At the very least, the authors say, the elongated neck would have allowed the reptile to sneak up and lunge at its prey in murky waters close to shorebefore the creature's full profile scared off a potential meal.
Michael LaBarbera, a study co-author and an organismal biologist at the University of Chicago, suggested a second hunting strategy that employs the neck ribs.
According to LaBarbera, contraction of Dinocephalosaurus's neck muscles would create a rapid straightening of the neck, thrusting the head toward the prey. At the same time the neck ribs would have splayed outward, increasing the volume of the esophagus.
This increased volume is important, according to the researchers. It would have created a suction force that allowed Dinocephalosaurus to swallow the pressure wave that was created as the reptile lunged its head forward through the water.
Pressure waves can serve as a warning signal to prey. Several animals employ strategies to swallow these waves in order to attack more stealthily. Dinocephalosaurus, according to the researchers, was no different.
"Looking back at Tanystropheus, it probably had the same mechanism, but the mechanism was not recognized by scientists," Rieppel said.
Hans-Dieter Sues, the associate director for research and collections at the Smithsonian Institution's National Museum of Natural History in Washington, D.C., voiced caution about this interpretation. His doubts are based on his own examination of Tanystropheus neck vertebrae.
"The cervical ribs of tanystropheid reptiles are very long, spanning multiple vertebrae. I think that, because of these ribs, the neck would have always been held fairly straight, with quite limited side-to-side and even less up-and-down mobility," he said.
Sues, who is a member of the National Geographic Society's Committee for Research and Exploration, added that the neck ribs may have splayed a little; most vertebrates that feed underwater incorporate some suction in capturing prey.
The lead author of the paper, Chun Li of the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences in Beijing, discovered Dinocephalosaurus in 2002.
He had been looking for a protorosaurian in southern China for three years, with no luck. Back in a local village after another disappointing day in the field, he was told about some "coarse bones" in limestone a farmer had dug up for use as cement.
"Although the farmer misunderstood the extremely long neck of the monster as its tail, as most people would do, I knew that it was the long-necked protorosaur, which I had searched for for more than three years," Li said.
He added, "I realized that new and different information would be known from this specimen, although I didn't know what at that moment."
According to Sues, reconstructions of well-preserved protorosaurian neck vertebrae are needed to fully understand the biomechanics of the creatures' elongated necks. Such reconstructions do not yet exist.
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