1. Axial Skeleton - Ribs Function – Protection – Respiration Phylogeny - new Endochondral

2. Ribs Dorsal ribs separate dorsal and ventral muscle mass Ventral ribs are in the body wall

4. Ribs Monocipital (snakes & monotremes) Bicipital – Dorsal head = tuberculum – Ventral head = capitulum

6. Ribs Costal = vertebral ribs Sternal = costal cartilage

9. Ribs - Fish Some have no ribs Some have dorsal ribs only (sharks) Some have ventral ribs Some have dorsal & ventral ribs

11. Ribs - Amphibians Short in anurans and urodeles Long in apodans

12. Ribs - Reptiles Typically short in neck and long in trunk Turtles – fused to carapace Snakes – long and curved Crocodiles – Gastralia are NOT ribs

14. Turtle skeleton CarapaceCarapace PlastronPlastron Fused vertebrae RibsRibs

17. Ribs - Birds Costal & Sternal Ribs Uncinate Processes for muscle attachment

19. Ribs - Mammals Thoracic (12 in human, 13 in cat) True rib False rib Floating rib

21. Sternum Needed for stronger & more mobile forelimbs Tetrapod feature only Function – protection, strengthens body wall, attaches muscles, rib attachment Endochondral bone

22. Sternum - amphibians Frogs & toads – ossified, but poor Urodeles – flimsy if present Caecilians - none

23. Sternum - reptiles Lizards – large Crocodiles – large cartilaginous plate Snakes – none Turtles – none needed

24. Sternum - birds Keel Carina For muscle attachment

26. Sternum - Mammal Segments Xiphoid process is caudal-most segment