DOCSLIB.ORG

The Narial Morphology of Metarhinus and Sphenocoelus (Mammalia, Perissodactyla, Brontotheriidae)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Narial Morphology of Metarhinus and Sphenocoelus (Mammalia, Perissodactyla, Brontotheriidae) Palaeontologia Electronica palaeo-electronica.org The narial morphology of Metarhinus and Sphenocoelus (Mammalia, Perissodactyla, Brontotheriidae) Bryn J. Mader ABSTRACT The brontothere genera Metarhinus and Sphenocoelus (= Dolichorhinus) are both characterized by an unusual redirection of the air passageway in which the internal nares are effectively closed off and new openings that serve as the functional internal nares have appeared posteriorly. Rather than passing lateral to the vomer, the air- stream appears to pass over or through the bone (thus bypassing the anatomical inter- nal nares) and exits through an enlarged vomerine notch. If correctly interpreted, this morphology is unique among mammals. In the past it has been suggested that the pos- terior displacement of the internal nares is either an amphibious adaptation or an adap- tation to enhance olfaction. The current paper favors the latter interpretation. Among other reasons is that the change in morphology channels the airstream directly toward the olfactory epithelium in the area of the ethmoid. In order for the vomer to channel air, the septal cartilage would require significant modification. It is speculated here that the respiratory septum (vomer, crest of the maxilla, and crest of the palatine) might have been wholly or partially isolated from the olfactory septum (perpendicular plate of the ethmoid and septal cartilage), allowing air to be channeled through (or over) the vomer. Bryn J. Mader. Department of Biological Sciences and Geology, Queensborough Community College, 222- 05 56th Avenue, Bayside, NY, 11364-1497, USA. [email protected] Keywords: titanothere; Dolichorhinus, vomer; nasal breather; nasal cycle; evo-devo Submission: 26 August 2018 Acceptance: 18 January 2019 INTRODUCTION nares have appeared posteriorly. Riggs (1912) was the first to recognize this in Sphenocoelus (= Doli- The brontothere genera Metarhinus and chorhinus), although he assigned the attribute to a Sphenocoelus are both characterized by an single species only. Peterson (1924, p. 442-443) unusual redirection of the air passageway in which recognized the broader distribution of the trait, the internal nares are effectively closed off and regarding it as a generic rather than a specific new openings that serve as the functional internal Mader, Bryn J. 2019. The narial morphology of Metarhinus and Sphenocoelus (Mammalia, Perissodactyla, Brontotheriidae). Palaeontologia Electronica 22.1.8A 1-15. https://doi.org/10.26879/919 palaeo-electronica.org/content/2019/2417-narial-morphology Copyright: February 2019 Society of Vertebrate Paleontology. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. creativecommons.org/licenses/by/4.0/creativecommons.org/licenses/by-nc-sa/4.0/ MADER: NARIAL MORPHOLOGY character. Peterson also more fully described the many mammals (e.g., Equus, Camelus, Panthera) anatomy (p. 409) noting peculiar pouch-like struc- there is a prominent anterior-posterior channel that tures (choanal pouches of Mader, 2008, and Mihl- runs down the length of the vomer medially. The bachler, 2008) that close off the internal nares and dorsal part of this channel is open anteriorly where re-direct the air stream posteriorly to exit at a new the bone articulates with the premaxilla (thus pre- opening between the pterygoid processes. Osborn senting a u-shaped cross section), but may be (1929) identified the choanal pouches of Spheno- closed posteriorly, thus forming a hollow tube. The coelus as maxilloturbinates, as did Mihlbachler septal cartilage fits into this u-shaped channel (= (2008). septal groove) and extends up to the dorsal roof of In 1981, an extremely well-preserved Metarhi- the nasal cavity as a continuous sheet. nus skull was collected by L. Shields of the Univer- Normally the air stream passes laterally on sity of Colorado. The skull was preserved in an each side of the vomer before exiting the nasal exceptionally soft matrix, which made it possible to cavity through the internal nares (= choanae). In prepare out structures that, otherwise, could not many mammals the vomer forks posteriorly where have been examined. This included structures in it joins the presphenoid (vomerine wings or alae) the internal nares similar to those of Sphenocoe- leaving a small, roughly triangular space between lus. A bony structure projecting from the internal the two bones known as the vomerine notch (see nares between the pterygoids in the same general Eisenmann et al., 1988, figure 1). The vomerine location as the choanal pouches of Sphenocoelus notch is also known by the Latin name, incisura was interpreted by Mihlbachler (2008) as posteri- vomeris (Sisson, 1910). orly displaced turbinates. However, Mader (2009) This vomerine notch is found in equids (e.g., identified this same structure as a greatly enlarged Equus