Linked from
The 34 pages that link to Reptile, each with the reason it gives.
EctothermyBroader topic: Most living reptiles rely substantially on environmental heat.
TetrapodBroader topic: Reptiles are one major living radiation within the tetrapod tree.
AmnioteBroader topic: Reptiles are one major living component of amniote diversity.
HerpetologyBroader topic: Reptiles are one of herpetology’s two principal study groups.