A contrast of the prepared fossil tarsometatarsus (foot bone) and a hypothesised shape of Archaehierax sylvestris (left) compared to the wedge-tailed eagle Aquila audax (right). The scale bar is 10 mm long. Credit: Jacob Blokland
” This types was somewhat smaller and leaner than the wedge-tailed eagle, but its the largest eagle known from this time duration in Australia,” states Flinders University PhD prospect Ellen Mather, very first author in the new paper published in the peer-reviewed journal Historical Biology.
” The foot span was nearly 15 cm long, which would have allowed it to understand big victim. The biggest marsupial predators at the time were about the size of a small pet or big cat, so Archaehierax was certainly ruling the roost.”
” With eagles at the top of the food cycle, they are always couple of in number– therefore are infrequently preserved as fossils,” says co-author Associate Professor Trevor Worthy.
” Its rare to find even one bone from a fossil eagle. To have most of the skeleton is pretty interesting, especially thinking about how old it is.”
The Australian environment throughout the Oligocene was very various to today.
The remains of Archaehierax were discovered on the barren coast of a dry lake (called Lake Pinpa) in a desolate sandy desert environment during ongoing Flinders University investigations into a lost ecosystem, when Australias interior was covered in trees and verdant forests.
Living in forests provides some obstacles for an animal that flies. How did Archaehierax avoid crashes with trees and branches while it hunted?
” The fossil bones reveal that the wings of Archaehierax (pron. ah-kay-hi-rax) were short for its size, similar to types of forest-dwelling eagles today. Its legs, on the other hand, were fairly long and would have given it substantial reach,” states Ms. Mather.
” The combination of these traits suggest Archaehierax was an agile however not especially quick flier and was most likely an ambush hunter. It was one of the leading terrestrial predators of the late Oligocene, diving upon birds and mammals that lived at the time.”
Archaehierax would have hunted koalas, possums, and other animals in trees surrounding a huge shallow lake, on which waterfowl, cormorants and flamingoes were plentiful.
Palaeontologists from Flinders University excavating fossils near Lake Pinpa, South Australia. L to R: Aaron Camens, Amy Tschirn, Jacob Blokland and Kailah Thorn. Credit: Trevor Worthy, Flinders University
Out of all the species known from this website, Archaehierax is one of the best preserved; the partial fossil skeleton is consisted of 63 bones.
” I have actually studied this system for several years now, and this is the most elegant fossil we have discovered to date,” says Associate Professor Trevor Worthy.
” The completeness of the Archaehierax skeleton enabled us to figure out where it fits on the eagle ancestral tree. It reveals a variety of functions unlike any seen amongst modern-day hawks and eagles,” Ms. Mather discusses.
” We found that Archaehierax didnt belong to any of the living genera or families. It appears to have actually been its own special branch of the eagle family,” she says.
” Its unlikely to be a direct ancestor to any species alive today.”
Referral: “A remarkable partial skeleton of a brand-new basal raptor (Aves: Accipitridae) from the late Oligocene Namba Formation, South Australia” 27 September 2021, Historical Biology.DOI: 10.1080/ 08912963.2021.1966777.
Archaehierax sylvestris. Credit: Jacob Blokland
63 bone fossil finding in desert is among the “best protected” eagles ever and a really uncommon discovery.
A 25-million-year-old eagle fossil discovered in South Australia includes to the long evolutionary history of raptors in Australia.
Paleontologists from Flinders University have actually discovered Australias oldest eagle fossils on a remote outback livestock station, explaining a new fossil species which lived during the late Oligocene. Called Archaehierax sylvestris, this species is among the earliest eagle-like raptors in the world.
A comparison of the prepared fossil tarsometatarsus (foot bone) and a hypothesised shape of Archaehierax sylvestris (left) compared to the wedge-tailed eagle Aquila audax (right). Credit: Jacob Blokland
” The fossil bones expose that the wings of Archaehierax (pron. Palaeontologists from Flinders University excavating fossils near Lake Pinpa, South Australia. Credit: Trevor Worthy, Flinders University