caballus), thus indicating its presence vomer. Mader noted that the internal nares were among Perissodactyla, but is also found in felids essentially closed off and that an opening posterior (e.g., Panthera leo, Felis concolor, Felis sylvestris), to the enlarged vomer was the functional exit for and canids (e.g., Canis lupus). The vomerine notch the airstream. Mader identified that opening as a in horses is rather small, but its morphology in cats highly modified vomerine notch. The purpose of and dogs may help to explain how the condition in the present paper is to review and expand upon dolichorhinine brontotheres (sensu Mader, 1989, the interpretations of these structures given by 1998, and 2008) could have evolved. It will be Mader (2008, 2009) and to further explore their noted from the lion skull pictured in Figure 1, that possible functional significance. there is a distinct gap between the presphenoid and vomer, and it is only the alae of the vomer that METHODS approach the anterior edge of the presphenoid. This large opening marks the exit of the anterior- The taxonomy employed in the present paper posterior channel of the vomer noted above. follows that of Mader (1998, 2008), which differs Hence, in osteological preparations (where the somewhat from that of Mihlbachler (2008), the septal cartilage is not preserved) there is a continu- other major recent reviser of North American bron- ous open passageway running through the interior totheres. of the vomer from the nasal cavity to the vomerine Institutional abbreviations. AMNH, American notch. It is speculated here that this passage Museum of Natural History, New York, New York, through the vomer became the functional air pas- USA; FMNH PM, Field Museum of Natural History, sageway in certain members of the Dolichorhin- Chicago, Illinois, USA; UCM, University of Colo- inae. rado Museum, Boulder, Colorado, USA. Dissection of the domestic cat (Felis catus) Narial Morphology of Typical Mammals performed for this study indicates that, in the living animal, the area of the vomerine notch lies within The following description of the narial mor- the nasopharynx, dorsal to the soft palate (the soft phology in typical mammals is an expansion of the palate must be removed in order to inspect the description given by Mader (2009). In most mam- area). The epithelial tissue covering the presphe- mals the vomer forms a thin, vertical plate that is noid/vomer area is thin and appears to be continu- part of the nasal septum and helps divide the pos- ous and uninterrupted. There is no perforation terior nasal cavity into right and left sides. The through the soft tissue allowing the vomerine notch nasal septum is also composed of the perpendicu- to communicate directly with the nasopharynx. lar plate of the ethmoid, the septal cartilage, the Therefore, if this became the air passageway in crest of the maxilla, and the crest of the palatine. In 2 PALAEO-ELECTRONICA.ORG FIGURE 1. Skull of African Lion (Panthera leo, author’s private collection) showing anatomy of vomer and vomerine notch. Turbinates in this specimen are largely missing. 1, anterior view; 2, ventral view; 3, detail of anterior nasal cav- ity; 4, detail of internal narial region. Abbreviations: IN, internal nares; Ps, presphenoid; V, vomer; VN, vomerine notch, the presumed functional internal nares (N) in all other figures. Rectangles superimposed on upper photo- graphs show areas of detail below. In 3 and 4 the vomer has been lightened for better clarity. certain dolichorhinine brontotheres, a perforation in tral pair. The ventral pair project from the lateral the soft tissue would have had to evolve. walls of the nasal cavity from the maxillae and are The turbinates (or conchae) are usually elabo- known as maxilloturbinates. The two pairs located rate scrolls of very thin bone that fill most of the above this (i.e., the middle pair and dorsal pair) interior of the nasal cavity on either side of the project from the ethmoid bone and are, thus, eth- nasal septum. There are three pairs of turbinates moturbinates. altogether: a dorsal pair, a middle pair, and a ven- 3 MADER: NARIAL MORPHOLOGY SYSTEMATIC PALEONTOLOGY body of the vomer and anterior to the presphenoid (labelled “N” in Figure 2). This opening is in the Order PERISSODACTYLA Owen, 1848 exact location of the vomerine notch found in Family BRONTOTHERIIDAE Marsh, 1873 horses and some other mammals and is identified Subfamily DOLICHORHININAE Riggs, 1912 by Mader (2009 and the present paper) as such. Genus METARHINUS Osborn, 1908 Regarding the vomer, the identity of this bone v. 1912 Rhadinorhinus Riggs, p. 36-37, pl. 11 (figs. was most evident when the skull was apart (prior to 2-3) (original description). restoration), and it could be readily viewed from v. 1914 Heterotitanops Peterson, p. 53-57, figs. 1-2, multiple angles. However, this same bone was pl. 11 (original description). identified as posteriorly shifted turbinates by Mihl- v. 2008 Fossendorhinus Mihlbachler, p. 63-69, figs. bachler (2008). That this bone does not represent 24-26 (new generic name).
