TL;DR: Three-dimensionally preserved avian remains from the early Eocene Fur Formation of Denmark are described and it is shown that the alleged parrot Mopsitta tanta, which was described on the basis of an isolated humerus from the Fur Formation, most likely belongs to the same species.
Abstract: We describe three-dimensionally preserved avian remains from the early Eocene Fur Formation of Denmark, which can be assigned to the taxon Rhynchaeites. This stem group representative of Threskiornithidae (ibises and spoonbills) was previously only known from the middle Eocene locality Messel in Germany. The Danish fossil, which consists of a partial postcranial skeleton, closely resembles the Messel species R. messelensis but is slightly larger and differs in a few osteological details. It allows the recognition of previously unknown osteological features of Rhynchaeites and constitutes the earliest fossil record of Threskiornithidae, predating the Messel fossils by 7 million years. We show that the alleged parrot Mopsitta tanta, which was described on the basis of an isolated humerus from the Fur Formation, most likely belongs to the same species. If specific distinctness of the Fur Formation Rhynchaeites is confirmed by future, more complete skeletons, it should thus be classified as R. tanta.
TL;DR: Although the phylogenetic position of Mopsitta is unclear, this form is phylogenetically closer to Recent Pstittacidae than to other known Palaeogene psittaciforms and may, therefore, represent the oldest known crown‐group parrot.
Abstract: Two new fossil psittaciform birds from the Lower Eocene 'Mo Clay' (Fur Formation) of Denmark (c. 54 Ma) are described. An unnamed specimen is assigned to the extinct avian family of stem-group parrots, Pseudas- turidae (genus and species incertae sedis), while a second (Mopsitta tanta gen. et sp. nov.) is the largest fossil parrot yet known. Both specimens are the first fossil records of these birds from Denmark. Although the phylogenetic posi- tion of Mopsitta is unclear (it is classified as family incer- tae sedis), this form is phylogenetically closer to Recent Pstittacidae than to other known Palaeogene psittaciforms and may, therefore, represent the oldest known crown- group parrot.