Mosasaurs feasted on own kind

The mosasaur was a feared underwater predator that devoured other species and dominated the oceans millions of years ago, yet new evidence proves it also feasted on its own kind.

Mosasaur fossil on display in the Natural History Museum in Maastricht. Mosasaurs were marine reptiles that lived during the Late Cretaceous period between 66 and 99 million years ago. Its name means 'Meuse river lizard' because the first fossil remains were discovered in a quarry at Maastricht on the Meuse in 1764 [Credit: Florian Monheim/Arcaid/Corbis]

Remains of three mosasaurs were discovered in the fossilised belly of a fourth as researchers excavated sandstone cliffs off the coast of Bentiaba in Angola.

The three mosasaurs are shown as being fully digested because their tooth enamel had been dissolved by the predator’s stomach acid.

Palaeontologist Louis Jacob and Michael Polcyn from the Southern Methodist University of Texas made the discovery.

Polcyn told LiveScience it’s long been known mosasaurs ate other mosasaurs, but this fossil evidence proves the theory.

This image shows the fossilised skeleton of a mosasaur marine reptile discovered off the coast of Angola. The bones from three other species of mosasaur are show protruding from the stomach, pictured right. It is thought the predator feasted on the carcasses of its own kind which were washed up by ocean currents [Credit: Michael Polcyn]

However, it's unlikely the predator hunted the other three mosasaurs for food, instead it is believed to have feasted on their carcasses after something else had killed them.

Mosasaurs were marine reptiles that lived during the Late Cretaceous period between 66 and 99 million years ago. The first mosasaurs lived on land and were similar in size and shape to the monitor dragon.

Its name means ‘Meuse river lizard' because the first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764.

The creatures eventually took to the water and evolved tails with dorsal flukes and fins, similar to how orca whales look today. They also hunted in a similar way to orcas and were deadly predators at the top of the food chain.

Researchers from the Southern Methodist University of Texas also discovered the jaw of the mosasaur, pictured, while excavating sandstone cliffs in the Bentiaba region. The creature is believed to have grown up to 30 feet in length [Credit: Michael Polcyn]

The site of Bentiaba during the Cretaceous period would have been situated off the coast of Africa and it’s thought carcasses of mosasaurs and other marine life would have washed up there because of the ocean's currents.

Polcyn said this area would have been known as an upwelling zone, in which strong winds and currents cause nutrients on the bottom of the ocean up to rise up to the surface.

This would also have caused carcasses to float to the surface and towards the shore.

Researchers discovered the fossil of the mosasaur in Bentiaba in 2006 but couldn't excavate it until 2010. It is being prepared by fossil technicians before being analysed further.

'The incredible richness of the site continues to amaze us,' Polcyn said. 'Each year we return, there is another significant discovery.'

Author: Victoria Woollaston | Source: Daily Mail [November 05, 2013]