DOCSLIB.ORG

ENGLISH-DISSERTATION-2018.Pdf (1.259Mb)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
ENGLISH-DISSERTATION-2018.Pdf (1.259Mb) Copyright by Lauren Taylor English 2018 The Dissertation Committee for Lauren Taylor English Certifies that this is the approved version of the following Dissertation: Evolution of Functional Morphology of Osteoderms Across Crocodylomorpha Committee: Julia A. Clarke, Supervisor Christopher J. Bell Christopher Brochu Matthew W. Colbert Rowan C. Martindale Liza J. Shapiro Evolution of Functional Morphology of Osteoderms Across Crocodylomorpha by Lauren Taylor English Dissertation Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy The University of Texas at Austin May 2018 Dedication To my parents, Pamela and Julian, and to my brothers, Lee and Logan, for being the first to inspire in me a love of science and continuing to do so when times were hard, for never allowing me to forget to think critically, and for always being there to commiserate over failures and celebrate over triumphs. Acknowledgements Many people have contributed to the research presented here, which I cannot thank enough for their assistance. I am particularly grateful to my advisor, Julia Clarke, for all the guidance and support she has gifted me from start to finish. I would also like to thank everyone who has served on my committee (Chris Bell, Chris Brochu, Matt Colbert, Brian Horton, Rowan Martindale, Tim Rowe, and Liza Shapiro) for all the feedback that has improved this manuscript. I would like to thank the following institutions and their staff for access to specimens and CT scans: the Museum of Natural History, University of Florida, the Museum of Vertebrate Zoology, University of California, Berkeley, the Saint Augustine Alligator Farm, the University of Texas at Austin – Biodiversity Collections, the Texas A&M University – Biodiversity Research and Teaching Collections, the American Museum of Natural History, the Carnegie Museum of Natural History, the Field Museum, the North Carolina Museum of Natural Sciences, the Natural History Museum in London, the Senckenberg Naturmuseum, the Science Museum of Minnesota, Stony Brook University, the University of California Museum of Paleontology, Berkeley, the National Museum of Natural History. I would also like to thank the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University and the University of Texas High- Resolution X-ray Computed Tomography Facility for scanning specimens and particularly to Matt Colbert and Jessie Maisano for advice on processing CT data. Financial support was provided in part by the Ernest and Judith Lundelius Endowment in Vertebrate Paleontology, the University of Austin off-campus research funds, and by the Jackson School of Geosciences Student Travel Grant. v I would like to thank the other students in my lab (James Proffitt, Chad Eliason, Katie Browne, Nick Crouch, Sarah Davis, Zhiheng Li, Grace Musser, Chris Torres, and Xia Wang,) for helpful discussions of methodology and presentation, the collections and specimen preparation staff (Liath Appleton, Kenneth Bader, Lisa Boucher, Matt Brown, Cissy Geigerman, Ernest Lundelius, the late Ann Molineux, Tim Rowe, Chris Sagebiel, and Deborah Wagner) for showing me the ins and outs of specimen care, Philip Guerrero for his indispensable assistance in navigating campus paperwork, and the all other staff and students at the Jackson School of Geosciences for all their assistance and companionship over the years. vi Abstract Evolution of Functional Morphology of Osteoderms Across Crocodylomorpha Lauren Taylor English, PhD The University of Texas at Austin, 2018 Supervisor: Julia A. Clarke The vertebrate integument is a complex anatomical system that has evolved a wide array of specialized structures that are related to an animal’s ecology and evolutionary history, including mineralized structures found in many clades and ecological niches called osteoderms. However, the development, functional morphology, and evolutionary history of osteoderms is still poorly understood in relation to other portions of the skeleton. Osteoderms have independently evolved multiple times and can be found in the skin of many vertebrate lineages, making up a significant portion of the evolutionary history of the tetrapod skeleton. Though several hypotheses of osteoderm function have been proposed based on their overall morphology, osteoderm function has rarely been the subject of experimental analyses and only in a few taxa. The major aims of this research are to test new and previously proposed hypotheses of osteoderms function and to better understand drivers of osteoderm morphological variation using Crocodylomorpha as the study group, both because of their long and rich history of ecological diversity and because of their exemplary fossil record compared with other osteoderm bearing taxa. Quantification of within-individual variation in extant vii crocodilians suggests that relaxed selection on osteoderm morphology only occurs in taxa thought to exhibit reduced intraspecific aggression, suggesting that osteoderms evolved in Crocodylia as a defensive structure in territorial disputes. This is corroborated by an ontogenetic analysis, which demonstrates that in at least some crocodilian species, osteoderm growth coincides with the onset of territorial behavior, contradicting previously proposed hypotheses that crocodilian osteoderms function in thermoregulation, in stabilization of the vertebral column, or as a defense against predators. In contrast with previous research that had demonstrated a reduction of body flexibility when osteoderms are present, a final comparative