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The neck of a plant-eating dinosaur that walked around China 162 million years ago was approximately 10 feet longer than the average school bus. It also had the longest neck of any known dinosaur.
The creature's 49.5-foot (15.1-meter) long neck would have allowed it stand in one place and pick up all the vegetation around it -- maximising its food intake while conserving energy.
Mamenchisaurus sinocanadorum was the first scientific paper to describe the fossilized remains of this dinosaur. They were found in China's northwest region of Xinjiang in 1987. Named after the Chinese-Canadian joint team that discovered the fossil, the dinosaur was also named.
Paleontologists used computerized topography scanning, which was not widely available in three decades ago, to analyze the fossil and compare it with other similar sauropods discovered in recent years.
"Mamenchisaurids were important because they broke the limit on the length of a neck and were the first sauropod line to do so. It looks like Mamenchisaurus Sinocanadorum may be the record-holder with a neck that measures 15 meters long,' stated Andrew Moore, study lead author and assistant professor at Stony Brook University in New York.
Paleontologists were able infer the length and shape of the neck from the three preserved vertebrae of the specimen. They also compared them to the neck bones of closely related dinosaurs.
"We happen to know the relative of this particular species, which allows us to make nice comparisons. Moore explained that in this case it is well nested evolutionaryally within a lineage we know to have 18 cervical (neck), vertebrae. Moore explained that we can use the comparators to determine absolute neck length.
Moore claimed that the fossilized dinosaur Xinjiangtitan has the longest complete neck. It was approximately 5 feet (1.55 meters) shorter than M. sinocanadorum's neck.
Hollow bones help to lighten the burden
This study revealed fascinating details about the massive dinosaurs. M. sinocanadorum's bones, similar to a bird's lightweight structure, were filled with air rather than marrow. This is a common characteristic of mammal bones. CT scans revealed that 69% to 77% (or more) of the volume of the vertebrae was made up by air.
Moore stated, "Presumably that's an important mechanism to build such a long neck, because that's going get quite heavy,"
Moore stated that while some sauropod species may have had a neck held straight in swanlike fashion, Moore claimed that biomechanical studies indicated that the Mamenchisaurid neck was raised at an angle of 20-30 degrees above the horizontal.
Nevertheless, even though the angle is relatively low, the neck's extreme length could still mean that the animal's head could reach heights around 24.6 to 32 feet (7.5 to 10 meters above the ground).
According to the study, the evolutionary adaptations of the sauropod -- its enormous size and vegetarian diet -- are not comparable to modern times. The lineage of long-necked dinosaurs was successful. Different sauropod species appeared in the early stages of the dinosaur era, and continued to thrive until their extinction 66 millions years ago.
They are apparently well-engineered to gather food efficiently and the neck allows them that ability.
"Why did Mamenchisaurus among sauropods have longer necks?" It could be that it is just more efficient. It's difficult to say, but it is clearly a central part of their biology.