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Jones KE, Angielczyk KD, Pierce SE. Origins of mammalian vertebral function revealed through digital bending experiments. Proc Biol Sci 2024; 291:20240820. [PMID: 38981526 DOI: 10.1098/rspb.2024.0820] [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: 04/08/2024] [Accepted: 06/13/2024] [Indexed: 07/11/2024] Open
Abstract
Unravelling the functional steps that underlie major transitions in the fossil record is a significant challenge for biologists owing to the difficulties of interpreting functional capabilities of extinct organisms. New computational modelling approaches provide exciting avenues for testing function in the fossil record. Here, we conduct digital bending experiments to reconstruct vertebral function in non-mammalian synapsids, the extinct forerunners of mammals, to provide insights into the functional underpinnings of the synapsid-mammal transition. We estimate range of motion and stiffness of intervertebral joints in eight non-mammalian synapsid species alongside a comparative sample of extant tetrapods, including salamanders, reptiles and mammals. We show that several key aspects of mammalian vertebral function evolved outside crown Mammalia. Compared to early diverging non-mammalian synapsids, cynodonts stabilized the posterior trunk against lateroflexion, while evolving axial rotation in the anterior trunk. This was later accompanied by posterior sagittal bending in crown mammals, and perhaps even therians specifically. Our data also support the prior hypothesis that functional diversification of the mammalian trunk occurred via co-option of existing morphological regions in response to changing selective demands. Thus, multiple functional and evolutionary steps underlie the origin of remarkable complexity in the mammalian backbone.
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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
- Department of Earth and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road , Manchester M13 9PL, UK
| | - Kenneth D Angielczyk
- Negaunee 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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2
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Kort AE, Jones KE. Function of revolute zygapophyses in the lumbar vertebrae of early placental mammals. Anat Rec (Hoboken) 2024; 307:1918-1929. [PMID: 37712919 DOI: 10.1002/ar.25323] [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: 06/05/2023] [Revised: 08/11/2023] [Accepted: 08/30/2023] [Indexed: 09/16/2023]
Abstract
The unique morphology of mammalian lumbar vertebrae allows the spine to flex and extend in the sagittal plane during locomotion. This movement increases stride length and allows mammals to efficiently breathe while running with an asymmetric gait. In extant mammals, the amount of flexion that occurs varies across different locomotor styles, with dorsostable runners relying more on movement of long limbs to run and dorsomobile runners incorporating more flexion of the back. Although long limbs and a stabilized lumbar region are commonly associated with each other in extant mammals, many "archaic" placental mammals with short limbs had lumbar vertebrae with revolute zygapophyses. These articulations with an interlocking S-shape are found only in artiodactyls among extant mammals and have been hypothesized to stabilize against flexion of the back. This would suggest that archaic placental mammals may not have incorporated dorsoventral flexion into locomotion to the same extent as extant mammals with similar proportions. We tested the relative mobility of fossil lumbar vertebrae from two early placental mammals, the creodonts Patriofelis and Limnocyon, to see how these vertebrae may have functioned. We compared range of motion (ROM) between the original vertebrae, with revolute morphology and digitally altered vertebrae with a flat morphology. We found that the revolute morphology had relatively little effect on dorsoventral flexion and instead that it likely prevented disarticulation due to shear forces on the spine. These results show that flexion of the spine has been an important part of mammalian locomotion for at least 50 million years.
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Affiliation(s)
- Anne E Kort
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Katrina E Jones
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
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3
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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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4
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Rytel A, Böhmer C, Spiekman SNF, Tałanda M. Extreme neck elongation evolved despite strong developmental constraints in bizarre Triassic reptiles-implications for neck modularity in archosaurs. ROYAL SOCIETY OPEN SCIENCE 2024; 11:240233. [PMID: 39076823 PMCID: PMC11285776 DOI: 10.1098/rsos.240233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 03/27/2024] [Indexed: 07/31/2024]
Abstract
The Triassic radiation of vertebrates saw the emergence of the modern vertebrate groups, as well as numerous extinct animals exhibiting conspicuous, unique anatomical characteristics. Among these, members of Tanystropheidae (Reptilia: Archosauromorpha) displayed cervical vertebral elongation to an extent unparalleled in any other vertebrate. Tanystropheids were exceptionally ecologically diverse and had a wide spatial and temporal distribution. This may have been related to their neck anatomy, yet its evolution and functional properties remain poorly understood. We used geometric morphometrics to capture the intraspecific variation between the vertebrae comprising the cervical column among early archosauromorphs, to trace the evolutionary history of neck elongation in these animals. Our results show that the cervical series of these reptiles can be divided into modules corresponding to those of extant animals. Tanystropheids achieved neck elongation through somite elongation and a shift between cervical and thoracic regions, without presacral vertebrae count increase-contrary to crown archosaurs. This suggests a peculiar developmental constraint that strongly affected the evolution of tanystropheids. The data obtained just at the base of the archosauromorph phylogenetic tree are crucial for further studies on the modularity of vertebral columns of not only Triassic reptile groups but extant and other extinct animals as well.
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Affiliation(s)
- Adam Rytel
- Institute of Paleobiology, Polish Academy of Sciences, , Warsaw00818, Poland
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, , Warsaw02089, Poland
| | - Christine Böhmer
- Zoological Institute, Christian-Albrechts-Universität zu Kiel, , Kiel24118, Germany
| | | | - Mateusz Tałanda
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, , Warsaw02089, Poland
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Belyaev RI, Nikolskaia P, Bushuev AV, Panyutina AA, Kozhanova DA, Prilepskaya NE. Running, jumping, hunting, and scavenging: Functional analysis of vertebral mobility and backbone properties in carnivorans. J Anat 2024; 244:205-231. [PMID: 37837214 PMCID: PMC10780164 DOI: 10.1111/joa.13955] [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: 05/01/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 10/15/2023] Open
Abstract
Carnivorans are well-known for their exceptional backbone mobility, which enables them to excel in fast running and long jumping, leading to them being among the most successful predators amongst terrestrial mammals. This study presents the first large-scale analysis of mobility throughout the presacral region of the vertebral column in carnivorans. The study covers representatives of 6 families, 24 genera and 34 species. We utilized a previously developed osteometry-based method to calculate available range of motion, quantifying all three directions of intervertebral mobility: sagittal bending (SB), lateral bending (LB), and axial rotation (AR). We observed a strong phylogenetic signal in the structural basis of the vertebral column (vertebral and joint formulae, length proportions of the backbone modules) and an insignificant phylogenetic signal in most characteristics of intervertebral mobility. This indicates that within the existing structure (stabilization of which occurred rather early in different phylogenetic lineages), intervertebral mobility in carnivorans is quite flexible. Our findings reveal that hyenas and canids, which use their jaws to seize prey, are characterized by a noticeably elongated cervical region and significantly higher SB and LB mobility of the cervical joints compared to other carnivorans. In representatives of other carnivoran families, the cervical region is very short, but the flexibility of the neck (both SB and LB) is significantly higher than that of short-necked odd-toed and even-toed ungulates. The lumbar region of the backbone in carnivorans is dorsomobile in the sagittal plane, being on average ~23° more mobile than in artiodactyls and ~38° more mobile than in perissodactyls. However, despite the general dorsomobility, only some representatives of Canidae, Felidae, and Viverridae are superior in lumbar flexibility to the most dorsomobile ungulates. The most dorsomobile artiodactyls are equal or even superior to carnivorans in their ability to engage in dorsal extension during galloping. In contrast, carnivorans are far superior to ungulates in their ability to engage ventral flexion. The cumulative SB in the lumbar region in carnivorans largely depends on the mode of running and hunting. Thus, adaptation to prolonged and enduring pursuit of prey in hyenas is accompanied by markedly reduced SB flexibility in the lumbar region. A more dorsostable run is also a characteristic of the Ursidae, and the peculiar maned wolf. Representatives of Felidae and Canidae have significantly more available SB mobility in the lumbar region. However, they fully engage it only occasionally at key moments of the hunt associated with the direct capture of the prey or when running in a straight line at maximum speed.
