The Skeletal Evidence for a Sister-Group Relationship of Anseriform and Galliform Birds: A Critical Evaluation

The osteological basis for the proposed close phylogenetical relationship of anseriform and galliform birds is evaluated and found to be very weak. Out of eleven postulated synapomorphies in cranial morphology (Cracraft 1988), three must be excluded since they express variation that is already covered by any of the other eleven characters. Another six of the postulated synapomorhies either cannot be verified to occur in most anseriforms and galliforms, or have a wide distribution outside this group. A re-analysis of the combined morphological and biochemical data set of Cracraft and Mindell (1989) with the questionable osteological characters excluded, does not corroborate an anseriform-galliform sister-group relationship, but leaves the Neognathae unresolved.