Lizards & Snakes
The prevailing theory is that snakes evolved from burrowing lizards 128 MYA, long after lizards 240 MYA descent. Instead, it is more likely that snakes descended from sea serpents: elongating their bodies and losing their stubby legs with flipper feet while slithering ashore.
In contrast, turtles most certainly evolved from lizards, and rather abruptly: trading celerity for a protective shell to facilitate better burrowing. This inclination for subterranean safety may have helped turtles survive the Permian mass extinction 252 MYA.