The blind Brazilian blind characid is related to tetras and piranha. Image credit: Dr. Cristiano Moreira, Federal University of Sao Paulo
In 1962 a strange blind fish was captured in a communal water well in Minas Gerais, Brazil. Ichthyologists identified it as a new species of Characiformes, an order that includes tetras and piranhas, but outside that one lonely specimen, the fish was never seen again.
Now, a team of researchers from the Federal University of Sao Paulo have rediscovered the fish—though the small population may already be doomed to extinction.
Researchers searched wells deep underground to find the fish. Image credit: Dr. Cristiano Moreira, Federal University of Sao Paulo
The team, led by Dr. Cristiano Moreira, began by interviewing locals living around the area of the first discovery. From these interviews, they collected several reports that the fish had been seen swimming in communal wells.
However, because the region is so dry, people rely on underground wells—and even these often end up being free of standing water. Moreira explained:
This was one of the problems we encountered to find this fish, since most of the open wells we could access to collect or put traps were dry.
Eventually, the team found two pools with enough water that they could place traps and collect fish.
Here fishy fishy fishy...Image credit: Dr. Cristiano Moreira, Federal University of Sao Paulo
And collect they did. The team ended up capturing 34 individuals that proved to be the elusive Stygichthys typhlops.
The rediscovery has allowed researchers to gain a better understanding of the fish, but much remains unknown.
Image credit: Dr. Cristiano Moreira, Federal University of Sao Paulo
Moreira commented that:
Morphologically, Stygichthys is very different from any species in the group, so much so that we are still not able to say to which species it is more related.
One thing is certain: The species is highly threatened.
Moreira explained that it is likely the species is mostly extinct, with only this one group surviving by virtue of it's until-now inaccessible habitat—what conservationists call a "relic species."
This protection, however, is vanishing rapidly. As surface wells become increasingly rare, people are pushed farther underground in search of water—and these deep pools, and the rare fish that call them home, face a dry future because of it.
Moreira explained that "this species seems to be the most threatened underground fish species in Brazil," likely relegated to a habitat only 25 kilometers long. And, he added, the withdrawal of water from this tiny aquifer will mean certain extinction for the species.