Mesozoic World

The fossilised remains of a crocodile, Dakosaurus andiniensis, which ruled the oceans 140 million years ago were discovered in Patagonia in 2005.

The US-Argentine team of researchers behind the discovery nicknamed the creature 'Godzilla', because of its dinosaur-like snout and jagged teeth. The team believed that the animal was a ferocious predator, feeding on other marine reptiles and large sea creatures. The findings were unveiled in the journal Science.

Strange morphology

Unlike modern crocodiles, it lived entirely in the water, and had fins instead of legs. It measured four metres (thirteen feet) from nose to tail and its jaws alone were 33% of a metre long (one foot).

Crocodiles became widespread during the Cretaceous period (146 to 65 million years ago). Other marine crocodiles alive at the same time had long, slim snouts and needle-like teeth which they used to catch small fish and molluscs. But this creature had a dinosaur-like snout and large, serrated teeth.

While features of this type are present in carnivorous dinosaurs like Tyrannosaurus rex, it showed an unexpected morphology which nobody thought could be present in a marine crocodile.

Family tree

Palaeontologist Zulma Gasparini, of the National University of La Plata, Argentina, first came across a 'Godzilla' specimen in 1996 in the Neuquen Basin, once a deep tropical bay of the Pacific Ocean. But it was little more than a fragment and it provided few clues to the creature's nature and habits.

However, two further specimens were more recently discovered, including a complete fossilised skull. Computer analysis of the bones showed that D andiniensis belonged on the family tree of crocodiles. The experts believed that it evolved a different feeding strategy from that of its contemporaries.

The shape and size of its jaws and teeth suggested that it hunted large marine vertebrates such as the giant marine reptile, Ichthyosaurus, rather than small fish.

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