crocodyliformgrade

Crocodyliformgrade refers to a posture and mode of locomotion observed in crocodylomorphs, the extinct and extant relatives of crocodiles. It is characterized by the limbs being held somewhat abducted from the body, resulting in a sprawling gait. This posture is contrasted with the erect or semi-erect postures seen in many other amniotes, including other archosaurs. In crocodyliformgrade locomotion, the animal walks with its belly close to the ground, with the legs splayed outwards to the sides. This gait is relatively inefficient for sustained terrestrial running compared to more erect postures.

Fossil evidence indicates that early crocodylomorphs, such as those from the Triassic period, possessed a more sprawling posture. Over evolutionary time, some crocodylomorph lineages, particularly those that led to modern crocodiles and alligators, developed the ability to lift their bodies off the ground to varying degrees. This semi-erect posture allows for a more effective gait for terrestrial movement, often referred to as a high-walk. However, even in modern crocodiles, a fully erect posture is generally not achieved. The term crocodyliformgrade is often used in paleontology to describe the ancestral or more primitive limb posture and gait within the crocodylomorph clade. The degree of limb adduction and the resulting height of the body off the ground can vary significantly among different crocodylomorph species and their fossil relatives, reflecting adaptations to different ecological niches and lifestyles.