Scientists Discover Terrifying Prehistoric Crocodile That Weighed 6,000 Pounds

The newly discovered Machimosaurus rex may have roamed southern Tunisia about 130 million years ago.

An extraordinary crocodile that terrorized the seas some 130 million years ago has been discovered, and scientists are going gaga.

Paleontologist Dr. Federico Fanti and his colleagues recently unearthed a skull and other fossilized bones in southern Tunisia that belong to the prehistoric beast Machimosaurus rex. Their research, which was supported by the National Geographic Society Committee for Research and Exploration, was published in the journal Cretaceous Research on Monday.

"We were very happy to find out that several skeletons of this new species were fossilized in very good condition," Fanti, a researcher at the University of Bologna in Italy, told The Huffington Post.

Open Image Modal
Federico Fanti and his colleagues next to the newly discovered skull and fossils of the giant marine crocodile Machimosaurus rex.
Federico Fanti

The fossils indicate that M. rex belonged to a group of crocodiles that inhabited the sea and coastal areas around the end of the Jurassic Period, but the species is not directly related to modern-day crocodiles, Fanti said.

It was also a whole lot bigger: The creature weighed three tons and likely grew to more than 30 feet long, National Geographic reported. Scientists believe M. rex had a powerful bite and short, stocky teeth. It likely ate turtles and fish, and may have scavenged for food as well.

"It would likely have been something of an ambush predator, hanging around in shallow water hunting turtles and fishes and maybe waiting for some land animals to come a little too close to the shore," Dr. Stephen Brusatte, a paleontologist at the University of Edinburgh in Scotland who was not involved in the new research, told National Geographic. "This is a neat new discovery from a part of the world that hasn’t been well-explored for fossils."

Open Image Modal
An illustration of Machimosaurus rex, based on the newfound fossils (in white). The drawing shows that the creature would have dwarfed a human.
Marco Auditore

The remains of other species that belonged to the extinct Machimosaurus genus of crocodiles have been discovered in Europe and North America. Analyses of those fossils reveal that the marine crocodiles were affected by a mass extinction near the end of the Jurassic Period.

However, the newly discovered remains of M. rex show that the species was still alive at that time, and may have continued to thrive for another roughly 25 million years after the supposed extinction event in other parts of the world, Fanti said.

"Therefore, this discovery sheds new light on the hypothesized mass extinction event at the end of the Jurassic -- a biological crisis currently much less understood than the famous extinction at the end of the Cretaceous that wiped out the dinosaurs," he added.

Also on HuffPost:

