulting in a system that is constrained in terms of count but highly variable in morphology. This study asks how thoracolumbar regionalization has impacted adaptation and evolvability across mammals. Using geometric morphometrics, we examine evolutionary patterns in five vertebral positions from diverse mammal species encompassing a broad range of locomotor ecologies. We quantitatively compare the effects of phylogenetic and allometric constraints, and ecological adaptation between regions, and examine their impact on evolvability (disparity and evolutionary rate) of serially-homologous vertebrae. RESULTS Although phylogenetic signal and allometry are evident throughout the trunk, the effect of locomotor ecology is partitioned between vertebral positions. Lumbar vertebral shape correlates most strongly with ecology, differentiating taxa based on their use of asymmetric gaits. Similarly, disparity and evolutionary rates are also elevated posteriorly, indicating a link between the lumbar region, locomotor adaptation, and evolvability. CONCLUSION Vertebral regionalization in mammals has facilitated rapid evolution of the posterior trunk in response to selection for locomotion and static body support.
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Affiliation(s)
- Katrina E. Jones
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138 USA
| | - Lorena Benitez
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138 USA
| | - Kenneth D. Angielczyk
- Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605-2496 USA
| | - Stephanie E. Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138 USA
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33
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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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34
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Felice RN, Randau M, Goswami A. A fly in a tube: Macroevolutionary expectations for integrated phenotypes. Evolution 2018; 72:2580-2594. [PMID: 30246245 PMCID: PMC6585935 DOI: 10.1111/evo.13608] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/07/2018] [Accepted: 09/13/2018] [Indexed: 02/03/2023]
Abstract
Phenotypic integration and modularity are ubiquitous features of complex organisms, describing the magnitude and pattern of relationships among biological traits. A key prediction is that these relationships, reflecting genetic, developmental, and functional interactions, shape evolutionary processes by governing evolvability and constraint. Over the last 60 years, a rich literature of research has quantified patterns of integration and modularity across a variety of clades and systems. Only recently has it become possible to contextualize these findings in a phylogenetic framework to understand how trait integration interacts with evolutionary tempo and mode. Here, we review the state of macroevolutionary studies of integration and modularity, synthesizing empirical and theoretical work into a conceptual framework for predicting the effects of integration on evolutionary rate and disparity: a fly in a tube. While magnitude of integration is expected to influence the potential for phenotypic variation to be produced and maintained, thus defining the shape and size of a tube in morphospace, evolutionary rate, or the speed at which a fly moves around the tube, is not necessarily controlled by trait interactions. Finally, we demonstrate this reduced disparity relative to the Brownian expectation for a given rate of evolution with an empirical example: the avian cranium.
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Affiliation(s)
- Ryan N Felice
- Department of Life Sciences, The Natural History Museum, London SW7 5DB, United Kingdom.,Department of Genetics, Evolution, and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Marcela Randau
- Department of Life Sciences, The Natural History Museum, London SW7 5DB, United Kingdom.,Department of Genetics, Evolution, and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Anjali Goswami
- Department of Life Sciences, The Natural History Museum, London SW7 5DB, United Kingdom.,Department of Genetics, Evolution, and Environment, University College London, London WC1E 6BT, United Kingdom
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35
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Böhmer C, Amson E, Arnold P, van Heteren AH, Nyakatura JA. Homeotic transformations reflect departure from the mammalian 'rule of seven' cervical vertebrae in sloths: inferences on the Hox code and morphological modularity of the mammalian neck. BMC Evol Biol 2018; 18:84. [PMID: 29879896 PMCID: PMC5992679 DOI: 10.1186/s12862-018-1202-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 05/23/2018] [Indexed: 11/10/2022] Open
Abstract
Background Sloths are one of only two exceptions to the mammalian ‘rule of seven’ vertebrae in the neck. As a striking case of breaking the evolutionary constraint, the explanation for the exceptional number of cervical vertebrae in sloths is still under debate. Two diverging hypotheses, both ultimately linked to the low metabolic rate of sloths, have been proposed: hypothesis 1 involves morphological transformation of vertebrae due to changes in the Hox gene expression pattern and hypothesis 2 assumes that the Hox gene expression pattern is not altered and the identity of the vertebrae is not changed. Direct evidence supporting either hypothesis would involve knowledge of the vertebral Hox code in sloths, but the realization of such studies is extremely limited. Here, on the basis of the previously established correlation between anterior Hox gene expression and the quantifiable vertebral shape, we present the morphological regionalization of the neck in three different species of sloths with aberrant cervical count providing indirect insight into the vertebral Hox code. Results Shape differences within the cervical vertebral column suggest a mouse-like Hox code in the neck of sloths. We infer an anterior shift of HoxC-6 expression in association with the first thoracic vertebra in short-necked sloths with decreased cervical count, and a posterior shift of HoxC-5 and HoxC-6 expression in long-necked sloths with increased cervical count. Conclusion Although only future developmental analyses in non-model organisms, such as sloths, will yield direct evidence for the evolutionary mechanism responsible for the aberrant number of cervical vertebrae, our observations lend support to hypothesis 1 indicating that the number of modules is retained but their boundaries are displaced. Our approach based on quantified morphological differences also provides a reliable basis for further research including fossil taxa such as extinct ‘ground sloths’ in order to trace the pattern and the underlying genetic mechanisms in the evolution of the vertebral column in mammals. Electronic supplementary material The online version of this article (10.1186/s12862-018-1202-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christine Böhmer
- UMR 7179 CNRS/MNHN, Muséum National d'Histoire Naturelle, 57 rue Cuvier, CP-55, Paris, France.
