The Palaeogene Old World potooParapreficaMayr, 1999 (Aves, Nyctibiidae): Its osteology and affinities to the New World Preficinae Olson, 1987

Synopsis New specimens of the poorly known Old World potoo Paraprefica kelleri Mayr, 1999 (Aves, Nyctibiidae) are described from the Middle Eocene of Messel in Germany, including the first complete skeleton with a well‐preserved skull. They provide additional details of the osteology of these birds and allow more detailed comparisons with the osteologically similar Prefica nivea Olson, 1987 from the Early Eocene of North America. For the first time, the phylogenetic relationships of Paraprefica and Prefica are evaluated in a cladistic context. Analysis of 98 characters supports a sister group relationship between Paraprefica and modern Nyctibiidae, whereas Prefica is shown to be the sister taxon of the Steatornithidae (oilbirds), as proposed in the original description. Some of the osteological similarities between Prefica and Paraprefica may be plesiomorphic for the Cypselomorphae, the taxon to which Nyctibiidae belong.