1
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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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Shipley AE, Elsler A, Singh SA, Stubbs TL, Benton MJ. Locomotion and the early Mesozoic success of Archosauromorpha. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231495. [PMID: 38328568 PMCID: PMC10846959 DOI: 10.1098/rsos.231495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 01/10/2024] [Indexed: 02/09/2024]
Abstract
The Triassic was a time of ecological upheaval as life recovered from the Permian-Triassic mass extinction. Archosauromorphs were a key component of the recovery, diversifying substantially during the Triassic and encompassing the origins of dinosaurs, pterosaurs and crocodylomorphs. Here, we explore the evolution of locomotion in Archosauromorpha to test whether dinosaurs show any distinctive locomotory features that might explain their success. We implement geometric morphometrics on limb bone shapes and use limb ratios to calculate bipedality and cursoriality metrics. We find that the Avemetatarsalia (dinosaurs, pterosaurs and relatives) exhibit more variable limb form and limb ratios than any other group, indicating a wider range of locomotory modes. The earliest avemetatarsalians were bipedal and cursorial, and their range of form increased through the Triassic with notable diversification shifts following extinction events. This is especially true of dinosaurs, even though these changes cannot be discriminated from a stochastic process. By contrast, the Pseudosuchia (crocodilians and relatives) were more restricted in limb form and locomotor mode with disparity decreasing through time, suggesting more limited locomotor adaptation and vulnerability to extinction. Perhaps the greater locomotor plasticity of dinosaurs gave them a competitive advantage in the changing climates of the Late Triassic.
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Affiliation(s)
- Amy E. Shipley
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - Armin Elsler
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
| | - Suresh A. Singh
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
| | - Thomas L. Stubbs
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
- School of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
| | - Michael J. Benton
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
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3
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Maina JN. A critical assessment of the cellular defences of the avian respiratory system: are birds in general and poultry in particular relatively more susceptible to pulmonary infections/afflictions? Biol Rev Camb Philos Soc 2023; 98:2152-2187. [PMID: 37489059 DOI: 10.1111/brv.13000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/01/2023] [Accepted: 07/07/2023] [Indexed: 07/26/2023]
Abstract
In commercial poultry farming, respiratory diseases cause high morbidities and mortalities, begetting colossal economic losses. Without empirical evidence, early observations led to the supposition that birds in general, and poultry in particular, have weak innate and adaptive pulmonary defences and are therefore highly susceptible to injury by pathogens. Recent findings have, however, shown that birds possess notably efficient pulmonary defences that include: (i) a structurally complex three-tiered airway arrangement with aerodynamically intricate air-flow dynamics that provide efficient filtration of inhaled air; (ii) a specialised airway mucosal lining that comprises air-filtering (ciliated) cells and various resident phagocytic cells such as surface and tissue macrophages, dendritic cells and lymphocytes; (iii) an exceptionally efficient mucociliary escalator system that efficiently removes trapped foreign agents; (iv) phagocytotic atrial and infundibular epithelial cells; (v) phagocytically competent surface macrophages that destroy pathogens and injurious particulates; (vi) pulmonary intravascular macrophages that protect the lung from the vascular side; and (vii) proficiently phagocytic pulmonary extravasated erythrocytes. Additionally, the avian respiratory system rapidly translocates phagocytic cells onto the respiratory surface, ostensibly from the subepithelial space and the circulatory system: the mobilised cells complement the surface macrophages in destroying foreign agents. Further studies are needed to determine whether the posited weak defence of the avian respiratory system is a global avian feature or is exclusive to poultry. This review argues that any inadequacies of pulmonary defences in poultry may have derived from exacting genetic manipulation(s) for traits such as rapid weight gain from efficient conversion of food into meat and eggs and the harsh environmental conditions and severe husbandry operations in modern poultry farming. To reduce pulmonary diseases and their severity, greater effort must be directed at establishment of optimal poultry housing conditions and use of more humane husbandry practices.
