PARIS (AFP) – One of the oldest known Homo sapiens fossils may be more than 35,000 years older than previously thought, according to a study that used volcanic ash to date the find.

Kibish Omo I, first unearthed in Ethiopia in 1967, contained only bone and skull fragments which were difficult to date directly and experts long remained divided over their age.

Geologists in 2005 analysed the layer of rock just underneath the find and determined Omo I was at least 195,000 years old.

That made the Homo sapiens fossil at least that old – and the oldest ever discovered at the time.

“But there was still a lot of uncertainty,” main author of the study published in leading scientific journal Nature Celine Vidal told AFP. Vidal, a volcano expert at the University of Cambridge, said getting a more precise date meant analysing the thick layer of ash deposited above the fossils.

“At the time that was nearly impossible since the ash was so fine, almost like flour,” she said.

But thanks to more refined methods available today Vidal’s team was able to link that layer of ash to a major eruption of a volcano named Shala.

According to the study, the ash revealed the layer where Omo I was found to be 233,000 years old, with a 22,000-year margin of error.

“This is a major jump in time,” said study co-author and paleoanthropologist Aurelien Mounier.

He added that the new minimum age for Omo I is more consistent with the most recent theories of human evolution.

It also brings it closer to the age given to what are today the oldest Homo sapiens remains, discovered in Morocco in 2017 and dated to 300,000 years ago.

The skulls and teeth unearthed in Jebel Irhoud torpedoed the long-held theory that we emerged from an East African “cradle of humankind”.

But for Mounier, the physical characteristics of the Moroccan fossils are a less convincing ancestor of today’s humans than Omo I.

The Jebel Irhoud fossils are described as having a modern face but a brain case that, though large, has a more archaic-looking shape.

“Omo I is the only fossil that has all the morphological characteristics of modern man,” said Mounier.

Curt Anderson

TALLAHASSEE, FLORIDA (AP) – An unprecedented, experimental attempt to feed manatees facing starvation in Florida has started slowly but wildlife officials expressed optimism on Thursday that it will work as cold weather drives the marine mammals toward warmer waters.

A feeding station established along the state’s east coast has yet to entice wild manatees with romaine lettuce even though the animals will eat it in captivity, officials said on a news conference held remotely.

Water pollution from agricultural, urban and other sources has triggered algae blooms that have decimated seagrass beds on which manatees depend, leading to a record 1,101 manatee deaths largely from starvation in 2021. The typical five-year average is about 625 deaths.

That brought about the lettuce feeding programme, part of a joint manatee death response group led by the Florida Fish and Wildlife Conservation Commission (FWC) and the United States (US) Fish and Wildlife Service. It remains a violation of state and federal law for people to feed manatees on their own.

“We have not documented animals foraging on the lettuce,” said chief of the joint effort’s provisioning branch Ron Mezich. “We know manatees will eat lettuce.”

During winter months, hundreds of manatees tend to congregate in warmer waters from natural springs and power plant discharges. Because this winter has been unusually mild in Florida so far, the animals have been more dispersed.

“They’re moving, but they are not being pressed by cold temperatures yet,” said south regional director for the FWC Tom Reinert. “We expect that to happen.”

In addition to the feeding experiment, officials are working with a number of facilities to rehabilitate distressed manatees that are found alive. These include Florida zoos, the SeaWorld theme park and marine aquariums. There were 159 rescued manatees in 2021, some of which require lengthy care and some that have been returned to the wild, officials said.

“Our facilities are at or near capacity,” said chief of rescue and recovery Andy Garrett. “These animals need long-term care. It’s been a huge amount of work to date.”

There are a minimum of 7,520 manatees in Florida waters currently, according to state statistics. The slow-moving, round-tailed mammals have rebounded enough to list them as a threatened species rather than endangered, although a push is on to restore the endangered tag given the starvation deaths.

Officials are also using USD8 million in state money on several projects aimed at restoring manatee habitat and planting new seagrass beds, but that is a slow process and won’t ultimately solve the problem until the polluted waters are improved.

People can report any manatee they see that might be distressed by calling a wildlife hotline at 888-404-FWCC (3922). Other ways to help are donating money through a state-sponsored fund or purchasing a Save the Manatee vehicle license plate.

That’s better than feeding manatees personally, which does more harm than good because the animals will associate humans with food, according to officials. People and manatees have struggled to coexist for decades.

“This is a very serious situation,” Reinert said. “Use your dollars and not heads of lettuce.”