1
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Green DR, Winkler DE, Leichliter JN, Harms GS, Hatt JM, Clauss M, Tütken T. Formation and Replacement of Bone and Tooth Mineralized Tissues in Green Iguanas (Iguana iguana) Revealed by In-Vivo Fluorescence Marking. Integr Comp Biol 2023; 63:515-529. [PMID: 37475667 DOI: 10.1093/icb/icad089] [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: 03/21/2023] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 07/22/2023] Open
Abstract
Hard tissue formation patterns and rates reveal details of animal physiology, life history, and environment, but are understudied in reptiles. Here, we use fluorescence labels delivered in vivo and laser confocal scanning microscopy to study tooth and bone formation in a managed group of green iguanas (Iguana iguana, Linné 1758) kept for 1.5 years under experimentally controlled conditions and undergoing several dietary switches. We constrain rates of tooth elongation, which we observe to be slow when enamel is initially deposited (c. 9 µm/day), but then increases exponentially in the dentin root, reaching c. 55 µm/day or more after crown completion. We further constrain the total timing of tooth formation to ∼40-60 days, and observe highly variable timings of tooth resorption onset and replacement. Fluorescent labels clearly indicate cohorts of teeth recruited within Zahnreihen replacement waves, with faster sequential tooth recruitment and greater wave sizes posteriorly, where each wave initiates. Fluorescence further reveals enamel maturation after initial deposition. Rates of hard tissue formation in long bones range from 0.4 to 3.4 µm/day, correlating with animal weight gain and cortical bone recording the entire history of the experiment. We suggest additional labeling experiments to study hard tissue formation patterns in other reptiles, and propose strategies for chemical analyses of hard tissues in order to extract temporal information about past environments, behaviors, and diets from reptilian fossils throughout the Phanerozoic.
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Affiliation(s)
- Daniel R Green
- Lamont-Doherty Earth Observatory, Climate School, Columbia University, 2910 Broadway Level A, New York, NY 10025, USA
| | - Daniela E Winkler
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany
- Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Jennifer N Leichliter
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany
- Emmy Noether Group for Hominin Meat Consumption, Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Gregory S Harms
- Imaging Core Facility, University Medical Center Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
- Departments of Biology and Earth Systems Science and Mathematics, Physics and Computer Science, WIlkes University, Wilkes-Barre, PA 18766, USA
| | - Jean-Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zürich, Winterthurerstrasse 260, 8057 Zurich, Switzerland
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zürich, Winterthurerstrasse 260, 8057 Zurich, Switzerland
| | - Thomas Tütken
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany
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2
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Wang Y, Li Z, Wang CC, Bailleul AM, Wang M, O'Connor J, Li J, Zheng X, Pei R, Teng F, Wang X, Zhou Z. Comparative microstructural study on the teeth of Mesozoic birds and non-avian dinosaurs. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230147. [PMID: 37206961 PMCID: PMC10189602 DOI: 10.1098/rsos.230147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/24/2023] [Indexed: 05/21/2023]
Abstract
Although it is commonly considered that, in birds, there is a trend towards reduced dentition, teeth persisted in birds for 90 Ma and numerous macroscopic morphologies are observed. However, the extent to which the microstructure of bird teeth differs from other lineages is poorly understood. To explore the microstructural differences of the teeth of birds in comparison with closely related non-avialan dinosaurs, the enamel and dentine-related features were evaluated in four Mesozoic paravian species from the Yanliao and Jehol biotas. Different patterns of dentinal tubular tissues with mineralized extensions of the odontoblast processes were revealed through the examination of histological sectioning under electron microscopy. Secondary modification of the tubular structures, forming reactive sclerotic dentin of Longipteryx, and the mineralization of peritubular dentin of Sapeornis were observed in the mantle dentin region. The new observed features combined with other dentinal-associated ultrastructure suggest that the developmental mechanisms controlling dentin formation are quite plastic, permitting the evolution of unique morphologies associated with specialized feeding behaviours in the toothed birds. Proportionally greater functional stress placed on the stem bird teeth may have induced reactive dentin mineralization, which was observed more often within tubules of these taxa. This suggests modifications to the dentin to counteract potential failure.
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Affiliation(s)
- Yan Wang
- Institute of Geology and Paleontology, Linyi University, Linyi, Shandong 276000
- Tianyu Natural History Museum of Shandong, Pingyi, Shandong 273300
| | - Zhiheng Li
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi-zhi-men-wai Street, Beijing 100044
| | - Chun-Chieh Wang
- National Synchrotron Radiation Research Center, Hsinchu 30076
- Department of Geosciences, National Taiwan University, Taipei City 10617
| | - Alida M. Bailleul
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi-zhi-men-wai Street, Beijing 100044
| | - Min Wang
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi-zhi-men-wai Street, Beijing 100044
| | - Jingmai O'Connor
- Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL 60605
| | - Jinhua Li
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences (IGGCAS), Beijing 100029
| | - Xiaoting Zheng
- Tianyu Natural History Museum of Shandong, Pingyi, Shandong 273300
| | - Rui Pei
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi-zhi-men-wai Street, Beijing 100044
| | - Fangfang Teng
- Xinghai Paleontological Museum of Dalian, Dalian, Liaoning 116023
| | - Xiaoli Wang
- Institute of Geology and Paleontology, Linyi University, Linyi, Shandong 276000
- Tianyu Natural History Museum of Shandong, Pingyi, Shandong 273300
| | - Zhonghe Zhou
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi-zhi-men-wai Street, Beijing 100044
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3
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García-Girón J, Chiarenza AA, Alahuhta J, DeMar DG, Heino J, Mannion PD, Williamson TE, Wilson Mantilla GP, Brusatte SL. Shifts in food webs and niche stability shaped survivorship and extinction at the end-Cretaceous. SCIENCE ADVANCES 2022; 8:eadd5040. [PMID: 36475805 PMCID: PMC9728968 DOI: 10.1126/sciadv.add5040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
It has long been debated why groups such as non-avian dinosaurs became extinct whereas mammals and other lineages survived the Cretaceous/Paleogene mass extinction 66 million years ago. We used Markov networks, ecological niche partitioning, and Earth System models to reconstruct North American food webs and simulate ecospace occupancy before and after the extinction event. We find a shift in latest Cretaceous dinosaur faunas, as medium-sized species counterbalanced a loss of megaherbivores, but dinosaur niches were otherwise stable and static, potentially contributing to their demise. Smaller vertebrates, including mammals, followed a consistent trajectory of increasing trophic impact and relaxation of niche limits beginning in the latest Cretaceous and continuing after the mass extinction. Mammals did not simply proliferate after the extinction event; rather, their earlier ecological diversification might have helped them survive.
