Crocodilians belong to the clade known as the Archosauria or ruling reptiles. The clade Archosauria represents one of the fundamental divisions of vertebrate phylogeny and has been a successful and at times dominant group ever since it originated in the Late Permian or Early Triassic. Today, the extant Archosauria consists of only the birds and crocodilians. This chapter explores the fossil history and categorization of crocodilians.
Reproductive Biology of the Crocodylia, 2022, pp 1-6,