Giant claw in the desert has experts baffled

Scientists have been making the pilgrimage to the Alcoota Scientific Reserve in the Northern Territory nearly every year since 1985. 

The Claw' from an unknown species found at the Alcoota Scientific Reserve [Credit: Caddie Brain]

The reserve, located about 160 kilometres north east of Alice Springs, is home to the largest and most concentrated fossil deposit of its kind in Australia. 

The deposit is remote, and so hot that the annual digs are limited to a short window each year. 

Taxidermist and preparator of the Museum and Art Gallery of the Northern Territory Jared Archibold says the site was first discovered in the 1950s. 

Flightless bird fossil found at Alcoota Scientific Reserve [Credit: Caddie Brain]

"It was first found by Aboriginal stockmen, we believe. They picked up crocodile teeth and shards of bone and handed them to the station manager at Alcoota." 

The manager took the bones to Alice Springs and from there the specimens were sent to Adelaide and then California in the United States. 

What they had found was essentially a mass grave of long-extinct giant mammals, about eight million years old, that are thought to have lived during the Miocene Epoch. 

Botonist Peter Latz excavates another pile of bones at the Alcoota Scientific Reserve [Credit: Caddie Brain]

But it's hard to say - anything beyond 50,000 years is difficult to carbon date, so scientists rely on "stage of evolution" dating. 

This year, scientists have found something a bit different lying preserved in the red dirt: a giant claw. 

Curator of Earth Sciences at the Museum of Central Australia Dr Adam Yates says they have no idea what the claw belonged to, and that it's discovery came a real surprise. 

"When we actually saw it for the first time completely uncovered we thought 'my god it's so big!'," he said. 

The main pit at Alcoota Scientific Reserve [Credit: Caddie Brain]

"Similar claws have been found in the past and they've been suggested to have come from a large goanna. That's a pretty big goanna - we're looking at something much bigger than a modern Komodo dragon. But we haven't found any other bones that we can attribute to a goanna of that size, so really we're scratching our heads." 

The specimen will be brought to the Museum of Central Australia in Alice Springs for analysis. 

But it won't be travelling alone - Dr Yates says the team have dug up plenty of other fascinating specimens. 

Bones found at the Alcoota Scientific Reserve [Credit: Caddie Brain]

"Take that very long bone there in front of us. It's the tibio tarsus, which is the shin bone of a giant flightless bird that goes by the name of dromornis stirtoni." 

And when Dr Yates says giant, he means giant. 

"It was three metres tall, weighing about half a tonne. It's quite probably the largest bird that ever lived." 

Bones laid out pit-side at the Alcoota Scientific Reserve [Credit: Caddie Brain]

The dromornis stirtoni, along with the other giant marsupial mammals it shares a grave with, are thought to have died during extreme drought. 

Dr Yates believes the site is evidence of a mass extinction event. 

"We think all these animals died all at the same time, around a waterhole during a really nasty drought. One of the things that has been revealed by palaeontology is that the earth goes through periodic paroxysms of extinctions or mass extinction events, like the one that wiped out the dinosaurs. They don't have a single cause." 

The dromornis stirtoni, a giant flightless bird that lived eight million years ago [Credit: Terre-Univers]

As well, he says that this pit contains a warning for our own age. 

"What seems to happen is once you start to loose a certain number of species then things go into a pretty drastic decline," Dr Yates says. 

"That's got implications for us for the future because we're losing species at a rapid rate at the moment. We don't want to go into a full mass extinction, becuse although life does recover, and diversity does increase afterwards, it takes five to ten million years to bounce back. We don't have five to ten million years, so it's pretty important that we try to avoid a mass extinction event." 

Author: Caddie Brain | Source: ABC News Website [July 30, 2012]