QL737 .R68B49 2005 Anatomy of the Woodchuck (Marmota monax) A. J. Bezuidenhout and H. E. Evans SPECIAL PUBLICATION NO. 13 AMERICAN SOCIETY OF MAMMALOGISTS LIBRARY OF THE /XT FOR THE ^> ^ PEOPLE ^ ^* <£ FOR _ EDVCATION O <£ FOR ^J O, SCIENCE j< Anatomy of the Woodchuck (Marmota monax) by A. J. Bezuidenhout and H. E. Evans SPECIAL PUBLICATION NO. 13 American Society of Mammalogists Published 21 February 2005 Price $45.00 includes postage and handling. American Society of Mammalogists P.O. Box 7060 Lawrence, KS 66044-1897 ISBN: 1-891276-43-3 Library of Congress Control Number: 2005921107 Printed at Allen Press, Inc., Lawrence, Kansas 66044 Issued: 21 February 2005 Copyright © by the American Society of Mammalogists 2005 SPECIAL PUBLICATIONS American Society of Mammalogists This series, published by the American Society of Mammalogists in association with Allen Press, Inc., has been established for peer-reviewed papers of monographic scope concerned with any aspect of the biology of mammals. Copies of Special Publications by the Society may be ordered from: American Society of Mammalogists, % Allen Marketing and Management, P.O. Box 7060, Lawrence, KS 66044-8897, or at www. mammalogy.org. Dr. Joseph F. Merritt Editor for Special Publications Department of Biology United States Air Force Academy 2355 Faculty Drive US Air Force Academy, CO 80840 Dr. David M. Leslie, Jr. Chair, ASM Publications Committee Oklahoma Cooperative Fish and Wildlife Research Unit United States Geological Survey 404 Life Sciences West Oklahoma State University Stillwater, OK 74078-3051 Anatomy of the Woodchuck (Marmota MONAX) A. J. Bezuidenhout and H. E. Evans Published by the American Society of Mammalogists Contents Page Acknowledgments vii Foreword ix Chapter 1. Introduction Introduction 1 Anatomical Terms 7 Integument 8 Chapter 2. Skeleton Axial Skeleton 11 Bones of the Face, Ossa Faciei 20 Vertebral Column, Columna Vertebralis 23 Sternum 26 Ribs 27 Appendicular Skeleton 27 Chapter 3. Joints and Ligaments Skull 39 Vertebral Column 39 Ribs 40 Thoracic Limb 40 Pelvic Limb 42 Chapter 4. Muscular System Head 45 Thoracic Limb 56 Trunk 65 Perineum 72 Pelvic Limb 73 Chapter 5. Digestive System Mouth and Associated Structures 81 Abdomen and Peritoneum 86 Liver, Hepar 94 Chapter 6. Respiratory System Nose, Nasal Cavity and Paranasal Sinuses 100 Pharynx 101 Larynx 102 Trachea 103 Thoracic Cavity and Pleurae 104 Lungs 105 Chapter 7. Urogenital Apparatus Urogenital Apparatus 108 v Male Genital Organs Ill Female Genital Organs 115 Chapter 8. Endocrine Organs Endocrine Organs 118 Chapter 9. Cardiovascular System Heart and Pericardium 119 Arterial System 123 Venous System 132 Lymphatic System 141 Chapter 10. Central Nervous System Meninges 145 Brain, Encephalon 145 Spinal Cord, Medulla Spinalis 153 Peripheral Nervous System, Cranial Nerves 154 Spinal Nerves, Nervi Spinales 161 Autonomic Nervous System 167 Chapter 11. Sensory Organs Eye 170 Ear 172 Bibliography 174 Acknowledgments The authors thank Dr. Bud Tennant of the Col- toria, South Africa, for granting him sabbatical lege of Veterinary Medicine at Cornell University leave to work on the project and providing their for his vision to initiate this study of woodchuck biomedical illustrator, Christine Seegers, who drew anatomy and for his financial support. His labora- most of the illustrations. tory supplied the skeletal material as well as the It was a pleasure to have the encouragement and advice of Virginia Hayssen, Merritt, animals that were dissected and illustrated. Without Joseph and Da- vid Leslie, Jr. of the Publications Committee of the his continued support and encouragement, it American Society of Mammalogists. We also thank would not have possible to complete the work. the hard-working reviewers, Stuart O. Landry, We thank the Department of Biomedical Scienc- Jr. and Richard W. Thorington, Jr., who caught many es in the College of Veterinary Medicine at Cornell errors and suggested improvements. Ken Armitage University for providing space and facilities to do of Lawrence, Kansas and Raymond Ramousse of the work. The College illustrator, Michael Sim- Lyon, France helped us with the literature. Vadim mons, prepared some of the artwork and finalized Rumiantsev of Russia put us in touch with many the numbering on all illustrations. The library and of his colleagues within and outside the former So- computer facilities at Cornell University aided us viet Union. A sizeable monetary subvention for greatly. publication was provided by Marmotech, Inc., Ith- Dr. Bezuidenhout thanks the University of Pre- aca, New York. Foreword The woodchuck (Marmota monax) or, as it is associated with HBV infection in humans. With Dr. known in the southern United States, the ground Javitt's encouragement, the following spring we ini- hog is 1 of 14 species of marmots (Rodentia: Sciur- tiated studies of woodchucks trapped in Tompkins idae), all of which are found in the Northern Hemi- County, New York. sphere. In North America, the woodchuck ranges It was recognized