Lithornithid birds (Aves, Palaeognathae) from the Lower Palaeogene of Denmark

Abstract

An incomplete sternum and imprints of a right part pelvis and an associated left femur from the uppermost Palaeocene/lowermost Eocene (Fur Formation) of Denmark are assigned to the extinct palaeognath bird order Lithornithiformes Houde 1988, and to the single described family thereof, the Lithornithidae. Morphological features indicate that both individuals were adult birds, smaller than Lithornis cf. nasi, which is represented by an incomplete humerus from the largely contemporaneous, marine Olst Formation in Denmark, and corresponding in size to the smallest known lithornithid, Lithornis hookeri. Lithornithiformes, common in the Palaeocene and Eocene of North America and Europe, were terrestrial birds capable of flight whose remains are often found in aquatic sediments. Both the depositional environment in which the Danish lithornithids were found, and the associated faunal components suggest that the birds were not transported by rivers. Some of the lithornithid species inhabiting NW Europe may have lived and foraged along the shores of the North Sea Basin.