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Cubo J, Sena MVA, Pellarin R, Faure-Brac MG, Aubier P, Cheyron C, Jouve S, Allain R, Jalil NE. Integrative paleophysiology of the metriorhynchoid Pelagosaurus typus (Pseudosuchia, Thalattosuchia). Anat Rec (Hoboken) 2024. [PMID: 39180142 DOI: 10.1002/ar.25548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 08/26/2024]
Abstract
Paleophysiology is an emergent discipline. Organismic (integrative) approaches seem more appropriate than studies focusing on the variation of specific features because traits are tightly related in actual organisms. Here, we used such an organismic approach (including lifestyle, thermometabolism, and hunting behavior) to understand the paleobiology of the lower Jurassic (Toarcian) thalattosuchian metriorhynchoid Pelagosaurus typus. First, we show that the lifestyle (aquatic, amphibious, terrestrial) has an effect on the femoral compactness profiles in amniotes. The profile of Pelagosaurus indicates that it was amphibious, with a foraging activity in shallow marine environments (as suggested by the presence of salt glands) and thermoregulatory basking behavior in land (as suggested by the presence of osteoderms with highly developed ornamentation). As for the thermometabolism, we show that the mass-independent resting metabolic rate of Pelagosaurus is relatively high compared to the sample of extant ectothermic amniotes, but analysis of vascular canal diameter and inferences of red blood cell size refute the hypothesis suggesting incipient endothermy. Finally, the foraging behavior was inferred using two proxies. Pelagosaurus had a mass-independent maximum metabolic rate and an aerobic scope higher than those measured in the almost motionless Iguana iguana, similar to those measured in the sit-and-wait predator Crocodylus porosus but lower than those quantified in the active hunter Varanus gouldii. These results suggest that Pelagosaurus may have had a hunting behavior involving a slow sustained swimming or a patient waiting in shallow waters, and may have caught preys like gharials, using fast sideways sweeping motions of the head.
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Affiliation(s)
- Jorge Cubo
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
| | - Mariana V A Sena
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
| | - Romain Pellarin
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
| | - Mathieu G Faure-Brac
- Naturhistorisk Museum, Universitetet i Oslo, Norsk Senter for Paleontologi, Oslo, Norway
| | - Paul Aubier
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
| | - Cassandra Cheyron
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
| | - Stéphane Jouve
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
| | - Ronan Allain
- Muséum National d'Histoire Naturelle, Sorbonne Université, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
| | - Nour-Eddine Jalil
- Muséum National d'Histoire Naturelle, Sorbonne Université, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), Paris, France
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de Araújo Sena MV, Cubo J. Inferring the lifestyles of extinct Crocodyliformes using osteoderm ornamentation. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2023; 110:41. [PMID: 37548714 DOI: 10.1007/s00114-023-01871-8] [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: 09/08/2022] [Revised: 07/09/2023] [Accepted: 07/20/2023] [Indexed: 08/08/2023]
Abstract
Osteoderms are bony plates formed within the dermis of diverse vertebrate groups. They are present in all crocodylomorphs but Metriorhynchidae. Most of them show typical bone ornamentation consisting of pits and ridges on their outer surface. The most widely discussed functional hypothesis suggests that the ornamentation of osteoderms influences heat exchange with the environment through the adjacent vascular network, facilitating the absorption of solar radiation. This process allows semiaquatic crocodiles to compensate for heat loss resulting from the high thermal conductivity of surrounding water. In order to test this assertion, we conducted a phylogenetic logistic regression analysis to evaluate the relationship between osteoderm relative area of pits (RAP) and lifestyle (terrestrial versus aquatic) in a sample of crocodyliforms. Our results revealed that lifestyle is significantly explained by RAP: the lower the degree of ornamentation (RAP), the higher the probability of a terrestrial lifestyle. We used this model to infer the lifestyle of two extinct taxa, Peirosaurus torminni and Microsuchus schilleri. We concluded that terrestrial notosuchians may have lost osteoderm ornamentation due to the lower thermal conductivity of air and reduced heat loss in a terrestrial environment compared to what happens in water. Among these notosuchians, we hypothesize that large terrestrial baurusuchids maintained a stable body temperature due to thermal inertia, whereas small notosuchians took advantage of the early morning sun exposure to warm up and stayed in terrestrial burrows during periods of intense solar radiation. Finally, unlike the almost motionless behavior of freshwater crocodiles, fully marine Metriorhynchidae probably lost osteoderms because they constantly swim, generating heat by muscular contraction, so osteoderms with a thermoregulatory function for heat absorption were no longer positively selected.
