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24-Sep-2004

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New sea predator with a long neck

Journalist please note: Mandatory image credit: Copyright AAAS/Science/Illustration:



An artists rendition of Dinocephalosaurus orientalis, a long-necked sea reptile that probably preyed on fish and squid in a shallow sea in present-day southeast China more than 230 million years ago. The creature's relatively stiff, 1.7-meter-long neck (approximately five and a half feet) was almost twice as long as its trunk which measured less than one meter in length. Every effort has been made to ensure the accuracy of this illustration of Dinocephalosaurus orientalis. It must be noted, however, that the tail and soft tissues, including the muscles, were not preserved with the skeleton. Also illustrated: Saurichthys curionii and schools of semionotid fishes. Mandatory Image credit: Copyright AAAS/Science/ Illustration: Carin L. Cain.
Click here for a high resolution photograph.

Scientists have discovered a long-necked sea reptile with small fangs that swam in shallow seas in present-day China more than 230 million years ago. The water-loving reptile hunted fish and squid, according to a new study published in the 24 September 2004 issue of the journal Science.

Science author Chun Li from the Chinese Academy of Sciences in Beijing, China named the new reptile Dinocephalosaurus orientalis which means "terrible headed lizard from the Orient."



The Middle Triasic marine protorosaur D. orientalis is know from a skull (bottom inset) and a nearly complete skeleton. The structure of its hindlimb (top inset) documents fully aquatic habits. Image Science.
Click here for a high resolution photograph.

The scientists are most excited about the reptile's neck. At 1.7 meters (approximately five and a half feet) the neck is almost twice as long as the skeleton's one-meter-long body. Many thin and flexible rib bones called "neck ribs" run along the neck portion of the creature's spine.

When the scientists tried to figure out how this new creature used its long neck lined with neck ribs, they looked to the turtles and fish that hunt using a technique called suction feeding. By dropping the floors of their specially designed mouths, the turtles and fish increase space (volume) and decrease pressure inside their mouths. This pressure drop creates suction that causes nearby water (and the potential meal swimming in that water) to flow into the predator's mouth and throat.

Okay, but what does this have to do with the new reptile?

The neck ribs might have helped the reptile increase throat volume, decrease pressure levels in the throat and create a suction force that helped it hunt.



See above photo caption
Click here for a high resolution photograph.

The scientists suggest that this suction might have allowed the reptile to swallow invisible pressure waves it created as it lunged forward in the water to try to catch a meal. If the predator did not swallow these pressure waves, the waves could reach the potential prey. The prey would interpret these "danger signals" as something like, "Look out! Something is swimming in your direction!"

The scientists are not sure the reptile actually used its neck in this way. While they found almost all the bones, they found no sign of the muscles that moved the bones. Without these muscles, it's hard to say exactly how the animal hunted.

The authors describe a second way the reptile might have used its neck during hunting.

In murky water near the shore, the long neck could have made it hard for a fish to see the larger body at the other end of the neck. With this threatening profile hidden, the reptile might have been able to move into striking distance before the fish got scared and swam away.

No matter how the creature used its neck, the scientists are pleased to have found its skeleton. This is the first report of a reptile of its kind from China. It should help scientists better understand similar reptiles from around the world that lived hundreds of millions of years ago.

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