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Affiliation(s)
- Ruslan I. Belyaev
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesMoscowRussian Federation
| | - Polina Nikolskaia
- Geological InstituteRussian Academy of SciencesMoscowRussian Federation
| | - Andrey V. Bushuev
- Department of Vertebrate Zoology, Faculty of BiologyLomonosov Moscow State UniversityMoscowRussian Federation
| | | | - Darya A. Kozhanova
- Department of Paleontology, Faculty of GeologyLomonosov Moscow State UniversityMoscowRussian Federation
| | - Natalya E. Prilepskaya
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesMoscowRussian Federation
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Selescu T, Bivoleanu RA, Iodi Carstens M, Manolache A, Caragea VM, Hutanu DE, Meerupally R, Wei ET, Carstens E, Zimmermann K, Babes A. TRPM8-dependent shaking in mammals and birds. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.27.573364. [PMID: 38234797 PMCID: PMC10793462 DOI: 10.1101/2023.12.27.573364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Removing water from wet fur or feathers is important for thermoregulation in warm-blooded animals. The "wet dog shake" (WDS) behavior has been largely characterized in mammals but to a much lesser extent in birds. Although it is known that TRPM8 is the main molecular transducer of low temperature in mammals, it is not clear if wetness-induced shaking in furred and feathered animals is dependent on TRPM8. Here, we show that a novel TRPM8 agonist induces WDS in rodents and, importantly, in birds, similar to the shaking behavior evoked by water-spraying. Furthermore, the WDS onset depends on TRPM8, as we show in water-sprayed mice. Overall, our results provide multiple evidence for a TRPM8 dependence of WDS behaviors in all tested species. These suggest that a convergent evolution selected similar shaking behaviors to expel water from fur and feathers, with TRPM8 being involved in wetness sensing in both mammals and birds.
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Formoso KK, Habib MB, Vélez-Juarbe J. The Role of Locomotory Ancestry on Secondarily Aquatic Transitions. Integr Comp Biol 2023; 63:1140-1153. [PMID: 37591628 DOI: 10.1093/icb/icad112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 08/19/2023] Open
Abstract
Land-to-sea evolutionary transitions are great transformations where terrestrial amniote clades returned to aquatic environments. These secondarily aquatic amniote clades include charismatic marine mammal and marine reptile groups, as well as countless semi-aquatic forms that modified their terrestrial locomotor anatomy to varying degrees to be suited for swimming via axial and/or appendicular propulsion. The terrestrial ancestors of secondarily aquatic groups would have started off swimming strikingly differently from one another given their evolutionary histories, as inferred by the way modern terrestrial amniotes swim. With such stark locomotor functional differences between reptiles and mammals, we ask if this impacted these transitions. Axial propulsion appears favored by aquatic descendants of terrestrially sprawling quadrupedal reptiles, with exceptions. Appendicular propulsion is more prevalent across the aquatic descendants of ancestrally parasagittal-postured mammals, particularly early transitioning forms. Ancestral terrestrial anatomical differences that precede secondarily aquatic invasions between mammals and reptiles, as well as the distribution of axial and appendicular swimming in secondarily aquatic clades, may indicate that ancestral terrestrial locomotor anatomy played a role, potentially in both constraint and facilitation, in certain aquatic locomotion styles. This perspective of the land-to-sea transition can lead to new avenues of functional, biomechanical, and developmental study of secondarily aquatic transitions.
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Affiliation(s)
- Kiersten K Formoso
- Department of Earth Sciences, University of Southern California, 3651 Trousedale Pkwy, Zumberge Hall, Los Angeles, CA 90089, USA
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Blvd, Los Angeles, CA 90007-4057, USA
| | - Michael B Habib
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Blvd, Los Angeles, CA 90007-4057, USA
- UCLA Cardiac Arrhythmia Center, Division of Cardiology, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
| | - Jorge Vélez-Juarbe
- Department of Mammalogy, Natural History Museum of Los Angeles County, 900 Exposition Blvd, Los Angelss, CA 90007-4057, USA
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Esteban JM, Martín-Serra A, Pérez-Ramos A, Mulot B, Jones K, Figueirido B. The impact of the land-to-sea transition on evolutionary integration and modularity of the pinniped backbone. Commun Biol 2023; 6:1141. [PMID: 37949962 PMCID: PMC10638317 DOI: 10.1038/s42003-023-05512-8] [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: 05/24/2023] [Accepted: 10/26/2023] [Indexed: 11/12/2023] Open
Abstract
In this study, we investigate how the terrestrial-aquatic transition influenced patterns of axial integration and modularity in response to the secondary adaptation to a marine lifestyle. We use 3D geometric morphometrics to quantify shape covariation among presacral vertebrae in pinnipeds (Carnivora; Pinnipedia) and to compare with patterns of axial integration and modularity in their close terrestrial relatives. Our results indicate that the vertebral column of pinnipeds has experienced a decrease in the strength of integration among all presacral vertebrae when compared to terrestrial carnivores (=fissipeds). However, separate integration analyses among the speciose Otariidae (i.e., sea lions and fur seals) and Phocidae (i.e., true seals) also suggests the presence of different axial organizations in these two groups of crown pinnipeds. While phocids present a set of integrated "thoracic" vertebrae, the presacral vertebrae of otariids are characterized by the absence of any set of vertebrae with high integration. We hypothesize that these differences could be linked to their specific modes of aquatic locomotion -i.e., pelvic vs pectoral oscillation. Our results provide evidence that the vertebral column of pinnipeds has been reorganized from the pattern observed in fissipeds but is more complex than a simple "homogenization" of the modular pattern of their close terrestrial relatives.
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Affiliation(s)
- Juan Miguel Esteban
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain.
| | - Alberto Martín-Serra
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
| | - Alejandro Pérez-Ramos
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
| | - Baptiste Mulot
- ZooParc de Beauval & Beauval Nature, 41110, Saint-Aignan, France
| | - Katrina Jones
- Department of Earth and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester, M13 9PL, UK
| | - Borja Figueirido
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
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Merten LJF, Manafzadeh AR, Herbst EC, Amson E, Tambusso PS, Arnold P, Nyakatura JA. The functional significance of aberrant cervical counts in sloths: insights from automated exhaustive analysis of cervical range of motion. Proc Biol Sci 2023; 290:20231592. [PMID: 37909076 PMCID: PMC10618861 DOI: 10.1098/rspb.2023.1592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 10/06/2023] [Indexed: 11/02/2023] Open
Abstract
Besides manatees, the suspensory extant 'tree sloths' are the only mammals that deviate from a cervical count (CC) of seven vertebrae. They do so in opposite directions in the two living genera (increased versus decreased CC). Aberrant CCs seemingly reflect neck mobility in both genera, suggesting adaptive significance for their head position during suspensory locomotion and especially increased ability for neck torsion in three-toed sloths. We test two hypotheses in a comparative evolutionary framework by assessing three-dimensional intervertebral range of motion (ROM) based on exhaustive automated detection of bone collisions and joint disarticulation while accounting for interacting rotations of roll, yaw and pitch. First, we hypothesize that the increase of CC also increases overall neck mobility compared with mammals with a regular CC, and vice versa. Second, we hypothesize that the anatomy of the intervertebral articulations determines mobility of the neck. The assessment revealed that CC plays only a secondary role in defining ROM since summed torsion (roll) capacity was primarily determined by vertebral anatomy. Our results thus suggest limited neck rotational adaptive significance of the CC aberration in sloths. Further, the study demonstrates the suitability of our automated approach for the comparative assessment of osteological ROM in vertebral series.
