Australia's Pleistocene Fowl, a Colossal Survivor.

Greetings. Genyornis newtoni. Often referred to as the Giga-Goose, this extinct species of large, flightless bird lived in Australia during the Pleistocene Epoch until approximately 50,000 years ago. 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. The species was not closely related to ratites such as emus, with their closest extant relatives being modern-day ducks and geese.

The species 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.

Genyornis newtoni was a medium-sized dromornithid, with adults measuring up to 2.15 meters tall and weighing a robust 250–350 kilograms. 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 fossilized remains. 

Prior to 2024, reconstructions of the skull of Genyornis newtoni were primarily based on those of its closest relatives, due to the heavily damaged nature of recovered remains. However, a 2024 study on the skull morphology of G. newtoni, incorporating a recently-discovered well-preserved skull, found the physical characteristics of the species' head to be far more unique than previously thought by paleontologists. Namely, the bill was found to be much more goose-like in appearance, with a raised triangular casque. This goose-like bill differed from even other mihirungs, and was likely an evolutionary 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 while feeding. 

In a 2022 study, fossil evidence suggests that the local population of Genyornis newtoni at Australia's Lake Callabonna expired around 50,000 years ago, as the lake dried up as a result of a drying climate. The birds recovered from the site seemed to have been particularly prone to osteomyelitis, as a result of getting stuck in the mud of the drying lake bed as the water gradually receded. Eventually, when the lake dried, the population was left without their main source of water and subsequently died out.

A 2024 study of the skull morphology of Genyornis newtoni found apparent adaptations to feeding on aquatic plants, making them closely tied to freshwater habitats. The species' reliance on these aquatic habitats may have made the birds uniquely vulnerable to the loss of freshwater lakes during the aridification of Australia during the late Pleistocene, potentially leading to its extinction.

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