Yungavolucris is a strange enantiornithean bird from the Late Cretaceous of Argentina. It has been interpreted as a foot-propelled diver due to its broad metatarsus, though given how stout it was and that several studies post Mortimer 2019 onwards recover it was closely related to the massive winged Grabauornis it might very well had been a wing propelled diver, either partially (like gannets and the extinct Gansus) or fully (like penguins and auks)
