DOCSLIB.ORG

Continuous Dental Replacement in a Hyper-Chisel Tooth Digging Rodent

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Continuous Dental Replacement in a Hyper-Chisel Tooth Digging Rodent Continuous dental replacement in a hyper-chisel tooth digging rodent a,1 a b c d Helder Gomes Rodrigues , Pauline Marangoni , Radim Sumbera , Paul Tafforeau , Wim Wendelen , and Laurent Viriota,1 aTeam “Evo-Devo of Vertebrate Dentition,” Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Unité Mixte de Recherche 5242, Centre National de la Recherche Scientifique, Université Claude Bernard de Lyon 1, Ecole Normale Supérieure de Lyon, 69364 Lyon Cedex 07, France; bDepartment of Zoology, Faculty of Science, University of South Bohemia, Ceské Budejovice 37005, Czech Republic; cEuropean Synchrotron Radiation Facility, 38043 Grenoble Cedex, France; and dVertebrate Section, Zoology Department, Royal Museum for Central Africa, B-3080 Tervuren, Belgium Edited by David B. Wake, University of California, Berkeley, CA, and approved September 8, 2011 (received for review June 15, 2011) Contrary to their reptilian ancestors, which had numerous dental mechanisms leading to CDR, notably the occurrence of super- generations, mammals are known to usually develop only two numerary teeth in mammals (8, 9), remain to be determined. generations of teeth. However, a few mammal species have Here we report a case of CDR in a subterranean rodent, the acquired the ability to continuously replace their dentition by silvery mole-rat Heliophobius argenteocinereus, belonging to Af- the constant addition of supernumerary teeth moving secondarily rican mole-rats (Bathyergidae, Rodentia), which could signifi- toward the front of the jaw. The resulting treadmill-like replace- cantly contribute to the understanding of this rare phenomenon. ment is thus horizontal, and differs completely from the vertical The dental peculiarities of this species further underscore the dental succession of other mammals and their extinct relatives. De- interest of African mole-rats as models for examining topical spite the developmental implications and prospects regarding the issues, such as “eusociality” (10, 11), extreme longevity (12), and origin of supernumerary teeth, this striking innovation remains cancer resistance (13). We investigated Heliophobius dentition poorly documented. Here we report another case of continuous compared with Trichechus, P. concinna, and another African dental replacement in an African rodent, Heliophobius argenteo- mole-rat (the Cape mole-rat, Georychus capensis) to appraise the cinereus, which combines this dental system with the progressive main dental characteristics of this rodent on the one hand and to eruption of high-crowned teeth. The escalator-like mechanism of identify the specific traits relevant to improved knowledge of the EVOLUTION Heliophobius constitutes an original adaptation to hyper-chisel CDR mechanism on the other. tooth digging involving high dental wear. Comparisons between Heliophobius and the few mammals that convergently acquired Results and Discussion continuous dental replacement reveal that shared inherited traits, Original System of Dental Replacement Among Mammals Combining including dental mesial drift, delayed eruption, and supernumerary Hypsodonty and Continuous Dental Replacement. Heliophobius dis- molars, comprise essential prerequisites to setting up this dental plays four to seven cheek teeth (Fig. 1 A–C and Tables S1 and mechanism. Interestingly, these dental traits are present to a lesser S2), whereas the maximum cheek tooth number per dental extent in humans but are absent in mouse, the usual biological quadrant does not usually exceed five in rodents and four in model. Consequently, Heliophobius represents a suitable model African mole-rats. It is thus the only known rodent displaying so to investigate the molecular processes leading to the development many supernumerary cheek teeth. Although its abnormal tooth of supernumerary teeth in mammals, and the accurate description number has previously been reported (14), the underlying dental fi of these processes could be a signi cant advance for further appli- mechanism has never been properly interpreted. Heliophobius cations in humans, such as the regeneration of dental tissues. has single-rooted and bilophate hypsodont teeth. Tooth occlusal surfaces