Fossils in Panama Suggest Alligators Came from South America

A study published in the Journal of Vertebrate Paleontology explains how the ancient alligator reptile swam to North America from South America some 10 million years back.

The finding is based on two crocodilian fossil skulls that were unearthed in the Panama Canal Zone that was formed 2.6 million years ago. These specimen throw light on the history of fossils. It explains the interchanging of reptiles between North and South America. It explains how the alligators from North America changed into caimans and alligators that are currently found in South America.

It was during the current expansion of the Panama Canal that this fossil was discovered as part of a fossil hunt called Panama Canal Project. The fossil belonged to two species of caiman. They were found embedded in rocks dating between 19.82 and 19.12 million years old. One was 6-7 feet in length while the other was 4-5.5 feet in length.

According to the researchers, when these creatures existed, North America and South America were separate. It was only when the Isthmus of Panama rose that the two continents were joined. The researchers believe that this bridge formed a channel through which the interchange of animals took place. For example, armadillos and giant sloths moved into the North and the South was occupied by relatives of modern horses, rabbits, dogs, elephants.

"These are the first fossil crocodilian skulls recovered from all of Central America. They fill a gap in evolution between the alligators of North America and the caimans of South America," fossil crocodilian specialist Alex Hastings, the lead author of the study, was quoted as saying in Science codex.

This finding surprises the researchers as the fossils suggest caimans spread to North from South America by the early Miocene era. Apart from this, caimans don't have the ability to throw the excess salt from their body and hence they reside in freshwaters. But based on the new findings, it seems they could have shifted to a close distance across the sea water, thereby supporting the latest finding that states Central and South America were much closer to each other some 19 million years ago.