Load more

Recommended publications
  • Zootaxa, a Species Level Revision of Bridgerian And
    ZOOTAXA 1837 A species level revision of Bridgerian and Uintan brontotheres (Mammalia, Perissodactyla) exclusive of Palaeosyops BRYN J. MADER Magnolia Press Auckland, New Zealand Bryn J. Mader A species level revision of Bridgerian and Uintan brontotheres (Mammalia, Perissodactyla) exclusive of Palaeosyops (Zootaxa 1837) 85 pp.; 30 cm. 30 July 2008 ISBN 978-1-86977-249-9 (paperback) ISBN 978-1-86977-250-5 (Online edition) FIRST PUBLISHED IN 2008 BY Magnolia Press P.O. Box 41-383 Auckland 1346 New Zealand e-mail: [email protected] http://www.mapress.com/zootaxa/ © 2008 Magnolia Press All rights reserved. No part of this publication may be reproduced, stored, transmitted or disseminated, in any form, or by any means, without prior written permission from the publisher, to whom all requests to reproduce copyright material should be directed in writing. This authorization does not extend to any other kind of copying, by any means, in any form, and for any purpose other than private research use. ISSN 1175-5326 (Print edition) ISSN 1175-5334 (Online edition) 2 · Zootaxa 1837 © 2008 Magnolia Press MADER Zootaxa 1837: 1–85 (2008) ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ ZOOTAXA Copyright © 2008 · Magnolia Press ISSN 1175-5334 (online edition) A species level revision of Bridgerian and Uintan brontotheres (Mammalia, Perissodactyla) exclusive of Palaeosyops BRYN J. MADER Department of Biological Sciences and Geology, Queensborough Community College, 222-05 56th Avenue, Bayside, NY, 11364-1497 Long Island Natural History Museum,
    [Show full text]
  • A New Brontothere from the Eocene of South China
    A new brontothere from the Eocene of South China ALEXANDER AVERIANOV, IGOR DANILOV, WEN CHEN, and JIANHUA JIN Averianov, A., Danilov, I., Chen, W., and Jin, J. 2018. A new brontothere from the Eocene of South China. Acta Palae- ontologica Polonica 63 (X): xxx–xxx. The upper Eocene Youganwo Formation in Maoming Province, Guangdong Province, China, produced abundant re- mains of turtles and crocodiles, but mammalian remains are rare. The previously found mammals from Youganwo Formation include a nimravid carnivore and an amynodontid perissodactyl. Here we report on a new brontotheriid perissodactyl from the Youganwo Formation. Maobrontops paganus gen. et sp. nov. is described based on a maxillary fragment with P4 and M1–2 (SYSU-M-4). Maobrontops paganus gen. et sp. nov. is characterized by the combination of a simple P4 without a hypocone with derived molars having large molar fossae and large anterolingual cingular cusp. A parsimony implied weighting character analysis places Maobrontops gen. nov. in the clade Embolotheriita as a sister taxon to the terminal subclade containing Nasamplus, Protembolotherium, and Embolotherium. Maobrontops paganus gen. et sp. nov. is one of the largest Asian brontotheres. The brontotheriid fauna of South China is endemic and includes at least three valid taxa: Dianotitan from Brontotheriita and Pygmaetitan and Maobrontops gen. nov. from Embolotheriita. Key words: Mammalia, Perissodactyla, Brontotheriidae, Eocene, China. Alexander Averianov [[email protected]], State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Zoological Institute of the Russian Academy of Sciences, Universitetskaya Nab. 1, St Petersburg 199034, Russia; and Institute of Geology and Petroleum Technology, Kazan Federal University, Kremlevskaya Str.
