Sunbittern’s display (Eurypyga helias)

The sunbittern (Eurypyga helias) is a bittern-like bird of tropical regions of the Americas, and the sole member of the family Eurypygidae (sometimes spelled Eurypigidae) and genus Eurypyga. It ranges from Guatemala to southern Peru, showing three extant subspecies. The sunbittern shows both morphological and molecular similarities with the kagu (Rhynochetos jubatus) of New Caledonia, indicating an gondwanic origin, being both placed in the clade Eurypygiformes. The sunbittern is usually placed in the Gruiformes, but this was always considered preliminary. Altogether, the bird is most similar to another bird that was provisionally placed in the Gruiformes, the kagu (Rhynochetos jubatus). Molecular studies seem to confirm that the kagu and sunbittern are each other’s closest living relatives and have a similar wing display. They are probably not Gruiformes (though the proposed Metaves are just as weakly supported). Altogether, the two species seem to form a minor Gondwanan lineage which could also include the