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Affiliation(s)
- Luisa J. F. Merten
- Comparative Zoology, Institute of Biology, Humboldt University of Berlin, Philippstrasse 12/13, 10115 Berlin, Germany
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany
| | - Armita R. Manafzadeh
- Yale Institute for Biospheric Studies, Yale University, New Haven, CT 06520, USA
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520, USA
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA
- Yale Peabody Museum of Natural History, New Haven, CT 06520, USA
| | - Eva C. Herbst
- Palaeontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
- Department of Health Sciences and Technology, ETH, University of Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | - Eli Amson
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
| | - P. Sebastián Tambusso
- Departamento de Paleontología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
| | - Patrick Arnold
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
| | - John A. Nyakatura
- Comparative Zoology, Institute of Biology, Humboldt University of Berlin, Philippstrasse 12/13, 10115 Berlin, Germany
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10
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Hellert SM, Grossnickle DM, Lloyd GT, Kammerer CF, Angielczyk KD. Derived faunivores are the forerunners of major synapsid radiations. Nat Ecol Evol 2023; 7:1903-1913. [PMID: 37798433 DOI: 10.1038/s41559-023-02200-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/06/2023] [Indexed: 10/07/2023]
Abstract
Evolutionary radiations generate most of Earth's biodiversity, but are there common ecomorphological traits among the progenitors of radiations? In Synapsida (the mammalian total group), 'small-bodied faunivore' has been hypothesized as the ancestral state of most major radiating clades, but this has not been quantitatively assessed across multiple radiations. To examine macroevolutionary patterns in a phylogenetic context, we generated a time-calibrated metaphylogeny ('metatree') comprising 1,888 synapsid species from the Carboniferous through the Eocene (305-34 Ma) based on 269 published character matrices. We used comparative methods to investigate body size and dietary evolution during successive synapsid radiations. Faunivory is the ancestral dietary regime of each major synapsid radiation, but relatively small body size is only established as the common ancestral state of radiations near the origin of Mammaliaformes in the Late Triassic. The faunivorous ancestors of synapsid radiations typically have numerous novel characters compared with their contemporaries, and these derived traits may have helped them to survive faunal turnover events and subsequently radiate.
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Affiliation(s)
- Spencer M Hellert
- Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, USA.
- Department of Science and Mathematics, Columbia College Chicago, Chicago, IL, USA.
| | - David M Grossnickle
- Department of Biology, University of Washington, Seattle, WA, USA
- Natural Sciences Department, Oregon Institute of Technology, Klamath Falls, OR, USA
| | | | | | - Kenneth D Angielczyk
- Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, USA
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11
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Marek RD, Felice RN. The neck as a keystone structure in avian macroevolution and mosaicism. BMC Biol 2023; 21:216. [PMID: 37833771 PMCID: PMC10576348 DOI: 10.1186/s12915-023-01715-x] [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: 05/18/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND The origin of birds from non-avian theropod dinosaur ancestors required a comprehensive restructuring of the body plan to enable the evolution of powered flight. One of the proposed key mechanisms that allowed birds to acquire flight and modify the associated anatomical structures into diverse forms is mosaic evolution, which describes the parcelization of phenotypic traits into separate modules that evolve with heterogeneous tempo and mode. Avian mosaicism has been investigated with a focus on the cranial and appendicular skeleton, and as such, we do not understand the role of the axial column in avian macroevolution. The long, flexible neck of extant birds lies between the cranial and pectoral modules and represents an opportunity to study the contribution of the axial skeleton to avian mosaicism. RESULTS Here, we use 3D geometric morphometrics in tandem with phylogenetic comparative methods to provide, to our knowledge, the first integrative analysis of avian neck evolution in context with the head and wing and to interrogate how the interactions between these anatomical systems have influenced macroevolutionary trends across a broad sample of extant birds. We find that the neck is integrated with both the head and the forelimb. These patterns of integration are variable across clades, and only specific ecological groups exhibit either head-neck or neck-forelimb integration. Finally, we find that ecological groups that display head-neck and neck-forelimb integration tend to display significant shifts in the rate of neck morphological evolution. CONCLUSIONS Combined, these results suggest that the interaction between trophic ecology and head-neck-forelimb mosaicism influences the evolutionary variance of the avian neck. By linking together the biomechanical functions of these distinct anatomical systems, the cervical vertebral column serves as a keystone structure in avian mosaicism and macroevolution.
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Affiliation(s)
- Ryan D Marek
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, London, UK.
| | - Ryan N Felice
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, London, UK
- Department of Life Sciences, Natural History Museum, London, UK
- Department of Genetics, Evolution, and Environment, University College London, London, UK
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12
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Marek RD. A surrogate forelimb: Evolution, function and development of the avian cervical spine. J Morphol 2023; 284:e21638. [PMID: 37708511 DOI: 10.1002/jmor.21638] [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: 07/10/2023] [Revised: 08/17/2023] [Accepted: 08/21/2023] [Indexed: 09/16/2023]
Abstract
The neck is a critical portion of the avian spine, one that works in tandem with the beak to act as a surrogate forelimb and allows birds to manipulate their surroundings despite the lack of a grasping capable hand. Birds display an incredible amount of diversity in neck morphology across multiple anatomical scales-from varying cervical counts down to intricate adaptations of individual vertebrae. Despite this morphofunctional disparity, little is known about the drivers of this enormous variation, nor how neck evolution has shaped avian macroevolution. To promote interest in this system, I review the development, function and evolution of the avian cervical spine. The musculoskeletal anatomy, basic kinematics and development of the avian neck are all documented, but focus primarily upon commercially available taxa. In addition, recent work has quantified the drivers of extant morphological variation across the avian neck, as well as patterns of integration between the neck and other skeletal elements. However, the evolutionary history of the avian cervical spine, and its contribution to the diversification and success of modern birds is currently unknown. Future work should aim to broaden our understanding of the cervical anatomy, development and kinematics to include a more diverse selection of extant birds, while also considering the macroevolutionary drivers and consequences of this important section of the avian spine.
