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Girdle Origins

Girdle Origins. Where are the pectoral fins?. -Axial musculature interrupted by …. -Dermal bone would provide attachment points for …. -Then joined with …. Girdle Origins. Pectoral girdle has dermal and endochondral elements

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Girdle Origins

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  1. Girdle Origins • Where are the pectoral fins? -Axial musculature interrupted by … -Dermal bone would provide attachment points for … -Then joined with …

  2. Girdle Origins • Pectoral girdle has dermal andendochondral elements • : clavicle, cleithrum, supracleithrum, postcleithrum, posttemporal • : scapulocoracoid, scapula, coracoid • Pelvic girdle has only … • One bone in fishes … • Multiple bones in …

  3. Actinopterygian Pectoral Girdle Fig. 7.22 Fig. 9.13

  4. Sarcopterygian Pectoral Girdle Fig. 9.16 Fig. 9.14

  5. Tetrapods • Move to land separated pectoral girdle and attached pelvic girdle • Pelvic girdle: ilium (attaches to vertebrae), ischium, pubis • Pectoral girdle: • Loss of many dermal bones that … (posttemporal, supracleithrum, postcleithrum) • Increasing terrestriality associated with loss of … • f

  6. Early Tetrapods Fig. 9.17

  7. Trends in Pectoral Girdles • Scapulocoracoid scapula and procoracoid in • Further modification in early amniotes: • “New” coracoid in early amniotes = • Ancestral coracoid = Scapula Procoracoid

  8. Trends in Pectoral Girdles -Loss of … -Increased prominence of … Fig. 9.19

  9. Trends in Pelvic Girdles Differences from pectoral girdle? -Despite shape differences… Fig. 9.21

  10. Body Support by Girdles Fig. 9.29

  11. Limb Organization Fig. 9.23

  12. Limb Organization Phalanges Pes Manus Fig. 9.23

  13. Lots of Variation Related to Lifestyle Fig. 9.44 Fig. 9.25

  14. Lots of Variation Related to Lifestyle Fig. 9.26

  15. Limb Posture and Girdles • Early tetrapods had … • Forces directed toward … • Still used by many tetrapods Fig. 9.32 Fig. 9.35

  16. Limb Posture and Girdles • Movement of limbs under body shifted forces to be … • Led to reduction/loss of medial elements and increase in … Fig. 9.32 Fig. 9.35

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