Most American crocodiles don’t need to look far to find the feature that sets them apart from Nile crocodiles. The difference lies right between their eyes and their nostrils. Of crocodiles living today, only the four crocodile species that live in the Americas have a small bump in the middle of their snouts.
But about seven million years ago, a ten-foot-long crocodile living in what’s now Libya had the same tell-tale lump, according to research published in Scientific Reports last week. A fossil skull of the extinct Crocodylus checchiai provides more evidence that crocodiles spread across the world by migrating from Australia, through Africa and finally to South America.
The fact that crocodiles live on both sides of the Atlantic Ocean has long puzzled biologists trying to figure out which direction the giant reptiles migrated. Genetic research in 2011 provided molecular evidence that crocodiles migrated from Africa to the Americas, but fossil evidence was scant.
At seven million years old, the C. checchiai skull predates all known crocodile fossils in America, the oldest of which are about five million years old, Lucy Hicks reports for Science magazine. That means that the timeline checks out: it’s possible that C. checchiai may have made their way from Libya to the western coast of Africa, swam across the Atlantic and landed on the shores of South America.
The continents were about the same distance apart seven million years ago as they are today, making the journey across the ocean quite a feat—but not impossible. The researchers point out in a statement that the Australian marine crocodile has been recorded travelling more than 300 miles in a day. The prehistoric croc may have also bobbed along on one of the ocean’s surface currents that travel west from Africa to the Americas.
https://www.smithsonianmag.com/smart-news/new-evidence-ancient-crocodiles-swam-africa-america-180975415/