70-million-year-old apex predator who ate dinosaurs found in Patagonia, named after Egyptian god

K. atrox was hypercarnivorous, meaning meat made up over 70 percent of its diet. (Image: Gabriel Diaz Yanten, CC-BY 4.0 )

Imagine walking through Patagonia 70 million years ago. Instead of quiet plains, you might have spotted a massive reptile lurking. A crocodile-like hunter lived here, sharing space with dinosaurs.

What was this predator called?
The creature is named Kostensuchus atrox. Its name combines the fierce Patagonian wind called “the Kosten” with Sobek, the crocodile-headed god from Egypt also known as Suchus.

Researchers say the reptile stretched about 11.5 feet long. It weighed nearly 250 kilograms, making it a powerful mid-sized predator.

When and where was it discovered?
The fossilised skeleton was found in 2020 in southern Patagonia. The bones were preserved in the Chorrillo rock formation, an important site for Cretaceous life.

K. atrox was hypercarnivorous, meaning meat made up over 70 percent of its diet. With a broad snout, large teeth, and strong forelimbs, it was built to take down prey.

Was it unique among crocodiles?
Yes, K. atrox belonged to peirosaurid crocodyliforms, now extinct relatives of modern crocodiles. According to scientists, its fossils are among the best preserved of this group, and it is the most complete broad-snouted member ever recorded.

Indeed, it shared its habitat with many dinosaurs. Around the same time, researchers also found Maip macrothorax, a huge megaraptor about 10 metres long. While smaller than M. macrothorax, K. atrox was strong enough to prey on small- to medium-sized dinosaurs.

Why is the discovery important?
Study lead author Fernando Novas said these findings show crocodylians were diverse and abundant in South America during the Cretaceous. They included both meat-eating and plant-eating types. Novas described the continent as a “land of crocs”, where crocodiles not only coexisted with dinosaurs but also often competed with them.

The research appeared on 27 August in the journal PLOS One. Scientists say the discovery helps explain how ancient ecosystems worked and highlights the role of crocodiles in shaping them.