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Affiliation(s)
- Jorge García-Girón
- Geography Research Unit, University of Oulu, PO Box 3000, FI-90014 Oulu, Finland
- Department of Biodiversity and Environmental Management, University of León, Campus de Vegazana, 24007 León, Spain
| | - Alfio Alessandro Chiarenza
- Departamento de Ecoloxía e Bioloxía Animal, Grupo de Ecología Animal, Centro de Investigacion Mariña, Universidade de Vigo, 36310 Vigo, Spain
| | - Janne Alahuhta
- Geography Research Unit, University of Oulu, PO Box 3000, FI-90014 Oulu, Finland
| | - David G. DeMar
- Department of Biology, University of Washington and the Burke Museum of Natural History and Culture, Seattle, WA 98105, USA
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Jani Heino
- Geography Research Unit, University of Oulu, PO Box 3000, FI-90014 Oulu, Finland
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, Gower Street, WC1E 6BT London, UK
| | | | - Gregory P. Wilson Mantilla
- Department of Biology, University of Washington and the Burke Museum of Natural History and Culture, Seattle, WA 98105, USA
| | - Stephen L. Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, James Hutton Road, EH9 3FE Edinburgh, UK
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4
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During MAD, Smit J, Voeten DFAE, Berruyer C, Tafforeau P, Sanchez S, Stein KHW, Verdegaal-Warmerdam SJA, van der Lubbe JHJL. The Mesozoic terminated in boreal spring. Nature 2022; 603:91-94. [PMID: 35197634 PMCID: PMC8891016 DOI: 10.1038/s41586-022-04446-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/19/2022] [Indexed: 12/26/2022]
Abstract
The Cretaceous-Palaeogene mass extinction around 66 million years ago was triggered by the Chicxulub asteroid impact on the present-day Yucatán Peninsula1,2. This event caused the highly selective extinction that eliminated about 76% of species3,4, including all non-avian dinosaurs, pterosaurs, ammonites, rudists and most marine reptiles. The timing of the impact and its aftermath have been studied mainly on millennial timescales, leaving the season of the impact unconstrained. Here, by studying fishes that died on the day the Mesozoic era ended, we demonstrate that the impact that caused the Cretaceous-Palaeogene mass extinction took place during boreal spring. Osteohistology together with stable isotope records of exceptionally preserved perichondral and dermal bones in acipenseriform fishes from the Tanis impact-induced seiche deposits5 reveal annual cyclicity across the final years of the Cretaceous period. Annual life cycles, including seasonal timing and duration of reproduction, feeding, hibernation and aestivation, vary strongly across latest Cretaceous biotic clades. We postulate that the timing of the Chicxulub impact in boreal spring and austral autumn was a major influence on selective biotic survival across the Cretaceous-Palaeogene boundary.
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Affiliation(s)
- Melanie A D During
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands. .,Subdepartment of Evolution and Development, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
| | - Jan Smit
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Dennis F A E Voeten
- Subdepartment of Evolution and Development, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,European Synchrotron Radiation Facility, Grenoble, France
| | | | - Paul Tafforeau
- European Synchrotron Radiation Facility, Grenoble, France
| | - Sophie Sanchez
- Subdepartment of Evolution and Development, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,European Synchrotron Radiation Facility, Grenoble, France
| | - Koen H W Stein
- Royal Belgian Institute of Natural Sciences, Directorate 'Earth and History of Life', Brussels, Belgium.,Earth System Science-AMGC, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Jeroen H J L van der Lubbe
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.,School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
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5
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Maderspacher F. Paleontology: Snow falling on dinosaurs. Curr Biol 2021; 31:R995-R998. [PMID: 34428420 DOI: 10.1016/j.cub.2021.07.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A treasure trove of dinosaur bones and teeth from Northern Alaska - many from juveniles and yearlings - reveals that dinosaurs lived year-round in the cold and dark environment of the high Arctic.