    [Show full text]
  • The Stratigraphic Importance of the Brontothere (Cf. Diplacodon Elatus) in the Brennan Basin Member of the Duchesne River Formation of Utah
    Foss. Rec., 17, 69–74, 2014 www.foss-rec.net/17/69/2014/ doi:10.5194/fr-17-69-2014 © Author(s) 2014. CC Attribution 3.0 License. The stratigraphic importance of the brontothere (cf. Diplacodon elatus) in the Brennan Basin Member of the Duchesne River Formation of Utah B. J. Burger and L. Tackett II Department of Geology, Utah State University, Uintah Basin Regional Campus 320 North Aggie Blvd. Vernal, UT 84078, USA Correspondence to: B. J. Burger ([email protected]) Received: 10 June 2014 – Revised: 6 August 2014 – Accepted: 12 August 2014 – Published: 27 August 2014 Abstract. We report on the first occurrence of an early southern Mississippia (Gazin and Sullivan, 1942), and the horned brontothere in the Brennan Basin Member of the Pacific Northwest (Mihlbacher, 2007). But nowhere is the Duchesne River Formation in northeastern Utah. This is the record of brontotheres as diverse as the fossil record ob- first record of a brontothere from the Brennan Basin Member. tained from the middle Eocene depositional basins located in Previously, brontotheres have been reported from the higher northeastern Utah, southwestern Wyoming and northwestern stratigraphic La Point Member (Duchesneodus uintensis) Colorado (Lull, 1905; Cook, 1926; Douglass, 1909; Gregory, and the lower stratigraphic Uinta Formation (Sphenocoelus 1912; Gunnell and Yarborough, 2000; Hatcher, 1895; Lucas uintensis, Fossendorhinus diploconus, Metarhinus fluviatilis, et al., 2004; Lucas and Holbrook, 2004; Lucas and Schoch, Metarhinus abbotti, Sthenodectes incisivum, Metatelmath- 1982; Mader, 2000, 2009a, b, Mihlbacher, 2008, 2011; Os- erium ultimum, Protitanotherium emarginatum, Pollyosbor- born, 1889, 1895, 1908, 1913, 1929; Peterson, 1914a, b, nia altidens, Diplacodon elatus).
    [Show full text]
  • The World at the Time of Messel: Conference Volume
    T. Lehmann & S.F.K. Schaal (eds) The World at the Time of Messel - Conference Volume Time at the The World The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment and the History of Early Primates 22nd International Senckenberg Conference 2011 Frankfurt am Main, 15th - 19th November 2011 ISBN 978-3-929907-86-5 Conference Volume SENCKENBERG Gesellschaft für Naturforschung THOMAS LEHMANN & STEPHAN F.K. SCHAAL (eds) The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates 22nd International Senckenberg Conference Frankfurt am Main, 15th – 19th November 2011 Conference Volume Senckenberg Gesellschaft für Naturforschung IMPRINT The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates 22nd International Senckenberg Conference 15th – 19th November 2011, Frankfurt am Main, Germany Conference Volume Publisher PROF. DR. DR. H.C. VOLKER MOSBRUGGER Senckenberg Gesellschaft für Naturforschung Senckenberganlage 25, 60325 Frankfurt am Main, Germany Editors DR. THOMAS LEHMANN & DR. STEPHAN F.K. SCHAAL Senckenberg Research Institute and Natural History Museum Frankfurt Senckenberganlage 25, 60325 Frankfurt am Main, Germany [email protected]; [email protected] Language editors JOSEPH E.B. HOGAN & DR. KRISTER T. SMITH Layout JULIANE EBERHARDT & ANIKA VOGEL Cover Illustration EVELINE JUNQUEIRA Print Rhein-Main-Geschäftsdrucke, Hofheim-Wallau, Germany Citation LEHMANN, T. & SCHAAL, S.F.K. (eds) (2011). The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates. 22nd International Senckenberg Conference. 15th – 19th November 2011, Frankfurt am Main. Conference Volume. Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main. pp. 203.
