Fossilized Croc and Hippo Remains in Panama Canal Shed Light on Distribution of Animals in Americas

Researchers have found fossilized remains of two crocodiles during research at the Panama Canal that may provide a link between the crocodiles now found in North and South Americas.

In addition to the remains of crocodiles, researchers from University of Florida have discovered remains of an ancient cousin of the modern-day hippo.

The study of fossils obtained from the Panama Canal excavations show how animals moved and how the environment responded to this migration. The animals discovered by the researchers are believed to have lived in Central America about 20 million years ago in an era known as Miocene, when most of the land-dwelling animals were essentially modern.

"In part we are trying to understand how ecosystems have responded to animals moving long distances and across geographic barriers in the past. It's a testing ground for things like invasive species - if you have things that migrated from one place into another in the past, then potentially you have the ability to look at what impact a new species might have on an ecosystem in the future," said study co-author Jonathan Bloch, associate curator of vertebrate paleontology at the Florida Museum of Natural History on the UF campus in a news release.

In the present study, researchers looked at samples of all known remains of crocodiles that were obtained from the Panama Canal which included ancient kin of the alligators called Central American caimans. One species of crocs called Culebrasuchus mesoamericanus shows the transition between caimans and alligators, Alex Hastings, lead author of the crocodilian study, explained.

"You mix an alligator and one of the more primitive caimans and you end up with this caiman that has a much flatter snout, making it more like an alligator. Before this, there were no fossil crocodilian skulls known from Central America," Hastings said.

The hippo-like cousin found by researchers was named Arretotherium meridionale, which is an even-toed hooved animal. The animal is said to be the size of an average cow and lived in a semi-aquatic environment, said Aldo Rincon, lead author of the study and UF graduate student.

"With the evolution of new terrestrial corridors like this peninsula connecting North America with Central America, this is one of the most amazing examples of the different kind of paths land animals can take. Somehow this anthracothere is similar to anthracotheres from other continents like northern Africa and northeastern Asia," Rincon said.

The research is published in the Journal of Vertebrate Paleontology.