A rare fish species living in an isolated cavern pool probably originated when the cavern first opened to the surface around 60,000 years ago.

The Devils Hole pupfish (Cyprinodon diabolis) is one of the world's rarest animals, and researchers debate whether humans introduced the fish to the pool in Devils Hole in the southwestern United States between 20,000 and 10,000 years ago. İsmail Sağlam and Michael Miller at the University of California, Davis, and their colleagues analysed the genomes of the fish and two related pupfish species, and concluded that the Devils Hole pupfish became an isolated population in the cavern roughly 60,000 years ago.

A geological event may have both opened up the cavern and introduced the pupfish into it, the authors suggest.

Mol. Ecol. http://doi.org/bj78 (2016)