    [Show full text]
  • Rhinoplasty and Septorhinoplasty These Services May Or May Not Be Covered by Your Healthpartners Plan
    Rhinoplasty and septorhinoplasty These services may or may not be covered by your HealthPartners plan. Please see your plan documents for your specific coverage information. If there is a difference between this general information and your plan documents, your plan documents will be used to determine your coverage. Administrative Process Prior authorization is not required for: • Septoplasty • Surgical repair of vestibular stenosis • Rhinoplasty, when it is done to repair a nasal deformity caused by cleft lip/ cleft palate Prior authorization is required for: • Rhinoplasty for any indication other than cleft lip/ cleft palate • Septorhinoplasty Coverage Rhinoplasty is not covered for cosmetic reasons to improve the appearance of the member, but may be covered subject to the criteria listed below and per your plan documents. The service and all related charges for cosmetic services are member responsibility. Indications that are covered 1. Primary rhinoplasty (30400, 30410) may be considered medically necessary when all of the following are met: A. There is anatomical displacement of the nasal bone(s), septum, or other structural abnormality resulting in mechanical nasal airway obstruction, and B. Documentation shows that the obstructive symptoms have not responded to at least 3 months of conservative medical management, including but not limited to nasal steroids or immunotherapy, and C. Photos clearly document the structural abnormality as the primary cause of the nasal airway obstruction, and D. Documentation includes a physician statement regarding why a septoplasty would not resolve the airway obstruction. 2. Secondary rhinoplasty (30430, 30435, 30450) may be considered medically necessary when: A. The secondary rhinoplasty is needed to treat a complication/defect that was caused by a previous surgery (when the previous surgery was not cosmetic), and B.
    [Show full text]
  • Download File
    Chronology and Faunal Evolution of the Middle Eocene Bridgerian North American Land Mammal “Age”: Achieving High Precision Geochronology Kaori Tsukui Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences COLUMBIA UNIVERSITY 2016 © 2015 Kaori Tsukui All rights reserved ABSTRACT Chronology and Faunal Evolution of the Middle Eocene Bridgerian North American Land Mammal “Age”: Achieving High Precision Geochronology Kaori Tsukui The age of the Bridgerian/Uintan boundary has been regarded as one of the most important outstanding problems in North American Land Mammal “Age” (NALMA) biochronology. The Bridger Basin in southwestern Wyoming preserves one of the best stratigraphic records of the faunal boundary as well as the preceding Bridgerian NALMA. In this dissertation, I first developed a chronological framework for the Eocene Bridger Formation including the age of the boundary, based on a combination of magnetostratigraphy and U-Pb ID-TIMS geochronology. Within the temporal framework, I attempted at making a regional correlation of the boundary-bearing strata within the western U.S., and also assessed the body size evolution of three representative taxa from the Bridger Basin within the context of Early Eocene Climatic Optimum. Integrating radioisotopic, magnetostratigraphic and astronomical data from the early to middle Eocene, I reviewed various calibration models for the Geological Time Scale and intercalibration of 40Ar/39Ar data among laboratories and against U-Pb data, toward the community goal of achieving a high precision and well integrated Geological Time Scale. In Chapter 2, I present a magnetostratigraphy and U-Pb zircon geochronology of the Bridger Formation from the Bridger Basin in southwestern Wyoming.
    [Show full text]
  • Rhinoplasty and Septoplasty
    Rhinoplasty and Septoplasty Surgically altering the nose is a common plastic surgery procedure that often has a profound impact on a patient’s life. In some cases this procedure is required to alter the internal anatomy of the nose in order to address functional breathing problems. In others a patient may desire to change the appearance of their nose. Rhinoplasty alters the external appearance of the nose, improving its shape and balance with the face. Frequently a combination of internal and external alterations are performed simultaneously. Functional Problems Airway obstruction is the most common functional nasal problem. It may be caused by either congenital or post- traumatic deformity of the nasal septum. Enlargement of the turbinates may also occur, creating an airway obstruction. All of these changes can exacerbate existing sinus problems. Cosmetic Deformity Some cosmetic deformities of the nose are post traumatic, while others are congenital. Both can be addressed similarly by surgically altering the underlying bony and cartilaginous framework of the nose. The Procedure Septoplasty and rhinoplasty are generally done on an outpatient basis and require either general anesthesia or sedation with a local. Airway problems are treated by removing or reshaping the septal cartilage. Some cases require a reduction in the size of the turbinates. Changes to the shape of the nose are accomplished by reshaping the bone and cartilage framework of the nose. In most cases the incisions can be located inside the nose resulting in no visible scars. Frequently used post-operative measures include splinting, taping and nasal packing. The Results Rhinoplasty can have a substantial effect on a person’s appearance and, ultimately, their general sense of well-being.
