Reptile MSK anatomy

Question 1

what are the 4 orders of the class Saropsida

reptiles

Answer 1

• crocodilia (crocodiles, aligators etc.)
• sphenodonita (2 species from new zealand)
• squamata (lizards and snakes)
• testudines (tortoises, turtles, terrapins)

Question 2

what is the reptile skeleton designed for in contrast to the mammalian skeleton

Answer 2

• flexibility

Question 3

what is gastralia

Answer 3

dermal ribs that form by intramembranous ossification caudal to the sternum that do not articulate with vertebrae. Present in some lizards and crocs

Question 4

what is the anomoly of reptile bone growth and remdelling

Answer 4

• slow and intermediate epiphyses never close in some species
• very dependent on external factors (food, temp, environment etc.)
• remodelling and growth takes longer (6-30 months) and there is less remodelling and periosteal growth

Question 5

what is caudal tail autonomy and how does it work

Answer 5

• an anti predator defence mechanism in which the lizard can detach its own tail if attacked, leaving the predator with a squirming tail as distraction
• breaks off at pre-determined fracture planes
• regrowth of tail is never the same as original tail. tail “bones” are cartilage.
• very costly (fat stores in tail, affects locomotion and repro)

Question 6

what are the 2 chelonian neck types

Answer 6

1. cryptodira (neck folds in)
2. pleurodira (neck tucks to side)