Evolution of flightless land birds on southern continents: Transferrin comparison shows monophyletic origin of ratites

Summary A biochemical approach was used to study the evolution of ratite birds, i.e., the ostriches, rheas, cassowaries, emus, and kiwis. Quantitative immunological comparison of transferrin from ratites, tinamous, and other flying birds indicates that all the ratites and tinamous are allied phylogenetically and that they are of monophyletic origin relative to other birds. To explain the current geographic distribution of ratites and the magnitude of the transferrin distances, it is supposed that the ancestors of these flightless birds walked across land bridges between the southern continents during Cretaceous times.Supported in part by grants GB-42028X from NSF and GM-21509 from NIH to ACW and by grants HD-00122 from NIH and GA-12607 from NSF to REF The following abbreviation is used in this work MCF micro-complement fixation