    [Show full text]
  • From the Upper Triassic of North-Central New Mexico
    Heckert, A.B., and Lucas, S.G., eds., 2002, Upper Triassic Stratigraphy and Paleontology. New Mexico Museum of Natural History and Science Bulletin No. 21. 189 THE TYPE LOCALITY OF BELODON BUCEROS COPE, 1881, A PHYTOSAUR (ARCHOSAURIA: PARASUCHIDAE) FROM THE UPPER TRIASSIC OF NORTH-CENTRAL NEW MEXICO SPENCER G. LUCAS, ANDREW B. HECKERT, KATE E. ZEIGLER and ADRIAN P. HUNT lNew Mexico Museum of Natural History, 1801 Mountain Road NW, Albuquerque, NM 87104-1375 Abstract-Here we establish the stratigraphic and geographic provenance of the "Belodon" buceros Cope. The holotype, originally collected by David Baldwin in 1881, is an incomplete phytosaur skull discov­ ered near "Huerfano Camp" in north-central New Mexico. This skull is the first phytosaur skull de­ scribed from the American West, and its precise provenance has never been established. Baldwin's use of the term Huerfano Camp may refer to Orphan Mesa, an isolated butte just south of Arroyo Seco. Fossils collected by Baldwin, and our subsequent collections from Orphan Mesa, are from a fossilifer­ ous interval high in the Petrified Formation of the Chinle Group. These strata yield a tetrapod fauna including the aetosaur Typothorax coccinarum and the phytosaur Pseudopalatus, both index taxa of the Revueltian (early-mid Norian) land-vertebrate faunachron. "Belodon" buceros is correctly referred to Pseudopalatus buceros (Cope) and is an index taxon of the Revueltian land-vertebrate faunachron. Keywords: phytosaur, Belodon, Pseudopalatus, Revueltian INTRODUCTION and its exact provenance has never been ascertained. Here, we establish the geographic and stratigraphic provenance of the ho­ In the Fall of 1874, Edward Drinker Cope (1840-1897) trav­ lotype of Belodon buceros and discuss its taxonomic position and eled through parts of north-central New Mexico and the San Juan biostratigraphic significance.
    [Show full text]
  • The Development of the Human Maxilla, Vomer, and Paraseptal Cartilages
    THE DEVELOPMENT OF THE HUMAN MAXILLA, VOMER, AND PARASEPTAL CARTILAGES. By Professor FAWCETT, M.D., University of Bristol. THE usually accepted descriptions of the development of the maxilla of man state that it arises by a number of separate centres-the number varying somewhat with the authority, likewise the situation of these centres. No description of the maxilla can be considered complete unless at the same time notice is taken of the manner of development of the premaxilla, which, of course, forms the anterior segment of the adult bone as usually interpreted. But the consideration of the development of the premaxilla may be left until that of the maxilla has been fully dealt with. Before breaking new ground, it may be well to state what are the usual statements with reference to the ossification of the maxilla. These statements are apparently for the most part based on work done by Callender, Toldt, Rambaud and Renault, and Bland Sutton, so far as concerns human anatomy. More recently Franklin Mall has given his views on the subject in the American Jouarnal of Anatomy, views based on observation of specimens treated by the "clearing" method of Schulze. So far as they go, these statements are in harmony with my own notions, which I have for several years now taught. A very precise account is given in Cunningham's Text-book of Anatomy. The maxilla is there stated to be developed in the connective tissue around the oral cavity of the embryo from centres which are not preceded by cartilage, of uncertain number, as early fusion takes place between them.
