original_query: What is the significance of the absence of hard-shelled reptilian eggs in Dinocephalosaurus?
query: What is the significance of the absence of hard-shelled reptilian eggs in Dinocephalosaurus?
answer: The absence of hard-shelled eggs in Dinocephalosaurus is significant because it supports the conclusion that the reptile was viviparous (gave birth to live young).  Hard-shelled eggs require gas exchange with the air, a process much slower in water.  Dinocephalosaurus's aquatic adaptations made laying and hatching eggs on land impossible.