Eusuchia

Eusuchia is a suborder of reptiles that includes modern alligators, true crocodiles, and gavials. These animals are characterized by their internal nostrils, which are located far back and surrounded by the pterygoid bone. Eusuchia evolved from earlier crocodilian groups, with their internal nostrils becoming increasingly posterior in their skull structure over time. The earliest known forms, like Protosuchia, appeared in the Late Triassic period, while true Eusuchia emerged in the Upper Jurassic. While classifications vary, alligators and true crocodiles are considered more closely related to each other than to gavials.123