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Affiliation(s)
- Mariana Valéria de Araújo Sena
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), 4 Place Jussieu, 104, 75005, Paris, BC, France.
- Museu de Paleontologia Plácido Cidade Nuvens, Rua Plácido Cidade Nuvens, 326, Santana do Cariri, Ceará, 63190-000, Brazil.
| | - Jorge Cubo
- Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), 4 Place Jussieu, 104, 75005, Paris, BC, France
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3
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Pochat-Cottilloux Y, Martin JE, Amiot R, Cubo J, de Buffrénil V. A survey of osteoderm histology and ornamentation among Crocodylomorpha: A new proxy to infer lifestyle? J Morphol 2023; 284:e21542. [PMID: 36533737 PMCID: PMC10108047 DOI: 10.1002/jmor.21542] [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: 07/26/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022]
Abstract
Osteoderms of eight extant and extinct species of crocodylomorphs are studied histologically and morphologically. Most osteoderms display the typical "crocodilian" structure with a woven-fibered matrix surrounded by an upper and a lower parallel fibered matrix. The dorsal ornamentation of those specimens consists of a pit-and-ridge structure, with corresponding remodeling mechanisms. However, an osteoderm of Iberosuchus, studied here for the first time, differs in being nearly devoid of ornamentation; moreover, it shows strong bundles of straight Sharpey's fibers perpendicular to the surface in its lateral and dorsal walls, along with a rough plywood-like structure in its basal plate. This suggests that this osteoderm was more deeply anchored within the dermis than the other osteoderms studied hitherto. This peculiar structure might have been linked to a terrestrial ecology and a specific thermoregulation strategy. Some other notosuchians in our sample do not exhibit ornamentation on their osteoderms, as opposed to neosuchians. Considering current interpretations of osteoderm function(s) in crocodilians, our observations are discussed in reference to possible ecophysiological peculiarities of Notosuchia in general, and Iberosuchus in particular.
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Affiliation(s)
| | - Jeremy E Martin
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, France
| | - Romain Amiot
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, France
| | - Jorge Cubo
- Centre de Recherche en Paléontologie-Paris (CR2P), Sorbonne Université, Paris, France
| | - Vivian de Buffrénil
- Centre de Recherche en Paléontologie-Paris (CR2P), Sorbonne Université, Paris, France
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4
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Broeckhoven C, du Plessis A. Osteoderms as calcium reservoirs: Insights from the lizard Ouroborus cataphractus. J Anat 2022; 241:635-640. [PMID: 35502528 PMCID: PMC9358765 DOI: 10.1111/joa.13683] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/13/2022] [Accepted: 04/13/2022] [Indexed: 11/27/2022] Open
Abstract
The functional significance of osteoderms-bony elements embedded in the dermis-remains a topic of much debate. Although many hypotheses have been put forward in the past, the idea that osteoderms can serve as calcium reservoirs has received little experimental attention thus far. In this study, we use micro-computed tomography to investigate inter- and intrasexual variation in osteoderm density in the viviparous lizard Ouroborus cataphractus and conduct histochemical analyses to unravel the potential mechanism involved in mineral resorption from the osteoderms. Our results show that females have denser, more compact osteoderms than males of similar body sizes, regardless of the season during which they were collected and their reproductive state. Furthermore, a histochemical study demonstrates the presence of mononucleated TRAP-positive cells in the vascular canals of the osteoderms. Based on the findings of this study, we suggest that the mineral storage hypothesis merits further attention as a candidate explanation for osteoderm evolution.
