CASANOVAS-VILAR, I. 2007. The rodent assemblages from the Late Aragonian and the Vallesian (Middle to Late Miocene) of the Vallès-Penedès Basin (Catalonia, Spain) A Roser 1 CASANOVAS-VILAR, I. 2007. The rodent assemblages from the Late Aragonian and the Vallesian (Middle to Late Miocene) of the Vallès-Penedès Basin (Catalonia, Spain) Contents PRÒLEG (prologue, in Catalan) ...................................................................8 AGRAÏMENTS (acknowledgements, in Catalan) .......................................11 Foreword. INTRODUCTION. AIM AND STRUCTURE OF THIS WORK ............................................................................................15 “Classical” thesis and compendia of publications .......................................15 Aim and structure of this work .....................................................................16 Chapter 1. INTRODUCTION TO FOSSIL RODENTS .............................19 1.1. The study of fossil rodents ......................................................................19 1.1.1.The study of fossil rodents in the Vallès-Penedès Basin, a historical perspective ....................................................................19 The early students.................................................................................19 From the 1950s to the late 1970s..........................................................20 From the 1970s to the present...............................................................21 1.1.2. Collecting methods...........................................................................22 1.2. What is a rodent? Origin and classification of rodents ........................25 1.2.1. Main anatomical traits of rodents .....................................................25 1.2.2. The origin of rodents and the Glires concept ...................................27 1.2.3. Major groups of rodents ...................................................................30 1.3. General remarks on the anatomy, biometry and classification of the families of rodents that appear on the systematic part of this work ....................................................................33 1.3.1. Methods and abbreviations...............................................................33 1.3.2. General remarks on the skull, mandible and incisors.......................34 1.3.3. Family Sciuridae...............................................................................35 Main anatomical characteristics ...........................................................35 Origin, diversity and classification of the Sciuridae.............................36 1.3.4. Family Castoridae.............................................................................38 Main anatomical characteristics ...........................................................38 Origin, diversity and classification of the Castoridae ..........................41 1.3.5. Family Gliridae.................................................................................43 Main anatomical characteristics ...........................................................43 Origin, diversity and classification of the Gliridae...............................45 1.3.6. Supefamily Muroidea .......................................................................48 Content of the superfamily Muroidea...................................................48 Main anatomical characteristics. The “cricetid plan”...........................49 Origin, diversity and classification of the “cricetids”...........................52 Chapter 2. GEOGRAPHICAL AND GEOLOGICAL BACKGROUND. BIOSTRATIGRAPHY AND BIOCHRONOLOGY .....................................................................................57 2.1. The Middle to Late Miocene sedimentary record of the Vallès-Penedès Basin ................................................................................57 2.1.1. Introduction ......................................................................................57 2.1.2. Major stratigraphic units of the Vallès-Pendès Basin ......................58 2.2. The Miocene fossil sites from the area of Els Hostalets de Pierola ..................................................................................61 2 CASANOVAS-VILAR, I. 2007. The rodent assemblages from the Late Aragonian and the Vallesian (Middle to Late Miocene) of the Vallès-Penedès Basin (Catalonia, Spain) 2.2.1. Historical background.......................................................................61 2.2.2. Geological setting.............................................................................63 2.2.3. The fauna ..........................................................................................65 Avifauna and herpetofauna...................................................................66 The macromammals .............................................................................66 Insectivores, chiropterans and lagomorphs ..........................................68 The rodents ...........................................................................................69 2.3. Biostratigraphy and biochronology of the Late Aragonian and Vallesian mammal successions of the Vallès-Penedès Basin and correlation to other areas .......................................................................71 2.3.1. A preliminary biozonation of the Late Aragonian of the Vallès-Penedès Basin............................................................................72 2.3.2. Biozonation of the Vallesian succession of the Vallès-Penedès Basin: state of art ..............................................................75 2.3.3. Geographical range of the proposed biozones and correlation to the continental record of other basins ..................................79 The Late Aragonian..............................................................................79 The Early Vallesian ..............................................................................82 The Late Vallesian................................................................................82 2.4. Conclusions ..............................................................................................83 Appendix 2.1. ...................................................................................................84 Appendix 2.2. ...................................................................................................86 Chapter 3. A NEW BEAVER SPECIES FROM ABOCADOR DE CAN MATA (VALLÈS-PENEDÈS BASIN, CATALONIA, SPAIN) AND A DISCUSSION ON THE TAXONOMY AND PALEOBILOGY OF THE GENUS Chalicomys KAUP, 1832 ...................89 3.1. Introduction .............................................................................................89 3.2. Systematic paleontology ..........................................................................90 3.2.1. Description of the holotype and paratypes .......................................93 3.2.2. Postcranial material ..........................................................................99 Measurements and description .............................................................99 Morphological comparisons .................................................................100 3.3. Discussion .................................................................................................102 3.3.1. Taxonomy.........................................................................................102 3.3.2. Nomenclatural issues........................................................................104 3.4. Paleobiology .............................................................................................105 3.4.1. Body mass estimation.......................................................................105 3.4.2. Mode of locomotion .........................................................................105 3.5. Paleoecological implications ...................................................................108 3.6. Conclusions ..............................................................................................109 Chapter 4. THE RODENTS FROM THE LATE ARAGONIAN (MIDDLE MIOCENE) OF BARRANC DE CAN VILA 1 (VALLÈS-PENEDÈS BASIN, CATALONIA, SPAIN) ..............................110 4.1. Introduction .............................................................................................110 4.2. The mammal fauna from Barranc de Can Vila 1 .................................111 4.3. Systematic paleontology ..........................................................................112 Spermophilinus bredai ..........................................................................112 Miopetaurista cf. crusafonti .................................................................115 Glirudinus undosus ...............................................................................116 Muscardinus sansaniensis ....................................................................119 Microdyromys complicatus ..................................................................122 3 CASANOVAS-VILAR, I. 2007. The rodent assemblages from the Late Aragonian and the Vallesian (Middle to Late Miocene) of the Vallès-Penedès Basin (Catalonia, Spain) Bransatoglis sp. ....................................................................................123 Eumyarion leemani ...............................................................................124 Megacricetodon minor minor ...............................................................135 A few words on the taxonomic