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Affiliation(s)
- John N Maina
- Department of Zoology, University of Johannesburg, Auckland Park Campus, Kingsway Avenue, Johannesburg, 2006, South Africa
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4
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Wang YY, Claessens LPAM, Sullivan C. Deep reptilian evolutionary roots of a major avian respiratory adaptation. Commun Biol 2023; 6:3. [PMID: 36650231 PMCID: PMC9845227 DOI: 10.1038/s42003-022-04301-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/25/2022] [Indexed: 01/19/2023] Open
Abstract
Vertebral ribs of the anterior thorax in extant birds bear bony prongs called uncinate processes, which improve the mechanical advantage of mm. appendicocostales to move air through the immobile lung and pneumatic air sacs. Among non-avian archosaurs, broad, cartilaginous uncinate processes are present in extant crocodylians, and likely have a ventilatory function. Preserved ossified or calcified uncinate processes are known in several non-avian dinosaurs. However, whether other fossil archosaurs possessed cartilaginous uncinate processes has been unclear. Here, we establish osteological correlates for uncinate attachment to vertebral ribs in extant archosaurs, with which we inferred the presence of uncinate processes in at least 19 fossil archosaur taxa. An ancestral state reconstruction based on the infer distribution suggests that cartilaginous uncinate processes were plesiomorphically present in Dinosauria and arguably in Archosauria, indicating that uncinate processes, and presumably their ventilatory function, have a deep evolutionary history extending back well beyond the origin of birds.
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Affiliation(s)
- Yan-yin Wang
- grid.17089.370000 0001 2190 316XDepartment of Biological Sciences, CW 405 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9 Canada
| | - Leon P. A. M. Claessens
- grid.5012.60000 0001 0481 6099Maastricht Science Programme, Faculty of Science and Engineering, Maastricht University, Maastricht, The Netherlands
| | - Corwin Sullivan
- grid.17089.370000 0001 2190 316XDepartment of Biological Sciences, CW 405 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9 Canada ,Philip J. Currie Dinosaur Museum, Wembley, AB T0H 3S0 Canada
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5
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Aureliano T, Ghilardi AM, Müller RT, Kerber L, Pretto FA, Fernandes MA, Ricardi-Branco F, Wedel MJ. The absence of an invasive air sac system in the earliest dinosaurs suggests multiple origins of vertebral pneumaticity. Sci Rep 2022; 12:20844. [PMID: 36494410 PMCID: PMC9734174 DOI: 10.1038/s41598-022-25067-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/24/2022] [Indexed: 12/13/2022] Open
Abstract
The origin of the air sac system present in birds has been an enigma for decades. Skeletal pneumaticity related to an air sac system is present in both derived non-avian dinosaurs and pterosaurs. But the question remained open whether this was a shared trait present in the common avemetatarsalian ancestor. We analyzed three taxa from the Late Triassic of South Brazil, which are some of the oldest representatives of this clade (233.23 ± 0.73 Ma), including two sauropodomorphs and one herrerasaurid. All three taxa present shallow lateral fossae in the centra of their presacral vertebrae. Foramina are present in many of the fossae but at diminutive sizes consistent with neurovascular rather than pneumatic origin. Micro-tomography reveals a chaotic architecture of dense apneumatic bone tissue in all three taxa. The early sauropodomorphs showed more complex vascularity, which possibly served as the framework for the future camerate and camellate pneumatic structures of more derived saurischians. Finally, the evidence of the absence of postcranial skeletal pneumaticity in the oldest dinosaurs contradicts the homology hypothesis for an invasive diverticula system and suggests that this trait evolved independently at least 3 times in pterosaurs, theropods, and sauropodomorphs.
