Archovember 2024 Day 7 - Vespersaurus paranaensis
The rare noasaurids were a family of theropod dinosaurs belonging to the group Ceratosauria, and were related to the short-armed abelisaurids. One noasaur, Masiakasaurus, brought the family into the limelight recently with its appearance on Prehistoric Planet. But in Cretaceous Brazil, a different noasaur left its strange, monodactyl footprints across the sand. Vespersaurus paranaensis had two “killing claws”, on each foot, but not like a Velociraptor, or a Balaur, or even like modern Accipitriformes. Instead, it walked on its middle toe, while its 2nd toe and outer toe were raised off the ground. This may have been an adaptation to moving swiftly across the hot sand of the Botucatu Formation, a vast Cretaceous desert. Such an adaption has not been found in any other archosaur. Vespersaurus probably didn’t actually use these claws for hunting, and was likely a generalist, chasing down small, fast animals, opportunistically scavenging the kills of other predators, or hunting weak and injured animals. It may have instead used its claws in powerful defensive kicks, similar to modern cassowaries.