    [Show full text]
  • SMC 136 Gazin 1958 1 1-112.Pdf
    SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 136, NUMBER 1 Cftarlesi 3B, anb JKarp "^aux OTalcott 3^es(earcf) Jf unb A REVIEW OF THE MIDDLE AND UPPER EOCENE PRIMATES OF NORTH AMERICA (With 14 Plates) By C. LEWIS GAZIN Curator, Division of Vertebrate Paleontology United States National Museum Smithsonian Institution (Publication 4340) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION JULY 7, 1958 THE LORD BALTIMORE PRESS, INC. BALTIMORE, MD., U. S. A. CONTENTS Page Introduction i Acknowledgments 2 History of investigation 4 Geographic and geologic occurrence 14 Environment I7 Revision of certain lower Eocene primates and description of three new upper Wasatchian genera 24 Classification of middle and upper Eocene forms 30 Systematic revision of middle and upper Eocene primates 31 Notharctidae 31 Comparison of the skulls of Notharctus and Smilodectcs z:^ Omomyidae 47 Anaptomorphidae 7Z Apatemyidae 86 Summary of relationships of North American fossil primates 91 Discussion of platyrrhine relationships 98 References 100 Explanation of plates 108 ILLUSTRATIONS Plates (All plates follow page 112) 1. Notharctus and Smilodectes from the Bridger middle Eocene. 2. Notharctus and Smilodectes from the Bridger middle Eocene. 3. Notharctus and Smilodectcs from the Bridger middle Eocene. 4. Notharctus and Hemiacodon from the Bridger middle Eocene. 5. Notharctus and Smilodectcs from the Bridger middle Eocene. 6. Omomys from the middle and lower Eocene. 7. Omomys from the middle and lower Eocene. 8. Hemiacodon from the Bridger middle Eocene. 9. Washakius from the Bridger middle Eocene. 10. Anaptomorphus and Uintanius from the Bridger middle Eocene. 11. Trogolemur, Uintasorex, and Apatcmys from the Bridger middle Eocene. 12. Apatemys from the Bridger middle Eocene.
    [Show full text]
  • Deviated Septum the Shape of Your Nasal Cavity Could Be the Cause of Chronic Sinusitis
    Deviated Septum The shape of your nasal cavity could be the cause of chronic sinusitis. The nasal septum is the wall dividing the nasal cavity into halves; it is composed of a central supporting skeleton covered on each side by mucous membrane. The front portion of this natural partition is a firm but bendable structure made mostly of cartilage and is covered by skin that has a substantial supply of blood vessels. The ideal nasal septum is exactly midline, separating the left and right sides of the nose into passageways of equal size. Estimates are that 80 percent of all nasal septums are off-center, a condition that is generally not noticed. A “deviated septum” occurs when the septum is severely shifted away from the midline. The most common symptom from a badly deviated or crooked septum is difficulty breathing through the nose. The symptoms are usually worse on one side, and sometimes actually occur on the side opposite the bend. In some cases the crooked septum can interfere with the drainage of the sinuses, resulting in repeated sinus infections. Septoplasty is the preferred surgical treatment to correct a deviated septum. This procedure is not generally performed on minors, because the cartilaginous septum grows until around age 18. Septal deviations commonly occur due to nasal trauma. A deviated septum may cause one or more of the following: • Blockage of one or both nostrils • Nasal congestion, sometimes one-sided • Frequent nosebleeds • Frequent sinus infections • At times, facial pain, headaches, postnasal drip • Noisy breathing during sleep (in infants and young children) In some cases, a person with a mildly deviated septum has symptoms only when he or she also has a "cold" (an upper respiratory tract infection).
    [Show full text]
  • Deviated Septum 402.484.5500
    575 S 70th Street, Suite 440 Lincoln, NE 68510 Deviated Septum 402.484.5500 A “deviated septum” occurs when the septum is severely shifted away from the midline. Estimates are that 80 percent of all nasal septums are off-center, a condition that generally goes unnoticed. The nasal septum is the wall dividing the nasal cavities into halves; it is composed of a central supporting skeleton covered on each side by mucous membrane. The front portion of this natural partition is a firm, but bendable structure mostly made of cartilage and is covered by skin with a substantial supply of blood vessels. The ideal nasal septum is exactly midline, separating the left and right sides of the nose into passageways of equal size. Symptoms Symptoms are usually worse on one side and sometimes occur on the side opposite the bend. In some cases, the crooked septum can interfere with sinus drainage, resulting in repeated sinus infections. A deviated septum may cause: Blockage of one or both nostrils Nasal congestion, sometimes one-sided Frequent nosebleeds Frequent sinus infections Facial pain Headaches Post-nasal drip Noisy breathing during sleep, especially in infants and young children In some cases, a person with a mildly deviated septum has symptoms only when he or she has a cold. The respiratory infection triggers nasal inflammation that temporarily amplifies any mild airflow problems related to the deviated septum. Once the cold resolves and the nasal inflammation subsides, symptoms of the deviated septum resolve, too. Treatment Surgery may be recommended if the deviated septum is causing troublesome nosebleeds or recurrent sinus infections.
    [Show full text]