analysis across Crocodylomorpha found no correlation between osteoderm aspect ratio and locomotor ecology, suggesting that osteoderm dimensions have no impact on flexibility. This research disputes some previously proposed hypotheses of osteoderm function and when placed in context of other research, reveals that osteoderms may have different functions in different taxa. viii Table of Contents Chapter 1: Variation in crocodilian dorsal scute organization and geometry with a discussion of possible functional implications ...........................................................1 Abstract .......................................................................................................................1 Introduction .................................................................................................................2 Materials and Methods................................................................................................4 Variation in scute dimensions .........................................................................5 Bilateral fluctuating asymmetry of carapace ..................................................5 Scutellation pattern .........................................................................................6 Results .........................................................................................................................7 Variation in scute dimensions .........................................................................7 Lateral asymmetry of carapace .......................................................................7 Rectangular vs. pentagonal/hexagonal scute arrangement .............................8 Discussion ...................................................................................................................8 Conclusions ...............................................................................................................10 Tables ........................................................................................................................11 Figures ......................................................................................................................12 Chapter 2: Late ontogenetic development of osteoderms and their role in social behavior.....................................................................................................................15 Abstract .....................................................................................................................15 Introduction ...............................................................................................................16 Materials and Methods..............................................................................................20 Specimens .....................................................................................................20 Assessment of maturity .................................................................................20 ix Results .......................................................................................................................21 General developmental patterns in all species ..............................................21 Life history & osteoderm development in Caiman crocodilus and Crocodylus niloticus ...............................................................................22 Discussion and Conclusions .....................................................................................23 Tables ........................................................................................................................26 Figures ......................................................................................................................28 Chapter 3: Assessment of the comparative morphology of osteoderms and locomotor ecology in Crocodylomorpha ....................................................................................30
Load more

Recommended publications
  • Pleistocene – Cretaceous One-Two Punch
    FOSSIL COLLECTING REPORT September 2008 Daniel A. Woehr and Friends and Family September 1, 2008: Pleistocene – Cretaceous One-Two Punch “It’s the sheriff!” is what I heard when I opened my eyes to blinding lights. It seems that Johnny Law is not used to seeing law abiding grown men sleeping in cars by the roadside. I explained that I was nothing more than a nerdy fossil hunter on a budget and after checking my ID and noting the boat on my roof I suppose he believed me, as did his backup in the second car with headlights in my face. Dawn found me at my second put-in and soon making my way to a distant gravel bar. I wasn’t expecting much but my first find was a worn but very welcome mastodon vertebra. Finds were slow to come but some were rather nice. A good horse tooth, horse tibia, bison astragulus and calcaneum, and a few other things came to hand and put some heft in my catch bag. Still, the ever elusive mammoth tooth evaded me once again. FIG 1: Alligator mississippiensis osteoderm from Site 373 FIGS 2-6: Bison sp. calcaneum above and astragulus below (both ankle bones), 2 more views of same followed by worn Glyptotherium osteoderm next page (Site 373) FIG 7: Unidentified distal radius and distal scapula followed by horse lower molar (Site 373) FIGS 8-9: Worn Mammut americanum (mastodon) vertebra (Site 373) FIGS 10-11: Unidentified proximal rib and vertebrae (Site 373) Switching gears, I began my drive home, learned that the wife and boy wouldn’t be home anytime soon, and opted to drop in once again on some parts of the Corsicana exposure that Weston and I didn’t have time to look over on prior trips.
