crocodylomorpha

Crocodylomorpha is a clade of archosaurs that includes the crocodile lineage and a broad array of extinct relatives. They form the crocodile branch within the larger archosaur radiation, and their members display a wide range of body sizes, ecologies, and morphologies. The earliest crocodylomorphs appear in the fossil record in the Late Permian or Early Triassic, with unambiguous Early Triassic fossils marking their early diversification.

The group encompasses a diverse assortment of life histories. Some crocodylomorphs were small and terrestrial, while others evolved into large, semi-aquatic or fully aquatic predators. Notable lineages include marine thalattosuchians, which adapted to life in the oceans, and notosuchians, a group with varied cheek teeth and terrestrial habits. Neosuchia is a major subgroup that includes many later crocodyliforms, among them the ancestors of modern crocodilians. The crown group Crocodylia (the true crocodilians) comprises living alligators, crocodiles, and gharials, along with several extinct relatives.

Anatomically, crocodylomorphs exhibit considerable diversity, but many share a tendency toward elongate snouts and strong jaws in predatory forms. Limb and tail adaptations vary with ecology, with several lineages showing adaptations for aquatic locomotion, including streamlined bodies and, in marine taxa, paddle-like tails.

Crocodylomorpha is important for understanding crocodile origins and archosaur evolution, illustrating the range of ecological roles and body plans that evolved along the crocodile lineage. It also highlights the deep time persistence of crocodilian anatomy and the diverse experiments in lifestyle that occurred within this lineage.

See also: Crocodylia, Notosuchia, Thalattosuchia, Neosuchia, Archosauria.