Zoology 10th Edition by Stephen Miller,John Harley

Exercise 9

Reptile skin is scaly, thick, dry, and keratinized. It functions in protection, locomotion, secretion, sex recognition, and thermoregulation. The reptile skull has a secondary palate and the axial skeleton has more cervical vertebrae than in the amphibian axial skeleton. Most reptiles are carnivores. The skulls of snakes show remarkable adaptations for swallowing large prey. Reptile hearts consist of two atria and a ventricle that is incompletely divided (except in crocodilians). Systemic and pulmonary arteries separate blood flow in pulmonary and systemic circuits. Reptiles use a negative-pressure mechanism to move air into and out of their lungs. Most reptiles are ectotherms. Vision is the dominant sense in most reptiles. Reptiles have metanephric kidneys. Excretion of uric acid helps conserve water. Following internal fertilization, female reptiles lay a shelled amniotic egg. Parthenogenesis occurs in some lizards. Eggs usually develop unattended by parents. Crocodilians are exceptions, as females tend their nests.
What adaptations are present in nonavian reptiles that have made life on land possible?