    [Show full text]
  • Crocodile Farming with Particular Reference to East Africa
    British Herpetological Sot 'co, Bulletin, No. 66, 1999 CROCODILE FARMING WITH PARTICULAR REFERENCE TO EAST AFRICA JOHN E. COOPER, DTVM, FRCPath, FIBiol, FRCVS Faculty of Veterinary Medicine, Sokoine University of Agriculture P.O. Box 3021, Morogoro, Tanzania Contact address in UK: Wildlife Health Services P.O. Box 153, Wellingborough, Northants NN8 2ZA INTRODUCTION The Class Crocodilia consists of the crocodiles, alligators, caimans and gharials. There are twenty-three extant species but, in the past, many more existed (Frye, 1994). Crocodiles are reptiles that are well adapted to life in water. While most are freshwater, one species is partly marine. The anatomy of crocodiles is dominated by their tough integument which, on the dorsum, is protected by plates of osteoderm. Internally, crocodiles have a well developed palate, a four chambered heart and a right aortic arch. All crocodilians are oviparous. In many species the female constructs a nest of decaying vegetable matter and as this decomposes, the temperature rises and assists in incubation. Sex determination in crocodilians is temperature-related. Crocodilians are unusual amongst reptiles in that the nests are guarded by the mother (possibly the father) who also protects the young, often for a considerable period of time. The Nile Crocodile (Crocodyhts nitoticits) is the most widespread of the three species of crocodile that are found in Africa. The Nile Crocodile is biologically similar to other crocodilians. It is an ectothermic vertebrate. The free-living crocodile reaches sexual maturity at between 20 and 35 years of age when the male is 3-3.3 m in length and the female is 2.4-2.8 m (Revol, 1995).
    [Show full text]
  • The Armor of FOSSIL GIANT ARMADILLOS (Pa1npatlzeriidae, Xenartlz Ra, Man1malia) A
    NUMBER40 PEARCE-SELLARDS SERIES The Armor of FOSSIL GIANT ARMADILLOS (Pa1npatlzeriidae, Xenartlz ra, Man1malia) A. GORDON EDMUND JUNE 1985 TEXAS MEMORIAL MUSEUM, UNIVERSITY OF TEXAS AT AUSTIN Pearce-Sellards Series 40 The Armor of FOSSIL GIANT ARMADILLOS (Pampatheriidae, Xenartlzra, Mammalia) A. GORDON EDMUND JUNE 1985 TEXAS MEMORIAL MUSEUM, UNIVERSITY OF TEXAS AT AUSTIN A. Gordon Edmund is Curator of Vertebrate Paleontology at the Royal Ontario Museum, Toronto, and Associate Professor of Geology at the University of Toronto. The Pearce-Sellards Series is an occasional, miscellaneous series of brief reports of Museum and Museum-associated field investigations and other research. All manuscripts are subjected to extramural peer review before being accepted. The series title commemorates the first two directors of Texas Memorial Museum, both now deceased: Dr. J. E. Pearce, Professor of Anthropology, and Dr. E. H. Sellards, Professor of Geology, The University of Texas at Austin. A portion of the Museum's general ope­ rating funds for this fiscal year has been provided by a grant from the Institute of Museum Services, a federal agency that offers general operating support to the nation's museums. © 1985 by Texas Memorial Museum The University of Texas at Austin All rights reserved Printed in the United States of America CONTENTS Abstract .... .............................................. I Sumario .................................................... 1 Acknowledgements . 2 Abbreviations ............................................... 2 Introduction . 3 A General Description of the Armor . 5 Types and Numbers of Osteoderms .... .. ........................ 6 Structure of Osteoderms . 7 Detailed Description of each Area ................................ 8 Conclusions. 19 References ............ .. .............. ............. ....... 19 LIST OF FIGURES Fig. 1. Restoration of Holmesina septentrionalis based on composite material from Florida ......... ...... .... facing 5 Fig.
