The bony palate diagnoses the two deepest clades of extant birds: Neognathae and Palaeognathae1,2,3,4,5.

Neognaths exhibit unfused palate bones and generally kinetic skulls, whereas palaeognaths possess comparatively rigid skulls with the pterygoid and palatine fused into a single element, a condition long considered ancestral for crown birds (Neornithes)3,5,6,7,8

However, fossil evidence of palatal remains from taxa close to the origin of Neornithes is scarce, hindering strong inferences regarding the ancestral condition of the neornithine palate

Janavis confirms the presence of an anatomically neognathous palate in at least some Mesozoic non-crown ornithurines10,11,12, suggesting that pterygoids similar to those of extant Galloanserae may be plesiomorphic for crown birds

Our results, combined with recent evidence on the ichthyornithine palatine12, overturn longstanding assumptions about the ancestral crown bird palate, and should prompt reevaluation of the purported galloanseran affinities of several bizarre early Cenozoic groups such as the ‘pseudotoothed birds’ (Pelagornithidae)13,14,15