rapidly become flat and undergo a series of shape mole-rats | intensive burrowing activity | hypsodonty | abrasion | attrition transformations, finally resulting in upper heart-shaped and lower pear-shaped teeth (Fig. 1 A–C) that lack enamel to varying ost nonmammalian vertebrates continuously replace their degrees and are covered by cementum. Morphometric compar- Mdentition, entailing many generations of identical teeth. In isons between occlusal crown shapes observed from rear to front contrast, mammals develop a limited dentition composed at and virtual transverse slices of an erupting tooth belonging to the most of two generations of heteromorphous teeth, decreasing in same row lead to the conclusion that the various crown shapes number but generally increasing in shape complexity during result from an increasing degree of dental wear (Fig. 1D). All evolution (1, 2). This has contributed to the acquisition of a more teeth have an overall identical cone-like shape and only their efficient masticatory apparatus than reptile jaws (3) that allowed relative size is susceptible to change during life. We cannot say mammals to diversify their feeding habits (4) and to include whether the first erupting tooth is a premolar (Fig. S1), as in tough and abrasive plants in their diets. To withstand abrasive most African mole-rats, but all subsequent teeth are molars. intakes, many mammals acquired a more durable dentition by Most specimens of Heliophobius show either one erupting or way of diverse evolutionary trends (5). The most frequently ob- freshly erupted molar behind the functional tooth row. After served is the increase in tooth height (i.e., hypsodonty), which eruption, each tooth drifts from rear to front. Evidence of hor- leads in extreme cases to ever-growing teeth. Another trend to izontal movements is demonstrated by continual remodeling of improve durability is continuous dental replacement (CDR), an extremely rare phenomenon in mammals. CDR corresponds to a progressive replacement of the dentition by regular develop- Author contributions: W.W. and L.V. designed research; H.G.R., P.M., and P.T. performed research; H.G.R. and P.M. analyzed data; and H.G.R., P.M., R.S., P.T., W.W., and L.V. wrote ment of additional teeth, which move from the rear to the front the paper. ’ of the jaw throughout the animal s life. Among the ca. 5,500 The authors declare no conflict of interest. species of mammals, only the three manatee species (Trichechus, This article is a PNAS Direct Submission. Sirenia) and the pygmy-rock wallaby (Petrogale concinna, Mac- 1To whom correspondence may be addressed. E-mail: helder.gomes.rodrigues@ens-lyon. ropodiformes) are known to display this striking innovation (6, 7). fr or [email protected]. To date, this mechanism appears poorly documented. Further- This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. more, the genetic etiology and the developmental and molecular 1073/pnas.1109615108/-/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.1109615108 PNAS Early Edition | 1of5 Downloaded by guest on September 27, 2021 are pushed out from the row alignment before being completely resorbed inside the bone (Figs. 1C and 2C). Because the molar progression is not synchronized between each quadrant, asym- metric dental rows occur (Fig. 1 A and B), as do rare cases of misalignment (Fig. S2B). Teeth also continue to grow and erupt vertically while moving to the front (Fig. 2 A and D). The orig- inality of the Heliophobius dental system relies on the superim- position of CDR over preexisting hypsodonty resulting in an escalator-like movement of teeth, constantly compensating for intensive dental wear. This dental replacement is not observed in other bathyergid rodents. Among other mammals, elephants present an analogous dental replacement, but their regular dentition develops sequentially, without the occurrence of any supplementary teeth. Unlike Heliophobius, Trichechus and P. concinna have low- crowned and bi- or trirooted cheek teeth but are bilophodont as well (Fig. 3 A and B). The replacement of their jugal dentition works like a simple treadmill in which each freshly developed molar erupts vertically at the rear of the row and then migrates horizontally toward the front (Fig. 3 C–F). A part of the regular dentition, including premolars (Fig. 3D), clearly develops before Fig. 1. Dental