Genyornis

Genyornis is an extinct genus of large, flightless bird that lived in Australia during the Pleistocene Epoch until around 50,000 years ago. Over two metres in height, they were likely herbivorous. Many other species of Australian megafauna became extinct in Australia around that time, coinciding with the arrival of humans. It is the last known member of the extinct flightless bird family Dromornithidae which had been part of the fauna of the Australian continent for over 30 million years. They are not closely related to ratites such as emus, and their closest living relatives are thought to be fowl.

The species Genyornis newtoni was first described in 1896 by Edward Charles Stirling and A. H. C. Zeitz, the authors giving the epithet newtoni for the Cambridge professor Alfred Newton. The name of the genus is derived from the ancient Greek γένυς (génus) 'jaw; chin' and ὄρνις (órnis) 'bird', because of the relatively large size of the lower mandible. The specimen is a left femur. It was found at Lake Callabonna in South Australia. The excavation was undertaken and described by Zietz. A description of the excavation was reported in Nature which had also unearthed material recognised as marsupials.

Numerous fragments of avian fossils were noticed in the clay surrounding the removal of diprotodont fossils, then largely complete specimens including crucial evidence of the crania emerged from the site. The paper reviewed previously described fossil remains of "struthious [ostrich-like] birds in Australia", which had either been assigned to the ancient emus of Dromaius or the only described species of Dromornis, D. australis Owen.

A letter from George Hurst concerning the discovery of a partial skeleton of the species alerted Stirling to its existence in 1893.

The placement of this dromornithid species may be summarised as:

Dromornithidae (8 species in 4 genera)

Genyornis newtoni was a medium-sized dromornithid with a robust body, measuring up to 2.15 metres (7.1 ft) tall and weighing around 250–350 kilograms (550–770 lb), though body mass estimation may vary based on different methods. While larger than Ilbandornis, it did not attain the height and weight of Dromornis stirtoni or Dromornis planei. The fossils of the species have been found remaining in articulation, and no other dromornithid species has been discovered in this state. The remains of eggs have also been attributed to this species. Gastroliths belonging to these animals have been found alongside their remains, a feature that has revealed the sometimes shallow site of fossils.

Prior to 2024, reconstructions of the skull of Genyornis were primarily based on those of its closest relatives, due to the heavily damaged nature of the holotype. However, a 2024 study on the skull morphology of Genyornis, incorporating a recently discovered well-preserved skull, found the physical appearance of the head of Genyornis to be much more different than previously believed. Namely, the bill was found to be much more goose-like, with a raised triangular casque. This goose-like bill differed from even other mihirungs, and may have been a specialization for feeding on aquatic vegetation. Other potential adaptations to an aquatic feeding style may have allowed for protection of the ears and throat when submerging their heads in water.