Taxonomy and Biogeography
Like the ostrich, rhea, cassowary, emu, kiwi and extinct moa, Mullerornis and Aepyornis were ratites; they could not fly, and their breast bones had no keel. Because Madagascar and Africa separated too long ago for the ratite lineage, Aepyornis had been thought to have dispersed and become flightless and gigantic in situ. A land bridge from elsewhere in Gondwana to Madagascar for the elephant bird-ostrich lineage was probably available around 85 million years ago. However, subfossil Aepyornis fragments have not yet been successfully sequenced for mitochondrial DNA. Some DNA has been extracted.
Supposed remains of "aepyornithid" eggs found on the eastern Canary Islands represent a major biogeographical enigma. These islands are not thought to have been connected to mainland Africa when elephant birds were alive. There is no indication that elephant birds evolved outside Madagascar, and today, the Canary Island eggshells are considered to belong to extinct North African birds that may or may not have been ratites (Eremopezus/Psammornis), or even Pelagornithidae, prehistoric seabirds of immense size.
Read more about this topic: List Of Elephant Birds