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6
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Druckenmiller PS, Erickson GM, Brinkman D, Brown CM, Eberle JJ. Nesting at extreme polar latitudes by non-avian dinosaurs. Curr Biol 2021; 31:3469-3478.e5. [PMID: 34171301 DOI: 10.1016/j.cub.2021.05.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 11/17/2022]
Abstract
The unexpected discovery of non-avian dinosaurs from Arctic and Antarctic settings has generated considerable debate about whether they had the capacity to reproduce at high latitudes-especially the larger-bodied, hypothetically migratory taxa. Evidence for dinosaurian polar reproduction remains very rare, particularly for species that lived at the highest paleolatitudes (>75°). Here we report the discovery of perinatal and very young dinosaurs from the highest known paleolatitude for the clade-the Cretaceous Prince Creek Formation (PCF) of northern Alaska. These data demonstrate Arctic reproduction in a diverse assemblage of large- and small-bodied ornithischian and theropod species. In terms of overall diversity, 70% of the known dinosaurian families, as well as avialans (birds), in the PCF are represented by perinatal individuals, the highest percentage for any North American Cretaceous formation. These findings, coupled with prolonged incubation periods, small neonate sizes, and short reproductive windows suggest most, if not all, PCF dinosaurs were nonmigratory year-round Arctic residents. Notably, we reconstruct an annual chronology of reproductive events for the ornithischian dinosaurs using refined paleoenvironmental/plant phenology data and new insights into dinosaur incubation periods. Seasonal resource limitations due to extended periods of winter darkness and freezing temperatures placed severe constraints on dinosaurian reproduction, development, and maintenance, suggesting these taxa showed polar-specific life history strategies, including endothermy.
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Affiliation(s)
- Patrick S Druckenmiller
- University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK 99775, USA; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
| | - Gregory M Erickson
- Department of Biological Science, Florida State University, 319 Stadium Drive, FL 32306, USA
| | - Donald Brinkman
- Royal Tyrrell Museum of Palaeontology, Drumheller, AB T0J 0Y0, Canada
| | - Caleb M Brown
- Royal Tyrrell Museum of Palaeontology, Drumheller, AB T0J 0Y0, Canada
| | - Jaelyn J Eberle
- Univerity of Colorado Museum of Natural History, 265 UCB, Boulder, CO 80309, USA; Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA
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7
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Blackburn DG, Stewart JR. Morphological research on amniote eggs and embryos: An introduction and historical retrospective. J Morphol 2021; 282:1024-1046. [PMID: 33393149 DOI: 10.1002/jmor.21320] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/31/2020] [Accepted: 01/01/2021] [Indexed: 12/21/2022]
Abstract
Evolution of the terrestrial egg of amniotes (reptiles, birds, and mammals) is often considered to be one of the most significant events in vertebrate history. Presence of an eggshell, fetal membranes, and a sizeable yolk allowed this egg to develop on land and hatch out well-developed, terrestrial offspring. For centuries, morphologically-based studies have provided valuable information about the eggs of amniotes and the embryos that develop from them. This review explores the history of such investigations, as a contribution to this special issue of Journal of Morphology, titled Developmental Morphology and Evolution of Amniote Eggs and Embryos. Anatomically-based investigations are surveyed from the ancient Greeks through the Scientific Revolution, followed by the 19th and early 20th centuries, with a focus on major findings of historical figures who have contributed significantly to our knowledge. Recent research on various aspects of amniote eggs is summarized, including gastrulation, egg shape and eggshell morphology, eggs of Mesozoic dinosaurs, sauropsid yolk sacs, squamate placentation, embryogenesis, and the phylotypic phase of embryonic development. As documented in this review, studies on amniote eggs and embryos have relied heavily on morphological approaches in order to answer functional and evolutionary questions.
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Affiliation(s)
- Daniel G Blackburn
- Department of Biology and Electron Microscopy Center, Trinity College, Hartford, Connecticut, USA
| | - James R Stewart
- Department of Biological Sciences, East Tennessee State University, Johnson City, Tennessee, USA
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8
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Kosch JCD, Zanno LE. Sampling impacts the assessment of tooth growth and replacement rates in archosaurs: implications for paleontological studies. PeerJ 2020; 8:e9918. [PMID: 32999766 PMCID: PMC7505082 DOI: 10.7717/peerj.9918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 08/20/2020] [Indexed: 11/20/2022] Open
Abstract
Dietary habits in extinct species cannot be directly observed; thus, in the absence of extraordinary evidence, they must be reconstructed with a combination of morphological proxies. Such proxies often include information on dental organization and function such as tooth formation time and tooth replacement rate. In extinct organisms, tooth formation times and tooth replacement rate are calculated, in part via extrapolation of the space between incremental lines in dental tissues representing daily growth (von Ebner Line Increment Width; VEIW). However, to date, little work has been conducted testing assumptions about the primary data underpinning these calculations, specifically, the potential impact of differential sampling and data extrapolation protocols. To address this, we tested a variety of intradental, intramandibular, and ontogentic sampling effects on calculations of mean VEIW, tooth formation times, and replacement rates using histological sections and CT reconstructions of a growth series of three specimens of the extant archosaurian Alligator mississippiensis. We find transect position within the tooth and transect orientation with respect to von Ebner lines to have the greatest impact on calculations of mean VEIW—a maximum number of VEIW measurements should be made as near to the central axis (CA) as possible. Measuring in regions away from the central axis can reduce mean VEIW by up to 36%, causing inflated calculations of tooth formation time. We find little demonstrable impact to calculations of mean VEIW from the practice of subsampling along a transect, or from using mean VEIW derived from one portion of the dentition to extrapolate for other regions of the dentition. Subsampling along transects contributes only minor variations in mean VEIW (<12%) that are dwarfed by the standard deviation (SD). Moreover, variation in VEIW with distance from the pulp cavity likely reflects idiosyncratic patterns related to life history, which are difficult to control for; however, we recommend increasing the number of VEIW measured to minimize this effect. Our data reveal only a weak correlation between mean VEIW and body length, suggesting minimal ontogenetic impacts. Finally, we provide a relative SD of mean VEIW for Alligator of 29.94%, which can be used by researchers to create data-driven error bars for tooth formation times and replacement rates in fossil taxa with small sample sizes. We caution that small differences in mean VEIW calculations resulting from non-standardized sampling protocols, especially in a comparative context, will produce inflated error in tooth formation time estimations that intensify with crown height. The same holds true for applications of our relative SD to calculations of tooth formation time in extinct taxa, which produce highly variable maximum and minimum estimates in large-toothed taxa (e.g., 718–1,331 days in Tyrannosaurus).