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Affiliation(s)
- Chris Broeckhoven
- Laboratory of Functional MorphologyUniversity of AntwerpWilrijkBelgium
| | - Anton du Plessis
- Object Research SystemsMontrealCanada
- Research group 3D InnovationStellenbosch UniversityStellenboschSouth Africa
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Cubo J, Sena MVA, Aubier P, Houee G, Claisse P, Faure-Brac MG, Allain R, Andrade RCLP, Sayão JM, Oliveira GR. Were Notosuchia (Pseudosuchia: Crocodylomorpha) warm-blooded? A palaeohistological analysis suggests ectothermy. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa081] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Most Notosuchia were active terrestrial predators. A few were semi-aquatic, or were insectivorous, omnivorous or herbivorous. A question relative to their thermometabolism remains to be answered: were Notosuchia warm-blooded? Here we use quantitative bone palaeohistology to answer this question. Two variables were used as proxies to infer thermometabolism: resting metabolic rate and red blood cell dimensions. Resting metabolic rate was inferred using relative primary osteon area and osteocyte size, shape and density. Blood cell dimensions were inferred using harmonic mean canal diameter and minimum canal diameter. All inferences were performed using phylogenetic eigenvector maps. Both sets of analyses suggest that the seven species of Notosuchia sampled in this study were ectotherms. Given that extant Neosuchia (their sister group) are also ectotherms, and that archosaurs were primitively endotherms, parsimony suggests that endothermy may have been lost at the node Metasuchia (Notosuchia–Neosuchia) by the Early Jurassic. Semi-aquatic taxa such as Pepesuchus may have had thermoregulatory strategies similar to those of recent crocodylians, whereas the terrestrial taxa (Araripesuchus, Armadillosuchus, Iberosuchus, Mariliasuchus, Stratiotosuchus) may have been thermoregulators similar to active predatory varanids. Thermal inertia may have contributed to maintaining a stable temperature in large notosuchians such as Baurusuchus.
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Affiliation(s)
- Jorge Cubo
- Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Centre de Recherche en Paléontologie—Paris, Paris, France
| | - Mariana V A Sena
- Universidade Federal de Pernambuco, Departamento de Geologia, Programa de Pós-Graduação em Geociências (PPGEOC), Recife, PE, Brazil
- Centro Universitário da Vitória de Santo Antão, Vitória de Santo Antão, PE, Brazil
| | - Paul Aubier
- Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Centre de Recherche en Paléontologie—Paris, Paris, France
| | - Guillaume Houee
- Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Centre de Recherche en Paléontologie—Paris, Paris, France
| | - Penelope Claisse
- Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Centre de Recherche en Paléontologie—Paris, Paris, France
| | - Mathieu G Faure-Brac
- Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Centre de Recherche en Paléontologie—Paris, Paris, France
| | - Ronan Allain
- Muséum national d’Histoire naturelle, Sorbonne Université, CNRS, Centre de Recherche en Paléontologie—Paris, Paris, France
| | - Rafael C L P Andrade
- Universidade Federal de Pernambuco, Laboratório de Paleobiologia e Microestruturas, Vitória de Santo Antão, PE, Brazil
| | - Juliana M Sayão
- Universidade Federal de Pernambuco, Laboratório de Paleobiologia e Microestruturas, Vitória de Santo Antão, PE, Brazil
| | - Gustavo R Oliveira
- Universidade Federal Rural de Pernambuco, Departamento de Biologia, Laboratório de Paleontologia & Sistemática, Recife, PE, Brazil
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Kuzmin I, Petrov I, Averianov A, Boitsova E, Skutschas P, Sues HD. The braincase of Bissektipelta archibaldi — new insights into endocranial osteology, vasculature, and paleoneurobiology of ankylosaurian dinosaurs. ACTA ACUST UNITED AC 2020. [DOI: 10.21638/spbu03.2020.201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We describe in detail three braincases of the ankylosaur Bissektipelta archibaldi from the Late Cretaceous (Turonian) of Uzbekistan with the aid of computed tomography, segmentation, and 3D modeling. Bissektipelta archibaldi is confirmed as a valid taxon and attributed to Ankylosaurinae based on the results of a phylogenetic analysis. The topographic relationships between the elements forming the braincase are determined using a newly referred specimen with preserved sutures, which is an exceedingly rare condition for