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Affiliation(s)
- Tito Aureliano
- grid.411087.b0000 0001 0723 2494Institute of Geosciences, University of Campinas (Unicamp), Campinas, Brazil ,grid.411233.60000 0000 9687 399XDiversity, Ichnology and Osteohistology Laboratory (DINOlab), Department of Geology, Federal University of Rio Grande Do Norte (URFN), Natal, Brazil ,grid.411247.50000 0001 2163 588XLaboratório de Paleoecologia E Paleoicnologia (LPP), Departamento de Ecologia E Biologia Evolutiva (DEBE), Federal University of São Carlos (UFSCar), São Carlos, Brazil
| | - Aline M. Ghilardi
- grid.411233.60000 0000 9687 399XDiversity, Ichnology and Osteohistology Laboratory (DINOlab), Department of Geology, Federal University of Rio Grande Do Norte (URFN), Natal, Brazil
| | - Rodrigo T. Müller
- grid.411239.c0000 0001 2284 6531Centro de Apoio À Pesquisa Paleontológica da Quarta Colônia (CAPPA), Federal University of Santa Maria (CAPPA/UFSM), São João Do Polêsine, Brazil ,grid.411239.c0000 0001 2284 6531Programa de Pós-Graduação Em Biodiversidade Animal, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Leonardo Kerber
- grid.411239.c0000 0001 2284 6531Centro de Apoio À Pesquisa Paleontológica da Quarta Colônia (CAPPA), Federal University of Santa Maria (CAPPA/UFSM), São João Do Polêsine, Brazil ,grid.411239.c0000 0001 2284 6531Programa de Pós-Graduação Em Biodiversidade Animal, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Flávio A. Pretto
- grid.411239.c0000 0001 2284 6531Centro de Apoio À Pesquisa Paleontológica da Quarta Colônia (CAPPA), Federal University of Santa Maria (CAPPA/UFSM), São João Do Polêsine, Brazil ,grid.411239.c0000 0001 2284 6531Programa de Pós-Graduação Em Biodiversidade Animal, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Marcelo A. Fernandes
- grid.411247.50000 0001 2163 588XLaboratório de Paleoecologia E Paleoicnologia (LPP), Departamento de Ecologia E Biologia Evolutiva (DEBE), Federal University of São Carlos (UFSCar), São Carlos, Brazil
| | - Fresia Ricardi-Branco
- grid.411087.b0000 0001 0723 2494Institute of Geosciences, University of Campinas (Unicamp), Campinas, Brazil
| | - Mathew J. Wedel
- grid.268203.d0000 0004 0455 5679College of Osteopathic Medicine of the Pacific and College of Podiatric Medicine, Western University of Health Sciences, Pomona, USA
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6
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Cuff AR, Demuth OE, Michel K, Otero A, Pintore R, Polet DT, Wiseman ALA, Hutchinson JR. Walking-and Running and Jumping-with Dinosaurs and Their Cousins, Viewed Through the Lens of Evolutionary Biomechanics. Integr Comp Biol 2022; 62:icac049. [PMID: 35595475 DOI: 10.1093/icb/icac049] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Archosauria diversified throughout the Triassic Period before experiencing two mass extinctions near its end ∼201 Mya, leaving only the crocodile-lineage (Crocodylomorpha) and bird-lineage (Dinosauria) as survivors; along with the pterosaurian flying reptiles. About 50 years ago, the "locomotor superiority hypothesis" (LSH) proposed that dinosaurs ultimately dominated by the Early Jurassic Period because their locomotion was superior to other archosaurs'. This idea has been debated continuously since, with taxonomic and morphological analyses suggesting dinosaurs were "lucky" rather than surviving due to being biologically superior. However, the LSH has never been tested biomechanically. Here we present integration of experimental data from locomotion in extant archosaurs with inverse and predictive simulations of the same behaviours using musculoskeletal models, showing that we can reliably predict how extant archosaurs walk, run and jump. These simulations have been guiding predictive simulations of extinct archosaurs to estimate how they moved, and we show our progress in that endeavour. The musculoskeletal models used in these simulations can also be used for simpler analyses of form and function such as muscle moment arms, which inform us about more basic biomechanical similarities and differences between archosaurs. Placing all these data into an evolutionary and biomechanical context, we take a fresh look at the LSH as part of a critical review of competing hypotheses for why dinosaurs (and a few other archosaur clades) survived the Late Triassic extinctions. Early dinosaurs had some quantifiable differences in locomotor function and performance vs. some other archosaurs, but other derived dinosaurian features (e.g., metabolic or growth rates, ventilatory abilities) are not necessarily mutually exclusive from the LSH; or maybe even an opportunistic replacement hypothesis; in explaining dinosaurs' success.