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Affiliation(s)
- Ryan D Marek
- Department of Cell and Developmental Biology, Centre for Integrative Anatomy, University College London, London, UK
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13
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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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14
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Belyaev RI, Kuznetsov AN, Prilepskaya NE. Truly dorsostable runners: Vertebral mobility in rhinoceroses, tapirs, and horses. J Anat 2023; 242:568-591. [PMID: 36519561 PMCID: PMC10008283 DOI: 10.1111/joa.13799] [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: 05/30/2022] [Revised: 11/16/2022] [Accepted: 11/20/2022] [Indexed: 12/23/2022] Open
Abstract
The vertebral column is a hallmark of vertebrates; it is the structural basis of their body and the locomotor apparatus in particular. Locomotion of any vertebrate animal in its typical habitat is directly associated with functional adaptations of its vertebrae. This study is the first large-scale analysis of mobility throughout the presacral region of the vertebral column covering a majority of extant odd-toed ungulates from 6 genera and 15 species. In this study, we used a previously developed osteometry-based method to calculate available range of motion. We quantified all three directions of intervertebral mobility: sagittal bending (SB), lateral bending (LB), and axial rotation (AR). The cervical region in perissodactyls was found to be the most mobile region of the presacral vertebral column in LB and SB. Rhinoceroses and tapirs are characterized by the least mobile necks in SB among odd-toed and even-toed ungulates. Equidae are characterized by very mobile necks, especially in LB. The first intrathoracic joint (T1-T2) in Equidae and Tapiridae is characterized by significantly increased mobility in the sagittal plane compared to the typical thoracic joints and is only slightly less mobile than typical cervical joints. The thoracolumbar part of the vertebral column in odd-toed ungulates is very stiff. Perissodactyls are characterized by frequent fusions of vertebrae with each other with complete loss of mobility. The posterior half of the thoracic region in perissodactyls is characterized by especially stiff intervertebral joints in the SB direction. This is probably associated with hindgut fermentation in perissodactyls: the sagittal stiffness of the posterior thoracic region of the vertebral column is able to passively support the hindgut heavily loaded with roughage. Horses are known as a prime example of a dorsostable galloper among mammals. However, based on SB in the lumbosacral part of the backbone, equids appear to be the least dorsostable among extant perissodactyls; the cumulative SB in equids and tapirs is as low as in the largest representatives of artiodactyls, while in Rhinocerotidae it is even lower representing the minimum across all odd-toed and even-toed ungulates. Morphological features of small Paleogene ancestors of rhinoceroses and equids indicate that dorsostability is a derived feature of perissodactyls and evolved convergently in the three extant families.
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Affiliation(s)
- Ruslan I Belyaev
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russian Federation
| | - Alexander N Kuznetsov
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russian Federation.,Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, Russian Federation
| | - Natalya E Prilepskaya
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russian Federation
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15
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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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16
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Li Y, Brinkworth A, Green E, Oyston J, Wills M, Ruta M. Divergent vertebral formulae shape the evolution of axial complexity in mammals. Nat Ecol Evol 2023; 7:367-381. [PMID: 36878987 PMCID: PMC9998275 DOI: 10.1038/s41559-023-01982-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/03/2023] [Indexed: 03/08/2023]
Abstract
Complexity, defined as the number of parts and their degree of differentiation, is a poorly explored aspect of macroevolutionary dynamics. The maximum anatomical complexity of organisms has undoubtedly increased through evolutionary time. However, it is unclear whether this increase is a purely diffusive process or whether it is at least partly driven, occurring in parallel in most or many lineages and with increases in the minima as well as the means. Highly differentiated and serially repeated structures, such as vertebrae, are useful systems with which to investigate these patterns. We focus on the serial differentiation of the vertebral column in 1,136 extant mammal species, using two indices that quantify complexity as the numerical richness and proportional distribution of vertebrae across presacral regions and a third expressing the ratio between thoracic and lumbar vertebrae. We address three questions. First, we ask whether the distribution of complexity values in major mammal groups is similar or whether clades have specific signatures associated with their ecology. Second, we ask whether changes in complexity throughout the phylogeny are biased towards increases and whether there is evidence of driven trends. Third, we ask whether evolutionary shifts in complexity depart from a uniform Brownian motion model. Vertebral counts, but not complexity indices, differ significantly between major groups and exhibit greater within-group variation than recognized hitherto. We find strong evidence of a trend towards increasing complexity, where higher values propagate further increases in descendant lineages. Several increases are inferred to have coincided with major ecological or environmental shifts. We find support for multiple-rate models of evolution for all complexity metrics, suggesting that increases in complexity occurred in stepwise shifts, with evidence for widespread episodes of recent rapid divergence. Different subclades evolve more complex vertebral columns in different configurations and probably under different selective pressures and constraints, with widespread convergence on the same formulae. Further work should therefore focus on the ecological relevance of differences in complexity and a more detailed understanding of historical patterns.
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Affiliation(s)
- Yimeng Li
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK.,Nanjing Institute of Geology and Palaeontology, CAS, Nanjing, China
| | - Andrew Brinkworth
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Emily Green
- Joseph Banks Laboratories, Department of Life Sciences, University of Lincoln, Lincoln, UK
| | - Jack Oyston
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Matthew Wills
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK.
| | - Marcello Ruta
- Joseph Banks Laboratories, Department of Life Sciences, University of Lincoln, Lincoln, UK.
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17
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Molnar J, Watanabe A. Morphological and functional regionalization of trunk vertebrae as an adaptation for arboreal locomotion in chameleons. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221509. [PMID: 36998764 PMCID: PMC10049746 DOI: 10.1098/rsos.221509] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
Regionalization of the vertebral column can help animals adapt to different kinds of locomotion, including arboreal locomotion. Although functional axial regionalization has been described in both chameleons and arboreal mammals, no morphological basis for this functional regionalization in chameleons has been proposed. However, recent studies have described regionalization in the presacral vertebral column of other extant squamates. To investigate possible morphological regionalization in the vertebral column of chameleons, we took morphometric measurements from the presacral vertebrae of 28 chameleon species representing all extant chameleon genera, both fully arboreal and ground-dwelling, and performed comparative analyses. Our results support chameleons exhibiting three or four presacral morphological regions that correspond closely to those in other sauropsids, but we detected evolutionary shifts in vertebral traits occurring in only arboreal chameleons. Specifically, the anterior dorsal region in arboreal chameleons has more vertically oriented zygapophyseal joints, predicting decreased mediolateral flexibility. This shift is functionally significant because stiffening of the anterior thoracic vertebral column has been proposed to help bridge gaps between supports in primates. Thus, specialization of existing morphological regions in the vertebral column of chameleons may have played an important role in the evolution of extreme arboreal locomotion, paralleling the adaptations of arboreal primates.
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Affiliation(s)
- Julia Molnar
- Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, NY 11568, USA
| | - Akinobu Watanabe
- Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, NY 11568, USA
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Life Sciences Department, Natural History Museum, London, SW7 5BD UK
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18
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Regionalization, constraints, and the ancestral ossification patterns in the vertebral column of amniotes. Sci Rep 2022; 12:22257. [PMID: 36564413 PMCID: PMC9789111 DOI: 10.1038/s41598-022-24983-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022] Open
Abstract
The development of the vertebral column has been studied extensively in modern amniotes, yet many aspects of its evolutionary history remain enigmatic. Here we expand the existing data on four major vertebral developmental patterns in amniotes based on exceptionally well-preserved specimens of the early Permian mesosaurid reptile Mesosaurus tenuidens: (i) centrum ossification, (ii) neural arch ossification, (iii) neural arch fusion, and (iv) neurocentral fusion. We retrace the evolutionary history of each pattern and reconstruct the ancestral condition in amniotes. Despite 300 million years of evolutionary history, vertebral development patterns show a surprisingly stability in amniotes since their common ancestor. We propose that this stability may be linked to conservatism in the constraints posed by underlying developmental processes across amniotes. We also point out that birds, mammals, and squamates each show specific trends deviating from the ancestral condition in amniotes, and that they remain rather unchanged within these lineages. The stability of their unique patterns demonstrates a certain homogeneity of vertebral developmental constraints within these lineages, which we suggest might be linked to their specific modes of regionalization. Our research provides a framework for the evolution of axial development in amniotes and a foundation for future studies.
