Guess it's tradition now to have the dino season be set in high school, much like how it's tradition for the villains of the Sentai dino shows being responsible for the extinction of the dinosaurs.
The dinosaurs died when Bandora killed them!
No wait, they died when Dezumozora killed them and the earth split into two, one is normal earth and one where humans evolved from lizards (oh god, Abaranger copied the Super Mario Bros movie) and some of the surviving dinosaurs became machines.
NO WAIT, the dinosaurs were killed by Deboss but some of them survived thanks to a bird-man.
Sentai "continuity" is weird. I know each one is meant to be a separate universe, but Gokaiger kind of made things weird.