"Sea Monsters" found in desert

[Madame Butterfly 0]

Sea monsters found in desert

Judy Skatssoon

ABC Science Online

Wednesday, 25 May 2005

 

 

 

One of the marine reptile fossils found at the Boulia site. This nose once belonged to an ichthyosaur, which looked like a dolphin (Image: Ben Kear)

Australia is emerging as a missing link in the evolution of giant prehistoric marine reptiles, says a scientist who has discovered what may be a new species of plesiosaur.

 

A team from the University of Adelaide and the South Australian Museum unearthed the remains of the creature in Queensland, at what was once a vast inland ocean.

 

Palaeontologist Dr Ben Kear says he thinks the reptile discovered at the Boulia site may be related to a group of long-necked plesiosaurs known as elasmosaurs.

 

Kear says teeth found on its jawbone provide the best clue that scientists are dealing with something new.

 

The jaw has a mouthful of "very large fangs" bunched together at the front and "no other plesiosaur ever discovered has teeth like that", Kear says.

 

This potentially new species of plesiosaur is one of two plesiosaurs found recently at Boulia.

 

The other set of remains belong to a kronosaur, which Kear says was a fearsome predator resembling "a gigantic salt water crocodile with flippers instead of legs".

 

The two plesiosaurs were found with remains of prehistoric sea turtles, sharks and ichthyosaurs, reptiles shaped like dolphins.

 

The finds date back to the early Cretaceous period about 110 million years ago when the world's sea levels were at their highest and the Eromanga Sea covered much of central Australia.

 

 

 

This arid site was once part of a vast inland sea (Image: Ben Kear)

Kear says Australia's ancient marine reptiles provide a missing link in the fossil record.

 

"The beauty of the Australian deposits is that if you look globally at the early records of marine mammals you've got a lot of early stuff from Europe and a lot of very late stuff from the US.

 

"There's a critical gap around the early Cretaceous period and we're the missing link.

 

"Australia is turning out to be a critical evolutionary melting pot for all of these kind of animals."

 

Australia now has several plesiosaurs waiting to be described in addition to the ones at Boulia, including:

 

• Eric, a new species of leptocleidus found by an opal miner in the South Australian town of Coober Pedy in 1987

 

• what appears to be a polar plesiosaur discovered in South Australia in 1983, believed to be a species of cimoliasaurus, and

 

• polycotylid remains related to the so-called Richmond plesiosaur, which had a long snout and a crocodile's head.

 

Spread of the sea monsters

 

As continental masses began to break up during the Jurassic period of 200 million to 140 million years ago, plesiosaurs spread across the world via shallow coastal seas.

 

By the Cretaceous period the northern and southern continental masses were beginning to spread, marking the emergence of polar plesiosaurs in the south.

 

Australia's polycotylids may represent the beginning of this southern polar radiation, while Eric probably represents the last of a long line of Jurassic plesiosaurs commonly found in Europe, Kear says.

 

He says these marine giants are fascinating to study because plesiosaurs are unrelated to anything alive today.

 

"You're trying to reconstruct an animal that has no living relatives or even a living analogue," he says.

 

"It's beautiful mystery that we have to try and solve."

[sea trooper 0]

How did they discover my base?!?!