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19
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Bendel EM, Kammerer CF, Luo ZX, Smith RMH, Fröbisch J. The earliest segmental sternum in a Permian synapsid and its implications for the evolution of mammalian locomotion and ventilation. Sci Rep 2022; 12:13472. [PMID: 35931742 PMCID: PMC9356055 DOI: 10.1038/s41598-022-17492-6] [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: 03/18/2022] [Accepted: 07/26/2022] [Indexed: 11/30/2022] Open
Abstract
The sternum is a stabilizing element in the axial skeleton of most tetrapods, closely linked with the function of the pectoral girdle of the appendicular skeleton. Modern mammals have a distinctive sternum characterized by multiple ossified segments, the origins of which are poorly understood. Although the evolution of the pectoral girdle has been extensively studied in early members of the mammalian total group (Synapsida), only limited data exist for the sternum. Ancestrally, synapsids exhibit a single sternal element and previously the earliest report of a segmental sternum in non-mammalian synapsids was in the Middle Triassic cynodont Diademodon tetragonus. Here, we describe the well-preserved sternum of a gorgonopsian, a group of sabre-toothed synapsids from the Permian. It represents an ossified, multipartite element resembling the mammalian condition. This discovery pulls back the origin of the distinctive “mammalian” sternum to the base of Theriodontia, significantly extending the temporal range of this morphology. Through a review of sternal morphology across Synapsida, we reconstruct the evolutionary history of this structure. Furthermore, we explore its role in the evolution of mammalian posture, gait, and ventilation through progressive regionalization of the postcranium as well as the posteriorization of musculature associated with mammalian breathing.
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Affiliation(s)
- Eva-Maria Bendel
- Museum Für Naturkunde, Leibniz-Institut Für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, 10115, Berlin, Germany. .,Institut Für Biologie, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany.
| | - Christian F Kammerer
- North Carolina Museum of Natural Sciences, 11 W Jones Street, Raleigh, NC, USA.,Evolutionary Studies Institute, University of the Witwatersrand, Yale Road, Johannesburg, 2000, South Africa
| | - Zhe-Xi Luo
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 E 57th Street, Chicago, IL, USA
| | - Roger M H Smith
- Evolutionary Studies Institute, University of the Witwatersrand, Yale Road, Johannesburg, 2000, South Africa.,Department of Karoo Palaeontology, Iziko South African Museum, 25 Queen Victoria Street, Cape Town, 8001, South Africa
| | - Jörg Fröbisch
- Museum Für Naturkunde, Leibniz-Institut Für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, 10115, Berlin, Germany.,Institut Für Biologie, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany.,Evolutionary Studies Institute, University of the Witwatersrand, Yale Road, Johannesburg, 2000, South Africa
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20
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Belyaev RI, Kuznetsov AN, Prilepskaya NE. From dorsomobility to dorsostability: A study of lumbosacral joint range of motion in artiodactyls. J Anat 2022; 241:420-436. [PMID: 35616615 PMCID: PMC9296042 DOI: 10.1111/joa.13688] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 03/23/2022] [Accepted: 04/27/2022] [Indexed: 11/28/2022] Open
Abstract
This study is the first analysis of mobility in the lumbosacral joint of even-toed ungulates covering the full range of body masses and running forms. In this study, we modified a previously developed osteometry-based method to calculate the available range of motion (aROM) in the lumbosacral joint in artiodactyls. We quantified all three directions of intervertebral mobility: sagittal bending (SB), lateral bending (LB), and axial rotation (AR). This research covers extant artiodactyls from 10 families, 57 genera, and 78 species. The lumbosacral joint in artiodactyls is on average almost twice as mobile in SB as the average intralumbar joint (aROM 15.68° vs 8.22°). In all artiodactyls, the first sacral prezygapophyses are equipped with postfacet fossae determining the available range of lumbosacral hyperextension. SB aROM in the lumbosacral joint in artiodactyls varies almost sevenfold (from 4.53° to 31.19°) and is closely related to the body mass and running form. An allometric equation was developed for the first time, for the joint angular amplitude of motion, exemplified by the artiodactyl lumbosacral SB aROMs, as a power function of body mass, the power coefficient value being close to -0.15. High SB aROM at the lumbosacral joint is characteristic of artiodactyls with at least one of the following characteristics: high cumulative and average SB aROM in the lumbar region (Pearson r = 0.467-0.617), small body mass (r = -0.531), saltatorial or saltatorial-cursorial running form (mean = 16.91-18.63°). The highest SB aROM in the lumbosacral joint is typical for small antelopes and Moschidae (mean = 20.24-20.27°). Among these artiodactyls SB aROMs in the lumbosacral joint are on par with various carnivores. Large and robust artiodactyls, adapted predominantly to mediportal and stilt (running on extremely tall limbs) running forms, have 2-3 times smaller SB aROMs in the lumbosacral joint. Adaptation to endurance galloping in open landscapes (cursorial running form) is accompanied by smaller lumbar and lumbosacral SB aROMs compared to that in saltatorial-cursorial artiodactyls of the same body mass. The wide range of species studied makes it possible to significantly expand the knowledge of relations of the mobility of the lumbosacral joint in artiodactyls to body mass and running form.
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Affiliation(s)
- Ruslan I. Belyaev
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesMoscowRussian Federation
| | - Alexander N. Kuznetsov
- Borissiak Paleontological Institute, Russian Academy of SciencesMoscowRussian Federation
| | - Natalya E. Prilepskaya
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesMoscowRussian Federation
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21
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Araújo R, David R, Benoit J, Lungmus JK, Stoessel A, Barrett PM, Maisano JA, Ekdale E, Orliac M, Luo ZX, Martinelli AG, Hoffman EA, Sidor CA, Martins RMS, Spoor F, Angielczyk KD. Inner ear biomechanics reveals a Late Triassic origin for mammalian endothermy. Nature 2022; 607:726-731. [PMID: 35859179 DOI: 10.1038/s41586-022-04963-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 06/10/2022] [Indexed: 01/12/2023]
Abstract
Endothermy underpins the ecological dominance of mammals and birds in diverse environmental settings1,2. However, it is unclear when this crucial feature emerged during mammalian evolutionary history, as most of the fossil evidence is ambiguous3-17. Here we show that this key evolutionary transition can be investigated using the morphology of the endolymph-filled semicircular ducts of the inner ear, which monitor head rotations and are essential for motor coordination, navigation and spatial awareness18-22. Increased body temperatures during the ectotherm-endotherm transition of mammal ancestors would decrease endolymph viscosity, negatively affecting semicircular duct biomechanics23,24, while simultaneously increasing behavioural activity25,26 probably required improved performance27. Morphological changes to the membranous ducts and enclosing bony canals would have been necessary to maintain optimal functionality during this transition. To track these morphofunctional changes in 56 extinct synapsid species, we developed the thermo-motility index, a proxy based on bony canal morphology. The results suggest that endothermy evolved abruptly during the Late Triassic period in Mammaliamorpha, correlated with a sharp increase in body temperature (5-9 °C) and an expansion of aerobic and anaerobic capacities. Contrary to previous suggestions3-14, all stem mammaliamorphs were most probably ectotherms. Endothermy, as a crucial physiological characteristic, joins other distinctive mammalian features that arose during this period of climatic instability28.
