1. Appendicular Skeleton
Appendages and supporting girdles

3. Pectoral Girdle
Function

4. Pectoral Girdle – Replacement bones
Coracoid
(Epicoracoid)
Scapula
Suprascapula

6. Pectoral Girdle – Membrane bones
Clavicle
Cleithrum
Supracleithrum
Postcleithrum
Posttemporal
Interclavicle
(Episternum in tetrapods)

8. Pectoral Girdle
Glenoid fossa on scapula for limb attachment

9. Key Point
What trend do you see as you look at the overview of pectoral girdles?

11. Pectoral Girdle - Placoderms
First to have a pectoral girdle

12. Pectoral Girdle - Chondrichthyes
Cartilage
No dermal elements
Coracoid, scapula, suprascapula (scapulacoracoid)
Not connect to axial skeleton, but fused at midline

14. Pectoral Girdle – Bony fish
Membrane bones
Clavicle, some have interclavicle
Cleithrum – largest
Supracleithrum, postcleithrum
Posttemporal – anchors to skull

16. Pectoral girdle – bony fish
Replacement bones
Coracoid
Scapula

18. Pectoral Girdle - amphibians
Membrane bones
Reduced
Lose posttemporal
Early amphibians gained an interclavicle as a brace

19. Pectoral Girdle - amphibians
Replacement bones
Coracoid
Scapula and suprascapula

21. Pectoral Girdle - amphibians
Urodeles have no membrane bones, including clavicle
Anurans have clavicle, no interclavicle and usually no cleithrum

22. Pectoral girdle - Reptiles
Stem reptiles & synapsids
Many membrane bones present
Most replacement bones present
New posterior coracoid present

24. Pectoral girdle - Reptiles
Modern reptiles have scapula, coracoid, sometimes clavicle, sometimes interclavicle
Crocodiles have reduced clavicle
Turtles have interclavicle fused with shell
Snakes have no girdle
Lizards have a significant clavicle and interclavicle

26. Pectoral Girdle - birds
Furcula (2 clavicles plus interclavicle)
Scapula – bladelike
Coracoid (anterior or pro-) which articulates with sternum

28. Pectoral Girdle - mammals
Monotremes similar to stem reptiles
Clavicle in most
Scapula
Coracoid process from posterior coracoid
Spine is new
Acromion process articulates with clavicle (not new)

33. Pelvic Girdle Stability, encloses pelvic cavity organs
In tetrapods, it has three parts called the ilium, pubis and ischium
When these three bones fuse into one, the fused bone is the innominate or coxal bone
Acetabulum is the socket for the thigh
Symphysis in all but birds
Replacement bone

36. Pelvic Girdle - Fish
Pelvic plate or symphysis

38. Pelvic Girdle - amphibians
Pubis
Ilium (long & slanted in frog)
Ischium

40. Pelvic Girdle - Reptile
Sacroiliac joint is stronger and broader for more muscle attachment and stability

42. Pelvic Girdle - birds
Synsacrum – Ilium is braced against fused vertebrae
No symphysis WHY??

44. Pelvic girdle - mammals
Epipubic bone in marsupials is unique for pouch support

46. FINS
Steering, rolling, braking, stabilizers, forward & vertical movement

47. Fin structure Skin epidermis covering Fin rays in dermis
Lepidotrichia (scale-hair) bony dermal scales, segmented
Ceratotrichia (horn-hair) cartilaginous unsegmented rays

49. Fin Structure Skeletal base (cartilage or bone) for support
Pterygiophores (bearing fin)
Basals are proximal
Radials are distal

51. Paired Fins Absent in agnathans Some in placoderms & acanthodians
Chondrichthyes
Fin Fold Fins – very broad based

53. Paired Fins
Bony fish
Actinopterygii has ray fins, very flexible with thin base
Sacrcopterygii has fleshy muscular base
Dipnoi has lobe fins
Crossopterygii has lobe fins that are called fringe fins & have pterygiophores on one side of fin axis

54. Osteichthyes skeleton
Dorsal fins
Caudal fin
Pectoral fin
Anal fin
Pelvic fin

58. Origins of fins From acanthodian spines? From fleshy folds?
From gills?

59. Median fins – Dorsal and Anal fins

60. Dorsal and Anal Fins Function for rolling, defense, display
Location – rests on vertebral column
Variations among groups

61. Caudal fins Heterocercal Hypocercal Diphycercal Homocercal Teleosts
Neural and Hemal arch for support
Bony sheath for notochord

62. Dorsal fins
Caudal fin
Pectoral fin
Anal fin
Pelvic fin

63. Fish tails
Heterocercal
Diphycercal
Homocercal