American crocs seem to descend from kin that crossed the Atlantic

Ancient skull unearthed in North Africa looks a lot like today’s American crocodiles

Crocodylus checchiai illustration

Crocodylus checchiai (illustrated) is an extinct crocodile that lived in Africa millions of years ago. Like American crocodiles, it sported a bump on its snout.

Dawid A. Iurino

A long-lost African crocodile shares more than a bumpy snout with modern American crocs. It may be their direct ancestor, a new study concludes. 

The skull comes from an extinct animal, Crocodylus checchiai. Its features hint that crocodiles may have journeyed from Africa to the Americas. If true, this would have been millions of years ago. Researchers described their findings July 23 in Scientific Reports.

They have been studying a roughly 7-million-year-old fossil. Unearthed in the 1930s from what is now Libya, it sat for decades in a museum. Now, scientists have mapped its skull using CT scans. The skull’s features tie the reptile to all four species of today’s American crocodiles.

It looks like an American croc, says Massimo Delfino. It just lived in Africa. Delfino studies ancient reptiles at the University of Turin in Italy.

The Nile crocodile, a modern African croc, also is related to American crocs. Scientists suspect long ago crocodiles lived in one region before spreading out to others. But fossils had never painted a clear picture of which came first — those in Africa or those in the Americas.

Some crocs swam in America waters as early as 5 million years ago. C. checchiai predates those ancient animals by about 2 million years. Though the extinct reptile is a close relative of American crocs, C. checchiai also is closely related to the Nile species. That means the fossil fills a gap between African and American species, Delfino’s team concludes.

Did a group of crocs swim from Africa to the Americas? Maybe, Delfino says. The continents would have been in about the same place as now. And today’s crocodiles can survive saltwater, he notes. In fact, they even travel hundreds of kilometers (miles) via ocean currents.

ancient African crocodile skull
The features of this C. checchiai skull place the animal at the base of American crocs’ branch in the crocodile evolutionary tree.Bruno Mercurio

Carolyn Wilke is a former staff writer at Science News Explores. She has a Ph.D. in environmental engineering. Carolyn enjoys writing about chemistry, microbes and the environment. She also loves playing with her cat.

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