Slurp. The most complete skeleton of Dinocephalosaurus suggests that it could have sucked prey into its mouth by contracting its neck.

Vacuum Predator of the Triassic

Staff Writer

Sneaking up on an unwary fish in dim waters, the 4-meter-long reptile is poised to strike. Its long neck, pulled back in a sideways "S," suddenly straightens, whipping the head forward. Sucking in liters upon liters of water, the animal grasps the fish with its fangs. This previously unknown style of predation, in which the expansion of a neck creates suction, has now come to light thanks to a new skeleton of the long-extinct reptile, Dinocephalosaurus orientalis.

This hunter swam in shallow seas 230 million years ago, in what is now southeast China. It was a protorosaur, a primitive reptile of which about a dozen genera are known. Many other kinds of reptiles swam in the Triassic oceans, but only the protorosaurs had elongated necks. Many millions of years later, in the Jurassic and Cretaceous periods, marine reptiles such as the elasmosaurs also evolved elongated necks. Elasmosaurs did this by adding vertebrae during development, which gave them great flexibility.

According to the new specimen of Dinocephalosaurus, the Triassic reptiles extended their necks in a different way. The specimen's neck has only 25 vertebrae, but they are stretched--up to 2.75 times longer than vertebrae in the rest of the body. The neck of the specimen was 1.7 meters in length. "It is particularly long for the Triassic," says paleontologist Olivier Rieppel of the Field Museum in Chicago.

Also unique is that the neck vertebrae have elongated cervical ribs that run parallel to the neck. This should have given the neck some added stiffness, and because muscles attached to these neck ribs, provided it with extra power to move. When the neck straightened, the rib would expand the throat and create suction to pull in squid and fish, the team speculates. Rieppel and his colleagues--Michael LaBarbara of the University of Chicago and Chun Li of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing--describe the fossil in the 24 September issue of Science.

The idea of suction hunting is raising eyebrows among vertebrate paleontologists. "Nothing comes to mind that does that today or in the fossil record," says Glenn Storrs, who studies fossil marine reptiles at the Cincinnati Museum Center in Ohio. "It's an unusual animal."

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Posted in Paleontology