Gigantic 23-Foot-Long Crocodile Ancestor Had "T. Rex-Like" Teeth


Robin Andrews

Science & Policy Writer

This creature weighed around a tonne. Fabio Manucci

The teeth of a Tyrannosaurus rex – which were essentially like serrated bananas – were the key to its success. Sure, its bite was powerful enough on its own, but the razor-sharp blades adorning its jaws were able to generate record-breaking pressures that could pulverize bone.

These teeth weren’t unique to the “Tyrant Lizard King” of course – something like that that’s so effective at killing prey is certain to have evolved on more than one occasion. Enter the Notosuchia, a group of crocodile-like beasts that – among a mosaic of other unusual physical adaptations – sometimes also featured some very T. rex-esque teeth, according to a new study in PeerJ.


Meet the Razanandrongobe sakalavae (“large ancestor lizard from Sakalava” in the local Malagasy dialect), which plodded around Madagascar during the Middle Jurassic no earlier than 174 million years ago. It is a distant ancestor of modern-day crocodiles, and part of the overarching archosaur group that includes dinosaurs, both living (birds) and extinct, as well as turtles and pterosaurs.

Nicknamed Razana, probably to save time, this 7-meter-long (23-foot) reptilian monster was armed with enormous serrated teeth that are similar in size and shape to those belonging to the T. rex, which wouldn’t make an appearance for another 106 million years. Some of the gnashers were 15 centimeters (around 6 inches) long.

This indicates that this particular predator, as well as eating smaller beasts, could also annihilate hard tissues, like the bones and muscle tendons on larger animals.

Eek. Fabio Manucci

Back when it was alive, Razana would have sprinted after its prey on all-fours, or snuck up on its dinner beneath the water of the swamps or rivers of the southern supercontinent Gondwana, before quickly trapping them in its terrifying maw. It would have been an apex predator, powerful enough to challenge even the most fearsome of two-legged carnivorous dinosaurs.


“Like these and other gigantic crocs from the Cretaceous, Razana could outcompete even theropod dinosaurs, at the top of the food chain,” Cristiano Dal Sasso, a renowned paleontologist at the Natural History Museum of Milan, said in a statement.

In terms of its evolutionary history, Razana is a primitive Notosuchia, perhaps the very first of their kind. From this point onwards, its descendants spread across the world and diversified into a veritable menagerie of monsters during the Cretaceous Period, the final chapter in the age of the dinosaurs.

Some became herbivorous, whereas others became omnivores. Many became “hypercarnivores”, animals that have diets of at least 70 percent meat. Others took a very different path and ended up with mammal-like teeth, fleshy cheeks, pig-like snouts, and even body armor similar to armadillos.

Modern crocodiles, which survived the asteroid impact, appeared around the time the T. rex made its debut.


  • tag
  • evolution,

  • jurassic,

  • teeth,

  • extinction,

  • T. rex,

  • crocodile,

  • Madagascar,

  • gigantic,

  • crocodile-like