Large crocodile
A salt water crocodile named "Too Long" holds a 6.5 kg pig head in its mouth during feeding time inside a crocodile park in Pasay city, metro Manila April 10, 2013. "Too Long" is approximately 16 feet (4.9 metres) long and is the largest salt water crocodile in the capital, an official of the crocodile park said. Reuters/Romeo Ranoco

The fossil of the world’s biggest ocean-dwelling crocodile has been found in the Tunisian desert. Palaeontologists named this croc Machimosaurus rex, which grew 9.6 metres long and weighed as much as three tonnes, a prehistoric predator that was twice the size of any crocodile seen today.

Lead author Federico Fanti from the University of Bologna in Italy described the animal as massive; even its skull is more than 5 feet long, just the same size as the scientist. Although little remained of the animal, it was enough to enable the researchers to identify it as the largest-known member of crocodiles that was the top predator in an ocean that separated Africa from Europe 130 million years ago.

Fanti, who was supported by the National Geographic Society, said that Machimosaurus rex was not as big as its relatives that lived in freshwater like the Sarcosuchus imperator, the biggest freshwater croc that grew up to 12 metres long and weighed up to eight metric tonnes. Nevertheless, its massive skull and short, stocky and round teeth suggest that it had a remarkable bite force that was capable of crushing large marine turtles.

Palaeontologist Stephen Brusatte from the University of Edinburgh who was not part of the study told National Geographic that the croc could have been an ambush predator lurking around in shallow water hunting turtles and fishes, and it probably also waited for some land animal to come too close to the shore.

Interestingly, the scientists believe that the discovery supports the theory that not all animals went extinct due to a mass extinction, if there ever was one. Brusatte suggests that this is evidence that a lot of marine reptiles survived the alleged extinction.

Machimosaurus was part of a group called the teleosaurids, which is thought to be among those that died during the extinction at the end of the Jurassic period 145 million years ago. Instead, the researchers claim that a complex sequence of local biological problems led the extinction of these animals rather than a rapid annihilation.

Other experts have also wondered why marine crocodiles were not able to reclaim their glory and thrive. Brusatte asserted that Machimosaurus rex was just a dead croc walking despite possessing an impressive size.