Dinos Dining: Prehistoric Predators
Leviathan(01 of17)
Open Image Modal
A 36-foot-long Pliosaurus attacks the plesiosaur Cryptoclidus, a marine reptile from the Late Jurassic Period. Also shown: the fish Pachycormus, a shoal of the belemnite Belemnoteuthis, and the ammonite Pectinatites.Acrylic Painting, 2008. (credit:Robert Nicholls)
Rugops Primus Environmental Scene(02 of17)
Open Image Modal
The scavenger Rugops, a dinosaur from the Late Cretaceous that lived in what is now Africa, driving a trio of the pterosaur Tupuxuara from the corpse of the sail-backed iguanadontid Ouranosaurus. The crocodylomorphs, relatives of the modern crocodile, are the 'boar-croc' Kaprosuchus. (credit:© Todd Marshall)
Double Death(03 of17)
Open Image Modal
Working together, a pair of Carcharodontosaurus saharicus, one of the largest carnivorous dinosaurs, steal away a juvenile Paralititan stromeri from its family herd. Paralititans were swamp-dwellers that grew to be one of the largest creatures to ever roam the Earth.Mixed media, 2011. (credit: © Robert Nicholls)
Ammonite Graveyard(04 of17)
Open Image Modal
Ammonites, so called after the Egyptian god Ammon, were carnivorous squidlike animals that could be over 3 feet in diameter. Here, several ammonites decay on the sea floor.Material: Gouache, 2011. Based on a prepared slab in Ulster Museum. Courtesy of A. Cowap. (credit: © John Sibbick)
Reaper In Paradise(05 of17)
Open Image Modal
The giant crocodile, Deinosuchus riograndensis, attacks an Albertosaurs, a smaller relative of the Tyrannosaurus, in Late Cretaceous North America, 75 million years ago.Acrylic painting, 2003. (credit: © Robert Nicholls)
Mammoths And Saber-Toothed Cats(06 of17)
Open Image Modal
A pride of Smilodon fatalis, often called a saber-toothed cat, attacks a calf belonging to a herd of mammoths while the mother moves to protect her offspring. Digital painting (credit: © Mauricio Anton)
Aucasaurus Attacking Titanosaur Nests(07 of17)
Open Image Modal
During the Late Cretaceous (85 million years ago) Aucasaurus, a pack-hunting dinosaur, attacks a group of startled titanosaurs in Argentina. Pushing past the adults guarding their nests, the Aucasauruses snap up the babies as they hatch.From National Geographic, March 2003, 'Dinosaurs - Flesh & Bone' (credit: © John Sibbick)
Gallimimus Bullatus & Tarbosaurus Bataarm(08 of17)
Open Image Modal
Tarbosaurus, a predatory reptile that lived 70 million years ago in parts of Asia, chases two Gallimimuses, ostrich-like dinosaurs that could grow nearly 30 feet long.Digital Art, 2010. (credit: © John Conway)
One Split Second: Triceratops Vs. Tyrannosaurus Rex(09 of17)
Open Image Modal
The T-Rex probably preyed on Triceratops, because their territories overlapped 65 million years ago. While the T-Rex had its famous bite to use for a weapon, triceratops' powerful horns were a formidable defense. Digital Painting/photographic composite. 2011. From the Golden Book of Dinosaurs, by Robert Baker/Rey. (credit: © Luis Rey)
Ambush In The Late Miocene Of Florida(10 of17)
Open Image Modal
This scene shows a prehistoric rhino struggling to escape the sharp claws of two saber-toothed cats.From left to right: Aelurodon, Teleoceras (rhino), Barbourofelis (saber-tooth), Neohipparion (horse), Aepycamelus (giraffe-like camels), Synthetoceras. (credit: © Mauricio Anton)
Smilodon & Paramylodon (11 of17)
Open Image Modal
A Smilodon, or saber-toothed cat, dispatches a ground sloth trapped in tar during the Ice Age in North America.Digital painting. (credit:© Mauricio Anton)
Beelzebufo Ampinga(12 of17)
Open Image Modal
A huge toad from the late Cretaceous of Madagascar that may have grown to over 16 inches long and could have weighed up to 9 pounds. It was certainly big enough to eat baby dinosaurs. Acrylics on illustration board, 2007. (credit:© Todd Marshall)
Cretaceous Rodeo (Aka T-Rex Family Life)(13 of17)
Open Image Modal
The Tyrannosaurus rex was one of the most formidable predators of all the dinosaurs. The 40-foot-long carnivore had teeth up to twelve inches long. However, there is a debate among paleontologists over whether the T-Rex was an apex predator or a scavenger.Acrylics & ink on cardboard, 2004. (credit:© Luis Rey)
Devourer Of Giants(14 of17)
Open Image Modal
Five million years ago, several Anacus - a straight-tusked member of the elephant family - have been caught in a flash flood and drowned. Washed out to sea, they attract two adult and a juvenile mega-shark named Carcharodon megalodon - at around 60 feet, probably the largest shark known.Acrylic painting, 2000. (credit:© RObert Nicholls)
Pristichampsus Attacking Early Horses(15 of17)
Open Image Modal
Pristichampsus is an extinct crocodile relative that could grow up to 10 feet long. The armored reptile lived mostly on land, and fed on land mammals like these early horses.Detail from composite scene for the TV show Animal Planet.Gouache (credit:© John Sibbick)
Megantereon Attacking Bushbuck(16 of17)
Open Image Modal
Megantereon, an early saber-toothed cat, may have eaten young rhinos, elephants, and horses. The felines probably bit their prey on the neck to kill them, and then let them bleed to death, like the bushbuck pictured here.Kromdraai A, Early Pleistocene of South Africa. Colored pencils, from Evolving Eden (Columbia University Press) (credit:© Mauricio Anton)
(17 of17)
Open Image Modal
Photos courtesy Titan Books

Our 2024 Coverage Needs You

As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.

Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.

to keep our news free for all.

Support HuffPost