characteristics of H. argenteocinereus (RMCA96.036-M-5467). the system changes course, such that a single molar could be- (A) X-ray synchrotron microtomographic 3D rendering of upper jugal tooth come regularly ever-duplicated. Such an assumption relies on rows. (B) X-ray synchrotron microtomographic 3D rendering of lower jugal the fact that additional molars are identical to the second molars tooth rows. (C) Virtual cross-section of upper jugal tooth rows from syn- fi chrotron microtomographic data. (D) Morphological correspondences be- in manatees (6). The distal root is rst intensively resorbed, and tween virtual transverse slices of erupting lower molar and dental wear the crown breaks away from the mesial root when the tooth stages observed from the rear to front of the lower tooth row. D → M, distal- reaches the front of the row (Fig. 3 C–F). Even if the crown is to-mesial point. severely eroded during the drift, it is not resorbed and vertical readjustments
Load more

Recommended publications
  • Pleistocene Mammals and Paleoecology of the Western Amazon
    PLEISTOCENE MAMMALS AND PALEOECOLOGY OF THE WESTERN AMAZON By ALCEU RANCY A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1991 . To Cleusa, Bianca, Tiago, Thomas, and Nono Saul (Pistolin de Oro) . ACKNOWLEDGMENTS This work received strong support from John Eisenberg (chairman) and David Webb, both naturalists, humanists, and educators. Both were of special value, contributing more than the normal duties as members of my committee. Bruce MacFadden provided valuable insights at several periods of uncertainty. Ronald Labisky and Kent Redford also provided support and encouragement. My field work in the western Amazon was supported by several grants from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) , and the Universidade Federal do Acre (UFAC) , Brazil. I also benefitted from grants awarded to Ken Campbell and Carl Frailey from the National Science Foundation (NSF) I thank Daryl Paul Domning, Jean Bocquentin Villanueva, Jonas Pereira de Souza Filho, Ken Campbell, Jose Carlos Rodrigues dos Santos, David Webb, Jorge Ferigolo, Carl Frailey, Ernesto Lavina, Michael Stokes, Marcondes Costa, and Ricardo Negri for sharing with me fruitful and adventurous field trips along the Amazonian rivers. The CNPq and the Universidade Federal do Acre, supported my visit to the. following institutions (and colleagues) to examine their vertebrate collections: iii . ; ; Universidade do Amazonas, Manaus
    [Show full text]
  • Mamiferosacuat/Cosdel Mioceno Medio Y Tardio De Argentina
    UNIVERSIDAD NACIONAL DE LA PLATA FACULTAD DE CIENCIAS NATURALES Y MUSEO MAMIFEROSACUAT/COSDEL MIOCENO MEDIO Y TARDIO DE ARGENTINA SISTEMATICA, EVOLUCION Y BIOGEOGRAFIA por Mario Alberto COZZUOL Trabajo de Tesis para optar al Título de '~\ ,-- DOCTOR EN CIENCIAS NATURALES Director de Tesis: Dr. Rosendo PASCUAL La Plata -1993- A mis padres, Ruggero y N elly, porque siempre entendieron, me apoyaron y nunca cuestionaron mi decisión de elegir esta carrera. y A Tere, mi esposa, porque siempre estuvo allí, y porque aún está aquí. j i 1 ii : : ; ¡ .: RESUMEN Algunos de los mamíferos acuáticos del Mioceno tardío de Argentina se cuentan entre los primeros vertebrados fósiles en ser descriptos en el país, pese a lo cual la atención que estos grupos recibieron fue comparativamente escasa en relación a los mamíferos terrestres. En el presente trabajo se reestudian las especies previamente descriptas, y se describen varios nuevos taxones. El estudio se ha dividido en especies procedentes de sedimentitas marinas informalmente agrupadas bajo el nombre de "Entrerriense", y aquellas especies procedentes de aguas continentales, de sedimentitas agrupadas en el Piso/Edad Mesopotamiense, por primera vez propuesto aquí de manera formal. Dentro de las especies procedentes de sedimentitas marinas se han reconocido dos asociaciones consideradas diacrónicas. Las más antigua, referida · al Mioceno medio, procede de los afloramientos del ·"Entrerriense" de Patagonia, agrupandó seis especies, en su mayoría descriptas aquí por primera vez: Patagophyseter rionegrensis (Gondar) nueva combinación (Cetacea, Physeteridae); Notoziphius bruneti gen. y esp. nuevos (Cetacea, Ziphiidae); Goos valdesensis gen. y esp. nuevos (Cetacea, Balenidae); "Plesiocetus" notopelagicus Cabrera, 1926 (Cetacea, Cetotheriidae); Kawas benegasii gen.