    [Show full text]
  • Unprovoked Mouth Gaping Behavior in Extant Crocodylia
    Journal of Herpetology, Vol. 54, No. 4, 418–426, 2020 Copyright 2020 Society for the Study of Amphibians and Reptiles Unprovoked Mouth Gaping Behavior in Extant Crocodylia 1,2 3 4 NOAH J. CARL, HEATHER A. STEWART, AND JENNY S. PAUL 1Reptile Department, St. Augustine Alligator Farm Zoological Park, St. Augustine, Florida, 32080, USA 3Department of Biology, McGill University, Montre´al, Que´bec, Canada H3A 1B1 4Greg A. Vital Center for Natural Resources and Conservation, Cleveland State Community College, Cleveland, Tennessee, 37320, USA ABSTRACT.—Unprovoked mouth gaping behavior is ubiquitous throughout 24 extant members of Crocodylia, yet information on gaping Downloaded from http://meridian.allenpress.com/journal-of-herpetology/article-pdf/54/4/418/2696499/i0022-1511-54-4-418.pdf by guest on 25 September 2021 is limited. Proposed hypotheses for gaping include thermoregulation and the evaluation of potential environmental conditions. To determine temperature effects, we tracked head surface (Tsh), body surface (Tsb), and ambient (Ta) temperatures with insolation utilization and positions. To evaluate potential environmental stimuli, we tested behavioral effects (i.e., open-eye frequency) and recorded conspecific presence, day and night events, and interaction with flies and fish. We included 24 extant species representatives, with detailed assessments of American Alligators (Alligator mississippiensis), Crocodylus siamensis, Crocodylus intermedius, Crocodylus rhombifer, and Crocodylus halli. Observations occurred during a range of Ta (3.89–32.228C) with mean Tsh consistently higher than both Tsb and Ta across all crocodilians. Differences in Tsh and Ta were most pronounced with head in the sun. However, no significant differences in Tsh and Tsb were detected for A.
    [Show full text]
  • Allen-Etal-Calcium-2009.Pdf
    This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy Comparative Biochemistry and Physiology, Part A 154 (2009) 437–450 Contents lists available at ScienceDirect Comparative Biochemistry and Physiology, Part A journal homepage: www.elsevier.com/locate/cbpa Calcium regulation in wild populations of a freshwater cartilaginous fish, the lake sturgeon Acipenser fulvescens Peter J. Allen a,b,⁎, Molly A.H. Webb c, Eli Cureton c, Ronald M. Bruch d, Cameron C. Barth a,b, Stephan J. Peake b, W. Gary Anderson a a Department of Biological Sciences, University of Manitoba, Winnipeg, Canada, MB R3T 2N2 b Canadian Rivers Institute, University of New Brunswick, Fredericton, Canada, NB E3B 5A3 c USFWS Bozeman Fish Technology Center, Bozeman, MT, 59715, USA d Wisconsin Department of Natural Resources, 625 East County Road Y, Suite 700, Oshkosh, WI 54901, USA article info abstract Article history: Lake sturgeon, Acipenser fulvescens, are one of a few species of cartilaginous fishes that complete their life Received 27 May 2009 cycle entirely in freshwater.
