Named “Ninumbeehan dookoodukah” by Eastern Shoshone students and elders, the creature burrowed in riverbeds to stay moist during extreme droughts
Eli Wizevich December 11, 2024 1:23 p.m.
In prehistoric times, western Wyoming was a land of lethal extremes. When it rained, it poured for months on end, and when the monsoons ceased, the area became so hot and dry that it was deadly for animals like amphibians, which require moist skin to stay alive.
But, according to a recent study published in Proceedings of the Royal Society B, a newly discovered species of salamander-like amphibian found a strategy to survive roughly 230 million years ago. The creature waited out the harsh climate of the Late Triassic by burrowing deep into moist riverbeds to avoid drying out between monsoon seasons in a process known as seasonal estivation.
This discovery began incidentally in 2014, when David Lovelace, a researcher at the University of Wisconsin-Madison, picked up a soccer ball-sized rock on the way back to his car after a day of picking through the Popo Agie formation near Dubois, Wyoming.
The Popo Agie (pronounced puh-POE-zha) comes from a Crow word for “beginning of the waters,” and although the formation is rife with ancient crocodiles and amphibians, most of the fossils were picked through in the early 20th century, long before Lovelace’s day. “Growing up in Wyoming, it had been known as the ‘Big Red Dead,’” Lovelace tells Sabrina Imbler of Defector. “There’s no fossils. It’s not worth your time.”
The rock he collected, however, came from a layer of sandstone below the Popo Agie and contained a small, fossilized burrow. Back at his lab in Madison, Lovelace decided to extract the burrow, which reminded him of a Pringles can.
“Being a good geologist, I hit the whole thing with my hammer,” Lovelace says to Defector. Instead of popping the burrow out of the surrounding rock, Lovelace’s hammer shattered the rock and revealed the skull of a small animal. At first, it looked reptilian, with its rows of tiny teeth. But after reconstructing the bones, Lovelace noticed indications of a lateral line organ, part of the sensory apparatus that amphibians use to react to changes in their aquatic environment.
With the help of researchers at the Field Museum in Chicago, he created high-resolution CT scans of a different fossil burrow from the site, revealing a partial skeleton inside.
“At this point, we were like, ‘Oh my god, we have something really cool,’” Lovelace says in a statement from the Field Museum. “I went back to put together the geological story of the site, and then we were just finding these burrows everywhere. We couldn’t not find them; the site was ridiculously loaded.”
Although his research group has not yet uncovered a full skeleton, they believe the ancient amphibian belonged to a group of primitive creatures known as temnospondyls. The animal was about a foot long and used its head, rather than its arms, to dig into the mud.
“Their skulls have kind of a scoop shape, so we think they used the head to scoop their way underground at the bottom of a riverbed and go through a period of having a lower metabolic rate so that they could survive the dry season,” says study lead author Cal So, an incoming researcher at the Field Museum, in the statement.
The ancient amphibians burrowed into the riverbed, seemingly seeking moisture when the monsoons ended. Though the strategy probably helped many of their kind withstand the dry season, these individuals were unlucky—their river likely changed paths when it re-formed, so they died in the ground when the waters never came.
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Lovelace named the site “Serendipity Beds,” referring to the rich stratum in the upper layer of the Jelm Formation of the Late Triassic where he found the burrows.
This part of Wyoming is now part of the ancestral lands of the Eastern Shoshone. Lynette St. Clair, an Eastern Shoshone linguist and cultural preservationist, tells Defector that “the presence of fossils throughout the Shoshone Homelands is evident through our creation stories, which tell us that the land was once covered by water.”
In partnership with the Eastern Shoshone community, Lovelace and his team of researchers led field trips to show tribal members and students at local schools the natural history beneath their feet.
Reba Teran was one of the Eastern Shoshone elders who came along. Teran’s “life’s work,” as she puts it to Jeanne Timmons of the New York Times, is maintaining the Shoshone language, despite the historic, systematic efforts of the United States government to erase it. She built an audio dictionary and creates new words to keep it alive, relevant and vibrant.
As part of that effort to honor and sustain the language, Teran, along with a class of seventh-grade students at the Fort Washakie School in Wyoming and tribal elders, collaborated to come up with a scientific name for the amphibian: Ninumbeehan dookoodukah.
In the Shoshone language, Teran explains, Ninumbee are spiritual beings known as “Little People.”
“We know they existed, and they still do,” she tells the New York Times. “Sometimes people talk about seeing them. And so that’s why I decided it would be nice if we could name them Ninumbee. Because it was found in their territory.”
Dookoodukah means “flesh-eater,” a reference to the sharp little teeth that Lovelace’s team discovered in the amphibian’s skull.
Taken together with the possessive han added to Ninumbee, the two words translate to “Little People’s flesh eater,” as if the amphibians were a prehistoric pet from hundreds of millions of years ago.
While the naming process offers hope for the revival of the Shoshone tongue, the discovery itself might hold clues for how modern amphibians could adapt to the extreme weather brought on by climate change.
“Modern amphibian diversity is under substantial threat, and climate change is a huge part of that,” says Jason Pardo, a researcher at the Field Museum, in the statement. “But the way that Ninumbeehan could slow down its metabolism to wait out the dry weather indicates that some lineages of modern amphibians that have similar seasonal behavior might allow for greater survivorship than some of the models suggest. It’s a little glimmer of hope.”