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Affiliation(s)
- A R Cuff
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, United Kingdom
- Human Anatomy Resource Centre, University of Liverpool, Liverpool, United Kingdom
| | - O E Demuth
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, United Kingdom
- Department of Earth Sciences, University of Cambridge, United Kingdom
| | - K Michel
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, United Kingdom
| | - A Otero
- CONICET - División Paleontología de Vertebrados, Facultad de Ciencias Naturales y Museo, Anexo Laboratorios, La Plata, Argentina
| | - R Pintore
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, United Kingdom
- Mécanismes adaptatifs et évolution (MECADEV) / UMR 7179, CNRS / Muséum National d'Histoire Naturelle, France
| | - D T Polet
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, United Kingdom
| | - A L A Wiseman
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, United Kingdom
- McDonald Institute for Archaeological Research, University of Cambridge, United Kingdom
| | - J R Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, United Kingdom
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7
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Schachner ER, Diaz RE, Coke R, Echols S, Osborn ML, Hedrick BP. Architecture of the bronchial tree in Cuvier's dwarf caiman (Paleosuchus palpebrosus). Anat Rec (Hoboken) 2022; 305:3037-3054. [PMID: 35377558 DOI: 10.1002/ar.24919] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/25/2022] [Accepted: 03/09/2022] [Indexed: 01/16/2023]
Abstract
We imaged the lungs of five Cuvier's dwarf caiman (Paleosuchus palpebrosus) via computed tomography (CT) and micro-computed tomography (μCT) and compared these data to the lungs of the American alligator (Alligator mississippiensis). These data demonstrate anatomical commonalities between the lungs of P. palpebrosus and A. mississippiensis, and a few notable differences. The structural similarities are (a) a proximally narrow, distally widened, hook-shaped primary bronchus; (b) a cervical ventral bronchus that branches of the primary bronchus and immediately makes a hairpin turn toward the apex of the lung; (c) a sequential series of dorsobronchi arising from the primary bronchus caudal to the cervical ventral bronchus; (d) intraspecifically highly variable medial sequence of secondary airways; (e) sac-like laterobronchi; and (f) grossly dead-ended caudal group bronchi in the caudal and ventral aspects of the lung. The primary differences between the two taxa are in the overall number of large bronchi (fewer in P. palpebrosus), and the number of branches that contribute to the cardiac regions. Imaging data of both a live and deceased specimen under varying states (postprandial, fasting, total lung capacity, open to atmosphere) indicate that the caudal margin and position of the lungs shift craniocaudally relative to the vertebral column. These imaging data suggest that the smooth thoracic ceiling may be correlated to visceral movement during ventilation, but this hypothesis warrants validation. These results provide the scaffolding for future comparisons between crocodilians, for generating preliminary reconstructions of the ancestral crocodilian bronchial tree, and establishing new hypotheses of bronchial homology across Archosauria.