    [Show full text]
  • Evolução, Hegemonia E Desaparecimento Dos Sirénios Dos Mares Europeus Ao Longo Do Cenozoico
    Universidade de Lisboa Faculdade de Ciências Departamento de Geologia Evolução, hegemonia e desaparecimento dos sirénios dos mares europeus ao longo do Cenozoico causas endógenas (alterações climáticas globais) ou exógenas (ambiente galáctico)? Gonçalo Abreu Prista Dissertação Mestrado em Ciências do Mar 2012 Universidade de Lisboa Faculdade de Ciências Departamento de Geologia Evolução, hegemonia e desaparecimento dos sirénios dos mares europeus ao longo do Cenozoico causas endógenas (alterações climáticas globais) ou exógenas (ambiente galáctico)? Gonçalo Abreu Prista Dissertação Mestrado em Ciências do Mar Orientadores: Professor Doutor Mário Albino Cachão Professor Doutor Rui Jorge Agostinho 2012 EVOLUÇÃO, HEGEMONIA E DESAPARECIMENTO DOS SIRÉNIOS DOS MARES EUROPEUS AO LONGO DO CENOZOICO causas endógenas (alterações climáticas globais) ou exógenas (ambiente galáctico)? GONÇALO ABREU PRISTA ORIENTAÇÃO CIENTÍFICA: PROF. DOUTOR MÁRIO ALBINO PIO CACHÃO Professor Auxiliar Agregado do Departamento de Geologia da Faculdade de Ciências da Universidade de Lisboa Membro do Centro de Geologia da Universidade de Lisboa PROF. DOUTOR RUI JORGE AGOSTINHO Professor Auxiliar Agregado do Departamento de Física da Faculdade de Ciências da Universidade de Lisboa Membro do Centro de Astronomia e Astrofísica da Universidade de Lisboa Director do Observatório Astronómico de Lisboa iii "Graças aos descobrimentos da Paleontologia, a História Natural é História, no sentido literal da palavra" Albert Gaudry (1827 - 1908). "O azoto no nosso DNA, o cálcio nos nossos dentes, o ferro no nosso sangue, o carbono nas nossas tartes de maçã foram feitos no interior de estrelas em colapso. Nós somos feitos de material estelar" Carl Sagan (1934 - 1996) iv AGRADECIMENTOS Primeiro aos meus pais, pois sem o seu apoio, a todos os níveis, este mestrado e esta dissertação não seriam possíveis.
    [Show full text]
  • APPENDIX 4. Classification and Synonymy of the Sirenia and Desmostylia
    revised 3/29/2010 APPENDIX 4. Classification and Synonymy of the Sirenia and Desmostylia The following compilation encapsulates the nomenclatural history of the Sirenia and Desmostylia as comprehensively as I have been able to trace it. Included are all known formal names of taxa and their synonyms and variant combinations, with abbreviated citations of the references where these first appeared and their dates of publication; statements of the designated or inferred types of these taxa and their provenances; and comments on the nomenclatural status of these names. Instances of the use of names or combinations subsequent to their original publication are, however, not listed. Of course, the choices of which taxa to recognize as valid and their proper arrangement reflect my own current views. This arrangement is outlined immediately hereafter to aid in finding taxa in this section. (Note that not all taxa in this summary list are necessarily valid; several are probable synonyms but have not been formally synonymized.) For a quick-reference summary of the names now in use for the Recent species of sirenians, see Appendix 5. – DPD Summary Classification and List of Taxa Recognized ORDER SIRENIA Illiger, 1811 Family Prorastomidae Cope, 1889 Pezosiren Domning, 2001 P. portelli Domning, 2001 Prorastomus Owen, 1855 P. sirenoides Owen, 1855 Family Protosirenidae Sickenberg, 1934 Ashokia Bajpai, Domning, Das, and Mishra, 2009 A. antiqua Bajpai, Domning, Das, and Mishra, 2009 Protosiren Abel, 1907 P. eothene Zalmout, Haq, and Gingerich, 2003 P. fraasi Abel, 1907 P. sattaensis Gingerich, Arif, Bhatti, Raza, and Raza, 1995 P. smithae Domning and Gingerich, 1994 ?P. minima (Desmarest, 1822) Hooijer, 1952 Family Trichechidae Gill, 1872 (1821) Subfamily Miosireninae Abel, 1919 Anomotherium Siegfried, 1965 1 Daryl P.
