A startling discovery of two massive prehistoric tusks – possibly the largest ever found in the world – could prove to be a “gold mine” for scientists seeking clues into Europe’s past, say Greek and Dutch researchers excavating the site in northern Greece.

The petrified remains of a mastodon – an elephant-like creature – with tusks measuring up to five metres long, were found in an area where excavations have uncovered the remains of several prehistoric animals over the past decade.

The research team said it was the largest tusk ever found from the primitive relative of the elephant.

“To find a tusk five metres long, that was a big surprise,” Evangelia Tsoukala, Assistant Professor of Geology at the University of Thessaloniki, told The Associated Press in a telephone interview from the site.

The second tusk found at the site near the village of Milia, 430km north of Athens, measured 4.6 metres.

“That’s absolutely astonishing. This is a fantastic find,” said Dave Martill, a palaeontologist at the University of Portsmouth in England, an independent expert not connected with the excavation.

“These animals, in their bones, hold a whole load of information about the environment at the time – not just the animal,” Martill said.

Because the tusks have “growth rings in them and you can analyse each individual layer and pick up signals about seasonality and climate. These offer fantastic potential for studying not just the animals themselves but ancient climates.”

Tsoukala led a team which excavated the two tusks from the same animal, together with leg bones and its upper and lower jaw still bearing teeth.

“It’s a very significant find because with these sections of the skeleton 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 remains a mystery. Mastodons are thought to have disappeared in Europe and Asia some 2 million years ago but survived in North America until 10,000 years ago.

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 6 tons,” Tsoukala said.

Veteran Dutch researcher Dick Mol, who aided the Greek excavation, said he hoped the find at Milia could also yield clues about the mastodon’s extinction.

“It’s really a gold mine,” said Mol, a research associate at the Museum of Natural History in Rotterdam. “These are the best preserved skeletons in the world of this species.”

Plant material found near the tusks will be analysed in Greece and the Netherlands, and could give scientists a “better idea of the environment this animal was living in,” Mol said.

The Milia bone remains will also be scoured for the remote chance of finding DNA material.

Researchers from Germany and the United States recently analysed genetic material from an American mastodon recovered from fossils up to 130,000 years old found in Alaska, providing clearer insight into elephants’ evolutionary development.

If DNA is recovered from the much older Milia animal – which Mol acknowledges is “very doubtful” – it could allow researchers to compare it directly to European and American mastodons at an unprecedented level of detail.

The five-metre tusk at Milia was discovered last October by an excavation machine operator working at a sand quarry, but it took months for the scientific investigation of the site to be organised.

Tsoukala, who has been conducting excavations in the region since 1990, found another mastodon tusk measuring 4.39 metres in the same area 10 years ago. She said the latest discovery is more significant because the skeleton remains are more complete.

Locally excavated fossils are carefully removed from the ground after being protected in plaster “jackets,” and are currently displayed at the village’s tiny museum of natural history.

Tsoukala is urging the government to fund a new site.

“We need a new museum because this is valuable material for international reference,” she said. “Whoever wants to study this animal must come to Milia.”