The biggest known crocodile has been found—and the 27-foot-long (8.3-meter-long) predator likely swallowed early humans whole, a new study says.

Crocodylus thorbjarnarsoni lurked in deep lakes near present-day Lake Turkana in Kenya (map) between about two and four million years ago.

Fossils of the giant were unearthed in the Lake Turkana Basin in the 1960s and '70s and stored in the National Museums of Kenya in Nairobi. The study authors only recently identified the remains as belonging to a new species.

View Images Sizes of the new croc, a Nile croc, an early human, and a modern human. Illustration courtesy Christopher A. Brochu, University of Iowa

According to their research, the ancient animal would've resembled a heavyset Nile crocodile, some of which can reach up to 20 feet (6 meters) long.

Other species in the wider category of crocodyliforms—part of a group that includes modern-day alligators, caimans, and more—are bigger, such as the 40-foot-long (12-meter-long) SuperCroc.

But the newfound behemoth is the biggest known true crocodile, said study leader Christopher Brochu, a paleontologist at the University of Iowa.

The largest living crocodile captured so far is likely Lolong, a 20.3-foot (6.1-meter) long saltwater crocodile discovered in the Philippines in 2011.

Giant Croc Swallowed Humans Whole

The prehistoric reptile likely got so big from eating plentiful large prey—including our ancestors, who at the time stood about 4 feet (1.2 meters) tall as adults.

These early humans may have been ambushed by the giant crocs when they went to collect lake water, Brochu said.

"It put our ancestors in a bad situation—you die if you don't drink, you may die if you do," he said. "It's the roll of the dice."

For now, there's no direct evidence of these ancient encounters, such as bite marks on human remains, Brochu noted.

But that isn't too troubling, said Alex Hastings, a University of Florida graduate student in vertebrate paleontology who wasn't involved in the new study.

When C. thorbjarnarsoni gobbled an early human, "the whole thing [probably went] down the gullet, so nothing gets fossilized," said Hastings, who discovered a prehistoric crocodile species in 2011.

"Crocodiles have very powerful stomachs—they swallow rocks to help mash up [bones], and everything comes out the end in one homogeneous mess," he said. (See alligator and crocodile pictures.)

Hastings thinks the new study is "giving us a much clearer picture of the dangers and threats that early man was faced with."

For instance, "we often think of ourselves as apex predators and kings of our environment, but in many given situations, we are not the top of the food chain."

Crocs Not Living Fossils

The newfound crocodile also helps to "debunk this myth that crocodiles are living fossils," said study leader Brochu, whose paper was published May 3 in the Journal of Vertebrate Paleontology.

In recent years, Brochu and other scientists have found a wealth of extinct crocodiles and croc relatives of various shapes and sizes, suggesting that the group is much more diverse than thought.

Croc "evolution is just as complex and rich as [that of] any other group," Brochu said.