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Affiliation(s)
- Emma R Schachner
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Raul E Diaz
- Department of Biological Sciences, California State University Los Angeles, Los Angeles, California, USA
| | - Rob Coke
- San Antonio Zoo, San Antonio, Texas, USA
| | - Scott Echols
- The Medical Center for Birds, Oakley, California, USA
| | - Michelle L Osborn
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Brandon P Hedrick
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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8
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Radermacher VJ, Fernandez V, Schachner ER, Butler RJ, Bordy EM, Naylor Hudgins M, de Klerk WJ, Chapelle KE, Choiniere JN. A new Heterodontosaurus specimen elucidates the unique ventilatory macroevolution of ornithischian dinosaurs. eLife 2021; 10:66036. [PMID: 34225841 PMCID: PMC8260226 DOI: 10.7554/elife.66036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 05/24/2021] [Indexed: 01/21/2023] Open
Abstract
Ornithischian dinosaurs were ecologically prominent herbivores of the Mesozoic Era that achieved a global distribution by the onset of the Cretaceous. The ornithischian body plan is aberrant relative to other ornithodiran clades, and crucial details of their early evolution remain obscure. We present a new, fully articulated skeleton of the early branching ornithischian Heterodontosaurus tucki. Phase-contrast enhanced synchrotron data of this new specimen reveal a suite of novel postcranial features unknown in any other ornithischian, with implications for the early evolution of the group. These features include a large, anteriorly projecting sternum; bizarre, paddle-shaped sternal ribs; and a full gastral basket – the first recovered in Ornithischia. These unusual anatomical traits provide key information on the evolution of the ornithischian body plan and suggest functional shifts in the ventilatory apparatus occurred close to the base of the clade. We complement these anatomical data with a quantitative analysis of ornithischian pelvic architecture, which allows us to make a specific, stepwise hypothesis for their ventilatory evolution. The fossilised skeletons of long extinct dinosaurs are more than just stones. By comparing these remains to their living relatives such as birds and crocodiles, palaeontologists can reveal how dinosaurs grew, moved, ate and socialised. Previous research indicates that dinosaurs were likely warm-blooded and also more active than modern reptiles. This means they would have required breathing mechanisms capable of supplying enough oxygen to allow these elevated activity levels. So far, much of our insight into dinosaur breathing biology has been biased towards dinosaur species more closely related to modern birds, such as Tyrannosaurus rex, as well as the long-necked sauropods. The group of herbivorous dinosaurs known as ornithischians, which include animals with head ornamentation, spikes and heavy body armour, like that found in Triceratops and Stegosaurus, have often been overlooked. As a result, there are still significant gaps in ornithischian biology, especially in understanding how they breathed. Radermacher et al. used high-powered X-rays to study a new specimen of the most primitive ornithischian dinosaur, Heterodontosaurus tucki, and discovered that this South African dinosaur has bones researchers did not know existed in this species. These include bones that are part of the breathing system of extant reptiles and birds, including toothpick-shaped bones called gastralia, paired sternal bones and sternal ribs shaped like tennis rackets. Together, these new pieces of anatomy form a complicated chest skeleton with a large range of motion that would have allowed the body to expand during breathing cycles. But this increased motion of the chest was only possible in more primitive ornithischians. More advanced species lost much of the anatomy that made this motion possible. Radermacher et al. show that while the chest was simpler in advanced species, their pelvis was more specialised and likely played a role in breathing as it does in modern crocodiles. This new discovery could inform the work of biologists who study the respiratory diversity of both living and extinct species. Differences in breathing strategies might be one of the underlying reasons that some lineages of animals go extinct. It could explain why some species do better than others under stressful conditions, like when the climate is warmer or has less oxygen.