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Affiliation(s)
- Ricardo Araújo
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal. .,Institut des Sciences de L'Évolution de Montpellier, Université de Montpellier, Montpellier, France.
| | - Romain David
- Natural History Museum, London, UK. .,Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany.
| | - Julien Benoit
- Evolutionary Studies Institute, University of Witwatersrand, Johannesburg, South Africa
| | - Jacqueline K Lungmus
- Department of Paleobiology, National Museum of Natural History, Washington DC, USA
| | - Alexander Stoessel
- Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany.,Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Jena, Germany
| | | | - Jessica A Maisano
- Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
| | - Eric Ekdale
- Department of Biology, San Diego State University, San Diego, CA, USA.,Department of Paleontology, San Diego Natural History Museum, San Diego, CA, USA
| | - Maëva Orliac
- Institut des Sciences de L'Évolution de Montpellier, Université de Montpellier, Montpellier, France
| | - Zhe-Xi Luo
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA
| | - Agustín G Martinelli
- Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', Buenos Aires, Argentina
| | - Eva A Hoffman
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Christian A Sidor
- Burke Museum and Department of Biology, University of Washington, Seattle, WA, USA
| | - Rui M S Martins
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Fred Spoor
- Natural History Museum, London, UK.,Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany.,Department of Anthropology, University College London, London, UK
| | - Kenneth D Angielczyk
- Neguanee Integrative Research Center, Field Museum of Natural History, Chicago, IL, USA.
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22
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Evans KM, Buser TJ, Larouche O, Kolmann MA. Untangling the relationship between developmental and evolutionary integration. Semin Cell Dev Biol 2022; 145:22-27. [PMID: 35659472 DOI: 10.1016/j.semcdb.2022.05.026] [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: 10/01/2021] [Revised: 04/29/2022] [Accepted: 05/25/2022] [Indexed: 11/15/2022]
Abstract
Patterns of integration and modularity among organismal traits are prevalent across the tree of life, and at multiple scales of biological organization. Over the past several decades, researchers have studied these patterns at the developmental, and evolutionary levels. While their work has identified the potential drivers of these patterns at different scales, there appears to be a lack of consensus on the relationship between developmental and evolutionary integration. Here, we review and summarize key studies and build a framework to describe the conceptual relationship between these patterns across organismal scales and illustrate how, and why some of these studies may have yielded seemingly conflicting outcomes. We find that among studies that analyze patterns of integration and modularity using morphological data, the lack of consensus may stem in part from the difficulty of fully disentangling the developmental and functional causes of integration. Nonetheless, in some empirical systems, patterns of evolutionary modularity have been found to coincide with expectations based on developmental processes, suggesting that in some circumstances, developmental modularity may translate to evolutionary modularity. We also advance an extension to Hallgrímsson et al.'s palimpsest model to describe how patterns of trait modularity may shift across different evolutionary scales. Finally, we also propose some directions for future research which will hopefully be useful for investigators interested in these issues.
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Affiliation(s)
- Kory M Evans
- Rice University, Biosciences Department, 6100 Main St, Houston, TX 77005, USA.
| | - Thaddaeus J Buser
- Rice University, Biosciences Department, 6100 Main St, Houston, TX 77005, USA
| | - Olivier Larouche
- Rice University, Biosciences Department, 6100 Main St, Houston, TX 77005, USA
| | - Matthew A Kolmann
- Rice University, Biosciences Department, 6100 Main St, Houston, TX 77005, USA
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23
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Brecko J, Kleinteich T, Herrel A, Adriaens D. Regional differences in vertebral shape along the axial skeleton in caecilians (Amphibia: Gymnophiona). J Anat 2022; 241:716-728. [PMID: 35488423 DOI: 10.1111/joa.13682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/13/2022] [Accepted: 04/13/2022] [Indexed: 10/18/2022] Open
Abstract
Caecilians are elongate, limbless and annulated amphibians that, as far as is known, all have an at least partly fossorial lifestyle. It has been suggested that elongate limbless vertebrates show little morphological differentiation throughout the postcranial skeleton. However, relatively few studies have explored the axial skeleton in limbless tetrapods. In this study, we used μCT data and three-dimensional geometric morphometrics to explore regional differences in vertebral shape across a broad range of caecilian species. Our results highlight substantial differences in vertebral shape along the axial skeleton, with anterior vertebrae being short and bulky, whereas posterior vertebrae are more elongated. This study shows that despite being limbless, elongate tetrapods such as caecilians still show regional heterogeneity in the shape of individual vertebrae along the vertebral column. Further studies are needed, however, to understand the possible causes and functional consequences of the observed variation in vertebral shape in caecilians.
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Affiliation(s)
- Aurélien Lowie
- Department of Biology, Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium
| | - Barbara De Kegel
- Department of Biology, Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium
| | - Mark Wilkinson
- Department of Life Sciences, Natural History Museum, London, UK
| | - John Measey
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - James C O'Reilly
- Department of Biomedical Sciences, Ohio University, Cleveland, Ohio, USA
| | - Nathan J Kley
- Department of Anatomical Sciences, Health Sciences Center, Stony Brook University, Stony Brook, New York, USA
| | - Philippe Gaucher
- USR 3456, CNRS, Centre de recherche de Montabo IRD, CNRS-Guyane, Cayenne, France
| | - Jonathan Brecko
- Royal Museum for Central Africa, Biological Collections and Data Management, Tervuren, Belgium
| | | | - Anthony Herrel
- Department of Biology, Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium.,UMR 7179 C.N.R.S/M.N.H.N, Département d'Ecologie et de Gestion de la Biodiversité, Paris Cedex 5, France
| | - Dominique Adriaens
- Department of Biology, Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium
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24
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Scholtes SJ, Arntzen JW, Ajduković M, Ivanović A. Variation in vertebrae shape across small-bodied newts reveals functional and developmental constraints acting upon the trunk region. J Anat 2022; 240:639-646. [PMID: 34761388 PMCID: PMC8930814 DOI: 10.1111/joa.13591] [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: 03/21/2021] [Revised: 10/31/2021] [Accepted: 11/01/2021] [Indexed: 11/26/2022] Open
Abstract
The salamander vertebral column is largely undifferentiated with a series of more or less uniform rib-bearing presacral vertebrae traditionally designated as the trunk region. We explored regionalization of the salamander trunk in seven species and two subspecies of the salamander genus Lissotriton by the combination of microcomputed tomography scanning and geometric morphometrics. The detailed information on trunk vertebral shape was subjected to a multidimensional cluster analysis and a phenotypic trajectory analysis. With these complementary approaches, we observed a clear morphological regionalization. Clustering analysis showed that the anterior trunk vertebrae (T1 and T2) have distinct morphologies that are shared by all taxa, whereas the subsequent, more posterior vertebrae show significant disparity between species. The phenotypic trajectory analysis revealed that all taxa share a common pattern and amount of shape change along the trunk region. Altogether, our results support the hypothesis of a conserved anterior-posterior developmental patterning which can be associated with different functional demands, reflecting (sub)species' and, possibly, regional ecological divergences within species.