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Affiliation(s)
- Jens C D Kosch
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
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9
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Blackburn DG. Functional morphology, diversity, and evolution of yolk processing specializations in embryonic reptiles and birds. J Morphol 2020; 282:995-1014. [PMID: 32960458 DOI: 10.1002/jmor.21267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/24/2020] [Accepted: 09/08/2020] [Indexed: 12/21/2022]
Abstract
Evolution of the terrestrial, amniotic egg of vertebrates required new mechanisms by which yolk material could be processed for embryonic use. Recent studies on each of the major extant reptile groups have revealed elaborate morphological specializations for yolk processing, features that differ dramatically from those of birds. In the avian pattern, liquid yolk is housed in a yolk sac whose endodermal lining absorbs and digests yolk material and sends resultant nutrients into the blood circulation. In snakes, lizards, turtles, and crocodilians, as documented herein, the yolk sac becomes invaded by endodermal cells that proliferate and phagocytose yolk material. Blood vessels then invade, and the endodermal cells become arranged around them, forming elongated "spaghetti-like" strands that fill the yolk sac cavity. This pattern provides an effective means by which yolk material is cellularized, digested, and transported by vitelline vessels to the developing embryo. Phylogenetically, the (non-avian) "reptilian" pattern was ancestral for sauropsids and was modified or replaced in ancestors to birds. This review postulates that evolution of the "avian" pattern involved increased reliance on extracellular digestion of yolk, allowing embryonic development to occur more rapidly than in typical reptiles. Comparative studies of yolk processing that draw on morphological, biochemical, molecular approaches are needed to explain how and why the "reptilian" pattern was replaced in birds or their archosaurian ancestors.
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Affiliation(s)
- Daniel G Blackburn
- Department of Biology, Electron Microscopy Center, Trinity College, Hartford, Connecticut, USA
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10
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11
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Wiens D, Sweet T, Worsley T. Validating the New Paradigm for Extinction: Overcoming 200 Years of Historical Neglect, Philosophical Misconception, and Inadequate Language. THE QUARTERLY REVIEW OF BIOLOGY 2020. [DOI: 10.1086/709086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Li Z, Wang CC, Wang M, Chiang CC, Wang Y, Zheng X, Huang EW, Hsiao K, Zhou Z. Ultramicrostructural reductions in teeth: implications for dietary transition from non-avian dinosaurs to birds. BMC Evol Biol 2020; 20:46. [PMID: 32316913 PMCID: PMC7171806 DOI: 10.1186/s12862-020-01611-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 04/06/2020] [Indexed: 12/31/2022] Open
Abstract
Background Tooth morphology within theropod dinosaurs has been extensively investigated and shows high disparity throughout the Cretaceous. Changes or diversification in feeding ecology, i.e., adoption of an herbivorous diet (e.g., granivorous), is proposed as a major driver of tooth evolution in Paraves (e.g., Microraptor, troodontids and avialans). Here, we studied the microscopic features of paravian non-avian theropod and avialan teeth using high-spatial-resolution synchrotron transmission X-ray microscopy and scanning electron microscopy. Results We show that avialan teeth are characterized by the presence of simple enamel structures and a lack of porous mantle dentin between the enamel and orthodentin. Reduced internal structures of teeth took place independently in Early Cretaceous birds and a Microraptor specimen, implying that shifts in diet in avialans from that of closely related dinosaurs may correlate with a shift in feeding ecology during the transition from non-avian dinosaurs to birds. Conclusion Different lines of evidence all suggest a large reduction in biting force affecting the evolution of teeth in the dinosaur-bird transition. Changes in teeth microstructure and associated dietary shift may have contributed to the early evolutionary success of stemward birds in the shadow of other non-avian theropods.
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Affiliation(s)
- Zhiheng Li
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing, 100044, China. .,CAS Center for Excellence in Life and Paleoenvironment, Beijing, 100044, China.
| | - Chun-Chieh Wang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan.
| | - Min Wang
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing, 100044, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, 100044, China
| | | | - Yan Wang
- Institute of Geology and Paleontology, Linyi University, Linyi, 276000, Shandong, China
| | - Xiaoting Zheng
- Tianyu Natural History Museum of Shandong, Pingyi, 273300, Shandong, China
| | - E-Wen Huang
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Kiko Hsiao
- Mr. Fossil Institute, New Taipei City, 23673, Taiwan
| | - Zhonghe Zhou
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing, 100044, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, 100044, China
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13
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Chapelle KEJ, Fernandez V, Choiniere JN. Conserved in-ovo cranial ossification sequences of extant saurians allow estimation of embryonic dinosaur developmental stages. Sci Rep 2020; 10:4224. [PMID: 32273522 PMCID: PMC7145871 DOI: 10.1038/s41598-020-60292-z] [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] [Received: 11/06/2019] [Accepted: 01/30/2020] [Indexed: 11/23/2022] Open
Abstract
Dinosaur embryos are among the rarest of fossils, yet they provide a unique window into the palaeobiology of these animals. Estimating the developmental stage of dinosaur embryos is hindered by the lack of a quantitative method for age determination, by the scarcity of material, and by the difficulty in visualizing that material. Here we present the results of a broad inquiry, using 3D reconstructions from X-ray computed tomography data, into cranial ossification sequences in extant saurian taxa and in well-preserved embryos of the early branching sauropodomorph dinosaur Massospondylus carinatus. Our findings support deep-time conservation of cranial ossification sequences in saurians including dinosaurs, allowing us to develop a new method for estimating the relative developmental percentage of embryos from that clade. We also observe null-generation teeth in the Massospondylus carinatus embryos which get resorbed or shed before hatching, similar to those of geckos. These lines of evidence allow us to confidently estimate that the Massospondylus carinatus embryos are only approximately 60% through their incubation period, much younger than previously hypothesized. The overall consistency of our results with those of living saurians indicates that they can be generalized to other extinct members of that lineage, and therefore our method provides an independent means of assessing the developmental stage of extinct, in-ovo saurians.