ankylosaurs. The mesethmoid appears to be a separate ossification in the newly referred specimen ZIN PH 281/16. We revise and discuss features of the neurocranial osteology in Ankylosauria and propose new diagnostic characters for a number of its subclades. We present a 3D model of the braincase vasculature of Bissektipelta and comment on vascular patterns of armored dinosaurs. A complex vascular network piercing the skull roof and the wall of the braincase is reported for ankylosaurs for the first time. We imply the presence of a lepidosaur-like dorsal head vein and the venous parietal sinus in the adductor cavity of Bissektipelta. We suggest that the presence of the dorsal head vein in dinosaurs is a plesiomorphic diapsid trait, and extant archosaur groups independently lost the vessel. A study of two complete endocranial casts of Bissektipelta allowed us to compare endocranial anatomy within Ankylosauria and infer an extremely developed sense of smell, a keen sense of hearing at lower frequencies (100–3000 Hz), and the presence of physiological mechanisms for precise temperature control of neurosensory tissues at least in derived ankylosaurids.
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Schucht PJ, Rühr PT, Geier B, Glaw F, Lambertz M. Armored with skin and bone: A combined histological and
μCT
‐study of the exceptional integument of the
Antsingy
leaf chameleon
Brookesia perarmata
(Angel, 1933). J Morphol 2020; 281:754-764. [DOI: 10.1002/jmor.21135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/12/2020] [Accepted: 04/17/2020] [Indexed: 12/20/2022]
Affiliation(s)
- Pia J. Schucht
- Institut für ZoologieRheinische Friedrich‐Wilhelms‐Universität Bonn, Poppelsdorfer Schloss Bonn Germany
| | - Peter T. Rühr
- AG Morphologische DynamikenInstitut für Zoologie, Biozentrum, Universität zu Köln Köln Germany
- Zentrum für Molekulare BiodiversitätsforschungZoologisches Forschungsmuseum Alexander Koenig Bonn Germany
| | - Benedikt Geier
- Max Planck Institute for Marine Microbiology Bremen Germany
| | - Frank Glaw
- Sektion HerpetologieZoologische Staatssammlung München (ZSM‐SNSB) Munich Germany
| | - Markus Lambertz
- Institut für ZoologieRheinische Friedrich‐Wilhelms‐Universität Bonn, Poppelsdorfer Schloss Bonn Germany
- Sektion HerpetologieZoologisches Forschungsmuseum Alexander Koenig Bonn Germany
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9
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Iacoviello F, Kirby AC, Javanmardi Y, Moeendarbary E, Shabanli M, Tsolaki E, Sharp AC, Hayes MJ, Keevend K, Li JH, Brett DJL, Shearing PR, Olivo A, Herrmann IK, Evans SE, Moazen M, Bertazzo S. The multiscale hierarchical structure of Heloderma suspectum osteoderms and their mechanical properties. Acta Biomater 2020; 107:194-203. [PMID: 32109598 DOI: 10.1016/j.actbio.2020.02.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/13/2020] [Accepted: 02/18/2020] [Indexed: 12/27/2022]
Abstract
Osteoderms are hard tissues embedded in the dermis of vertebrates and have been suggested to be formed from several different mineralized regions. However, their nano architecture and micro mechanical properties had not been fully characterized. Here, using electron microscopy, µ-CT, atomic force microscopy and finite element simulation, an in-depth characterization of osteoderms from the lizard Heloderma suspectum, is presented. Results show that osteoderms are made of three different mineralized regions: a dense apex, a fibre-enforced region comprising the majority of the osteoderm, and a bone-like region surrounding the vasculature. The dense apex is stiff, the fibre-enforced region is flexible and the mechanical properties of the bone-like region fall somewhere between the other two regions. Our finite element analyses suggest that when combined into the osteoderm structure, the distinct tissue regions are able to shield the body of the animal by bearing the external forces. These findings reveal the structure-function relationship of the Heloderma suspectum osteoderm in unprecedented detail. STATEMENT OF SIGNIFICANCE: The structures of bone and teeth have been thoroughly investigated. They provide a basis not only for understanding the mechanical properties and functions of these hard tissues, but also for the de novo design of composite materials. Osteoderms, however, are hard tissues that must possess mechanical properties distinct from teeth and bone to function as a protective armour. Here we provide a detailed analysis of the nanostructure of vertebrate osteoderms from Heloderma suspectum, and show that their mechanical properties are determined by their multiscale hierarchical tissue. We believe this study contributes to advance the current knowledge of the structure-function relationship of the hierarchical structures in the Heloderma suspectum osteoderm. This knowledge might in turn provide a source of inspiration for the design of bioinspired and biomimetic materials.