    [Show full text]
  • The Morphology and Sculpture of Ossicles in the Cyclopteridae and Liparidae (Teleostei) of the Baltic Sea
    Estonian Journal of Earth Sciences, 2010, 59, 4, 263–276 doi: 10.3176/earth.2010.4.03 The morphology and sculpture of ossicles in the Cyclopteridae and Liparidae (Teleostei) of the Baltic Sea Tiiu Märssa, Janek Leesb, Mark V. H. Wilsonc, Toomas Saatb and Heli Špilevb a Institute of Geology at Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; [email protected] b Estonian Marine Institute, University of Tartu, Mäealuse Street 14, 12618 Tallinn, Estonia; [email protected], [email protected], [email protected] c Department of Biological Sciences and Laboratory for Vertebrate Paleontology, University of Alberta, Edmonton, Alberta T6G 2E9 Canada; [email protected] Received 31 August 2009, accepted 28 June 2010 Abstract. Small to very small bones (ossicles) in one species each of the families Cyclopteridae and Liparidae (Cottiformes) of the Baltic Sea are described and for the first time illustrated with SEM images. These ossicles, mostly of dermal origin, include dermal platelets, scutes, tubercles, prickles and sensory line segments. This work was undertaken to reveal characteristics of the morphology, sculpture and ultrasculpture of these small ossicles that could be useful as additional features in taxonomy and systematics, in a manner similar to their use in fossil material. The scutes and tubercles of the cyclopterid Cyclopterus lumpus Linnaeus are built of small denticles, each having its own cavity viscerally. The thumbtack prickles of the liparid Liparis liparis (Linnaeus) have a tiny spinule on a porous basal plate; the small size of the prickles seems to be related to their occurrence in the exceptionally thin skin, to an adaptation for minimizing weight and/or metabolic cost and possibly to their evolution from isolated ctenii no longer attached to the scale plates of ctenoid scales.
    [Show full text]
  • The Respiratory Mechanics of the Yacare Caiman (Caiman Yacare Daudine)
    First posted online on 29 November 2018 as 10.1242/jeb.193037 Access the most recent version at http://jeb.biologists.org/lookup/doi/10.1242/jeb.193037 The Respiratory Mechanics of the Yacare Caiman (Caiman yacare Daudine) Michelle N. Reichert1, Paulo R.C. de Oliveira2, 3, George M.P.R. Souza4, Henriette G. Moranza5, Wilmer A.Z. Restan5, Augusto S. Abe6, Wilfried Klein2, William K. Milsom7 1Royal Veterinary College, University of London, London, UK 2Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil 3Instituto Federal do Paraná- Câmpus Avançado Goioerê, Goioerê, PR, Brazil 4School of Medicine of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil 5Clinica Médica Veterinária, Universidade Estadual Paulista, Jaboticabal, SP, Brazil 6Departamento de Zoologia, Universidade Estadual Paulista, Rio Claro, SP, Brazil 7Department of Zoology, University of British Columbia, Vancouver, B.C., Canada Author for correspondence: Michelle N Reichert, [email protected] Key words: respiratory mechanics, static compliance, dynamic compliance, elastic forces, resistive forces, work of breathing Summary Statement: The respiratory system of the caiman stiffens during development as the body wall becomes more muscular and keratinized. Most of the work of breathing is required to overcome elastic forces and increases when animals are submerged. Flow resistance, primarily arising from the lungs, plays a significant role at higher ventilation frequencies. © 2018. Published by The Company of Biologists Ltd. Journal of Experimental Biology • Accepted manuscript Abstract The structure and function of crocodilian lungs are unique compared to other reptiles. We examine the extent to which this, and the semi-aquatic lifestyle of crocodilians affect their respiratory mechanics.
    [Show full text]
  • The Osteoderm Microstructure in Doswelliids and Proterochampsids and Its Implications for Palaeobiology of Stem Archosaurs
    The osteoderm microstructure in doswelliids and proterochampsids and its implications for palaeobiology of stem archosaurs DENIS A. PONCE, IGNACIO A. CERDA, JULIA B. DESOJO, and STERLING J. NESBITT Ponce, D.A., Cerda, I.A., Desojo, J.B., and Nesbitt, S.J. 2017. The osteoderm microstructure in doswelliids and proter- ochampsids and its implications for palaeobiology of stem archosaurs. Acta Palaeontologica Polonica 62 (4): 819–831. Osteoderms are common in most archosauriform lineages, including basal forms, such as doswelliids and proterochamp- sids. In this survey, osteoderms of the doswelliids Doswellia kaltenbachi and Vancleavea campi, and proterochampsid Chanaresuchus bonapartei are examined to infer their palaeobiology, such as histogenesis, age estimation at death, development of external sculpturing, and palaeoecology. Doswelliid osteoderms have a trilaminar structure: two corti- ces of compact bone (external and basal) that enclose an internal core of cancellous bone. In contrast, Chanaresuchus bonapartei osteoderms are composed of entirely compact bone. The external ornamentation of Doswellia kaltenbachi is primarily formed and maintained by preferential bone growth. Conversely, a complex pattern of resorption and redepo- sition process is inferred in Archeopelta arborensis and Tarjadia ruthae. Vancleavea campi exhibits the highest degree of variation among doswelliids in its histogenesis (metaplasia), density and arrangement of vascularization and lack of sculpturing. The relatively high degree of compactness in the osteoderms of all the examined taxa is congruent with an aquatic or semi-aquatic lifestyle. In general, the osteoderm histology of doswelliids more closely resembles that of phytosaurs and pseudosuchians than that of proterochampsids. Key words: Archosauria, Doswelliidae, Protero champ sidae, palaeoecology, microanatomy, histology, Triassic, USA.
