TWO huge prehistoric tusks could prove a "gold mine" of clues about Europe's past, say researchers excavating the site in Greece where they were found.
The petrified remains of a mastodon - a primitive elephant-like creature - with tusks up to 16ft long, were found in an area where digs have uncovered remains of several prehistoric animals over the past decade.
The team said the tusks were the largest to be found from the ancestor of the elephant.
"To find a tusk five metres long was a big surprise," Evangelia Tsoukala, assistant professor of geology at the University of Thessaloniki, said.
The second tusk found near Milia, 260 miles north of Athens, measured more than 15 feet.
"That's astonishing. This is a fantastic find," said Dave Martill, a paleontologist at the University of Portsmouth, an independent expert.
"These animals, in their bones, hold a whole load of information about the environment at the time - not just the animal," Mr Martill said. The tusks have growth rings in them, which scientists can analyse for signals about seasonality and climate. "They offer fantastic potential for studying not just the animals but ancient climates."
Ms Tsoukala led a team that excavated the two tusks from the same animal, as well as leg bones and its jaws, still bearing teeth.
"It's a very significant find. We can draw conclusions about this animal and its development," she said. "We are also looking for clues about its extinction."
Mastodons were similar to woolly mammoths but had straighter tusks as well as different teeth and eating habits.
They roamed Europe, Asia and North America, but how they became extinct is a mystery. Mastodons are thought to have disappeared in Europe and Asia two million years ago but survived in America until 10,000 years ago.
Ms Tsoukala said the male animal discovered in Milia lived about 2.5 million years ago. "This animal was in its prime. It was 25 to 30 years old; they lived until about 55. It was about 3.5 metres tall at the shoulder, and weighed around six tonnes."
Dick Mol, a Dutch researcher who helped with the excavation, said he hoped the find could also yield clues about the mastodon's extinction.
"It's really a gold mine," said Mr Mol. "These are the best preserved skeletons in the world of this species."
Plant material found near the tusks could give scientists a "better idea of the environment this animal was living in", Mr Mol said.
The Milia bone remains will also be scoured in the remote chance of finding DNA material. Researchers recently analysed genetic material from an American mastodon recovered in Alaska from fossils up to 130,000 years old, providing clearer insight into elephants' evolutionary development.
If DNA is recovered from the much older Milia animal it could let researchers compare European and American mastodons in unprecedented detail.
The tusk at Milia was discovered last October by an excavation machine operator in a sand quarry, but it took months for scientific investigation of the site to be organised.
Ms Tsoukala, who has been conducting excavations in the region since 1990, found another mastodon tusk measuring 14.4 feet in the same area ten years ago. She said the latest discovery was more significant because the skeleton is more complete.
Fossils from the dig are currently displayed at the village's tiny museum of natural history. Ms Tsoukala is urging the government to fund a new museum.