| | - Eli Amson
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt Universität zu Berlin, Philippstraße 13, 10115, Berlin, Germany.,Image Knowledge Gestaltung: An Interdisciplinary Laboratory, Humboldt University, Philippstraße 13, 10115, Berlin, Germany.,Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, 10115, Berlin, Germany
| | - Patrick Arnold
- Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, Friedrich-Schiller-Universität Jena, Erbertstraße 1, 07743, Jena, Germany.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
| | - Anneke H van Heteren
- Sektion Mammalogie, SNSB - Zoologische Staatssammlung, Münchhausenstraße 21, 81247, München, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Straße 10, 80333, Munich, Germany.,Department Biologie II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany
| | - John A Nyakatura
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt Universität zu Berlin, Philippstraße 13, 10115, Berlin, Germany.,Image Knowledge Gestaltung: An Interdisciplinary Laboratory, Humboldt University, Philippstraße 13, 10115, Berlin, Germany
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36
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Villamil CI. Phenotypic integration of the cervical vertebrae in the Hominoidea (Primates). Evolution 2018; 72:490-517. [DOI: 10.1111/evo.13433] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Catalina I. Villamil
- Department of Anthropology; Dickinson College; P.O. Box 1773 Carlisle Pennsylvania 17013
- Center for the Study of Human Origins, Department of Anthropology; New York University; 25 Waverly Place New York New York 10003
- New York Consortium in Evolutionary Primatology; New York New York 10024
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37
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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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Shape Covariation (or the Lack Thereof) Between Vertebrae and Other Skeletal Traits in Felids: The Whole is Not Always Greater than the Sum of Parts. Evol Biol 2018; 45:196-210. [PMID: 29755151 PMCID: PMC5938317 DOI: 10.1007/s11692-017-9443-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/18/2017] [Indexed: 12/25/2022]
Abstract
Within carnivorans, cats show comparatively little disparity in overall morphology, with species differing mainly in body size. However, detailed shape analyses of individual osteological structures, such as limbs or skulls, have shown that felids display significant morphological differences that correlate with their observed ecological and behavioural ranges. Recently, these shape analyses have been extended to the felid axial skeleton. Results demonstrate a functionally-partitioned vertebral column, with regions varying greatly in level of correlation between shape and ecology. Moreover, a clear distinction is evident between a phylogenetically-constrained neck region and a selection-responsive posterior spine. Here, we test whether this regionalisation of function reflected in vertebral column shape is also translated into varying levels of phenotypic integration between this structure and most other skeletal elements. We accomplish this comparison by performing pairwise tests of integration between vertebral and other osteological units, quantified with 3D geometric morphometric data and analysed both with and without phylogenetic correction. To our knowledge, this is the first study to test for integration across a comprehensive sample of whole-skeleton elements. Our results show that, prior to corrections, strong covariation is present between vertebrae across the vertebral column and all other elements, with the exception of the femur. However, most of these significant correlations disappear after correcting for phylogeny, which is a significant influence on cranial and limb morphology of felids and other carnivorans. Our results thus suggest that the vertebral column of cats displays relative independence from other skeletal elements and may represent several distinct evolutionary morphological modules.
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