Unlocking the early evolution of brain and feeding strategies in Anseriformes: the case of Conflicto antarcticus

Abstract

The early Palaeocene Conflicto antarcticus reveals a mosaic pattern of brain and skull evolution relative to other Anseriformes. Despite its hyperinflated brain and ventrally displaced optic lobes, Conflicto lacks the Wulst, an absence shared with the Eocene Presbyornis and interpreted as a primitive trait for Neornithes. Enlarged olfactory bulbs suggest enhanced olfactory capabilities uncommon in modern birds, possibly compensating for the reduced visual and tactile specializations typically associated with filter feeding. The morphology of its straight, non-spatulate beak and the relatively undeveloped trigeminal system suggest a foraging strategy based more on ground-pecking than filtering. These findings provide critical insight into the early stages of anseriform evolution, indicating that key neural adaptations for filter feeding seen in modern taxa were absent or incipient in Conflicto. Moreover, Conflicto’s brain morphology suggests that several features evolved convergently across Neornithes.