A family from Mobile found the fossil of a newly discovered genus of the endangered leatherback sea turtle along a riverbank in south Alabama.
And thanks to a series of events that unfolded over the last four years, you can see it at the McWane Science Center in Birmingham.
“When we came across that, we all just kind of stared at each other for a minute, like ‘This is it,’” said Adrienne Coleman, whose 13-year-old daughter spotted the fossil during a family boat trip along the Alabama River around two hours north of Mobile, in the Black Belt region.
But this story is about so much more than that.
“We still have a great deal to learn from [this fossil],” said Andrew Gentry, the paleontologist at Gulf State Park who first identified the fossil.
To start, we need to go back 32 million years, to a time when the world was coming out of a much warmer, greenhouse-like period and starting to cool, Gentry said. The lower quarter or even third of Alabama was underwater.
This is tens of millions of years before the Underwater Forest, a trove of fossilized trees off the coast of Alabama, existed, and roughly 31.7 million years before humans existed.
Leatherback sea turtles are unique. In addition to being by far the largest sea turtles in the world, their shells are made up of thousands of “ossicles,” tiny, tile-like bones, instead of plates. The ossicles are held together by soft collagen, like a mosaic.
This shell design is designed for deep dives: as the water pressure increases, the shell can flex to handle the added pressure, Gentry said. But it also means that, when the turtles die, their shells usually fall apart as the collagen decomposes.
“Often, we get only a handful of isolated ossicles,” Gentry said. “Seeing an intact mosaic of these leatherback ossicles…seeing it for the first time, it was certainly something I will never forget.”
This turtle was likely buried in sediment shortly after it died, said Gentry, which prevented the shell from being pulled apart by scavengers or eaten away by decomposing bacteria.
Over millions of years, the sediment hardened around the shell into limestone. The shell remained intact, embedded into the boulder.
It was so intact that the Coleman family from Mobile knew right away they found something special.
Adam and Adrienne Coleman posing with the “Ueloca” leatherback sea turtle fossil. The Colemans’ daughter, Talah, first spotted the fossil on a family boating trip in 2021. (Photo by Drew Gentry)Drew Gentry
“When I got over there, there was no question that it was something,” said Adrienne Coleman. “You could tell, but it’s nothing that we thought it was going to be.”
Adrienne and her husband, Adam, grew up hunting for fossils as kids in Alabama. They continue that hobby with their two kids: Talah, 17, and Corey, 12.
In 2021, the Colemans were boating down the Alabama River when they decided to stop on the riverbank to eat lunch. Their eyes were still searching for fossils, even though they weren’t actively looking, Adrienne said.
It was Talah who first spotted the fossil, her mom said.
“We were really, really excited, but it was crazy how quiet we were that first day about it, because we were just looking at everything so hard, examining everything, kind of just in awe,” Adrienne Coleman said.
At first, the Colemans didn’t know what to do with their find. They decided to make it their special lunch spot for a while.
Eventually, the family decided more people should know about it. Adrienne Coleman reached out to a researcher at the University of South Alabama but never heard back.
In the fall of 2022, she reached out to Gentry after reading an article on him and a turtle fossil discovered in north Alabama.
Gentry went with Adam Coleman to the site of the fossil. Right away, he knew the significance of the find.
“It took me a few minutes to collect myself and to start to begin to realize what was ahead,” he said.
The leatherback sea turtle fossil being lifted out of the transport boat by tractor. The fossil is embedded into limestone, so some of the rock had to be excavated with it. In total, it weighed around 1,800 pounds, Gentry said. (Photo by Erik Lizee)Erik Lizee
Gentry knew that he had quite a challenge in front of him. Because the fossil is in a remote location and only accessible by boat, it couldn’t be excavated with heavy machinery. The stone in which the fossil was embedded was the size of an SUV, so it wasn’t going to be easy to transport.
