Beijing -- The only known female member of one of the world's rarest turtle species has died at a zoo in southern China, officials said Sunday. The animal was one of four Yangtze giant softshell turtles known to be remaining in the world. The Suzhou zoo, where the female turtle lived, also houses a male Yangtze giant softshell turtle. The other two live in Vietnam, but their genders are unknown.

The turtle died Saturday afternoon, the Suzhou city government said in a statement, citing the zoo. It said experts have already used technology to collect the turtle's ovarian tissue for future research.

The state-run People's Daily reported that the turtle was over 90 years old and had undergone a fifth attempt at artificial insemination shortly before she died.

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A medical examination found the turtle to be in good health prior to the procedure, the People's Daily said, and the artificial insemination appeared to go smoothly. But the turtle died the following day.

Yangtze giant softshell turtles originated in China, making their homes in the Yangtze River and Taihu Lake, according to the People's Daily.

Suzhou authorities said Chinese and foreign experts are investigating the cause of the turtle's death.

A female Yangtze giant softshell turtle, one of four remaining in the world, is seen at Suzhou Zoo in China in a 2015 file photo. Gerald Kuchling

Scientists announced in 2015 that they would be trying to artificially inseminate the female at Suzhou zoo, as a last-ditch effort to save what is often referred to as the most endangered turtle in the world.

"It now appears that artificial insemination is the only possible option for the pair," said Lu Shunqing, Wildlife Conservation Society China's reptile program director, at the time. "The fate of the most endangered softshell turtle of the world is now in the balance."

Listed as critically endangered by the International Union for Conservation of Nature, the Yangtze giant softshell turtle is the most critically endangered turtle in the world. Its status in the wild has long been recognized as grim, but extinction risk now is believed higher than ever. Much of its demise has been attributed to over-harvesting and the degradation of its freshwater habitat in China.