New records of exceptionally well-preserved fossil birds from the danish Lower Eocene

DYKE, G.J.; BERTELLI, S.; CHIAPPE, L.M.; LINDOW, B.E.K.

Mesa, Arizona

Congreso; Sixty-Fifth Annual Meeting of the Society of Vertebrate Paleontology; 2005

Society of Vertebrate Paleontology

Well-preserved fossils that document early phases of modern bird evolution (Neornithes) are exceptionally rare. By far the bulk of described fossil specimens from the Cretaceous- Eocene are too incomplete, cnished or fragmentary to be usefully induded within morphology-based phytogenetic hypotheses for the intra and inter-relationships of major clades, Our work aims to re-dress this balance: we present new, and remarkably three-dimensionally preserved, fossil neornithine birds from the marine Für Formation of Denmark. Exposed in the Limfjord area of Jutland, the Pur Formation documents local upwellings of warm water and preserves a rieh fauna, including birds and other vertebrates. Exceptional preservation of vertebrate carcasses in themuddy Für Sediments is äs a resultofanoxic burial conditions?fossils are often preserved in 3D, encapsulated within calcareous cementstone nodules. Aeid preparation of these nodules has revealed exquisite details in many birds?fine details of cranial anatomy,stomach Contents, tendons, and feathering. Although the bulk of the Für avian diversity remains undescribed in detail, we have identified representatives of at least 13 neomithine clades (includiag palaeognaths, Galliformes, Charadriiformes, Psittaciifornieg, Coraciiformes, and Apodiformes) within the fauna by use of morphological character analyses. Complete descriptions of the remainderof this diversity are ongoing. Because of the age and articulation of the Danish birds, their importance lies in their inclusion within phylogenetic hypotheses for the modern avian radiation; fossil specimens add character combiaations not seen in their extant counterparts. Although the bulk of these Danish fossil birds currently remain undescribed in detail, our ongoing systematic studies will allow us to add these new taxa and their aovel character combinations to a number of regions of the modern avian tree.