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Affiliation(s)
- Viktor J Radermacher
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, United States
| | - Vincent Fernandez
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,European Synchrotron Radiation Facility, Grenoble, France.,Natural History Museum, Imaging and Analysis Centre, London, United Kingdom
| | - Emma R Schachner
- Department of Cell Biology & Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, United States
| | - Richard J Butler
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Emese M Bordy
- Department of Geological Sciences, University of Cape Town, Cape Town, South Africa
| | | | - William J de Klerk
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Earth Sciences, Albany Museum, Grahamstown, South Africa
| | - Kimberley Ej Chapelle
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Division of Paleontology, American Museum of Natural History, New York, United States
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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9
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Cramberg M, Greer S, Young BA. The functional morphology of the postpulmonary septum of the American alligator (Alligator mississippiensis). Anat Rec (Hoboken) 2021; 305:3055-3074. [PMID: 34128345 DOI: 10.1002/ar.24692] [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: 12/10/2020] [Revised: 02/22/2021] [Accepted: 04/03/2021] [Indexed: 11/08/2022]
Abstract
The American alligator (Alligator mississippiensis) has a postpulmonary septum (PPS) that partitions the intracoelomic cavity. The PPS adheres to the capsule of the liver caudally and to the visceral pleura of the lung cranially; the ventrolateral portions of the PPS are invested with smooth muscle, the remainder is tendinous. Differential pressure transducers were used to record the intrathoracic (ITP) and intraperitoneal (IPP) pressures, and determine the transdiaphragmatic pressure (TDP). Each ventilatory pulse resulted in a pulse in ITP and a significantly lower pulse in IPP; meaning that a TDP was established, and that the pleural and peritoneal cavities were functionally isolated. The anesthetized alligators were tilted 30° head-up or head-down in order to displace the liver. Head-up rotations caused a significant increase in IPP, and a significant decrease in ITP (which became negative); head-down rotations produced the opposite effect. During these rotations, the PPS maintained opposite pressures (positive or negative) in the pleural and peritoneal cavities, and established TDPs greater than have been reported for some mammals. Two types of "breaths" were recorded during these experiments. The first was interpreted as a contraction of the diaphragmaticus muscle, which displaces the liver caudally; these breaths had the same effect as the head-up rotations. The second type of breath was interpreted as constriction of the thoracic and abdominal body walls; this type of breath produced pronounced, long-duration, roughly parallel, increases in ITP and IPP. The smooth muscle within the PPS is suggestive of higher-order adjustment or tuning of the PPS's tensile state.
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Affiliation(s)
- Michael Cramberg
- Department of Anatomy, Kirksville College of Osteopathic Medicine, AT Still University, Kirksville, Missouri, USA
| | - Skye Greer
- Department of Anatomy, Kirksville College of Osteopathic Medicine, AT Still University, Kirksville, Missouri, USA
| | - Bruce A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, AT Still University, Kirksville, Missouri, USA
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10
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Lawson AB, Hedrick BP, Echols S, Schachner ER. Anatomy, variation, and asymmetry of the bronchial tree in the African grey parrot (Psittacus erithacus). J Morphol 2021; 282:701-719. [PMID: 33629391 DOI: 10.1002/jmor.21340] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 12/16/2022]
Abstract
The avian bronchial tree has a unique and elaborate architecture for the maintenance of unidirectional airflow. Gross descriptions of this bronchial arrangement have traditionally relied upon dissection and casts of the negative (air-filled) spaces. In this study, the bronchial trees of five deceased African grey parrots (Psittacus erithacus) were segmented from micro-computed tomography (μCT) scans into three-dimensional (3D) surface models, and then compared. Select metrics of the primary bronchi and major secondary branches in the μCT scans of 11 specimens were taken to assess left-right asymmetry and quantify gross lung structure. Analysis of the 3D surface models demonstrates variation in the number and distribution of secondary bronchi with consistent direct connections to specific respiratory air sacs. A single model of the parabronchi further reveals indirect connections to all but two of the nine total air sacs. Statistical analysis of the metrics show significant left-right asymmetry between the primary bronchi and the origins of the first four secondary bronchi (the ventrobronchi), consistently greater mean values for all right primary bronchus length metrics, and relatively high coefficients of variation for cross-sectional area metrics of the primary bronchi and secondary bronchi ostia. These findings suggest that the lengths of the primary bronchi distal to the ventrobronchi do not preserve lung symmetry, and that aerodynamic valving can functionally accommodate a wide range of bronchial proportions.
