Extinct Australian eagles and vulture unveiled

Flinders University researchers are unveiling a vivid portrayal of Australia's Pleistocene birds of prey, bringing to life the only known Australian vulture and an extinct eagle dating back over 50,000 years. The newly named eagle, Dynatoaetus pachyosteus, and the Australian vulture, Cryptogyps lacertosus, are showcased in a bold pictorial reconstruction at the Naracoorte Caves in South Australia's Limestone Coast.

Dr. Ellen Mather from the Flinders University lab envisions these majestic birds competing for food in landscapes inhabited by megafauna like the giant Diprotodon optatum and the ‘marsupial lion' Thylacoleo carnifex. The team's work extends beyond these birds to extinct megafauna, including the largest eagle in Australia, Dynatoaetus gaffae.

In their latest paper published in Alcheringa: An Australasian Journal of Palaeontology, Dr. Mather and Associate Professor Trevor Worthy, along with fellow Flinders paleontologists, describe Dynatoaetus pachyosteus. This second-largest eagle, found exclusively in the Victoria Cave at the Naracoorte Caves, is suggested to be similar in wingspan to a wedge-tailed eagle but more robust, especially in its leg bones, indicating greater power.

The genus Dynatoaetus is deemed endemic to Australia, implying its presence over an extended period. The researchers propose a relation to the large Crested Serpent Eagle and Philippine Eagle found in Southeast Asia and New Guinea.

The team also introduces the Australian vulture, Cryptogyps lacertosus, sizing up to a modern wedge-tailed eagle. Fossil bones from the Green Waterhole or Fossil Cave near Mount Gambier and a Nullarbor cave in Western Australia connect, suggesting that Cryptogyps was a more primitive vulture than previously believed.

Dr. Mather notes the unique features of Cryptogyps, such as the absence of adaptations seen in other vultures, indicating potential inefficiency in soaring flight compared to its living relatives.

Both Dynatoaetus species were inhabitants of Victoria Fossil Cave deposits between 200,000 and 500,000 years ago. While the timing of eagle extinction remains uncertain due to the rarity of eagle , uranium-series dating of Cryptogyps fossils suggests its existence around 60,000 years ago, surviving until Australia's megafaunal mass extinction.

Dr. Mather suggests that the extinction of large marsupials likely played a significant role in the demise of Cryptogyps and possibly the giant eagles. This loss emphasizes Australia's current status with only one largish raptor in its inland fauna, a rarity compared to most continents with multiple eagles and vultures. The research sheds light on the intricate ecological changes shaping Australia's avian fauna over millennia.

Source: Flinders University

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