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Affiliation(s)
| | | | - Maja Ajduković
- Department of Evolutionary BiologyInstitute for Biological Research “Siniša Stanković”National Institute of Republic of SerbiaUniversity of BelgradeBelgradeSerbia
| | - Ana Ivanović
- Faculty of BiologyUniversity of BelgradeBelgradeSerbia
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25
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Brocklehurst N, Ford DP, Benson RBJ. Early origins of divergent patterns of morphological evolution on the mammal and reptile stem-lineages. Syst Biol 2022; 71:1195-1209. [PMID: 35274702 PMCID: PMC9366456 DOI: 10.1093/sysbio/syac020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/09/2022] [Accepted: 03/05/2022] [Indexed: 11/28/2022] Open
Abstract
The origin of amniotes 320 million years ago signaled independence from water in vertebrates and was closely followed by divergences within the mammal and reptile stem lineages (Synapsida and Reptilia). Early members of both groups had highly similar morphologies, being superficially “lizard-like” forms with many plesiomorphies. However, the extent to which they might have exhibited divergent patterns of evolutionary change, with the potential to explain the large biological differences between their living members, is unresolved. We use a new, comprehensive phylogenetic dataset to quantify variation in rates and constraints of morphological evolution among Carboniferous–early Permian amniotes. We find evidence for an early burst of evolutionary rates, resulting in the early origins of morphologically distinctive subgroups that mostly persisted through the Cisuralian. Rates declined substantially through time, especially in reptiles. Early reptile evolution was also more constrained compared with early synapsids, exploring a more limited character state space. Postcranial innovation in particular was important in early synapsids, potentially related to their early origins of large body size. In contrast, early reptiles predominantly varied the temporal region, suggesting disparity in skull and jaw kinematics, and foreshadowing the variability of cranial biomechanics seen in reptiles today. Our results demonstrate that synapsids and reptiles underwent an early divergence of macroevolutionary patterns. This laid the foundation for subsequent evolutionary events and may be critical in understanding the substantial differences between mammals and reptiles today. Potential explanations include an early divergence of developmental processes or of ecological factors, warranting cross-disciplinary investigation. [Amniote; body size; constraint; phylogeny; rate.]
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Affiliation(s)
- Neil Brocklehurst
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, UK
| | - David P Ford
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, UK
| | - Roger B J Benson
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, UK
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26
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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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27
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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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28
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Belyaev RI, Kuznetsov AN, Prilepskaya NE. How the even-toed ungulate vertebral column works: Comparison of intervertebral mobility in 33 genera. J Anat 2021; 239:1370-1399. [PMID: 34365661 PMCID: PMC8602029 DOI: 10.1111/joa.13521] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 07/03/2021] [Accepted: 07/07/2021] [Indexed: 11/28/2022] Open
Abstract
In this study, we used a previously developed osteometry-based method to calculate available range of motion in presacral intervertebral joints in artiodactyls. We have quantified all three directions of intervertebral mobility: sagittal bending (SB), lateral bending (LB), and axial rotation (AR). This research covers 10 extant families of artiodactyls from 33 genera and 39 species. The cervical region in artiodactyls is the most mobile region of the presacral vertebral column in SB and LB. Mobility is unevenly distributed throughout the joints of the neck. The posterior neck joints (C4-C7) are significantly more mobile (on average by 2.5-3.5°) to anterior joints (C2-C4) and to the neck-thorax joint (C7-T1) in SB and LB. An increase in the relative length of the cervical region in artiodactyls is accompanied by an increase in the bending amplitudes (SB: Pearson r = 0.781; LB: r = 0.884). Animals with the most mobile necks (representative of Giraffidae and Camelidae) are 2-3 times more mobile in SB and LB compared to species with the least mobile necks. The thoracic region in artiodactyls, as in other mammals, is characterized by the greatest amplitudes of AR due to the tangential orientation of the zygapophyseal articular facets. The lowest AR values in the thoracic region are typical for the heaviest artiodactyls-Hippopotamidae. The highest AR values are typical for such agile runners as cervids, musk deer, pronghorn, as well as large and small antelopes. SB mobility in the posterior part of the thoracic region can be used by artiodactyls during galloping. The highest values of SB aROM in the posterior part of the thoracic region are typical for small animals with high SB mobility in the lumbar region. The lumbar region in mammals is adapted for efficient SB. Both the cumulative and average SB values in the lumbar region showed correspondence to the running type employed by an artiodactyl. The greatest SB amplitudes in the lumbar region are typical for small animals, which use saltatorial and saltatorial-cursorial running. An increase in body size also corresponds to a decrease in lumbar SB amplitudes. The lowest SB amplitudes are typical for species using the so-called mediportal running. Adaptation to endurance galloping in open landscapes is accompanied by a decrease in lumbar SB amplitudes in artiodactyls. The consistency of the approach used and the wide coverage of the studied species make it possible to significantly expand and generalize the knowledge of the biomechanics of the vertebral column in artiodactyls.
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Affiliation(s)
- Ruslan I. Belyaev
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesMoscowRussian Federation
| | | | - Natalya E. Prilepskaya
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesMoscowRussian Federation
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29
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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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30
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Jones KE, Brocklehurst RJ, Pierce SE. AutoBend: An Automated Approach for Estimating Intervertebral Joint Function from Bone-Only Digital Models. Integr Org Biol 2021; 3:obab026. [PMID: 34661062 PMCID: PMC8514422 DOI: 10.1093/iob/obab026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/06/2021] [Accepted: 09/08/2021] [Indexed: 11/16/2022] Open
Abstract
Deciphering the biological function of rare or extinct species is key to understanding evolutionary patterns across the tree of life. While soft tissues are vital determinants of joint function, they are rarely available for study. Therefore, extracting functional signals from skeletons, which are more widely available via museum collections, has become a priority for the field of comparative biomechanics. While most work has focused on the limb skeleton, the axial skeleton plays a critical role in body support, respiration, and locomotion, and is therefore of central importance for understanding broad-scale functional evolution. Here, we describe and experimentally validate AutoBend, an automated approach to estimating intervertebral joint function from bony vertebral columns. AutoBend calculates osteological range of motion (oROM) by automatically manipulating digitally articulated vertebrae while incorporating multiple constraints on motion, including both bony intersection and the role of soft tissues by restricting excessive strain in both centrum and zygapophyseal articulations. Using AutoBend and biomechanical data from cadaveric experiments on cats and tegus, we validate important modeling parameters required for oROM estimation, including the degree of zygapophyseal disarticulation, and the location of the center of rotation. Based on our validation, we apply a model with the center of rotation located within the vertebral disk, no joint translation, around 50% strain permitted in both zygapophyses and disks, and a small amount of vertebral intersection permitted. Our approach successfully reconstructs magnitudes and craniocaudal patterns of motion obtained from ex vivo experiments, supporting its potential utility. It also performs better than more typical methods that rely solely on bony intersection, emphasizing the importance of accounting for soft tissues. We estimated the sensitivity of the analyses to vertebral model construction by varying joint spacing, degree of overlap, and the impact of landmark placement. The effect of these factors was small relative to biological variation craniocaudally and between bending directions. We also present a new approach for estimating joint stiffness directly from oROM and morphometric measurements that can successfully reconstruct the craniocaudal patterns, but not magnitudes, derived from experimental data. Together, this work represents a significant step forward for understanding vertebral function in difficult-to-study (e.g., rare or extinct) species, paving the way for a broader understanding of patterns of functional evolution in the axial skeleton.
