Everyone knows crocodilians have been around a long, long time, but the common claim that they’re “virtually unchanged” from the time of the dinosaurs is a little disingenuous: Case in point: Anthracosuchus balrogus, a 900-lb, 16-foot long dyrosaur discovered in South America by researchers from the Florida Museum of Natural History. One look at the header image is all you need to know that it has very little in common with today’s comparatively diminutive crocs and gators.

Balrogus, which tangled with enormous ancient snakes and turtles in the Amazon Rainforest for a few million years after the dinosaurs went extinct, gets its name from the “Balrog” creature mentioned in J.R.R. Tolkien’s The Lord of the Rings series. Like the fictional Balrog, balrogus was found deep within a mine. This one happened to be the Cerrejón coal mine of northern Colombia, not the Mines of Moria, but still a mine all the same.

Balrogus, along with two other intrepid ancient crocodilian species, is believed to have ambled its way across the Atlantic from Africa some 75 million years ago. They adapted to a freshwater ecosystem that was far warmer and swampier than it is now, and even managed to survive the mass-extinction that killed off the dinosaurs. That adaptation, scientists say, might be useful in determining how animals might adapt in the face of climate change.

“This group offers clues as to how animals survive extinctions and other catastrophes,” Alex Hastings, a postdoctoral researcher at Martin Luther Universität Halle-Wittenberg and former graduate student at the Florida Museum of Natural History, said in a statement. “As we face climates that are warmer today, it is important to understand how animals responded in the past. This family of crocodyliforms in Cerrejón adapted and did very well despite incredible obstacles, which could speak to the ability of living crocodiles to adapt and overcome.”

Other fossils uncovered in Cerrejón include Titanoboa, a 48-foot long snake, as well as fossils of turtles with shells as thick as textbooks. Based on the size of balrogus’ head, neither of those sound like they were much of a problem.