SYSTEMATIC RELATIONSHIPS OF THE PALEOGENE FAMILY PRESBYORNITHIDAE (AVES, ANSERIFORMES)

The early Tertiary (Paleocene and Eocene) family Presbyornithidae is o ne of the most completely known group of fossil birds. Essentially all parts of the skeleton are represented in the fossil record, allowing a thorough analysis of the phylogenetic position of the family. Forty- two families of nonpasserine birds representing the orders Ciconiiform es, Anseriformes, Galliformes, Gruiformes and Charadriiformes, were in cluded in a cladistic analysis of 71 skeletal characters. The previous ly suggested anseriform affinity of the Presbyornithidae was confirmed . Furthermore, the family proved to be closer to the Anatidae than to the Anhimidae or Anseranatidae. The many postcranial similarities with certain charadriiform birds as the Burhinidae, obviously are plesiomo rphies. By this observation, a better undestanding of character evolut ion in nonpasserine skeletal morphology is gained. The often suggested close relationship of anseriform and galliform birds is not confirmed by osteology. Instead, the Anseriformes and the Phoenicopteridae form a monophyletic clade that is the sister to the remaining ciconiiform birds. This result renders the Ciconiiformes sensu Wetmore (1960) poly phyletic. (C) 1997 The Linnean Society of London.