    [Show full text]
  • Amazonia: Landscape and Species Evolution a Look Into the Past
    Amazonia: landscape and species evolution A look into the past Edited by C. Hoorn University of Amsterdam, The Netherlands F.P. Wesselingh Naturalis, Leiden, The Netherlands Editorial advisors H.B. Vonhof Vrije Universiteit, Amsterdam, The Netherlands S.B. Kroonenberg Delft University of Technology, The Netherlands H. Hooghiemstra University of Amsterdam, The Netherlands HHoorn_Fm_Final.inddoorn_Fm_Final.indd SSec1:iiiec1:iii 110/30/20090/30/2009 110:18:280:18:28 SShobhahobha HHoorn_Fm_Final.inddoorn_Fm_Final.indd SSec1:xivec1:xiv 110/30/20090/30/2009 110:18:300:18:30 SShobhahobha HHoorn_Frontispiece_Final.inddoorn_Frontispiece_Final.indd i 110/24/20090/24/2009 11:36:05:36:05 SShobhahobha MIDDLE TO LATE MIOCENE POACEAE Phoberomys Ceiba + Ludwigia Gryposuchus Anacardium Euterpe Anhinga Amanoa Humiriastrum Bactris Cariniana Terminalia Astrapotherium Terminalia Mauritia Mauritia Pachira Barinasuchus Pseudoprepotherium Purussaurus PAMPATHERIIDAE Anhinga + Pristobrycon Trigodon Calophyllum Mourasuchus Bairdemys PTERIDOPHYTA GASTROPODA Mauritia POACEAE + Ludwigia SERRASALMIDAE (Serrasalmus, MIDDLE TO Pygocentrus or Pristobrycon) Plicodontinia LATE SERRASALMIDAE (Serrasalmus, Carcharhinus Pygocentrus or Pristobrycon) MIOCENE Charactosuchus Arapaima Phractocephalus Ribodon Colossoma Cariniana Oxydoras Pseudopimelodus Corydoras Chelus Terminalia Hoplias CHAROPHYTA Potamotrygon GASTROPODA These plates show a reconstruction of the Middle to Late Miocene (16—7 million years ago) terrestrial and underwater landscape in Amazonia. Names for taxa are
    [Show full text]
  • Evolution of the Sirenia: an Outline
    Caryn Self-Sullivan, Daryl P. Domning, and Jorge Velez-Juarbe Last Updated: 8/1/14 Page 1 of 10 Evolution of the Sirenia: An Outline The order Sirenia is closely associated with a large group of hoofed mammals known as Tethytheria, which includes the extinct orders Desmostylia (hippopotamus-like marine mammals) and Embrithopoda (rhinoceros-like mammals). Sirenians probably split off from these relatives in the Palaeocene (65-54 mya) and quickly took to the water, dispersing to the New World. This outline attempts to order all the species described from the fossil record in chronological order within each of the recognized families of Prorastomidae, Protosirenidae, Dugongidae, and Trichechidae. This outline began as an exercise in preparation for my Ph. D. preliminary exams and is primarily based on decades of research and peer-reviewed literature by Dr. Daryl P. Domning, to whom I am eternally grateful. It has been recently updated with the help of Dr. Jorge Velez-Juarbe. However, this document continues to be a work-in-progress and not a peer reviewed publication! Ancestral line: Eritherium Order Proboscidea Elephantidae (elephants and mammoths) Mastodontidae Deinotheriidae Gomphotheriidae Ancestral line: Behemotops Order Desmostylia (only known extinct Order of marine mammal) Order Sirenia Illiger, 1811 Prorastomidae Protosirenidae Dr. Daryl Domning, Howard University, November 2007 Dugongidae with Metaxytherium skull. Photo © Caryn Self-Sullivan Trichechidae With only 5 species in 2 families known to modern man, you might be surprised to learn that the four extant species represent only a small fraction of the sirenians found in the fossil record. As of 2012, ~60 species have been described and placed in 4 families.
