Later that year, in the same marine limestone, Li discovered a nearly complete skeleton of China's first protorosaur. This skull measured 15.5 centimeters in length (about 6 inches).
While Tanystropheus had a giraffe-style neck comprised of a small number (12) of extremely elongated neck or cervical vertebrae, the new fossil's long neck contains 25 somewhat less elongated neck vertebrae.
With relatively short and broad limbs containing few bones, Dinocephalosaurus, more than other protorosaurs, appears fully designed for life in the water. Though protorosaurs with more extensive bony limb structures would have had an easier time on land, Chun Li said Dinocephalosaurus may have ventured onto land to lay eggs.
To breathe, Dinocephalosaurus probably held its neck parallel to the water's surface. Extending the head and neck vertically to gulp air would have been impossible because surrounding water pressure would have prevented the lungs from inflating.
Both Dinocephalosaurus and Tanystropheus have rib-like bones that extended parallel to the neck vertebrae, bridged the space between vertebrae and restricted neck movement. (These ribs prevented the extreme neck flexibility seen in herons, for example.) The authors report that Dinocephalosaurus' long neck presumably served a functional role in hunting and present two possible strategies.
With its long slender neck and small head, the reptile may have been able to sneak up and lunge at a fish or other aquatic prey in murky near-shore waters before the predator's full profile scared off the potential meal.
Based on Dinocephalosaurus' tooth and fang arrangement which is unlike other protorosaurs, the creature could have attacked with jaws opening sideways like a crocodile.
Coauthor Michael LaBarbera from the University of Chicago in Chicago, Illinois proposed a second hunti
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Contact: Jessica Lawrence-Hurt
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American Association for the Advancement of Science
23-Sep-2004