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Affiliation(s)
- Kimberley E J Chapelle
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa.
- School of Geosciences, University of the Witwatersrand, Johannesburg, Gauteng, South Africa.
| | - Vincent Fernandez
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
- European Synchrotron Radiation Facility, Grenoble, France
- Imaging and Analysis Centre, Natural History Museum, London, United Kingdom
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
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14
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High-latitude neonate and perinate ornithopods from the mid-Cretaceous of southeastern Australia. Sci Rep 2019; 9:19600. [PMID: 31862946 PMCID: PMC6925213 DOI: 10.1038/s41598-019-56069-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/26/2019] [Indexed: 12/27/2022] Open
Abstract
Dinosaurs were remarkably climate-tolerant, thriving from equatorial to polar latitudes. High-paleolatitude eggshells and hatchling material from the Northern Hemisphere confirms that hadrosaurid ornithopods reproduced in polar regions. Similar examples are lacking from Gondwanan landmasses. Here we describe two non-iguanodontian ornithopod femora from the Griman Creek Formation (Cenomanian) in New South Wales, Australia. These incomplete proximal femora represent the first perinatal ornithopods described from Australia, supplementing neonatal and slightly older ‘yearling’ specimens from the Aptian–Albian Eumeralla and Wonthaggi formations in Victoria. While pseudomorphic preservation obviates histological examination, anatomical and size comparisons with Victorian specimens, which underwent previous histological work, support perinatal interpretations for the Griman Creek Formation femora. Estimated femoral lengths (37 mm and 45 mm) and body masses (113–191 g and 140–236 g), together with the limited development of features in the smallest femur, suggest a possible embryonic state. Low body masses (<1 kg for ‘yearlings’ and ~20 kg at maturity) would have precluded small ornithopods from long-distance migration, even as adults, in the Griman Creek, Eumeralla, and Wonthaggi formations. Consequently, these specimens support high-latitudinal breeding in a non-iguanodontian ornithopod in eastern Gondwana during the early Late Cretaceous.
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15
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Bailleul AM, O’Connor J, Schweitzer MH. Dinosaur paleohistology: review, trends and new avenues of investigation. PeerJ 2019; 7:e7764. [PMID: 31579624 PMCID: PMC6768056 DOI: 10.7717/peerj.7764] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 08/26/2019] [Indexed: 12/12/2022] Open
Abstract
In the mid-19th century, the discovery that bone microstructure in fossils could be preserved with fidelity provided a new avenue for understanding the evolution, function, and physiology of long extinct organisms. This resulted in the establishment of paleohistology as a subdiscipline of vertebrate paleontology, which has contributed greatly to our current understanding of dinosaurs as living organisms. Dinosaurs are part of a larger group of reptiles, the Archosauria, of which there are only two surviving lineages, crocodilians and birds. The goal of this review is to document progress in the field of archosaur paleohistology, focusing in particular on the Dinosauria. We briefly review the "growth age" of dinosaur histology, which has encompassed new and varied directions since its emergence in the 1950s, resulting in a shift in the scientific perception of non-avian dinosaurs from "sluggish" reptiles to fast-growing animals with relatively high metabolic rates. However, fundamental changes in growth occurred within the sister clade Aves, and we discuss this major evolutionary transition as elucidated by histology. We then review recent innovations in the field, demonstrating how paleohistology has changed and expanded to address a diversity of non-growth related questions. For example, dinosaur skull histology has elucidated the formation of curious cranial tissues (e.g., "metaplastic" tissues), and helped to clarify the evolution and function of oral adaptations, such as the dental batteries of duck-billed dinosaurs. Lastly, we discuss the development of novel techniques with which to investigate not only the skeletal tissues of dinosaurs, but also less-studied soft-tissues, through molecular paleontology and paleohistochemistry-recently developed branches of paleohistology-and the future potential of these methods to further explore fossilized tissues. We suggest that the combination of histological and molecular methods holds great potential for examining the preserved tissues of dinosaurs, basal birds, and their extant relatives. This review demonstrates the importance of traditional bone paleohistology, but also highlights the need for innovation and new analytical directions to improve and broaden the utility of paleohistology, in the pursuit of more diverse, highly specific, and sensitive methods with which to further investigate important paleontological questions.
