A New Avian Species with Tubercle-bearing Cervical Vertebrae from the Middle Eocene of Messel (Germany)

abstract. A new avian species, Perplexicervix microcephalon n.gen. and n.sp., is described from the Middle Eocene of Messel in Germany. It is most unusual in that the cervical vertebrae of five of the six known specimens bear numerous bony tubercles. Such tubercles were also reported from another avian fossil from the Messel deposits, which is a representative of the extinct taxon Idiornithidae. Although the osteology of P. microcephalon is not known well enough for a reliable phylogenetic assignment, the new species clearly does not belong to the Idiornithidae. Compared to extant birds, it agrees with Anhimidae and Cathartidae in some osteological features. The origin of the vertebral tubercles remains mysterious. The fact that these structures are now known from two unrelated avian taxa supports previous assumptions, that they represent a pathologic condition. Not in line with this assumption, however, is their occurrence in all specimens referred to P. microcephalon, in which cervical vertebrae are preserved. Mayr, Gerald, 2010. A new avian species with tubercle-bearing cervical vertebrae from the Middle Eocene of Messel