    [Show full text]
  • Article VIII.-FOSSIL SIRENIA of FLORIDA and the EVOLUTION of the SIRENIA by GEORGE GAYLORD SIMPSON CONTENTS PAGE INTRODUCTION
    56.9, 55 Article VIII.-FOSSIL SIRENIA OF FLORIDA AND THE EVOLUTION OF THE SIRENIA BY GEORGE GAYLORD SIMPSON CONTENTS PAGE INTRODUCTION ........................................................ 419 PREVIOUS KNOWLEDGE OF AMERICAN FOSSIL SIRENIA.420 SYNOPTIC CLASSIFICATION OF THE SIRENIA................................. 422 MIOCENE SIRENIA OF FLORIDA .......................................... 425 Occurrence............................................. 425 Materials............................................. 425 Taxonomy............................................. 426 Morphology............................... 427 Affinities ............................................. 442 POSSIBLE MIOCENE SIRENIA OF SOIUTH CAROLINA.. 443 PLIOCENE SIRENIA OF FLORIDA.. 445 Occurrence.. 445 Materials.. 446 Taxonomy.. 447 Morphology.. 448 Affinities .. 468 PLEISTOCENE SIRENIA OF FLORIDA.. 470 REVIEW OF OTHER TERTIARY SIRENIA.. 470 Eocene Sirenia.. 470 European Halitheriinse .. 474 Divergent European Lines.. 480 Other Genera.. 481 RECENT SIRENIA.. 482 Osteology of Recent Genera.. 482 Origin of Dugong. 482 Origin of Hydrodamalis. 485 Origin of Trichechus. 488 AFFINITIES OF THE SIRENIA.. 492 DISTRIBUTION OF THE SIRENIA .. 496 BIBLIOGRAPHY.. 500 INTRODUCTION Florida is one of the last strongholds of the sirenians in North America, as a small number of manatees there still withstand the on- slaught of civilization. It is a matter of peculiar interest that sirenians have long been abundant along its shores. In the shallow-water marine and estuarine deposits of the
    [Show full text]
  • Population Genetics and Conservation of the Florida Manatee: Past, Present, and Future
    POPULATION GENETICS AND CONSERVATION OF THE FLORIDA MANATEE: PAST, PRESENT, AND FUTURE By ROBERT KNUDSEN BONDE A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2009 1 © 2009 Robert Knudsen Bonde 2 To the perpetuation of mermaid myths 3 ACKNOWLEDGMENTS I would like to thank my committee, especially Dr. Peter McGuire whose ideas, guidance, and direction were a major contributor for all our present day understanding of sirenian genetics. It was through his unselfish determination and fortitude that all of his enthusiastic graduate students, me included, found their strengths. Dr. Roger Reep was the guiding light that led me into graduate school so many years after establishing my career with the Sirenia Project. Roger’s encouragement, perseverance, and compassion helped mold my personality and way of approaching problems too. Dr. Lynn Lefebvre was my mentor and direct-line supervisor for much of my professional career with U. S. Geological Survey (USGS) Sirenia Project. Through her support, I was able to juggle the responsibilities of my job with those required of my academic career. Dr. Tim King of the USGS Leetown Science Center whose expertise on population genetics is rivaled by few in the world; Tim your guidance and advice are ingrained and treasured by all immersed in wildlife genetics today. Finally, Dr. Ruth Francis-Floyd, who joined my committee in the later stages and still provided upbeat enthusiasm, even when times appeared discouraging. Thanks to all. Of particular importance to me and my career is Dr.