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Affiliation(s)
- K E Jones
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - R J Brocklehurst
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - S 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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31
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Wimberly AN, Slater GJ, Granatosky MC. Evolutionary history of quadrupedal walking gaits shows mammalian release from locomotor constraint. Proc Biol Sci 2021; 288:20210937. [PMID: 34403640 PMCID: PMC8370795 DOI: 10.1098/rspb.2021.0937] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/22/2021] [Indexed: 02/04/2023] Open
Abstract
Vertebrates employ an impressive range of strategies for coordinating their limb movements while walking. Although this gait variation has been quantified and hypotheses for its origins tested in select tetrapod lineages, a comprehensive understanding of gait evolution in a macroevolutionary context is currently lacking. We used freely available internet videos to nearly double the number of species with quantitative gait data, and used phylogenetic comparative methods to test key hypotheses about symmetrical gait origin and evolution. We find strong support for an ancestral lateral-sequence diagonal-couplet gait in quadrupedal gnathostomes, and this mode is remarkably conserved throughout tetrapod phylogeny. Evolutionary rate analyses show that mammals overcame this ancestral constraint, resulting in a greater range of phase values than any other tetrapod lineage. Diagonal-sequence diagonal-couplet gaits are significantly associated with arboreality in mammals, though this relationship is not recovered for other tetrapod lineages. Notably, the lateral-sequence lateral-couplet gait, unique to mammals among extant tetrapods, is not associated with any traditional explanations. The complex drivers of gait diversification in mammals remain unclear, but our analyses suggest that their success was due, in part, to release from a locomotor constraint that has probably persisted in other extant tetrapod lineages for over 375 Myr.
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Affiliation(s)
- Alexa N. Wimberly
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| | - Graham J. Slater
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA
| | - Michael C. Granatosky
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
- Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, NY 11568, USA
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32
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Smith SM, Stayton CT, Angielczyk KD. How many trees to see the forest? Assessing the effects of morphospace coverage and sample size in performance surface analysis. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13624] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephanie M. Smith
- Negaunee Integrative Research Center Field Museum of Natural History Chicago IL USA
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33
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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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34
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Weisbecker V. Evolution: Bend it like basal synapsids. Curr Biol 2021; 31:R437-R439. [PMID: 33974869 DOI: 10.1016/j.cub.2021.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mammals can amplify their strides through unique up-and-down spinal movements. This ability was long considered to have evolved from lizard-like ancestors with spines moving sideways. A new study now suggests that, instead, it derived from an extinct, previously unknown spinal form.
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Affiliation(s)
- Vera Weisbecker
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia.
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35
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Lungmus JK, Angielczyk KD. Phylogeny, function and ecology in the deep evolutionary history of the mammalian forelimb. Proc Biol Sci 2021; 288:20210494. [PMID: 33878918 PMCID: PMC8059613 DOI: 10.1098/rspb.2021.0494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 03/29/2021] [Indexed: 11/12/2022] Open
Abstract
Mammals are the only living members of the larger clade Synapsida, which has a fossil record spanning 320 Ma. Despite the fact that much of the ecological diversity of mammals has been considered in the light of limb morphology, the ecological comparability of mammals to their fossil forerunners has not been critically assessed. Because of the wide use of limb morphology in testing ecomorphological hypothesis about extinct tetrapods, we sought: (i) to estimate when in synapsid history, modern mammals become analogues for predicting fossil ecologies; (ii) to document examples of ecomorphological convergence; and (iii) to compare the functional solutions of distinct synapsid radiations. We quantitatively compared the forelimb shapes of the multiple fossil synapsid radiations to a broad sample of extant Mammalia representing a variety of divergent locomotor ecologies. Our results indicate that each synapsid radiation explored different areas of morphospace and arrived at functional solutions that reflected their distinctive ancestral morphologies. This work counters the narrative of non-mammalian synapsid forelimb evolution as a linear progression towards more mammalian morphologies. Instead, a disparate array of early-evolving shapes subsequently contracted towards more mammal-like forms.
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Affiliation(s)
- Jacqueline K. Lungmus
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605-2496, USA
| | - Kenneth D. Angielczyk
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605-2496, USA
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36
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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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Jones KE, Dickson BV, Angielczyk KD, Pierce SE. Adaptive landscapes challenge the "lateral-to-sagittal" paradigm for mammalian vertebral evolution. Curr Biol 2021; 31:1883-1892.e7. [PMID: 33657406 DOI: 10.1016/j.cub.2021.02.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/08/2021] [Accepted: 02/03/2021] [Indexed: 11/28/2022]
Abstract
The evolution of mammals from their extinct forerunners, the non-mammalian synapsids, is one of the most iconic locomotor transitions in the vertebrate fossil record. In the limb skeleton, the synapsid-mammal transition is traditionally characterized by a shift from a sprawling limb posture, resembling that of extant reptiles and amphibians, to more adducted limbs, as seen in modern-day mammals. Based on proposed postural similarities between early synapsids and extant reptiles, this change is thought to be accompanied by a shift from ancestral reptile-like lateral bending to mammal-like sagittal bending of the vertebral column. To test this "lateral-to-sagittal" evolutionary paradigm, we used combinatorial optimization to produce functionally informed adaptive landscapes and determined the functional trade-offs associated with evolutionary changes in vertebral morphology. We show that the synapsid adaptive landscape is different from both extant reptiles and mammals, casting doubt on the reptilian model for early synapsid axial function, or indeed for the ancestral condition of amniotes more broadly. Further, the synapsid-mammal transition is characterized by not only increasing sagittal bending in the posterior column but also high stiffness and increasing axial twisting in the anterior column. Therefore, we refute the simplistic lateral-to-sagittal hypothesis and instead suggest the synapsid-mammal locomotor transition involved a more complex suite of functional changes linked to increasing regionalization of the backbone. These results highlight the importance of fossil taxa for understanding major evolutionary transitions.
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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; Department of Earth and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, UK.
| | - Blake V Dickson
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA; Department of Evolutionary Anthropology, Duke University, Biological Sciences Building, 130 Science Drive, Durham, NC 27708, USA
| | - Kenneth D Angielczyk
- Negaunee 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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Müller MA, Merten LJF, Böhmer C, Nyakatura JA. Pushing the boundary? Testing the "functional elongation hypothesis" of the giraffe's neck. Evolution 2021; 75:641-655. [PMID: 33443310 DOI: 10.1111/evo.14171] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 11/28/2022]
Abstract
Although giraffes maintain the usual mammalian cervical number of seven vertebrae, their first thoracic vertebra (T1) exhibits aberrant anatomy and has been hypothesized to functionally elongate the neck. We test this "functional elongation hypothesis" by combining phylogenetically informed analyses of neck length, three-dimensional (3D) vertebral shape, and of the functional significance of shape differences across a broad sample of ruminants and camelids. Digital bone models of the cervicothoracic transition were subjected to 3D geometric morphometric analysis revealing how the shape of the seventh cervical (C7) has converged in several long-necked species. However, we find a unique "cervicalization" of the giraffe's T1. In contrast, we demonstrate a "thoracalization" of C7 for the European bison. Other giraffids (okapi and extinct Sivatherium) did not exhibit "cervicalized" T1 morphology. Quantitative range of motion (ROM) analysis at the cervicothoracic transition in ruminants and camelids confirms the "functional elongation hypothesis" for the giraffe in terms of increased mobility, especially with regard to dorsoventral flexion/extension. Additionally, other factors related to the unique morphology of the giraffe's cervicothoracic transition such as neck posture and intervertebral stability are discussed and should be considered in future studies of giraffe neck evolution.
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Affiliation(s)
- Marilena A Müller
- AG Vergleichende Zoologie, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Luisa J F Merten
- AG Vergleichende Zoologie, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Christine Böhmer
- UMR 7179 CNRS/MNHN, Département Adaptations du Vivant, Muséum National d'Histoire Naturelle, Paris, 75005, France.,Department für Geo- und Umweltwissenschaften und GeoBio-Center, Ludwig-Maximilians-Universität München, München, 80333, Germany
| | - John A Nyakatura
- AG Vergleichende Zoologie, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
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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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