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Affiliation(s)
- Francesco Iacoviello
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London WC1E 7JE, UK
| | - Alexander C Kirby
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - Yousef Javanmardi
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Emad Moeendarbary
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Murad Shabanli
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Elena Tsolaki
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - Alana C Sharp
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Matthew J Hayes
- Department of Ophthalmology, University College London, London WC1E 6BT, UK
| | - Kerda Keevend
- Department of Materials, Meet Life, Swiss Federal Laboratories for Materials Science and Technology, (Empa), Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Jian-Hao Li
- Department of Materials, Meet Life, Swiss Federal Laboratories for Materials Science and Technology, (Empa), Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Daniel J L Brett
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London WC1E 7JE, UK
| | - Paul R Shearing
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London WC1E 7JE, UK
| | - Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - Inge K Herrmann
- Department of Materials, Meet Life, Swiss Federal Laboratories for Materials Science and Technology, (Empa), Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Susan E Evans
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Mehran Moazen
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Sergio Bertazzo
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK.
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Clarac F, Scheyer TM, Desojo JB, Cerda IA, Sanchez S. The evolution of dermal shield vascularization in Testudinata and Pseudosuchia: phylogenetic constraints versus ecophysiological adaptations. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190132. [PMID: 31928197 PMCID: PMC7017437 DOI: 10.1098/rstb.2019.0132] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2019] [Indexed: 01/18/2023] Open
Abstract
Studies on living turtles have demonstrated that shells are involved in the resistance to hypoxia during apnea via bone acidosis buffering; a process which is complemented with cutaneous respiration, transpharyngeal and cloacal gas exchanges in the soft-shell turtles. Bone acidosis buffering during apnea has also been identified in crocodylian osteoderms, which are also known to employ heat transfer when basking. Although diverse, many of these functions rely on one common trait: the vascularization of the dermal shield. Here, we test whether the above ecophysiological functions played an adaptive role in the evolutionary transitions between land and aquatic environments in both Pseudosuchia and Testudinata. To do so, we measured the bone porosity as a proxy for vascular density in a set of dermal plates before performing phylogenetic comparative analyses. For both lineages, the dermal plate porosity obviously varies depending on the animal lifestyle, but these variations prove to be highly driven by phylogenetic relationships. We argue that the complexity of multi-functional roles of the post-cranial dermal skeleton in both Pseudosuchia and Testudinata probably is the reason for a lack of obvious physiological signal, and we discuss the role of the dermal shield vascularization in the evolution of these groups. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- François Clarac
- Department of Organismal Biology, Subdepartment of Evolution and Development, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
| | - Torsten M. Scheyer
- Paleontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Julia B. Desojo
- CONICET, División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n°, B1900FWA La Plata, Argentina
| | - Ignacio A. Cerda
- CONICET, Argentina y Instituto de Investigacion en Paleobiología y Geología, Universidad Nacional de Río Negro, Museo Carlos Ameghino, Belgrano 1700, Paraje Pichi Ruca (predio Marabunta), 8300 Cipolletti, Río Negro, Argentina
| | - Sophie Sanchez
- Department of Organismal Biology, Subdepartment of Evolution and Development, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS-40220, 38043 Grenoble Cedex, France
