Two hundred and thirty million years ago, the landscape of modern-day Wyoming in USA faced climatic extremes. Torrential rains drenched the region for months during mega-monsoons, transforming the land into a sodden expanse.
But when the rains ceased, scorching, arid conditions dominated, creating a hostile environment for life forms that relied on moisture to survive.
Yet, one group of salamander-like creatures devised a unique survival strategy, leaving behind evidence of their ingenuity in the form of fossilised remains preserved within peculiar, torpedo-shaped burrows.
In a recent study published in Proceedings of the Royal Society B, scientists described this new amphibian species – Ninumbeehan dookoodukah – whose fossils tell a fascinating story of life, death and adaptation in prehistoric times.
Buried treasures
The trail leading to this discovery began in 2014 when David Lovelace, an ichnology (the study of fossilised tracks, burrows and trails) enthusiast and research scientist at the University of Wisconsin Geology Museum, was out exploring rock layers in Wyoming. It was then that he spotted a series of unusual cylindrical rock structures resembling "Pringle cans" in the ground. These formations, he realised, were fossilised burrows – traces of an ancient creature’s life.
One particularly small burrow caught his eye. “It was tiny, it was so cute,” Lovelace recalls. Back in his lab, he opened the burrow with a hammer, revealing a skull with sharp, pointy teeth. Initially mistaking it for a baby crocodile, further examination revealed the fossil belonged to an amphibian. This moment marked the beginning of a collaboration that would bring these ancient animals to light.
Unlocking secrets with technology
Lovelace reached out to Jason Pardo, a fossil amphibian specialist at the Field Museum. Using high-resolution CT scans, Pardo examined the burrows and uncovered partial skeletons of the amphibians inside. The findings were exhilarating. “At this point, we were like, ‘Oh my god, we have something really cool,’” says Lovelace.
With more excavations and the help of then-undergraduate Cal So, the team collected around 80 fossil burrows, many containing bones or skulls.
The remains suggested that these amphibians were about a foot long with diminutive, underdeveloped limbs. Yet, their most striking feature was their scoop-shaped skulls, likely used for digging.
Researchers hypothesise that during the wet season, these amphibians thrived in rivers. When the rivers dried up, they burrowed headfirst into muddy riverbeds, entering a state similar to hibernation to survive the drought.
A glimpse into prehistoric lives
The burrows offered a snapshot of the amphibians’ lifestyle. Their torpedo-shaped shelters likely provided a moist refuge during the dry season, safeguarding them from dehydration.
However, these burrows also became their tombs. As rivers shifted course, some burrows were no longer replenished with water, leaving their occupants stranded and fossilised for millions of years.
Honouring heritage
This discovery, nestled in the ancestral lands of the Eastern Shoshone people, spurred a unique partnership. Lovelace and his team collaborated with local schools and Eastern Shoshone elders to study the fossils, sharing knowledge and fostering a connection between the fossils and the region's cultural heritage.
The collaboration culminated in a name for the newly described amphibian: Ninumbeehan dookoodukah. Translated from the Shoshone language, it means “Little People’s flesh eater.”
The name reflects the amphibian's sharp teeth and pays homage to the Little People, who hold a revered place in Shoshone culture. “This process brought together scientists, community members and students, creating an intergenerational connection to the land and its history,” says Amanda LeClair-Diaz, Office of Indian Education Coordinator and a co-author of the study.
Ancient lessons for a changing climate
The fossil record of Ninumbeehan offers a window into life during the Triassic and hints at the resilience of amphibians under extreme conditions, says Pardo: “Small amphibians from this period are rare, making this find particularly exciting. The burrowing behaviour of these creatures may also hold lessons for modern amphibians facing the pressures of climate change.
“With climate change threatening amphibian diversity, the seasonal strategies of Ninumbeehan offer a glimmer of hope,” Pardo adds. Some modern amphibians exhibit similar behaviours, which could help them weather the challenges posed by global warming.
The discovery of Ninumbeehan dookoodukah is not just a tale of ancient survival; it’s a story of community, collaboration and respect for the past, the authors conclude.
Find out more about the study: Fossil amphibian offers insights into the interplay between monsoons and amphibian evolution in palaeoequatorial Late Triassic systems
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