All crocodilians both extinct and extant, as well as their
close relatives, fall into the Crocodylomorpha. The slatoposuchids and
sphenosuchids were Late Triassic to Mid Jurassic terrestrial, long-legged
forms. The remaining crodoilians adopted a more aquatic lifestyle, and
had shorter limbs and adaptations for swimming. Many groups evolved in the
Jurassic and Cretaceous, and there are only three living families. Extinct
families are indicated with a dagger ().