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Affiliation(s)
- Adam B Lawson
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Brandon P Hedrick
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Scott Echols
- The Medical Center for Birds, Oakley, California, USA
| | - Emma R Schachner
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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11
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Lovelace DM, Hartman SA, Mathewson PD, Linzmeier BJ, Porter WP. Modeling Dragons: Using linked mechanistic physiological and microclimate models to explore environmental, physiological, and morphological constraints on the early evolution of dinosaurs. PLoS One 2020; 15:e0223872. [PMID: 32469936 PMCID: PMC7259893 DOI: 10.1371/journal.pone.0223872] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 05/12/2020] [Indexed: 11/29/2022] Open
Abstract
We employed the widely-tested biophysiological modeling software, Niche Mapper™ to investigate the metabolic function of the Late Triassic dinosaurs Plateosaurus and Coelophysis during global greenhouse conditions. We tested a variety of assumptions about resting metabolic rate, each evaluated within six microclimate models that bound paleoenvironmental conditions at 12° N paleolatitude, as determined by sedimentological and isotopic proxies for climate within the Chinle Formation of the southwestern United States. Sensitivity testing of metabolic variables and simulated “metabolic chamber” analyses support elevated “ratite-like” metabolic rates and intermediate “monotreme-like” core temperature ranges in these species of early saurischian dinosaur. Our results suggest small theropods may have needed partial to full epidermal insulation in temperate environments, while fully grown prosauropods would have likely been heat stressed in open, hot environments and should have been restricted to cooler microclimates such as dense forests or higher latitudes and elevations. This is in agreement with the Late Triassic fossil record and may have contributed to the latitudinal gap in the Triassic prosauropod record.
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Affiliation(s)
- David M. Lovelace
- University of Wisconsin Geology Museum, Department of Geosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (DL); (WP)
| | - Scott A. Hartman
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Paul D. Mathewson
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Benjamin J. Linzmeier
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Warren P. Porter
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (DL); (WP)
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12
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Gardner JD, Laurin M, Organ CL. The relationship between genome size and metabolic rate in extant vertebrates. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190146. [PMID: 31928192 PMCID: PMC7017434 DOI: 10.1098/rstb.2019.0146] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2019] [Indexed: 12/13/2022] Open
Abstract
Genome size has long been hypothesized to affect the metabolic rate in various groups of animals. The mechanism behind this proposed association is the nucleotypic effect, in which large nucleus and cell sizes influence cellular metabolism through surface area-to-volume ratios. Here, we provide a review of the recent literature on the relationship between genome size and metabolic rate. We also conduct an analysis using phylogenetic comparative methods and a large sample of extant vertebrates. We find no evidence that the effect of genome size improves upon models in explaining metabolic rate variation. Not surprisingly, our results show a strong positive relationship between metabolic rate and body mass, as well as a substantial difference in metabolic rate between endothermic and ectothermic vertebrates, controlling for body mass. The presence of endothermy can also explain elevated rate shifts in metabolic rate whereas genome size cannot. We further find no evidence for a punctuated model of evolution for metabolic rate. Our results do not rule out the possibility that genome size affects cellular physiology in some tissues, but they are consistent with previous research suggesting little support for a direct functional connection between genome size and basal metabolic rate in extant vertebrates. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Jacob D. Gardner
- Department of Earth Sciences, Montana State University, Bozeman, MT 59717, USA
| | - Michel Laurin
- Centre de Recherches sur la Paléobiologie et les Paléoenvironnements (CR2P), Centre National de la Recherche Scientifique (CNRS)/Muséum National d'Histoire Naturelle (MNHN)/Sorbonne Université, Paris, France
| | - Chris L. Organ
- Department of Earth Sciences, Montana State University, Bozeman, MT 59717, USA
