Frogs Were Florida's First-Known Vertebrates from the Caribbean
Published:21 Dec.2023 Source:Florida Museum of Natural History
Deep in the forests of Haiti lives the blue-eyed La Hotte glanded frog (Eleutherodactylus glandulifer), which once went 20 years without being observed by scientists. It belongs to a diverse genus from the Caribbean that also includes the much more common coquí frog (Eleutherodactylus coquí), a cultural icon in Puerto Rico. Now, a new fossil study shows that frogs from the genus Eleutherodactylus are geologically the oldest Caribbean vertebrates to be found in Florida. They also arrived in North America much earlier than previously thought.
Scientists have an incomplete record of the evolutionary history of frogs. Data analyses show that frog families underwent rapid diversification after the Cretaceous-Paleogene mass extinction that famously killed off the dinosaurs 66 million years ago. Frogs continued to diversify for the next several million years. They first show up in Florida's fossil record during the Oligocene Epoch, which lasted from around 34 to 23 million years ago. However, records from these eras are patchy.
DNA analysis led scientists to believe that Caribbean frogs in the genus Eleutherodactylus first arrived in Central America during the middle Miocene Epoch, 16 to 11 million years ago, before dispersing to North America. The fossils from this study, however, show rain frogs were in Florida during the late Oligocene, several million years before their recorded dispersal into Central America. Rain frogs are evidently good at getting around, but it's not clear how they made it to Florida. Overwater dispersal on flotsam or other buoyant debris seems the likeliest scenario.