from the beginning that to use from north Georgia to the maritime provinces of the woodchuck as an experimental animal model Canada, west to Oklahoma, Missouri, and Iowa, for studies of the pathogenesis of viral hepatitis, a across Canada to the Yukon Territory and to south- breeding colony would be required to produce eastern Alaska. Other marmot species live in colo- pathogen-free experimental animals. A colony of nies and often at high elevations. The woodchuck, WHV-free woodchucks was established at Cornell however, is a solitary species, the largest among in 1979. Subsequently, support for the colony was marmots, and lives at low elevations. obtained from the National Institute of Allergy and For a century, the woodchuck has been the sub- Infectious Diseases (NIAID) and the National Can- ject of a diverse series of studies conducted by fac- cer Institute (NCI). The initial program officers ulty at Cornell University. These included some of from those institutes were Dr. Frank Tyeryar the earliest investigations of the physiology of hi- (NIAID) and Dr. John Cole (NCI). The successful bernation in which the possible role of brown fat production of laboratory-born and reared wood- was recognized. The wide-ranging field studies of chucks led to collaborative experimental studies Prof. William Hamilton culminated in the publi- with Dr. John L. Gerin and colleagues from the cation of his classic monograph on the natural his- Division of Molecular Virology and Immunology, tory of the woodchuck. In more recent years, the Georgetown University School of Medicine, Dr. woodchuck has been used in studies of the patho- Robert H. Purcell and associates from the Hepatitis genesis of viral hepatitis and primary liver cancer Viruses Section, Laboratory of Infectious Diseases, (hepatocellular carcinoma). The comprehensive NIAID, and the late Dr. Hans Popper of the Mt. study of woodchuck anatomy described in this vol- Sinai School of Medicine. The woodchuck now is ume by my colleagues Dr. Abraham J. Bezuiden- recognized as a valuable animal model for HBV and hout and Prof. Howard E. Evans, 2 of the world's liver cancer research and for preclinical evaluation most distinguished and productive anatomists, was of new strategies for the treatment and prevention a critical part of the development of the woodchuck of these important human diseases. The model is as a laboratory animal model for biomedical re- now used widely throughout the United States, search. Canada, Europe, and Asia. In 1978, I received a telephone call from Dr. Since discovery of WHV, members of the hepa- Norman Javitt, then Chief of Gastroenterology at titis B family of viruses (Hepadnaviridae) have been Cornell Medical College, asking me what I knew identified in California ground squirrels (Spermo- about woodchucks. I explained that my knowledge philus beecheyi), Arctic ground squirrels (S. parryii), at the time was limited to the well recognized role and Richardson's ground squirrels (S. richardsonii) of the woodchuck in decimating vegetable gardens In all of these species, viral infection has been as- and to the alleged role of woodchuck burrows in sociated with chronic hepatitis and hepatocellular the etiology of long bone fractures of livestock. Dr. carcinoma. Other related members of the family lavitt then told me of a recent report by Dr. Jesse Sciuridae also are known to have similar liver dis- Summers and colleagues from the Fox Chase Can- eases (e.g., black-tailed prairie dog, Cynomys ludov- cer Center describing a virus isolated from wood- icianus) but have not yet been shown to be infected chucks that appeared to be closely related to the with a hepadnavirus. hepatitis B virus (HBV) of humans. The wood- Significant variations in the prevalence of HBV chucks described by Dr. Summers and associates infection are recognized in different parts of the had been trapped originally in the native habitat of world. Very high rates of HBV infection and pri- Pennsylvania and maintained and studied in an ex- mary liver cancer exist in Sub-Saharan Africa and perimental colony at the Philadelphia Zoological Asia, while the respective frequencies are low in Garden by Dr. Robert Snyder. Prior to the virolog- North America and Western Europe. Interestingly, ical studies, woodchucks from the colony had ex- woodchuck hepatitis virus (WHV) infection is hy- perienced high rates of chronic hepatitis and he- perendemic in the mid-Atlantic states where rates patocellular carcinoma, complications known to be of infection as high as 59% have been reported and where one-half of the infected woodchucks are the work in this volume. Special thanks must be chronic carriers. In Tompkins County, New York, given to the American Society of Mammalogists the infection rate is about 1% and the carrier rate that recognized the scientific value of the manu- is < 0.1%. In the other parts of the United States script, provided editorial review, and sponsored and Canada so far studied, WHV infection rates are publication of the book.