Phylogeny of Early Tertiary Swifts and Hummingbirds (Aves: Apodiformes)

Abstract

The phylogenetic relationships between early Tertiary and extant apodiform birds are only poorly understood, and this study is the first cladistic approach to this problem in which the Trochilidae are included. The analysis supports monophyly of the Lower Oligocene Jungornis and extant Trochilidae, as well as monophyly of the Middle Eocene Scaniacypselus and extant Apodidae. The “Jungornithidae” sensu Karhu (1999) are shown to be paraphyletic with the Upper Eocene Argornis being the sister taxon of the taxon (Jungornis + extant Trochilidae). The osteology of Jungornis provides a transition between that of the highly derived extant Trochilidae and that of more generalized apodiform birds. An Argornis-like apodiform bird from the Middle Eocene of Messel shows a completely unexpected combination of a greatly abbreviated, apodiform humerus with a short and broad wing, and might indicate that the Trochilidae evolved from a short-winged ancestor.