Scientists have identified a previously unknown nematode species in the Great Salt Lake, marking only the third animal group able to survive its extreme salinity. Named Diplolaimelloides woaabi with input from Indigenous elders, the worm appears endemic to the lake. The discovery raises questions about its origins and potential role in monitoring the lake's health.
In a breakthrough for microbial ecology, researchers from the University of Utah have described a new species of roundworm thriving in the hypersaline waters of the Great Salt Lake. The nematode, formally named Diplolaimelloides woaabi, was first spotted in 2022 during field expeditions led by then-postdoctoral researcher Julie Jung. She collected samples from the lake's microbialites—hardened mounds built by microbial communities—while navigating the area by kayak and bicycle.
The name honors the Northwestern Band of the Shoshone Nation, whose elders suggested "Wo'aabi," the Indigenous word for worm. Led by biology professor Michael Werner, the team confirmed the species' novelty after three years of taxonomic analysis. "We thought that this was probably a new species of nematode from the beginning, but it took three years of additional work to taxonomically confirm that suspicion," Jung, now an assistant professor at Weber State University, explained.
This finding adds nematodes to the short list of animals enduring the lake's conditions, joining brine shrimp and brine flies, which support migratory birds. Genetic data hints at a possible second undescribed species, as noted by undergraduate researcher Thomas Murray: "Genetically we can see that there are at least two populations out there."
The worm belongs to the ancient Monhysteridae family, typically found in marine or brackish waters, making its presence in this inland, elevated lake puzzling. Two theories emerge: it may trace back to Cretaceous-era seas that once covered Utah, as suggested by coauthor Byron Adams, or birds could have transported it from distant saline lakes. "The null hypothesis is that they're here because they've always kind of been here," Adams said.
In the field, females dominate samples at over 99%, contrasting with lab cultures showing a 50-50 sex ratio. The nematodes inhabit the top layers of algal mats on microbialites, feeding on bacteria. As potential bioindicators, they could signal changes in salinity or water quality amid human pressures on the lake. "They tell you how healthy is your ecosystem," Adams added.
The study, published in the November 2025 Journal of Nematology, underscores the lake's hidden biodiversity and its vulnerability.