    [Show full text]
  • Trichechidae, Sirenia): a Detailed Look at Modern Trichechus and a Review of the Fossil Record
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Open Marine Archive THE ANATOMICAL RECORD 295:1504–1512 (2012) Osteological Associations With Unique Tooth Development in Manatees (Trichechidae, Sirenia): A Detailed Look at Modern Trichechus and a Review of the Fossil Record BRIAN LEE BEATTY,1* TAISIA VITKOVSKI,1 OLIVIER LAMBERT,2 3 AND THOMAS E. MACRINI 1New York College of Osteopathic Medicine, Old Westbury, New York 2Departement de Paleontologie, Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium 3Department of Biological Sciences, St. Mary’s University, San Antonio, Texas ABSTRACT Modern manatees have a unique type of tooth development, continu- ally forming identical new molars in the posterior end of each quadrant of their mouths, and then progressively moving teeth anteriorly, only to reabsorb roots and spit out worn crowns. This process is not only develop- mentally complex, but requires space in the oral cavity that imposes its own limitations on other uses of that space. To gain a clearer understand- ing of the anatomical constraints on the evolution of this unique develop- mental process, we identified the specialized craniodental features in modern Trichechus that permit this specialization using visual observa- tion and CT. Furthermore, to better understand the evolution of these traits, we review the fossil record of trichechids for these traits, including CT analysis of the skull of Miosiren kocki, a possible early member of the family from the Early Miocene of Belgium. Anat Rec, 295:1504–1512, 2012. VC 2012 Wiley Periodicals, Inc. Key words: Sirenia; Trichechidae; polyphyodonty; tooth development; Trichechus; Miosiren Manatees (Trichechus) are unusual animals in many in Peradorcas concinna is not well understood, but as ways, including having pachyosteosclerotic skeletons many as nine molars may erupt successively in each (Domning and Buffrenil, 1991) and vascular corneas quadrant (Thomas, 1904).
    [Show full text]
  • El Neógeno De La Mesopotamia Argentina
    EL NEÓGENO DE LA MESOPOTAMIA ARGENTINA Diego Brandoni Jorge I. Noriega e d i t o r e s Asociación Paleontológica Argentina Publicación Especial 14 El Neógeno de la Mesopotamia argentina Diego Brandoni y Jorge I. Noriega, Editores (2013) Asociación Paleontológica Argentina, Publicación Especial 14 Asociación Paleontológica Argentina Comisión Directiva (2012-2013) Presidente: Dr. Emilio Vaccari Vicepresidente: Dr. Francisco J. Prevosti Secretario: Dr. Javier N. Gelfo Prosecretaria: Dra. Carolina Acosta Hospitaleche Tesorero: Dr. Leandro Martínez Protesorero: Dra. Verónica Krapovickas Vocales titulares: Dra. Andrea Arcucci Dra. Raquel Guerstein Dra. Ana Carignano Vocales suplentes: Dra. María Teresa Dozo Dra. Lucía Balarino Dr. Oscar Gallego Órgano de Fiscalización Titulares: Lic. Mariano Bond Dra. Julia Brenda Desojo Dr. Darío Lazo Suplente: Dra. Cecilia Deschamps ISSN 0328-347X A.P.A. Asociación Paleontológica Argentina Maipú 645 1º piso (C1006ACG) Ciudad autónoma de Buenos Aires, República Argentina. Teléfono y fax: 54-(0)11-4326-7463 E-mail: [email protected] http://www.apaleontologica.org.ar COPYRIGHT STATEMENT. Where necessary, permission is granted by the copyright owner for libraries and others registered with the Copyright Clearence Center (CCC) to photocopy an article herein for US$ 0.50 per page. Payments should be sent directly to the CCC P.O. 222 Rosewood Drive, Danvers, Massa- chusetts 01923 USA. Copying done for other than personal or internal referenc- es use without permission of Asociación Paleontológica Argentina is prohibited. Requests for special permission should be addressed to Maipú 645, 1er piso, 1006 Buenos Aires, Argentina. 0328-347X/07$00.00+.50 ÍNDICE LEANDRO M. PÉREZ Nuevo aporte al conocimiento de la edad de la Formación Paraná, Mioceno de la provincia de Entre Ríos, Argentina ...........................................................................................7 ERNESTO BRUNETTO, JORGE I.
