Meet the dinosaur that had a neck bigger than a school bus

A herbivorous sauropod that roamed what is now China some 162 million years ago had a neck about 3 meters longer than a typical school bus – and the longest of any known dinosaur.

The creature’s 50-foot neck would have allowed it to suck up surrounding vegetation – maximizing the amount of food it consumed while conserving energy.

The fossilized remains of the dinosaur, called Mamenchisaurus sinocanadorum, were discovered in 1987 in northwest China’s Xinjiang region and first described in a 1993 scientific paper. The dinosaur was named after the joint Chinese-Canadian team that unearthed the fossil.

In a new analysis of the fossil published in the Journal of Systematic Paleontology on Wednesday, paleontologists used computerized scanning of topography that wasn’t widely available three decades ago to compare M. sinocanadorum with other related sauropods unearthed in recent years. .

“Mamenchysaurids are important because they surpassed the limits of the length of a neck and were the first lineage of sauropods to do so. With a 50-foot-long neck, it looks like Mamenchisaurus sinocanadorum could be a record-breaker — at least until something longer is discovered,” said study lead author Andrew Moore, a paleontologist and assistant professor at Stony Brook University in New York. York in a study.

Paleontologists were able to infer neck length by studying the specimen’s three preserved vertebrae and comparing them to the neck bones of closely related dinosaurs.

“We actually know who it’s related to, which provides good comparisons. In this case, it’s nestled very evolutionarily within a lineage that we know has 18 cervical (neck) vertebrae,” explained Moore.

“We can scale up the comparators to find the absolute neck length.”

The longest complete neck documented by scientists belongs to a fossilized dinosaur called Xinjiangtitan, Moore said, and was about 1.5 meters shorter than the neck of M. sinocanadorum.

Hollow bones lighten the load

The study also revealed intriguing details about these huge dinosaurs.

Similar to the lightweight skeleton of a bird, M. sinocanadorum bones were filled with air rather than marrow, which is a feature of most mammalian bones. Computed tomography scans showed that air accounted for 69% to 77% of the volume of the vertebrae.

“Presumably this is an important mechanism for building such a long neck, because it will be very heavy,” Moore said.

While the posture of some sauropod species might have an erect, swan-like neck, Moore said biomechanical studies suggested that the Mamenchisaurid’s neck was elevated at an angle of about 20 to 30 degrees above the horizontal.

However, even at this relatively shallow angle, the extreme length of the neck still means the animal’s head can reach heights of around 7.5 meters to 10 meters above the ground.

The sauropod’s evolutionary adaptations — gigantic size and vegetarian diet — have no modern equivalent, according to the study. But the lineage of these long-necked dinosaurs was very successful, with different species of sauropods appearing early in the age of dinosaurs and thriving until their extinction 66 million years ago.

“They are apparently well designed to be efficient food gatherers and that’s what the neck allows them to do… plant themselves in a space, eat the vegetation that is around them and then move only when necessary.

“As for why Mamenchisaurus among sauropods had relatively longer necks? Maybe it’s much more efficient. … It’s hard to say, but it’s clearly something central to their biology.”