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11
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Janis CM, Napoli JG, Warren DE. Palaeophysiology of pH regulation in tetrapods. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190131. [PMID: 31928199 DOI: 10.1098/rstb.2019.0131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The involvement of mineralized tissues in acid-base homeostasis was likely important in the evolution of terrestrial vertebrates. Extant reptiles encounter hypercapnia when submerged in water, but early tetrapods may have experienced hypercapnia on land due to their inefficient mode of lung ventilation (likely buccal pumping, as in extant amphibians). Extant amphibians rely on cutaneous carbon dioxide elimination on land, but early tetrapods were considerably larger forms, with an unfavourable surface area to volume ratio for such activity, and evidence of a thick integument. Consequently, they would have been at risk of acidosis on land, while many of them retained internal gills and would not have had a problem eliminating carbon dioxide in water. In extant tetrapods, dermal bone can function to buffer the blood during acidosis by releasing calcium and magnesium carbonates. This review explores the possible mechanisms of acid-base regulation in tetrapod evolution, focusing on heavily armoured, basal tetrapods of the Permo-Carboniferous, especially the physiological challenges associated with the transition to air-breathing, body size and the adoption of active lifestyles. We also consider the possible functions of dermal armour in later tetrapods, such as Triassic archosaurs, inferring palaeophysiology from both fossil record evidence and phylogenetic patterns, and propose a new hypothesis relating the archosaurian origins of the four-chambered heart and high systemic blood pressures to the perfusion of the osteoderms. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Christine M Janis
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.,School of Earth Sciences, University of Bristol, Bristol BS8 1RL, UK
| | - James G Napoli
- Richard Gilder Graduate School and Division of Paleontology, American Museum of Natural History, New York, NY 10024-5102, USA
| | - Daniel E Warren
- Department of Biology, Saint Louis University, St Louis, MO 63103, USA
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12
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Canoville A, Schweitzer MH, Zanno L. Identifying medullary bone in extinct avemetatarsalians: challenges, implications and perspectives. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190133. [PMID: 31928189 DOI: 10.1098/rstb.2019.0133] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Medullary bone (MB) is a sex-specific tissue produced by female birds during the laying cycle, and it is hypothesized to have arisen within Avemetatarsalia, possibly outside Avialae. Over the years, researchers have attempted to define a set of criteria from which to evaluate the nature of purported MB-like tissues recovered from fossil specimens. However, we argue that the prevalence, microstructural and chemical variability of MB in Neornithes is, as of yet, incompletely known and thus current diagnoses of MB do not capture the extent of variability that exists in modern birds. Based on recently published data and our own observations of MB distribution and structure using computed tomography and histochemistry, we attempt to advance the discourse on identifying MB in fossil specimens. We propose: (i) new insights into the phylogenetic breadth and structural diversity of MB within extant birds; (ii) a reevaluation and refinement of the most recently published list of criteria suggested for confidently identifying MB in the fossil record; (iii) reconsideration of some prior identifications of MB-like tissues in fossil specimens by taking into account the newly acquired data; and (iv) discussions on the challenges of characterizing MB in Neornithes with the goal of improving its diagnosis in extinct avemetatarsalians. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Aurore Canoville
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Mary H Schweitzer
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA.,Museum of the Rockies, Montana State University, Bozeman, MT 59717, USA.,Department of Geology, Lund University, 223 62 Lund, Sweden
| | - Lindsay Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
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