The Devils Hole pupfish (Cyprinodon diabolis), a small fish that can withstand temperatures of 89 degrees Fahrenheit, and found only in Devils Hole in Nevada side of Death Valley, may have gotten to its habitat between 105 and 830 years ago, rather than 10,000 years that was the previous timeline, according to a study published in the Proceedings of the Royal Society B.
The pupfish population in Devils Hole has fluctuated between 35 and 548 fish since the population was subject to record keeping in the 1970s. And this population should have died off as they became severely inbred, but this hasn’t been the case. So scientists, led by Christopher Martin, a biologist at the University of North Carolina, Chapel Hill looked at the genetics of the fish and sequenced 13,000 different DNA sequences from 56 pupfish found in Death Valley and throughout the world, enabling the scientists to create the pupfish’s family tree and determine when the different species of pupfish diverged.
Martin speculates that the Devils Hole pupfish arrived in Devils Hole during a flooding event and his timeline fits that of the great flood of 1862, which recorded the largest amount of rainfall in California and Nevada. He also says it is possible that birds may have inadvertently brought them to the remote body of water because the eggs of this fish are super sticky, and they could have traveled on the bird legs to Devils Hole.
The Devils Hole pupfish is different from its relatives in that it is smaller and less aggressive than other pupfish species. It has larger eyes and its scales are darker, and it doesn’t have the pelvic fins that every other pupfish species in the desert has, Martin said.
“They are special fish,” said Dr Martin. “The ecology of the Devils Hole is reflected by the very phenotypic distinctiveness of these pupfish. They have not only reduced aggression and a darker metallic colouration, but they have completely lost their pelvic fins. We don’t know whether the loss of this major appendage is due to the effects of severe inbreeding over time or if it’s adaptive in this habit.”