An indigenous tribe from India's Andaman Islands, thought to have existed for 65,000 years, has disappeared with the death of its last member.
According to the indigenous advocacy group Survival International, Boa Senior, the last known member of the Bo tribe, died last week at the age of 85.
She was also the last speaker of the Bo language.
"With the death of Boa Senior and the extinction of the Bo language, a unique part of human society is now just a memory," Stephen Corry, director of London-based organisation which lobbies for tribal groups, said in a statement.
"Boa's loss is a bleak reminder that we must not allow this to happen to the other tribes of the Andaman Islands."
The Bo are thought to have been among 10 distinct Great Andamanese tribes which numbered around 5,000 strong when the British colonised the Andaman Islands in 1858.
Most were killed or died of disease, with just 52 now thought to survive.
Narayan Choudhary, a linguist at New Delhi's Jawaharlal Nehru University who is part of an Andaman research team, wrote on his website that Boa Senior "epitomised a totality of humanity in all its hues and with a richness that is not to be found anywhere else."
Her death, he said, not only represented the end of her tribe, but was also "a loss of several disciplines of studies put together, including anthropology, linguistics, history, psychology, and biology".
Boa Senior survived the Asian tsunami of December 2004, which swept over the Andaman Islands less than an hour after the initial earthquake off northern Sumatra.
She reportedly told linguists afterwards: "We were all there when the earthquake came. The eldest told us 'the Earth would part, don't run away or move'."
At least 1,300 people are believed to have died in the Andaman and Nicobar islands when the tsunami struck.
Though Bo the language has been closely studied by researchers of linguistic history, Boa Senior spent the last few years of her life unable to converse with anyone in her mother tongue.
Boa Senior's follows the the passing last November of Boro Senior, another woman who was the last surviving speaker of Khoro, another Great Andamanese language.
Anvita Abbi, a linguist, who knew Boa Senior for many years, said that among the Great Andamanese population, there are only speakers of the Jeru and Sare ancient languages remaining.
There are up to five speakers of the languages on the islands and they have not been transferred to younger generations, she told Al Jazeera.
"These languages will live as long as they live, and it is a very sad situation," she said.
"Languages are not only a string of words, it exposes a different kind of society and worldview, and they were the only link to the past culture and ultimately, memories of that commuinity."
Abbi said that since Boa Senior was the only speaker of Bo she was very lonely as she had no one to converse with.
"Boa Senior had a very good sense of humour and her smile and full throated laughter were infectious," she said.
"You cannot imagine the pain and anguish that I spend each day in being a mute witness to the loss of a remarkable culture and unique language."
Boa Senior also told Abbi she felt the neighbouring Jarawa tribe, whose population had not dramatically declined, were lucky to live in their forest away from the non-native settlers who now occupy much of the islands.
The few surviving members of the Great Andamanese tribes are now largely confined to one small island.
They are reported to depend largely on the Indian government for food and shelter, and abuse of alcohol is rife.