Fragmentary but distinctive: three new avian species from the early Eocene of Messel, with the earliest record of medullary bone in a Cenozoic bird

摘要

Three new avian species are reported from the early Eocene German fossil site Messel, two of which are named. Lapillavis incubarens gen. et sp. nov. is based on a partial postcranial skeleton, which shows some resemblance to the recently described Foshanornis songi from the early Eocene of China. The phylogenetic affinities of L. incubarens are uncertain, but the holotype exhibits medullary bone, which is characteristic of females shortly before and during egg laying. The specimen constitutes the earliest evidence of medullary bone in a Cenozoic bird and allows the first gender determination of a fossil bird from Messel. Another new species, Cypseloramphus dimidius gen. et sp. nov., is tentatively identified as a basal representatives of the Apodiformes. Furthermore reported is an isolated skull, which resembles the skull of the significantly larger Foro panarium (Foratidae) from the early Eocene North American Green River Formation.