Crocodylimorph Fossils: Alligators, Crocodiles, Caimans and Kin | Darwin and Wallace: A Nature & Fossil Store

Crocodylimorph Fossils: Alligators, Crocodiles, Caimans and Kin



       Crocodylimorphs are a clade of reptiles that consist of modern Crocodilians, as well as several extinct cousins and ancestors that evolved as a group in the Triassic period, approximately 230 million years ago. Prehistoric crocs were as diverse as dinosaurs, having evolved into several different forms and fulfilling more ecological niches than they do today. The earliest variety was the Triassic-age Sphenosuchians, which were built more like terrestrial, long-legged dogs, as opposed to the lumbering water-dwellers of today. The sister-group to Sphenosuchians were the Mesoeucrocodilians, which consist of Thalattosuchians (Jurassic and Cretaceous-age crocs that adapted a fully marine lifestyle, with some having evolved flippers and a shark-like tail fluke), the Notosuchians (Cretaceous-age, short-faced, armored crocs that adapted herbivory), and the Eusuchians (the group that consists of modern crocs and their closest extinct relatives). Eusuchia translates to "true crocodiles," and refers to the same basic morphological body style that all crocodilians of today possess. The Eusuchians evolved in the Late Cretaceous period approximately 85 million years ago, and are the only clade of Crocodylimorphs alive today. The extant Eusuchians include multiple species consisting of crocodiles, gharials, caimans, and alligators. Today's crocs are amphibious fish-eaters and ambush predators, taking down large mammals and birds from the shores of lakes and rivers. Often is the case where a croc will then perform a "death roll," which involves the animal spinning itself with its prey in its jaws until it has drowned, or has become dismembered. Though the largest croc alive today is the Saltwater Crocodile (reaching up to 22' in length), the largest croc known in prehistory is the Deinosuchus of America, reaching lengths of nearly 50' long!

 Click on the images below to see the incredible specimens we offer in our crocodylimorph selection: