The Academy's Herpetology collection of amphibians and reptiles is one of the 10 largest in the world, containing more than 309,000 cataloged specimens from 175 countries. Learn more about the department's staff, research, and expeditions.
The Lesser Antilles archipelago harbors an abundance of species, some of which are found nowhere else on Earth. But because these islands have long been connected to one another by human activity, they pose a unique challenge for the biodiversity scientists who study them: Which species evolved on which islands?
Though the Lesser Antillean whistling frog (Eleutherodactylus johnstonei)—bug-eyed and about the size of a thumbnail—can be found throughout the archipelago in staggering numbers, its native island is unknown. For Academy Curator of Herpetology Rayna Bell, PhD, solving the mystery of its origins—and those of other cryptogenic species, or species whose origins are unknown or uncertain—is critical for conserving island biodiversity. Bell and a team of collaborators conducted broad surveys across the Lesser Antilles, sampling frogs from populations on almost every island. “We were specifically looking for populations with more genetic diversity,” Bell says. Non-native species typically have lower genetic diversity, as all descendants would have come from just a handful of introduced individuals. After careful study of the frogs’ genetic makeup, the team was able to determine that E. johnstonei is native to the island of Montserrat, where the frogs had the highest genetic diversity, and that it has been introduced to every other island they’ve sampled so far.