    [Show full text]
  • Genus/Species Tusks Skull Ht Lt Wt Stage Range Afrochoerodon L-M.Miocene Kenya,Egypt A. Chioticus Orleanian-Astaracian Greece A. Kisumuensis L-M.Miocene Kenya,Egypt A
    Genus/Species Tusks Skull Ht Lt Wt Stage Range Afrochoerodon L-M.Miocene Kenya,Egypt A. chioticus Orleanian-Astaracian Greece A. kisumuensis L-M.Miocene Kenya,Egypt A. ngorora M.Miocene Kenya A. zaltaniensis L.Miocene Libya Aleamastodon see Haplomastodon Ambelodon see Amebelodon Amblychilus see Dugong Amebelodon 2.8 mj 3 m M.Miocene-L.Pliocene Africa,Asia,USA A. barbourensis see Gomphotherium? U.Miocene Florida(US) A. britti 1.8 m Hemphillian Florida,Kansas,Texas,Oklahoma(US) A. cf. Barbourensis(barbouri) 3.4 t U.Miocene Nebraska(US) A. floridanus Hemphillian Florida,Colorado,Kansas(US) A. fricki Hemphillian Texas,Colorado,Nebraska,Montana(US) A. hicksi see Amebelodon floridanus Hemphillian Texas(US) A. nov.sp. Hemphillian Florida(US) A. paladentatus see Amebelodon floridanus A. sinclairi A. sp. Hemphillian Texas,Oklahoma,Nebraska,Kansas,Oregon(US) A. tobieni Miocene Ningxia(China) Anancus 4 m 3 m L.Miocene-M.Pleistocene Europe,Africa,Asia cf. A. arvernensis Turolian Concud Cerro de la Garita(Spain) cf. A. Lothagam type see Anancus sp.A A. aff. Kenyensis see Anancus sp.C A. arvernensis 3 m 3 m L.Pliocene-M.Pleistocene Europe(widespread) A. a. brevirostris? A. a. dissimilis? A. a. macroplus? A. bensonensis see Stegomastodon mirificus Arizona(US) A. brazosius Texas(US) A. brevirostris A. cuneatus China? A. kenyensis L.Pliocene-L.Pleistocene Kenya,Tanzania,Ethiopia,S Africa A. macroplus see Anancus arvernensis A. n.sp. see Anancus sp.D Kalaloo(Ethiopia) A. osiris L.Pliocene-M.Pleistocene Egypt to Morocco to Chad A. paisuyensis see Anancus cuneatus A. perimensis Pliocene India A. p.
    [Show full text]
  • The Evolutionary History of Manatees Told by Their Mitogenomes
    www.nature.com/scientificreports OPEN The evolutionary history of manatees told by their mitogenomes Érica Martinha Silva de Souza1,9*, Lucas Freitas1,9, Elisa Karen da Silva Ramos1,9, Giovanna Selleghin‑Veiga1,9, Michelle Carneiro Rachid‑Ribeiro1,9, Felipe André Silva1, Miriam Marmontel2, Fabrício Rodrigues dos Santos3, Anne Laudisoit4, Erik Verheyen5,6, Daryl P. Domning7,8 & Mariana Freitas Nery1,9* The manatee family encompasses three extant congeneric species: Trichechus senegalensis (African manatee), T. inunguis (Amazonian manatee), and T. manatus (West Indian manatee). The fossil record for manatees is scant, and few phylogenetic studies have focused on their evolutionary history. We use full mitogenomes of all extant manatee species to infer the divergence dates and biogeographical histories of these species and the efect of natural selection on their mitogenomes. The complete mitochondrial genomes of T. inunguis (16,851 bp), T. senegalensis (16,882 bp), and T. manatus (16,882 bp), comprise 13 protein‑coding genes, 2 ribosomal RNA genes (rRNA ‑ 12S and 16S), and 22 transfer RNA genes (tRNA), and (D‑loop/CR). Our analyses show that the frst split within Trichechus occurred during the Late Miocene (posterior mean 6.56 Ma and 95% HPD 3.81–10.66 Ma), followed by a diversifcation event in the Plio‑Pleistocene (posterior mean 1.34 Ma, 95% HPD 0.1–4.23) in the clade composed by T. inunguis and T. manatus; T. senegalensis is the sister group of this clade with higher support values (pp > 0.90). The branch‑site test identifed positive selection on T. inunguis in the 181st position of the ND4 amino acid gene (LRT = 6.06, p = 0.0069, BEB posterior probability = 0.96).
    [Show full text]