Scientists have solved a long-standing reptile mystery as to whether crocodiles first appeared in Africa or America.
Analysis of a seven-million-year-old specimen of an extinct African species shows that it is closely related to modern American crocodiles.
However, the oldest crocodile ever found in America is only five million years old.
As a result, scientists believe that crocodiles that first appeared in Australia first migrated to Africa and then conquered the Americas during the late Miocene epoch, which spanned from 11 to five million years ago.
The ancient crocodile skull is kept in the Museum of Earth Sciences of the Sapienza University of Rome and was first discovered in 1939 during excavations in Libya.
Scientists placed the skull through a CT scan to take extremely detailed images of the skull, and discovered some features that had not been previously documented.
Most notable is the protrusion in the middle of the animal’s snout, which belonged to the species Crocodylus checchiai.
Although this animal was found in Africa, no other African crocodile has such an anatomical feature.
But four species of crocodiles living over the Atlantic in North and South America have a very similar bump on their noses.
Researchers from the Autonomous University of Barcelona used this to try to piece together an evolutionary chronology of when this trait appeared and how it would have spread to different species around the world.
It was previously known that crocodiles first appeared in Australia, but it was a mystery whether they reached America from Africa or Vice versa.
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But, as they write in their study published in Scientific reports, scientists say that crocodiles reached the Americas by migrating West from Australasia through Africa.
“There are two possible scenarios for the spread of crocodiles to Neotropical areas: from Australasia to Neotropical areas and then to Africa, or alternatively from Australasia to Africa and then to Neotropical areas,” their article says.
- Thanks to our results, the late Miocene Crocodile cecchiai could offer… direct evidence of dispersal from Africa to America and a suggestion to reject the other option.’