Giant Purussaurus neivensis Was South America's Apex Predator

Modern crocodiles rank among the planet's most feared predators, yet their ancient kin make present-day crocs look about as menacing as a cuddly kitten with a cold.

It took time to reach that point. Since crocodyliforms emerged more than 200 million years ago, they have passed through comparatively harmless phases of vegetarianism and even adopted a distinctly cat-like body form.

Eventually, however, evolution produced some truly outrageous forms that dominated their ecosystems with a scaly grip.

Purussaurus neivensis: a giant Miocene predator

Meet the cold-blooded Purussaurus neivensis, an ancestral relative of caimans that reached 7 metres in length and weighed 1,800 kilograms – roughly the mass of an average car.

First formally described in 1941 and named for the nearby Purus River, this colossal animal has been identified by a new study in the Journal of Vertebrate Paleontology as South America's apex predator during the Miocene, 23 million to 5.3 million years ago. That conclusion comes from the battered remains of its victims.

P. neivensis bringing down its prey, the mammal Pericotoxodon platignathus, in an artistic reconstruction based on existing fossil evidence. (Wilson et al., J. Vertebr. Paleontol., 2026/artist Miguel Hernandez)

By examining gruesome fossil traces recovered from Colombia's present-day La Tatacoa Desert, the researchers reconstructed these ancient crocodyliforms' hunting methods and bone-crushing strength.

The material comprises four fossils dating from 10.5 to 16 million years ago, all bearing evidence of a prehistoric assault: part of a skull, a femur, and two lower jawbones. They came from three kinds of ungulate – hoofed mammals that generally eat plants.

The dimensions and form of the bite marks indicate that these unfortunate ungulates were probably meals for P. neivensis.

One of the four fossil specimens presented: the skull of P. platignathus, bearing a puncture mark apparently made by P. neivensis. (University of Helsinki)

These plant-eating prey animals were formidable in their own right, with some members of their species potentially exceeding a tonne in mass.

They also possessed striking features, including tree-trunk-like legs, tusks and rhino-like bodies – as well as suitably weighty, Star Wars-style names such as Granastrapotherium snorki.

A reconstruction of G. snorki, one of the prey species assessed in this study. (Rextron/Wikimedia Commons/CC BY-SA 3.0)

"The frequency of marks likely made by Purussaurus suggests that it was an important predator in these tropical ecosystems," says Oscar Wilson, a vertebrate palaeontologist at the University of Helsinki and the study's lead author.

South America's predators before the Great American Biotic Interchange

Large placental mammal predators may dominate today's animal communities, but that was not invariably true.

Before the Great American Biotic Interchange – a major movement of land and sea animals between North and South America, rather like a continental Pokémon trade – other types of predator held prominent roles.

For instance, P. neivensis inhabited its environment alongside intimidating non-mammalian hunters, among them enormous madtsoiid constrictor snakes.

It also lived with phorusrhacid 'terror birds', whose enormous beaks and height meant that, standing on their lethal-clawed tiptoes, they could have dunked a basketball.

"There was so much prey available that mammalian predators couldn't have eaten it all," Wilson explains.

"Our new study shows that crocodylians in particular were the region's most important predators, especially when it came to hunting large prey."

Crocodilians and the hunt for giant prey

Evidence from living species supports crocodilians' taste for enormous prey.

Saltwater crocodiles (Crocodylus porosus), the biggest crocodiles alive today, can reach about 1,200 kilograms. They are known to target domestic horses and bulls, along with feral water buffalo in Australia.

Likewise, Nile crocodiles have been documented eating hippos and rhinos in Africa, although their ancient relatives may have hunted prey that was proportionally even larger, the researchers note.

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Taken together, the study tells a story of immense power preserved through the ages, recreating hunting episodes lost for millions upon millions of years.

To produce the fossil evidence studied here, P. neivensis may have seized unsuspecting victims by the head as they drank, crushed their skulls with a bite possibly more powerful than that of Tyrannosaurus rex, then torn them apart with the feared death roll.

In doing so, it may have aided its Miocene companions by leaving scraps behind.

Those aforementioned scraps: the terrestrial crocodyliform Langstonia huilensis scavenges the carcass of Xenastrapotherium kraglievichi. Its fossil mandible, examined in this study, bears marks consistent with scavenging as well as punctures probably inflicted by P. neivensis. (Wilson et al., J. Vertebr. Paleontol., 2026/artist Miguel Hernandez)

Finally, it sustained aquatic ecosystems by moving nutrients from land into the water – in its poo.

This research appeared in the Journal of Vertebrate Paleontology.

This article was fact-checked by Rachel Garner and edited by Rebecca Dyer. Although we take pride in our process, we are only human. If you notice an error, please let us know.