Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms, a group which includes all living crocodilians.
Sphenosuchia
Image: Dibothrosuchus BW
Image: Dyoplax holotype
Image: Junggarsuchus sloani
Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably more ecologically diverse than modern crocodillians. The earliest and most primitive crocodylomorphs are represented by "sphenosuchians", a paraphyletic assemblage containing small-bodied, slender forms with elongated limbs that walked upright, which represents the ancestral morphology of Crocodylomorpha. These forms persisted until the end of the Jurassic. During the Jurassic, crocodylomorphs morphologically diversified into numerous niches, with the subgroups Neosuchia and the extinct Thalattosuchia adapting to aquatic life, while some terrestrial groups adopted herbivorous and omnivorous lifestyles. Terrestrial crocodylomorphs would continue to co-exist alongside aquatic forms until becoming extinct during the Miocene.
Crocodylomorpha
Life restoration of Hesperosuchus