Catfish beats Columbus to America
So did the ancestors of American Indians, of course, but a catfish seems to have beat them by about 50 million years. "Discovery of African roots for the Mesoamerican Chiapas catfish, Lacantunia enigmatica, requires an ancient intercontinental passage" by John Lundberg, John Sullivan, Rocio Rodiles-Hernandez, and Dean Hendrickson, was published in Proceedings of the Academy of Natural Sciences of Philadelphia.
This aptly-named catfish species, recently discovered in Mexico, appears to be most related to catfish in Africa. A family tree based on DNA and calibrated using fossils suggests that the last common ancestor of the Mexican and African species lived 75 to 94 million years ago. This was after continental drift separated Africa from South America.
How did the fish get to Mexico? It swam, presumably. The problem is that catfish are freshwater fish. The authors suggest that partial melting of polar ice during the Eocene may have made the Arctic Ocean warm enough and fresh enough for the ancestors of the Mexican catfish to survive a long ocean swim.