Australia has always been a biodiversity hotspot, with a number of extinct megafauna in its natural history. Huge, flightless ‘thunderbirds’ or mihirungs once roamed the rugged Australian outback. The last remaining mihirung species was the approximately 2.5 meter high Genyornis newtoni. These stocky birds became extinct about 45,000 years ago and lived alongside humans for a while. Now, after more than a century of digging, researchers in Australia have uncovered for the first time a complete skull of this giant goose-like bird. The specimen is described in a study published June 3 in the journal Historical Biology. (Related: An Extinct 10-Foot Eagle Can Pick Up Kangaroos With Its Fearsome Talons.) Parrot or something else? Previously, the only known skull of this mihirungs species was a badly damaged specimen discovered in 1913. Very little of the original bone was left, so paleontologists couldn’t infer much about this species’ skull. In 2019, a team from Flinders University found these new fossils near Lake Callabonna, a remote area in inland South Australia. The skull fossils were associated with some nearly complete fossils of the rest of the bird’s body. With this extra piece of skeleton, the team confirmed that the skull is likely that of Genyornis newtoni. An artistic reconstruction of the skull of Genyornis newtoni in section, based on the fossil material. Here is a photo of the skull of Genyornis newtoni. Illustration by Jacob C. Blokland. Used with permission. Available for media and current affairs use; all other rights reserved. With this more complete skeleton in hand, the team can investigate more of the animal’s ecology, structure and evolutionary relationships. They believe it was about 507 pounds, about the same as two and a half kangaroo combined. Its skull reveals a huge braincase, with large jaws. Its upper beak also had a surprising shape, which set it apart from its closest relatives. “Genyornis newtoni had a long and mobile upper jaw like that of a parrot, but in the shape of a goose, a wide opening, a strong bite force and the ability to crush soft plants and fruits on the palate,” study co-author and Flinders University palaeontology PhD candidate Phoebe McInerney said in a statement. A giant goose Parts of the well-preserved skull also showed some similarities to South American screamers and the Australian magpie goose. “The exact relationships of Genyornis within this group have been complicated to unravel, but with this new skull we have begun to piece together the puzzle that, simply put, shows that this species is a giant goose,” McInerney said. According to study co-author and Flinders University palaeontologist Trevor Worthy, this upper beak fossil particularly helped them “put a face on this bird, a face that is very different from all other birds, but still resembles a goose.” ‘ The proposed relationships of Genyornis newtoni within the waterfowl clade with a comparison of the size of Genyornis with its close relative, Anhima cornuta and unrelated cassowary. CREDIT: Illustration by Phoebe McInerney. Used with permission. Available for media and current affairs use; all other rights reserved. Analyzing the skull also gave the team a better idea of how this giant prehistoric goose head might have functioned. “The shape of a bone, and the structures on it, are partly related to the soft tissues that interact with it, such as muscles and ligaments, and their attachment sites or passages,” co-author and PhD student Jacob Blokland said in a study. rack. (Related: Australian Cockatoos Teach Each Other to Open Trash Cans.) To survive in their more aquatic habitat, Genyornis likely also had some unusual adaptations that protected their ears and throats from the influx of water when they submerged their heads. However, these adaptations may be related to their extinction as the former freshwater bodies of northern South Australia are now mainly salt lakes where they could not survive. The team hopes that further study of these special prehistoric geese will deepen our understanding of these birds and their eventual disappearance.