    [Show full text]
  • The Integumental Appendages of the Turtle Shell: an Evo-Devo Perspective JACQUELINE E
    COMMENTARY AND PERSPECTIVE The Integumental Appendages of the Turtle Shell: An Evo-Devo Perspective JACQUELINE E. MOUSTAKAS-VERHO1* 2 AND GENNADII O. CHEREPANOV 1Institute of Biotechnology, University of Helsinki, Helsinki, Finland 2Department of Vertebrate Zoology, Faculty of Biology, St. Petersburg State University, St. Petersburg, Russia ABSTRACT The turtle shell is composed of dorsal armor (carapace) and ventral armor (plastron) covered by a keratinized epithelium. There are two epithelial appendages of the turtle shell: scutes (large epidermal shields separated by furrows and forming a unique mosaic) and tubercles (numerous small epidermal bumps located on the carapaces of some species). In our perspective, we take a synthetic, comparative approach to consider the homology and evolution of these integumental appendages. Scutes have been more intensively studied, as they are autapomorphic for turtles and can be diagnostic taxonomically. Their pattern of tessellation is stable phylogenetically, but labile in the individual. We discuss the history of developmental investigations of these structures and hypotheses of evolutionary and anomalous variation. In our estimation, the scutes of the turtle shell are an evolutionary novelty, whereas the tubercles found on the shells of some turtles are homologous to reptilian scales. J. Exp. Zool. (Mol. Dev. Evol.) 324B:221–229, 2015. © 2015 Wiley Periodicals, Inc. J. Exp. Zool. (Mol. Dev. Evol.) How to cite this article: Moustakas-Verho JE, Cherepanov GO. 2015. The integumental 324B:221–229, appendages of the turtle shell: An evo-devo perspective. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 2015 221–229. EVOLUTIONARY ORIGIN AND DEVELOPMENT OF TURTLE Turtles can often be recognized by the pattern of scutes, or lack SCUTES thereof, on their shell.
    [Show full text]
  • The Role of Collagen in the Dermal Armor of the Boxfish
    j m a t e r r e s t e c h n o l . 2 0 2 0;9(xx):13825–13841 Available online at www.sciencedirect.com https://www.journals.elsevier.com/journal-of-materials-research-and-technology Original Article The role of collagen in the dermal armor of the boxfish a,∗ b c b Sean N. Garner , Steven E. Naleway , Maryam S. Hosseini , Claire Acevedo , d e a e c Bernd Gludovatz , Eric Schaible , Jae-Young Jung , Robert O. Ritchie , Pablo Zavattieri , f Joanna McKittrick a Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093–0411, USA b Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA c Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USA d School of Mechanical & Manufacturing Engineering, UNSW Sydney, NSW 2052, Australia e Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA f Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093–0411, USA a r t i c l e i n f o a b s t r a c t Article history: This research aims to further the understanding of the structure and mechanical properties Received 1 June 2020 of the dermal armor of the boxfish (Lactoria cornuta). Structural differences between colla- Accepted 24 September 2020 gen regions underlying the hexagonal scutes were observed with confocal microscopy and Available online 5 October 2020 microcomputed tomography (␮-CT). ␮-CT revealed a tapering of the mineral plate from the center of the scute to the interface between scutes, suggesting the structure allows for more ␮ Keywords: flexibility at the interface.