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Affiliation(s)
- Alida M. Bailleul
- Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
| | - Jingmai O’Connor
- Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
| | - Mary H. Schweitzer
- Department of Biology, North Carolina State University, Raleigh, NC, USA
- North Carolina Museum of Natural Science, Raleigh, NC, USA
- Department of Geology, Lund University, Lund, Sweden
- Museum of the Rockies, Montana State University, Bozeman, MT, USA
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16
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Słowiak J, Tereshchenko VS, Fostowicz-Frelik Ł. Appendicular skeleton of Protoceratops andrewsi (Dinosauria, Ornithischia): comparative morphology, ontogenetic changes, and the implications for non-ceratopsid ceratopsian locomotion. PeerJ 2019; 7:e7324. [PMID: 31367485 PMCID: PMC6657679 DOI: 10.7717/peerj.7324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/19/2019] [Indexed: 11/20/2022] Open
Abstract
Protoceratops andrewsi is a well-known ceratopsian dinosaur from the Djadokhta Formation (Upper Cretaceous, Mongolia). Since the 1920s, numerous skeletons of different ontogenetic stages from hatchlings to adults, including fully articulated specimens, have been discovered, but the postcranial anatomy of Protoceratops has not been studied in detail. A new, mostly articulated subadult individual provides an excellent opportunity for us to comprehensively describe the anatomy of the limb skeleton, to compare to other ceratopsian dinosaurs, and to study the ontogenetic and intraspecific variation in this species. New data provided by the specimen shed light on the lifestyle of P. andrewsi. The young subadult individuals present an array of morphological characters intermediate between the bipedal Psittacosaurus and fully quadrupedal adult P. andrewsi. We compare these observations with a broad range of non-ceratopsid Neoceratopsia (of various locomotor adaptations) and Psittacosauridae (obligate bipeds), which gives us insight into the evolution of the skeletal characters informative for the postural change in ceratopsian dinosaurs.
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Affiliation(s)
- Justyna Słowiak
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland
| | - Victor S Tereshchenko
- Laboratory of Paleoherpetology, Paleontological Institute, Russian Academy of Sciences, Moscow, Russia
| | - Łucja Fostowicz-Frelik
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.,Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
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17
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Lee SA. Trends in embryonic and ontogenetic growth metabolisms in nonavian dinosaurs and extant birds, mammals, and crocodylians with implications for dinosaur egg incubation. Phys Rev E 2019; 99:052405. [PMID: 31212519 DOI: 10.1103/physreve.99.052405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Indexed: 11/07/2022]
Abstract
The embryonic metabolism of the saurischian dinosaur Troodon formosus and the ornithischian dinosaurs Protoceratops andrewsi and Hypacrosaurus stebingeri have been determined by using a mass growth model based on conservation of energy and found to be very similar. Embryonic and ontogenetic growth metabolisms are also evaluated for extant altricial birds, precocial birds, mammals, and crocodylians to examine for trends in the different groups of animals and to provide a context for interpreting our results for nonavian dinosaurs. This analysis reveals that the embryonic metabolisms of these nonavian dinosaurs were closer to the range observed in extant crocodylians than extant birds. The embryonic metabolisms of nonavian dinosaurs were in the range observed for extant mammals of similar masses. The measured embryonic metabolic rates for these three nonavian dinosaurs are then used to calculate the incubation times for eggs of 22 nonavian dinosaurs from both Saurischia and Ornithischia. The calculated incubation times vary from about 50 days for Archaeopteryx lithographica to about 150 days for Alamosaurus sanjuanensis.
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Affiliation(s)
- Scott A Lee
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
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18
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Yang TR, Sander PM. The origin of the bird's beak: new insights from dinosaur incubation periods. Biol Lett 2019; 14:rsbl.2018.0090. [PMID: 29794006 DOI: 10.1098/rsbl.2018.0090] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/30/2018] [Indexed: 11/12/2022] Open
Abstract
The toothless beak of modern birds was considered as an adaption for feeding ecology; however, several recent studies suggested that developmental factors are also responsible for the toothless beak. Neontological and palaeontological studies have progressively uncovered how birds evolved toothless beaks and suggested that the multiple occurrences of complete edentulism in non-avian dinosaurs were the result of selection for specialized diets. Although developmental biology and ecological factors are not mutually exclusive, the conventional hypothesis that ecological factors account for the toothless beak appears insufficient. A recent study on dinosaur incubation period using embryonic teeth posited that tooth formation rate limits developmental speed, constraining toothed dinosaur incubation to slow reptilian rates. We suggest that selection for tooth loss was a side effect of selection for fast embryo growth and thus shorter incubation. This observation would also explain the multiple occurrences of tooth loss and beaks in non-avian dinosaur taxa crownward of Tyrannosaurus Whereas our hypothesis is an observation without any experimental supports, more studies of gene regulation of tooth formation in embryos would allow testing for the trade-off between incubation period and tooth development.
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Affiliation(s)
- Tzu-Ruei Yang
- Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 8, 53115 Bonn, Germany
| | - P Martin Sander
- Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 8, 53115 Bonn, Germany.,Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA
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19
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Why did the dinosaurs become extinct? Could cholecalciferol (vitamin D 3) deficiency be the answer? J Nutr Sci 2019; 8:e9. [PMID: 30911383 PMCID: PMC6425225 DOI: 10.1017/jns.2019.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 02/19/2019] [Accepted: 02/21/2019] [Indexed: 11/07/2022] Open
Abstract
Palaeontological deductions from the fossil remnants of extinct dinosaurs tell us much about their classification into species as well as about their physiological and behavioural characteristics. Geological evidence indicates that dinosaurs became extinct at the boundary between the Cretaceous and Paleogene eras, about 66 million years ago, at a time when there was worldwide environmental change resulting from the impact of a large celestial object with the Earth and/or from vast volcanic eruptions. However, apart from the presumption that climate change and interference with food supply contributed to their extinction, no biological mechanism has been suggested to explain why such a diverse range of terrestrial vertebrates ceased to exist. One of perhaps several contributing mechanisms comes by extrapolating from the physiology of the avian descendants of dinosaurs. This raises the possibility that cholecalciferol (vitamin D3) deficiency of developing embryos in dinosaur eggs could have caused their death before hatching, thus extinguishing the entire family of dinosaurs through failure to reproduce.
