Paraprefica
Paraprefica is an extinct bird belonging to the Caprimulgiformes, from the middle Eocene (c. 48 million years ago). Its fossil remains have been found in the Messel pit at Messel, Germany. Description. This bird is known from fossil remains which include a skeleton and many well-preserved skulls, and is one of the best preserved Eocene birds. "Paraprefica", a medium-sized bird, has skull and legs somewhat resembling today's potoos, in the genus "Nyctibius". The head has a thin beak and a very wide mouth, while the wings are relatively large, though smaller than those of extant potoos . Classification. Described for the first time in 1999 by G. Mayr, this bird was at first placed in the genus "Prefica", a North American fossil closely related to modern oilbirds ("Steatornis caripensis"). Later research showed however that "Paraprefica" had characteristics found only in the family Nyctibiidae, order Caprimulgiformes (the nightjars). It is possible that the similarities between the bones of "Prefica" and "Paraprefica" are due to primitive characters found in all Cypselomorphs, the group that also includes the Caprimulgiformes. There are two species in the genus: "Paraprefica kelleri", the best known, and "Paraprefica major". Distribution. The existing finds from Germany  present a puzzle on the birds' distribution, as modern potoos are found only in the New World, from Mexico to the north of Argentina and the Caribbean islands of Jamaica, Hispaniola and Tobago, making them Neotropical. Either the group was once cosmopolitan, and has become limited to the Americas, or it was Eurasian and has at some time shifted its distribution.