APPENDICULAR SKELETON

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APPENDICULAR SKELETON

• I. OriginA. Fin-fold theory - remnants of fleshy
  folds of skin running length of the body

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• B. Fin spine hypothesis - Gregory Ravensome
  spines remainedfossil acanthodians have spine
  in fins

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II. Pectoral Girdles

• A. Pectoral girdle of fish7 paired bones
  141. Cartilage bones - scapulae, coracoids
• 2. Dermal bones - clavicles, cleithra,
  supracleithra, postemporals

Supra- cleithrum
Cleithrum
Clavicle
Post- temporal
Coracoid
Scapula
Supra- scapula
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Supra- cleithrum
Cleithrum
Clavicle
Post- temporal
Coracoid
Scapula
Supra- scapula
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B. Pectoral girdle trends among vertebrates

• 1. General patterns
• Cartilagenous fishes

Supra- cleithrum
Cleithrum
Clavicle
Post- temporal
Coracoid
Scapula
Supra- scapula
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Pectoral girdle of amphibians - salamander
Supra- cleithrum
Cleithrum
Clavicle
Post- temporal
Coracoid
Scapula
Supra- scapula
Fused
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Pectoral girdle of amphibians - frogs
Supra- cleithrum
Cleithrum
Clavicle
Post- temporal
Coracoid
Scapula
Supra- scapula
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Pectoral girdle of reptiles and birds
Interclavicle
Supra- cleithrum
Cleithrum
Clavicle
Post- temporal
Coracoid
Scapula
Supra- scapula
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Pectoral girdle of mammals
Coracoid coracoid process of scapula
Supra- cleithrum
Cleithrum
Clavicle
Post- temporal
Coracoid
Scapula
Supra- scapula
Fused
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2. Specific trends in mammals

• a. clavicle lost in ungulates and aquatic
  mammals, small in cats - reduced for swimming or
  rapid locomotion
• b. clavicle large - digging, flying or climbing
  and braces scapula against the sternum

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III. Pelvic Girdle

• A. Pelvic girdle of fishFish - ischiopubic plate

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B. Pelvic girdles of tetrapods

• 1. General pattern

Acetabulum
Pubis
Ilium
Ischium
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2. Specific patterns
Cat
Human
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IV. Icthyopterygium
Basals
Radials
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Lobe-finned fishes
Primitive Amphibian
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V. Cheiropterygium (cheiro hand)

• A. Regions1. Propodium - humerus and femur2.
  Epipodium - radius/ulna and tibia/fibulalittle
  variation3. Mesopodium - carpels or tarsus4.
  Metapodium - metacarpels and metatarses5.
  Phalanges and digits

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B. Variations on a theme

• 1. Manus - forelimb
• 2. Pes - hindlimb

Flight
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Archaeopteryx lithographica
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Digging
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Locomotion
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Perissodactyls - Odd-toed Ungulates
Artiodactyls - Even-toed Ungulates
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C. Reductions

• 1. digit V gone on amphibians
• 2. birds - IV V gone from manus, V gone on pes
• 3. sequence of loss in mammals - 1 - 5 - 2 - 4 -
  3

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D. Other trends 1. decrease in the number of
elements, especially digits 2. more efficient
support 3. limbs elevated body for speed
4. functional diversification of long bones
Tibiotarsus
Hind limb of a bird
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VI. Unpaired appendages

• A. Caudal fins

Heterocercal
Diphycercal
Homocercal