    [Show full text]
  • Carapacial Scute Anomalies of Star Tortoise (Geochelone Elegans) In
    TAPROBANICA, ISSN 1800-427X. October, 2012. Vol. 04, No. 02: pp. 105-107, 1 pl. © Taprobanica Private Limited, 146, Kendalanda, Homagama, Sri Lanka. Carapacial scute anomalies of star tortoise arrangement and the carapace drawings are (Geochelone elegans) in Western India from the sources of Deraniyagala (1939). But the ‘Figure 5’ (on page 13) shows something The basic taxonomy and classification of reptile else, an illustration which is not a typical scale species and genera often use pholidotic drawing of the species. This figure of a tortoise characters. Despite that each species has a shows abnormal scales and scutes, especially standard pattern, there are always deviant vertebral, costal and marginal scutes, which are individuals in terms of scale number, shape, in higher numbers than the provided description size, or color. Turtles are excellent models for of the species by Schoepff (1795). the study of developmental instability because anomalies are easily detected in the form of Observations (see plate 1 for figures) malformations, additions, or reductions in the During the last eleven years (1990-2011), I number of scutes or scales (Velo-Antón et al., have come across many star tortoises in the 2011). The normal number of carapacial scutes wild (n=65) and in captivity (n=135), belonging in turtles is five vertebrals, four pairs of costals, to different ages and sizes (from hatchlings to a and 12 pairs of marginals, a pattern known as 55 year old, which was the largest one) (Vyas, “typical chelonian carapacial scutation” 2011). All specimens were bred under natural (Deraniyagala, 1939). Any deviation of conditions (although 5 of the 6 specimens with vertebral, costal, or marginal scute numbers or anomalies were later kept in captivity).
    [Show full text]
  • Osteoderm Microstructure of Riostegotherium Yanei, the Oldest Xenarthra
    Anais da Academia Brasileira de Ciências (2019) 91(Suppl. 2): e20181290 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 http://dx.doi.org/10.1590/0001-3765201920181290 www.scielo.br/aabc | www.fb.com/aabcjournal Osteoderm microstructure of Riostegotherium yanei, the oldest Xenarthra LÍLIAN P. BERGQVIST1, PAULO VICTOR LUIZ G.C. PEREIRA2, ALESSANDRA S. MACHADO3, MARIELA C. DE CASTRO4, LUIZA B. MELKI2 and RICARDO T. LOPES3 1Departamento de Geologia, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos 274, Bl. G, Sala G1053, Ilha do Fundão, 21941-611 Rio de Janeiro, RJ, Brazil 2Programa de Pós-graduação em Geologia, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos 274, Bl. G, sala G1053, Ilha do Fundão, 21941-611 Rio de Janeiro, RJ, Brazil 3Laboratório de Instrumentação Nuclear, Universidade Federal do Rio de Janeiro. Centro de Tecnologia, Bloco I, Sala I-133, Ilha do Fundão, 21941-972 Rio de Janeiro, RJ, Brazil 4Departamento de Ciências Biológicas, IBiotec, Universidade Federal de Goiás, Regional Catalão, Av. Castelo Branco, s/n, St. Universitário Campus II, Sala 6, 75704-020 Catalão, GO, Brazil Manuscript received on December 3, 2018; accepted for publication on May 3, 2019 How to cite: BERGQVIST LP, PEREIRA PVLGC, MACHADO AS, CASTRO MC, MELKI LB AND LOPES RT. 2019. Osteoderm microstructure of Riostegotherium yanei, the oldest Xenarthra. An Acad Bras Cienc 91: e20181290. DOI 10.1590/0001-3765201920181290. Abstract: Riostegotherium yanei from the Itaboraí Basin, Brazil, is the oldest known Xenarthra. This paper aims to describe the internal morphology of the osteoderms of Riostegotherium yanei from the perspective of histology and micro-CT approaches, expanding the available data on cingulate osteoderm microstructure.
    [Show full text]