1. Appendicular Skeleton Includes all of the following: limbs or fins pectoral girdle pelvic girdle

2. Pectoral Girdles Primative Condition: 3 pairs of endochondral replacement bones (coracoid, scapula and suprascapular) 4 pairs of dermal investing bones (clavicle, cleithrum, supracleithrum, posttemporal)

3. Modern Teleosts cleithrum becomes major bone of pg clavicle is lost scapula and coracoid become smaller and/or fuse to form a coracoscapula

4. Early Tetrapods similar to bony fish with… loss of the posttemporal and… gain of an interclavicle Modern Tetrapods supracleithrum and cleithrum are reduced then lost… interclavicle and clavicle (dermal) and coracoid and scapula (endochondral) remain.

5. What happens to the remaining bones??? Interclavicle: absent in amphibians, persists in reptiles, birds and lower mammals. Clavicle: absent in amphibians (except frogs) and some reptiles. Present in birds and mammals. Coracoids: replace clavicle in lower tetrapods. absent in mammals except for coracoid process. Scapula: present in all tetrapods. Forms the glenoid fossa which allows articulation with humerus.

6. Pelvic Girdles Ischiopubic plates in fish Plates in amphibians ossify to form pubis and ischium. Additional ossification center forms the ilium These bones ankylose to form innominate bone

7. Acetabulum forms at junction of these 3 bones, Tetrapod ilium articulates with transverse processes of sacral vertebrae forming sacroiliac joint. Pubic symphysis in all vertebrates except birds Obturator foramen between ischium and pubic bones transmits obturator nerve and associated blood vessels

8. Fins and Limbs

9. Fins serve as steering, stabilizing and inclination devices composed of two integumental surfaces reinforced by dermal fin rays resting on a base of cartilage dermal elements are lepidotrichia (bony fish) or ceratotrichia (cartilaginous fish) actinotrichia are distal elements in both groups pterygiophores form the skeletal base

10. Paired fins brace against a girdle. 3 Categories: Lobed fins - fleshy proximal region, distal membranous component reinforced by fin rays - Dipnoans Fin fold fins - broad base - cartilaginous fish Ray fins - reduction of basal elements with increased flexibiity - bony fish (actinopterygians)

11. Median fins Act as keels to prevent rolling Several median fins may be present including median dorsal fin and midventral anal fin. Anal fins may be modified as gonopodia (claspers)

12. Caudal fins Classified by direction of terminal notochord Heterocercal - notochord turns upward - modern sharks. Diphycercal - little bending of notochord - Dipnoans. Homocercal - notochord turns dorsally - bony fish.

13. Tetrapod Limbs Various modifications for locomotion 5 basic skeletal elements in all limbs: propodium - proximal element - humerus/femur epipodium - forelimb elements - radius/ulna or tibia/fibula mesopodium - carpal/tarsal bones metapodium - metacarpals/metatarsals phalanges - digital bones of fingers and toes