A head like a horse
Found at the Bullock Creek fossil site in Australia's Northern Territory, the skull of Bullockornis planei is a specimen from the Miocene epoch, approximately 15 million years ago. This flightless bird stood about 2.5 meters tall and weighed up to 250 kilograms. Its most distinct feature was its massive head, which was comparable in size to that of a small horse. The skull housed an enormous and powerful beak suited for shearing and crushing.
The discovery of a near-complete skull was significant because it provided the first clear anatomical evidence linking dromornithids, the family to which Bullockornis belongs, to modern waterfowl like ducks and geese. Previously, these giant birds were often thought to be related to flightless ratites like emus and ostriches. Despite the skull's large external dimensions, the cranial vault protecting the brain was up to 40 mm thick, meaning the actual brain volume was quite small relative to its head size. The scientific name has also been updated; it was initially placed in its own genus, Bullockornis, but many researchers now classify it as Dromornis planei.