Scientists have discovered that a tooth found near Old Crow, Yukon, in 2018 belonged to the oldest Lanudo Lanudo in North America.
The discovery challenges the popular belief that mammoths crossed North America from Siberia in the last 100,000 years, said Love Dalén, a professor of evolutionary genomics at the University of Stockholm and one of the scientists behind the research.
“We have had results in previous investigations that suggest that mammoths were in North America a long time ago, hundreds of thousands of years ago, but those specimens have never been identified,” said Dalen. “So, finding this really confirms our previous theory.”
The findings are detailed in a paper Published last week that informs a million years of genomic evolution in mammoths. Dalen was among a team of scientists who analyzed mitochondrial DNA, genomes in the parts of the cell responsible for generating energy, based on samples that covered more than one million years of time. In doing so, the research team also developed a new method to date, which will help scientists track the movements of the old mammoths of hundreds of thousands of years.
Yukon’s paleontologist, Grant Zazula, along with a team of researchers, found the tooth in the Old Crow river basin in the traditional territory of Vuntut Gwitchin in 2018. Every summer, in collaboration with the first nation, scientists visit the basin in search of old fossils.
“It is probably one of the most amazing places in the world for the paleontology of the ice age because it seems that every time we are going there, there is another spectacular discovery,” said Zazula. “For many species, it seems to be the place where we find these unique specimens.”
“We have been in this type of search for several years looking for the first Mammists in North America in the Old Crow region,” Zazula said.
In 2018, Zazula and his team were looking in a prominent bed for volcanic ashes inside the basin. The volcanic ashes beds are important, he says, because they provide time markers from the ice age. Any fossil that is in that bed is at least 160,000, says Zazula.
One morning, while looking for the team, the team saw what they had been looking for.
“We saw only a splinter of this gigantic tooth that stood out from the cliff in a place that we knew was under volcanic ash,” he said. “When I saw the tooth, I knew it was morphologically a gigantic Lanudo.”
Zazula sent a tooth sample to the Dalen Laboratory, where the team analyzed the mitochondrial tooth DNA. The analysis confirmed that the tooth belonged to a gigantic Lanudo and dated it about 220,000 years.
“It is really very old. It is not the last ice age, it is not even the ice age before that, but probably the ice age before that ice age where this gigantic lived,” Dalen said.
The discovery leaves scientists with a “mystery”
The discovery has left scientists with many unanswered questions, says Dalen.
The mitochondrial DNA analysis also showed that the tooth belongs to a genetic lineage different from most mammoths in North America during the last ice age, he said.
“There is still a mystery here,” Dalén said. “What is happening with gigantic woolly evolution in North America that we have not sent their heads completely?”
There are three different lineages of woolly mammoths based on their mitochondrial DNA, says Dalén. Two of those lineages in North America have been found, but almost all samples of the last ice age belong to a lineage known as Cade One.
However, the tooth that was discovered in Old Crow in 2018 belongs to a lineage known as Cade Three, Dalén said.
“So the question is, where is the clade?”
To determine the origin of the woolly mammoths of clado one and their relationship with the previous mammoths in Cade Three, Dalen says that scientists should look for more gigantic wool remains of the same period of time as the old crow’s tooth.
This summer, Dalen plans to take a team to another place in the Old Crow river basin in search of more fossils to help them unravel this mystery.
“If we can find some gigantic material in this other site this summer … these could be really important to connect the points between the first mammoths in North America and Mammoths in Siberia,” Zazula said.