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Legendre LJ, Davesne D. The evolution of mechanisms involved in vertebrate endothermy. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190136. [PMID: 31928191 DOI: 10.1098/rstb.2019.0136] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Endothermy, i.e. the endogenous production of metabolic heat, has evolved multiple times among vertebrates, and several strategies of heat production have been studied extensively by physiologists over the course of the twentieth century. The independent acquisition of endothermy by mammals and birds has been the subject of many hypotheses regarding their origin and associated evolutionary constraints. Many groups of vertebrates, however, are thought to possess other mechanisms of heat production, and alternative ways to regulate thermogenesis that are not always considered in the palaeontological literature. Here, we perform a review of the mechanisms involved in heat production, with a focus on cellular and molecular mechanisms, in a phylogenetic context encompassing the entire vertebrate diversity. We show that endothermy in mammals and birds is not as well defined as commonly assumed by evolutionary biologists and consists of a vast array of physiological strategies, many of which are currently unknown. We also describe strategies found in other vertebrates, which may not always be considered endothermy, but nonetheless correspond to a process of active thermogenesis. We conclude that endothermy is a highly plastic character in vertebrates and provides a guideline on terminology and occurrences of the different types of heat production in vertebrate evolution. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Lucas J Legendre
- Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
| | - Donald Davesne
- Department of Earth Sciences, University of Oxford, Oxford, UK
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14
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Bal NC, Periasamy M. Uncoupling of sarcoendoplasmic reticulum calcium ATPase pump activity by sarcolipin as the basis for muscle non-shivering thermogenesis. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190135. [PMID: 31928193 DOI: 10.1098/rstb.2019.0135] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Thermogenesis in endotherms relies on both shivering and non-shivering thermogenesis (NST). The role of brown adipose tissue (BAT) in NST is well recognized, but the role of muscle-based NST has been contested. However, recent studies have provided substantial evidence for the importance of muscle-based NST in mammals. This review focuses primarily on the role of sarcoplasmic reticulum (SR) Ca2+-cycling in muscle NST; specifically, it will discuss recent data showing how uncoupling of sarcoendoplasmic reticulum calcium ATPase (SERCA) (inhibition of Ca2+ transport but not ATP hydrolysis) by sarcolipin (SLN) results in futile SERCA pump activity, increased ATP hydrolysis and heat production contributing to muscle NST. It will also critically examine how activation of muscle NST can be an important factor in regulating metabolic rate and whole-body energy homeostasis. In this regard, SLN has emerged as a powerful signalling molecule to promote mitochondrial biogenesis and oxidative metabolism in muscle. Furthermore, we will discuss the functional interplay between BAT and muscle, especially with respect to how reduced BAT function in mammals could be compensated by muscle-based NST. Based on the existing data, we argue that SLN-mediated thermogenesis is an integral part of muscle NST and that muscle NST potentially contributed to the evolution of endothermy within the vertebrate clade. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Naresh C Bal
- KIIT School of Biotechnology, KIIT University, Bhubaneswar, Odisha 751021, India
| | - Muthu Periasamy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
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Abstract
Physiology is a functional branch of the biological sciences, searching for general rules by which explanatory hypotheses are tested using experimental procedures, whereas palaeontology is a historical science dealing with the study of unique events where conclusions are drawn from congruence among independent lines of evidence. Vertebrate palaeophysiology bridges these disciplines by using experimental data obtained from extant organisms to infer physiological traits of extinct ones and to reconstruct how they evolved. The goal of this theme issue is to understand functional innovations imprinted on modern vertebrate clades, and how to infer (or 'retrodict') physiological capacities in their ancient relatives a posteriori. As such, the present collection of papers deals with different aspects of a rapidly growing field to understand innovations in: phospho-calcic metabolism, acid-base homeostasis, thermometabolism, respiratory physiology, skeletal growth, palaeopathophysiology, genome size and metabolic rate, and it concludes with a historical perspective. Sometimes, the two components (physiological mechanism and palaeobiological inference) are proposed in separate papers. Other times, the two components are integrated in a single paper. In all cases, the approach was comparative, framed in a phylogenetic context, and included rigorous statistical methods that account for evolutionary patterns and processes. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Jorge Cubo
- Sorbonne Université, MNHN, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), 4 Place Jussieu, 75005 Paris, France
| | - Adam K Huttenlocker
- Department of Integrative Anatomical Sciences, University of Southern California, Los Angeles, CA, USA
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