A new species of tortoise has been hiding in plain sight in the Galápagos. Now it has a name.

There are two populations of giant tortoises on the island of Santa Cruz: The ones that live on the island’s east side are known as the Cerro Fatal tortoises, and the ones in the west and southwest are called the Reserva tortoises. The two groups look so much alike that until recently they were considered the same species, Chelonoidis porteri.

When a research team led by Yale evolutionary biologist Adalgisa Caccone analyzed chunks of repetitive nuclear DNA and maternally inherited mitochondrial DNA from the two populations, they discovered that the smaller Cerro Fatal and larger Reserva populations were not only different species,