What characteristic of the ancient Chubut environment might have influenced the specialized tarsus of *Xenotarsosaurus*?
Being a floodplain environment suggesting soft or uneven substrates.
The location where *Xenotarsosaurus* fossils were recovered, the Bajo Barreal Formation in Chubut, points toward a specific type of ancient terrain, often described as a floodplain environment. Locomotion mechanics, particularly specialized features like the tarsus, are highly sensitive to the substrate an animal regularly traverses. The unique structure of the *Xenotarsosaurus* ankle suggests significant adaptations related to how it managed weight bearing or achieved purchase during movement on soft, potentially muddy, or uneven ground typical of a floodplain setting. This adaptation in foot mechanics might have provided significant advantages in terms of quick turns or acceleration necessary for hunting in that specific terrain.
