lecture 5 - jaws and teeth
TRANSCRIPT
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Canis familiaris. P.D. Polly
Reading: Benton, Chapter 10
Comparative structure
Jaws and Teeth
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Barghusen and Hopson, 1979, The Endoskeleton
Branchial basket of lamprey (agnathan)
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
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Barghusen and Hopson, 1979, The Endoskeleton
Shark jaws (Chondricthyes)
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
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Teleost protrusible jaws
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Barghusen and Hopson, 1979, The Endoskeleton
Comparative jaw muscles in mammal and reptile
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Barghusen and Hopson, 1979, The Endoskeleton
Jaw suspension in vertebrates
Amphistylic (ancestral condition)
Hyostylic (condrichthyes)
Autostylic (Sarcopterygians and tetrapods)
Department of Geological Sciences | Indiana University (c) 2011, P. David Polly
G404 Geobiology
Dog skull (P. David Polly)
Structures associated with jaw movements in mammals
Joint: condyle of the mandible fits into the glenoid fossa of the squamosal (note same name as glenoid fossa of the pectoral girdle)
Zygomatic Arch: composed of the jugal (or zygomatic) and squamosal bones, muscle attachment along lower margin
Temporal Fossa: area for muscle attachment and movement of the mandible, site of muscle attachment
Coronoid process of the mandible: site of muscle attachment
Masseteric fossa of the mandible: site of muscle attachment
Angular process of the mandible: site of muscle attachment
Department of Geological Sciences | Indiana University (c) 2011, P. David Polly
G404 Geobiology
(Evans, Miller’s Anatomy of the Dog)
Muscles that move the mandibleTemporalis - originates on the side of the braincase, inserts on the coronoid process, pulls the mandible upward and backward.
Masseter - originates on the zygomatic arch, inserts in the masseteric fossa and on the lateral angle of the mandible, pulls the mandible upward, laterally, and forward.
Pterygoideus - originates on the pterygoid plates, inserts on the medial angle of the mandible, pulls the mandible upward, medially, and forward.
Temporalis
Masseter
Pterygoideus
Department of Geological Sciences | Indiana University (c) 2011, P. David Polly
G404 Geobiology
Dog skull (P. David Polly)
Muscle action to elevate (close) the mammalian mandible
Massete
r
Temporalis
Department of Geological Sciences | Indiana University (c) 2011, P. David Polly
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temporalis
masseter pterygoideus
Dorsal and medio-lateral action of the muscles
Department of Geological Sciences | Indiana University (c) 2011, P. David Polly
G404 Geobiology
Model by Alistair Evans, Monash Universityhttp://users.monash.edu.au/~arevans/3d.html
Animated model of teeth in actionNote how tall trigonid of lower molars passes between upper teeth and how the protocone of the upper molars slides across low talonid basin of lowers in mortar-and-pestle fashion
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Mesial
Distal
Lingual (or Palatal)
Labial (or Buccal)
Anatomical directions for the dentition
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Homo sapiens. P. D. Polly
Human jaws and dentition
Alveolar bone
Coronoid process
Condylar process
Angular process
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
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Tooth eruption in humans
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Tooth development schematic view
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Barghusen and Hopson, 1979, The Endoskeleton
Tooth structure, development, and attachment
Pleurodont Acrodont Thecodont
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
The Fossil Forum
Scales and teeth - developmentally homologous structures
Gar scales
•Composed of bone, dentine, and enamel (or variants)•Develop from interaction between
surface ectoderm layer and deeper mesoderm layer•Mouth of deuterostomes is formed by
invagination of ectoderm to connect with gut tube
Shark teeth
Department of Geological Sciences | Indiana University (c) 2013, P. David Polly
G404 Geobiology
Splanchnocranium in humans