Crocodile smile: Broad-jawed prehistoric caymen that could crush CLAMS with their teeth ruled Peru 13 million years ago

By Richard Gray For Mailonline

Scientists discovered seven species of caymen in Pebas, northern Perus
The area at the time 13m years ago was covered in a huge swampy wetland
The fossils show the area supported a ‘hyperdiverse’ crocodile population
Three of the fossils discovered are new species of broad-snouted caymen
One had a shovel-shaped snout and peg-like teeth for crushing shell fish
Snout-nosed crocodiles with jaws strong enough to crush clam shells ruled the swampy wetlands that covered Peru 13 million years ago.
Palaeontologists have discovered the remains of seven different species of crocodile and caymen, including three new species, in the area around the modern Amazon river.
The fossils were found in the Pebas district of northern Peru.
One of the new species, named Gnatusuchus pebasensis, had blunt, peg-like teeth and used its broad snout to dig shellfish from the muddy swamp floor.
It grew up to 5.2ft (1.6 metres) in length and had just 11 teeth. Most cayman, which are related to alligators, tend to have around 20 teeth.
Another blunt nosed crocodile was named Kuttanacaiman iquitosensis, which means ‘grinding or crushing machine’.
The scientists estimate it grew up to 6.2ft (1.9 metres) in length.
However, these new species were dwarved by two other previously known species of giant cayman whose fossils were also found nearby.
Purussaurus neivensis and Mourasuchus atopus are thought to have grown up to 39ft (12 metres) in length and were more generalised predators.
The researchers say that it is highly unusual to have found a habitat that had so many species of cayman living alongside each other.
There are six cayman species that live in the whole of the Amazon basin today, but only three are ever found in the same area and they rarely share the same habitat.
The large number of cayman found in Pebas has been described by the researchers leading the excavation as ‘hyperdiverse’.
Dr Rodolfo Salas Gismondi, from the University of Montpelier in France, said the huge wetland habitat that covered the area led to an explosion in the number of crocodile species.
He said: ‘We have uncovered this special momen in time when the ancient mega-wetaland ecosystem reached its peak in size and complexity, just before its demise and the start of the modern Amazon River system.
‘At this moment, most known cayman groups co-existed.
‘Ancient lineages bearing unusual blunt snouts and globular teeth along with those more generalised feeders representing the beginning of what was to come.’
The fossils may now help scientists unravel the evolutionary origins of cayman that live in the Amazon basin.
They describe the discovery in a paper published in the journal Proceedings of the Royal Society B.
The Gnatusuchus pebasensis name is derived from ‘Natu’, which is Quechua for ‘small nose’, along with the name of the village where it was found, Pebas, and the Greek for crocodile – Souchos.
The animal, which is new to science, is thought to have used its snout as a shovel in to search for shellfish in the muddy depths of the swamps.
Dr Salas Gismondi said: ‘When we analysed Gnatusuchus bones and realised that it was probably a head-burrowing and shovelling caiman preying on mollusks living in muddy river and swamp bottoms, we knew it was a milestone for understanding proto-Amazonian wetland feeding dynamics.’
The scientists also describe a third new species of prehistoric caymen called Caiman wannlangstoni, which they estimate grew up to 7ft (2.2 metres) long.
It is thought to have resembled the broad-snouted caymen that lives in fresh water marshes and swamps thought out central and eastern south America.
PREHISTORIC CROCODILES ‘RAN LIKE DOGS’ TO ESCAPE PREDATORS
Prehistoric crocodiles escaped the jaws of predatory dinosaurs by running like dogs, according to a study published last year.
The findings explain how the reptiles evolved in a dinosaur dominated world.
While most modern crocodiles live in freshwater habitats and feed on mammals and fish, their ancestors ran around on land like dogs while others adapted to life in the open ocean, imitating the behaviour of whales.
The study, by Bristol University, revealed how the jaws of the ancient crocodiles evolved to enable the fierce animals to survive in vastly different environments.
The team examined variation in the shape and biomechanics function of the lower jaws in over 100 ancient crocodiles during the Mesozoic – a period which began 251 million years ago and covered over 170 million years.
The study revealed that ancient crocodiles invaded the Jurassic seas and evolved jaws built primarily for water efficiency to capture agile prey, such as fish.
After the devastating extinction that ended the Triassic period, crocodile ancestors invaded the seas and evolved jaws primarily built to efficiently swim in the water to catch agile prey such as fish.
They also evolved a great variety of lower jaw shapes during the Cretaceous Period – about 145 million to 65 million years ago – as they adapted to a diverse range of niches and environments alongside the dinosaurs, including eating plants.
Instead, the fossil record points towards novel adaptations in other areas of their anatomy, such as armadillo-like body armour.

IMAGES:
The new species of caymen Gnatusuchus pebasensis (shown in the reconstruction above) had a short but wide jaw that was powerful enough to crush clams and other shell fish. It used its snout to dig in the mud
Scientists found fossilised remains of seven ancient caymen species in Pebas, northern Peru
The fossilised skulls shown above belong to the three new snout nosed caymen species Gnatusuchus pebasensis (a) Kuttanacaiman iquitosensis (b) and the much larger Caiman wannlangstoni (c)
Caiman wannlangstoni, one of the new species, resembled the broad snouted caymen

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