Scientists Searching for Extinct Minnow Discover New Species Already on Brink of Survival
A research team looking for an extinct fish in a South African river instead found an entirely new species — one already classified as critically endangered and known from only a single river system in the world.
In 2017, researchers traveled to South Africa’s Umzimkhulu River searching for the Maluti redfin minnow, a species declared extinct after introduced trout devastated its population. They didn’t find it. Instead, they collected a dozen minnows that resembled the lost species, triggering what the researchers called a “long-standing debate” over what they had actually caught.
Years of analysis finally provided an answer. According to a study published Jan. 2 in the peer-reviewed journal Zoosystematics and Evolution, the fish turned out to be an entirely unknown species: Pseudobarbus kubhekai, commonly known as the Umzimkhulu redfin minnow.
Researchers immediately classified it as “a critically endangered species.” In an unusual step, they withheld the fish’s exact location “due to conservation sensitivities,” according to the study.
The backstory is inseparable from a familiar ecological tragedy. The Maluti redfin minnow had been abundant in a nearby area during the early 1900s. It was later declared extinct due to “predation and competition” with introduced trout, the study said.
That pattern — a non-native predator introduced for recreational fishing, subsequently decimating native populations — drove researchers to hope the Maluti redfin minnow might be only locally extinct and that undiscovered populations survived elsewhere. That hope led them to the Umzimkhulu River, located in eastern South Africa, approximately 400 miles southeast of Johannesburg.
The research team — which included Fatah Zarei, Xiluva Mathebula and Albert Chakona — conducted DNA analysis, examined the fish’s physical characteristics and compared them to related species. The analysis confirmed the fish were not the extinct Maluti redfin minnow. They were something entirely new.
The study found the new species has at least 6% genetic divergence from related species. It was identified based on its scale pattern, coloring, skeleton and other subtle physical features.
Umzimkhulu redfin minnows can grow to more than 3 inches long, the study said. They have “large” heads with “blunt” snouts, “large” eyes and “sickle-shaped” mouths. Their “moderately elongate” bodies are covered “with numerous” small bumps. The species has “olive-brown” coloring and “bright orange-red” spots near its fins.
The fish live in shallow, rocky streams in the Umzimkhulu River. Researchers said much of the species’ biology and lifestyle remains unknown — a significant gap that underscores how much work lies ahead if the species is to be understood and protected.
The species name kubhekai honors Skhumbuzo Kubheka, a wildlife researcher who helped discover it “through extensive sampling efforts,” according to the study. The common name refers to the Umzimkhulu River, the only known location where the species has been found.
That a species known from just one river system already carries a critically endangered designation speaks to the precariousness of its existence. A single catastrophic event — pollution, drought, or the further spread of invasive species — could eliminate the Umzimkhulu redfin minnow before scientists fully understand its role in the ecosystem.
The researchers’ deliberate decision to withhold the species’ precise location reflects a hard-won understanding that publicly disclosing the whereabouts of a critically endangered species can sometimes invite the very threats scientists are trying to prevent — from collectors to habitat disturbance. For a species found in only one known location, the stakes of disclosure are especially high.
The researchers did not simply document the species and move on. They urged conservationists and government officials to take action to protect it from extinction, according to the study.
That plea carries particular weight given the ecological history already embedded in this story. The Maluti redfin minnow — the species the researchers originally set out to find — was lost to the pressures of introduced trout. The Umzimkhulu redfin minnow now faces an uncertain future in the same broader watershed. Without formal government protection, the species’ survival may depend on whether its story reaches the right people in time.
The pressures of invasive species on native freshwater populations, the critical importance of government protections for endangered species, and the tension between public knowledge and conservation security are debates playing out in river systems everywhere.
BOTTOM LINE: The Umzimkhulu redfin minnow exists in a single river system with no formal government protection, and researchers warn that without swift conservation action, it could follow the same path to extinction as the species they originally went looking for.
Production of this article included the use of AI. It was reviewed and edited by a team of content specialists.
