RODENTS FROM THE DESEADAN OLIGOCENE OF BOLIVIA AND THE RELATIONSHIPS OF THE CAVIOMORPHA BRYAN PATTERSON' and ALBERT E. WOOLF CONTENTS Abstract 372 Introduction 373 Acknowledgments 379 Abbreviations 379 Taxonomy and Morpholog>' 380 Infraorder Caviomorpha 380 Superfamily Octodontoidea 380 Family Octodontidae 380 Migraveramus new genus 380 M. beatus new species 380 Family Echimyidae 382 Sallamys Hoffstetter and Lavocat 382 S. pascuali Hoffstetter and Lavocat 383 Superfamily Cavioidea 395 Family Dasyproctidae 395 Incamys Hoffstetter and Lavocat 395 /. bolivianus Hoffstetter and Lavo-cat 395 Undescribed Genus, Dasyproctidae aff. Neoreomys 430 Cephalomys bolivianus Lavocat 430 Dasyproctidae inc. sed. 431 Family Dinomyidae 431 Branisamys Hoffstetter and Lavocat 431 B. luribayensis Hoffstetter and La-vocat 431 Caviomorpha inc. sed. 448 Luribayomys masticator L.a.vocat 448 Palmiramys waltheri Kraglievich 448 Discussion 449 Conflicting Theories of the Origin of the Caviomorpha 449 Eocene Geography 451 Distribution of Hystricognathous Rodents in the Eocene 453 The Composition of the Deseadan and Fa-vum Rodent Faunas 460 ' Late Professor of Vertebrate Paleontology, Emeritus, Harvard University, Cambridge, Massa-chusetts. ^ Professor of Biology, Emeritus, Amherst Col-lege, Amherst, Massachusetts. Present address: 20 Hereford Avenue, Cape Mav Court House, New Jersey 08210. The Evidence from Parasitic Nematodes — 471 Comparisons of Caviomorpha and Old World Hystricognathi 475 General 475 Hystricognath Mandible 476 Pter\goid Fossa 478 Jugal Fossa 479 Hystricomorphy 481 Heaviness and Suture of Malar 481 Middle Ear, Malleus and Incus 482 Openings at Base of Skull; Cephalic Arter-ies 484 Alisphenoid 487 Squamosal-Mastoid-Parietal-Occipital Junction 487 Clef^ Between Bulla and Squamosal 488 Maxillar\ in Orbitotemporal Fossa 488 Interparietal 488 Lacrimal Foramen 489 Tibia 489 Brain 489 Molars, Premolars and Deciduous Teeth 491 Multiserial Incisor Enamel 503 Ectoparasites 505 Other Features 506 Summar>' 507 The Classification of the Suborder Hystrico-gnathi 509 The Superfamilies of the Caviomorpha _-509 Other Taxonomic Problems of the Hystri-cognathi 512 General 512 Infraorder Franimorpha 513 Cylindrodontidae and Tsaganomyidae 514 Bathyergidae 516 Hystricidae 518 Thryonomyoidea 519 Classification of the Suborder Hystrico-gnathi 522 Conclusions 523 Appendix 1: Referred Specimens of Sallamys pascuali, Incamys bolivianus and Brani-samys luribayensis 528 Appendix 2: Validation oi Acarechimys 529 Literature Cited 529 Addendum 538 Index 539 Bull. Mus. Comp. Zool., 149(7): 371-543, January, 1982 371
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