He contacted Jun Ebersole, a paleontologist at McWane Science Center in Birmingham, to try to figure out how to excavate the fossil. Gentry and Ebersole assembled a team of researchers from McWane, the Geological Survey of Alabama, the National Oceanic and Atmospheric Administration and other agencies to work on the fossil.
The weather also impacted their plans to excavate the fossil. The team had to work during the summer, when temperatures regularly reached above 90 degrees. The riverbank also floods periodically, so they had to wait until the water level was low enough to reach the fossil.
Finally, on July 8, 2023, the team was able to fracture the boulder and carry out the piece containing the fossil.
By the time they made it to the boat ramp in Clarke County, word had spread about the fossil. A crowd of people were waiting at the ramp for the researchers’ arrival.
And it was lucky there was a crowd: when they arrived, the researchers were unsure how to get the boulder from the boat onto the trailer. A local volunteered to use his John Deere front end loader for the fossil. He was able to move the fossil onto the trailer with ease.
“It doesn’t seem to matter where I’m collecting fossils or where I go in the state, but fossils specifically seem to have this way of turning people who are strangers into collaborators, and into colleagues,” Gentry said. “Everyone seems to have this shared love of fossils.”
But the most special thing about the fossil wasn’t discovered until it was in a lab: it belongs to not just a newly discovered species of leatherback sea turtle, but an entirely new genus, or group of species.
At the time this turtle lived (32 million years ago), there were two lineages of leatherback sea turtles: one with ridges along its back and one without. The fossil is from the lineage with smooth backs.
Both adapted to deepwater diving, but only the lineage with ridges survived. The other went extinct, Gentry said.
“Despite the fact that they had, clearly, a similar ecology and a similar anatomy, the ridgeless group went extinct,” he said. “The modern leatherback sea turtle is the only surviving member of either lineage.”
The fossil species was named Ueloca colemanorum (pronounced “Wee-low-juh kohl-man-or-um”). The genus, Ueloca, comes from the Muscogee word for water, Uewa, and turtle, Locv.
Muscogee is the language of the Creek Indians, and the fossil was found in their ancestral homeland, according to a news release from the tribe. A researcher on the team, Kimberly Gregson, is a member of the Poarch Band of Creek Indians, and Muscogee speakers with the Poarch Creek Indians’ cultural department worked with researchers on the name.
“This is the first fossil to carry a Muscogee name and it’s exciting to see our language recognized in this way,” said Samatha Martin, Creek Language Coordinator for the Poarch Creek Indians, in the release. “Opportunities like this weave our voice into history and ensure it’s never forgotten.”
The species name, Colemanorum, is a tribute to the Coleman family for their discovery. Adrienne Coleman said the research team has kept them in the loop throughout the research process.
An artist’s rendering of Ueloca colemanorum exhibiting the deep-diving behavior characteristic of leatherback sea turtles. Unlike modern leatherback sea turtles, this ancient species does not have ridges along its back. (Rendering by Elizabeth (Medena Drakorus) Hiley)Elizabeth Hiley
The fossil is now on display at the McWane Science Center in Birmingham. But even though Gentry calls it the “Rosetta Stone” of ridgeless leatherback fossils, the discovery of this fossil is just the beginning.
For starters, the exact location where the fossil was discovered remains a secret. Gentry said it’s likely that there are more fossils out there, and they want to protect the site from fossil hunters who may find items and decide to keep them for themselves.
But more importantly, the fossil provides scientists their “best glimpse” into the Oligocene Epoch 32 million years ago, Gentry said. Not only can scientists learn about leatherback sea turtles, but they can also learn about Alabama at the time.
“Finding anything from this time period is obviously very significant in our efforts to reconstruct what the environments in Alabama during that time would have looked like,” Gentry said.
The Colemans are going to keep hunting for fossils. While they don’t ever expect to find anything like that again, they know how to keep their eyes peeled.
“That right there just set more of a little fire for it,” Adrienne said. “The kids are always looking, trying to find a turtle now…we’re just going to keep what we do, and just enjoy it.”
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