A NEW CYPSELOMORPH BIRD FROM THE MIDDLE EOCENE OF GERMANY AND THE EARLY DIVERSIFICATION OF AVIAN AERIAL INSECTIVORES

Abstract

Abstract A new taxon of the Cypselomorphae—the clade including nightjars, potoos, owlet-nightjars, and apodiform birds—is described from the middle Eocene of Messel in Germany. Phylogenetic analysis of 49 characters shows Protocypselomorphus manfredkelleri gen. et sp. nov. to be the sister group of all other cypselomorph taxa, although this placement was not robust to bootstrapping. As evidenced by its swift-like beak, long forearm, and reduced feet, P. manfredkelleri was hawking insects on the wing. Thus it adds a distinctive new taxon to the already diverse assemblage of Paleogene aerial insectivores, all of which belong to the Cypselomorphae. This strongly contrasts with the extant avifauna where many aerial insectivores belong to songbirds, and among the insectivorous cypselomorph taxa only swifts and nightjars are species rich and widely distributed. The diversity of aerial insectivores among the Cypselomorphae may have been reduced by food competition with songbirds, which do not become the dominant...