Passerine diversity in the late Oligocene of Germany: earliest evidence for the sympatric coexistence of Suboscines and Oscines

A passerine avifauna from the late Oligocene ( c. 26–25 mya) of Germany was characterized by a high diversity of conspicuously small birds ranging in size from the smallest known Oscines to moderately small forms. The avifauna comprised both Oscines and Suboscines. Other passerine fragments showed such an unexpected mosaic of characters that it was impossible to assign them with certainty to any subordinate clade within the Passeriformes. The isolated remains of oscine passerines are the earliest evidence of this taxon in the Northern Hemisphere. Coexistence of oscine and suboscine passerines during the late Oligocene is also documented for the first time in the Northern Hemisphere. These finds reduce a major gap in the passerine fossil record and allow new insights into the composition and natural history of ancient avifaunas.