In the animal kingdom, there are only four true species of crocodiles and six species of alligators. These numbers are vastly different compared to about 5 million years ago when there were a total of 14 different species of crocodiles.

Today, no more than two or three species live within close proximity of each other when millions of years ago seven species of crocodiles occupied the same region. A team of paleontologists at the University of Zurich revealed this updated information on these aquatic reptiles.

Crocodiles, at times referred to as true crocodiles, live in tropical areas of Africa, Asia, Australia and North and South America. A large amount of very diverse species of crocodiles lived in areas that no longer exist like the Urumaco, a river that was once located in the Gulf of Venezuela.  

Scientists discovered two new crocodile species while they were studying ancient crocodiles from the Miocene in the area of what once was the Urumaco. The new species found are known as the Globidentosuchus brachyrostris, which had sphere-shaped teeth and belonged to the caiman family, and also the species Crocodylus falconensis, which researchers theorized grew to over four meters or 13 feet long.

Paleontologist Marcelo Sanchez discovered that all of the crocodiles that exist around the globe today are included in Venezuela's fossils.

"There were no predators back then in South America that could have hunted the three-meter-long turtles or giant rodents. Giant crocodiles occupied this very niche," paleontologist Torsten Scheyer said.

This includes the Crocodylidae which are called the true crocodiles; the Alligatoridae, which are the true alligators (also include caimans) and the Gavialidae, which are found today dwelling in Southeast Asia and are known for their extremely long, thin snouts.