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20
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Chen J, LeBlanc ARH, Jin L, Huang T, Reisz RR. Tooth development, histology, and enamel microstructure in Changchunsaurus parvus: Implications for dental evolution in ornithopod dinosaurs. PLoS One 2018; 13:e0205206. [PMID: 30403689 PMCID: PMC6221265 DOI: 10.1371/journal.pone.0205206] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/20/2018] [Indexed: 11/24/2022] Open
Abstract
The great diversity of dinosaurian tooth shapes and sizes, and in particular, the amazing dental complexity in derived ornithischians has attracted a lot of attention. However, the evolution of dental batteries in hadrosaurids and ceratopsids is difficult to understand without a broader comparative framework. Here we describe tooth histology and development in the "middle" Cretaceous ornithischian dinosaur Changchunsaurus parvus, a small herbivore that has been characterized as an early ornithopod, or even as a more basal ornithischian. We use this taxon to show how a "typical" ornithischian dentition develops, copes with wear, and undergoes tooth replacement. Although in most respects the histological properties of their teeth are similar to those of other dinosaurs, we show that, as in other more derived ornithischians, in C. parvus the pulp chamber is not invaded fully by the newly developing replacement tooth until eruption is nearly complete. This allowed C. parvus to maintain an uninterrupted shearing surface along a single tooth row, while undergoing continuous tooth replacement. Our histological sections also show that the replacement foramina on the lingual surfaces of the jaws are likely the entry points for an externally placed dental lamina, a feature found in many other ornithischian dinosaurs. Surprisingly, our histological analysis also revealed the presence of wavy enamel, the phylogenetically earliest occurrence of this type of tissue. This contradicts previous interpretations that this peculiar type of enamel arose in association with more complex hadrosauroid dentitions. In view of its early appearance, we suggest that wavy enamel may have evolved in association with a shearing-type dentition in a roughly symmetrically-enameled crown, although its precise function still remains somewhat of a mystery.
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Affiliation(s)
- Jun Chen
- International Center of Future Science, Dinosaur Evolution Research Center, Jilin University, Changchun, China
- The Key-Lab for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, China, Changchun, China
| | - Aaron R. H. LeBlanc
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Liyong Jin
- International Center of Future Science, Dinosaur Evolution Research Center, Jilin University, Changchun, China
- The Key-Lab for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, China, Changchun, China
| | - Timothy Huang
- International Center of Future Science, Dinosaur Evolution Research Center, Jilin University, Changchun, China
| | - Robert R. Reisz
- International Center of Future Science, Dinosaur Evolution Research Center, Jilin University, Changchun, China
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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21
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Abstract
Dinosaurs were large-bodied land animals of the Mesozoic that gave rise to birds. They played a fundamental role in structuring Jurassic–Cretaceous ecosystems and had physiology, growth, and reproductive biology unlike those of extant animals. These features have made them targets of theoretical macroecology. Dinosaurs achieved substantial structural diversity, and their fossil record documents the evolutionary assembly of the avian body plan. Phylogeny-based research has allowed new insights into dinosaur macroevolution, including the adaptive landscape of their body size evolution, patterns of species diversification, and the origins of birds and bird-like traits. Nevertheless, much remains unknown due to incompleteness of the fossil record at both local and global scales. This presents major challenges at the frontier of paleobiological research regarding tests of macroecological hypotheses and the effects of dinosaur biology, ecology, and life history on their macroevolution.
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Affiliation(s)
- Roger B.J. Benson
- Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, United Kingdom
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22
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An Intermediate Incubation Period and Primitive Brooding in a Theropod Dinosaur. Sci Rep 2018; 8:12454. [PMID: 30127534 PMCID: PMC6102251 DOI: 10.1038/s41598-018-30085-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 07/24/2018] [Indexed: 11/09/2022] Open
Abstract
Non-avian dinosaurs such as oviraptorosaurs and troodontids share several important reproductive characters with modern birds, including eggshell microstructure and iterative egg production. Nevertheless, debate exists concerning their incubation strategies. Here we estimate incubation period for the troodontid, Troodon formosus, by examining a near-term embryonic tooth. Synchrotron scanning and histologic thin sections allowed counting of daily (von Ebner) growth lines. The tooth preserves 31 intact lines with an average spacing of 3.3 ± 0.96 μm. Adding 8 more for the missing crown tip gives a total age of 39 days. Modern crocodilians begin to establish their functional dentition at approximately 47% through incubation. Thus, this tooth age suggests a Troodon incubation period of 74 days, falling midway between avian (44.4 days) and reptilian (107.3 days) values predicted by the Troodon egg mass (314 g). An accelerated incubation relative to modern reptiles supports brooding and concurs with a suite of features in oviraptorosaurs and troodontids (sequential laying, large complex clutches, and precocial young) that appear dependent upon both adult body and incubation temperatures elevated over ambient conditions. However, the largely buried condition of Troodon clutches may have prohibited efficient brooding, necessitating longer incubation than that of modern birds with fully exposed eggs.
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23
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Waugh DA, Suydam RS, Ortiz JD, Thewissen JGM. Validation of Growth Layer Group (GLG) depositional rate using daily incremental growth lines in the dentin of beluga (Delphinapterus leucas (Pallas, 1776)) teeth. PLoS One 2018; 13:e0190498. [PMID: 29338011 PMCID: PMC5770016 DOI: 10.1371/journal.pone.0190498] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 12/15/2017] [Indexed: 12/04/2022] Open
Abstract
Counts of Growth Layer Groups (GLGs) in the dentin of marine mammal teeth are widely used as indicators of age. In most marine mammals, observations document that GLGs are deposited yearly, but in beluga whales, some studies have supported the view that two GLGs are deposited each year. Our understanding of beluga life-history differs substantially depending on assumptions regarding the timing of GLG deposition; therefore, resolving this issue has important considerations for population assessments. In this study, we used incremental lines that represent daily pulses of dentin mineralization to test the hypothesis that GLGs in beluga dentin are deposited on a yearly basis. Our estimate of the number of daily growth lines within one GLG is remarkably close to 365 days within error, supporting the hypothesis that GLGs are deposited annually in beluga. We show that measurement of daily growth increments can be used to validate the time represented by GLGs in beluga. Furthermore, we believe this methodology may have broader applications to age estimation in other taxa.
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Affiliation(s)
- David A. Waugh
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
- * E-mail:
| | - Robert S. Suydam
- North Slope Borough, Department of Wildlife Management, Barrow, Alaska, United States of America
| | - Joseph D. Ortiz
- Department of Geology, Kent State University, Kent, Ohio, United States of America
| | - J. G. M. Thewissen
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
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24
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Button K, You H, Kirkland JI, Zanno L. Incremental growth of therizinosaurian dental tissues: implications for dietary transitions in Theropoda. PeerJ 2017; 5:e4129. [PMID: 29250467 PMCID: PMC5729821 DOI: 10.7717/peerj.4129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/14/2017] [Indexed: 11/20/2022] Open
Abstract
Previous investigations document functional and phylogenetic signals in the histology of dinosaur teeth. In particular, incremental lines in dentin have been used to determine tooth growth and replacement rates in several dinosaurian clades. However, to date, few studies have investigated the dental microstructure of theropods in the omnivory/herbivory spectrum. Here we examine dental histology of Therizinosauria, a clade of large-bodied theropods bearing significant morphological evidence for herbivory, by examining the teeth of the early-diverging therizinosaurian Falcarius utahensis, and an isolated tooth referred to Suzhousaurus megatherioides, a highly specialized large-bodied representative. Despite attaining some of the largest body masses among maniraptoran theropod dinosaurs, therizinosaurian teeth are diminutive, measuring no more than 0.90 cm in crown height (CH) and 0.38 cm in crown base length (CBL). Comparisons with other theropods and non-theropodan herbivorous dinosaurs reveals that when controlling for estimated body mass, crown volume in therizinosaurians plots most closely with dinosaurs of similar dietary strategy as opposed to phylogenetic heritage. Analysis of incremental growth lines in dentin, observed in thin sections of therizinosaurian teeth, demonstrates that tooth growth rates fall within the range of other archosaurs, conforming to hypothesized physiological limitations on the production of dental tissues. Despite dietary differences between therizinosaurians and hypercarnivorous theropods, the types of enamel crystallites present and their spatial distribution—i.e., the schmelzmuster of both taxa—is limited to parallel enamel crystallites, the simplest form of enamel and the plesiomorphic condition for Theropoda. This finding supports previous hypotheses that dental microstructure is strongly influenced by phylogeny, yet equally supports suggestions of reduced reliance on oral processing in omnivorous/herbivorous theropods rather than the microstructural specializations to diet exhibited by non-theropodan herbivorous dinosaurs. Finally, although our sample is limited, we document a significant reduction in the rate of enamel apposition contrasted with increased relative enamel thickness between early and later diverging therizinosaurians that coincides with anatomical evidence for increased specializations to herbivory in the clade.
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Affiliation(s)
- Khai Button
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America.,Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, United States of America
| | - Hailu You
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China.,College of Earth Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - James I Kirkland
- Utah Geological Survey, Salt Lake City, UT, United States of America
| | - Lindsay Zanno
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America.,Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, United States of America
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25
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Affiliation(s)
- D Charles Deeming
- School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Lincoln LN6 7DL, UK.
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26
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Hughes NC, Hong PS, Hou J, Fusco G. The Development of the Silurian Trilobite Aulacopleura koninckii Reconstructed by Applying Inferred Growth and Segmentation Dynamics: A Case Study in Paleo-Evo-Devo. Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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27
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Lee SA. Embryonic metabolism of the ornithischian dinosaurs Protoceratops andrewsi and Hypacrosaurus stebingeri and implications for calculations of dinosaur egg incubation times. Phys Rev E 2017; 95:042407. [PMID: 28505802 DOI: 10.1103/physreve.95.042407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Indexed: 06/07/2023]
Abstract
The embryonic metabolisms of the ornithischian dinosaurs Protoceratops andrewsi and Hypacrosaurus stebingeri have been determined and are in the range observed in extant reptiles. The average value of the measured embryonic metabolic rates for P. andrewsi and H. stebingeri are then used to calculate the incubation times for 21 dinosaurs from both Sauischia and Ornithischia using a mass growth model based on conservation of energy. The calculated incubation times vary from about 70 days for Archaeopteryx lithographica to about 180 days for Alamosaurus sanjuanensis. Such long incubation times seem unlikely, particularly for the sauropods and large theropods. Incubation times are also predicted with the assumption that the saurischian dinosaurs had embryonic metabolisms in the range observed in extant birds.
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Affiliation(s)
- Scott A Lee
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
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