A neck of more than 15 meters for the Mamenchisaurus sinocanadorum
Artistic illustration of sauropod species 'Mamenchisaurus sinocanadorum' which had a neck 15 meters long.
A sauropod dinosaur that inhabited East Asia 162 million years ago had an impressive neck 15.1 meters (50 feet) long, shows a new estimate by an international team led by American paleontologist Andrew Moore of Stony University Brook.
Sauropods were large plant-eating dinosaurs, already known for their long limbs. Among these, the Mamenchisaurus sinocanadorum was the overall champion: it had the longest neck of all!
By comparison, its neck was six times longer than that of a giraffe, the longest-necked animal alive today, and was about 10 feet longer than a typical school bus.
- The first sauropods appeared in the Triassic, around 210 million years ago. It was not until the Jurassic, however, that they became gigantic and diverse.
- The last ones disappeared 66 million years ago, at the end of the Cretaceous, at the same time as& #x27;a large number of other animals.
- These herbivorous quadrupeds usually lived in herds.
Establishing which of the sauropods had the longest neck is not easy. It is difficult to properly describe the largest sauropods since finding complete fossilized specimens is a challenge due to their immense size, explain in a press release the authors of this work published in the Journal of Systematic Palaeontology(in English).
Some fragmentary fossils suggested that species of sauropods developed necks over 10 meters in length, but poor preservation of specimens made these estimates rather imprecise.
In the case of Mamenchisaurus sinocanadorum, the first fossilized remains were discovered in 1987 in rocky sediments in Xinjiang, northwest China, by the China-Canada Dinosaur Project team, after whom it was named in 1993.
Paleontologist Andrew Moore and his colleagues were able, from a handful of neck and skull bones, to compare it with other more complete skeletons of relatives, including Xinjiangtitan, a 13-meter (44-foot) sauropod discovered in 2013 and the previous record holder for the longest neck.
This work led to the conclusion that the Mamenchisaurus sinocanadorum had a neck about 15.1 meters long, the longest neck that can be inferred with certainty for a known sauropod, the researchers note.
This work is part of a larger research aimed at documenting the anatomical diversity and evolutionary history of the family Mamenchisauridae, sauropod dinosaurs that lived in Asia during the Jurassic.
The way these sauropods managed to grow such a long neck and such a massive body without collapsing under their own weight remains a biomechanical puzzle.
Specimens like Mamenchisaurus sinocanadorumhowever, provide some clues. CT scans show that his bones were mostly air (between 69 and 77% of their volume), which is comparable to percentages seen in bird skeletons.
Such a light skeleton may suggest that the beast was likely to be injured easily. This was not the case since the Mamenchisaurus sinocanadorum also had cervical ribs in the form of rods 4 meters long. These bony extensions of the vertebrae overlapped on either side of his neck, stiffening him and increasing his stability.
Biomechanical studies of its neck suggest that it was elevated only at a relatively small angle above the horizontal (20-30°). However, even at this angle, the extreme length of the neck meant that the animal's head could reach heights of 7.5 to 10 meters, making it easy to forage in tree foliage. , explains paleobiologist Paul Upchurch, professor at University College London and co-author of the study.
With such a size, sauropods had to be efficient in collecting of food, and that's what the long neck was for. A sauropod could stand in one place and eat the surrounding vegetation, conserving its energy while absorbing tons of food.
In addition, a long neck probably allowed the huge sauropods to evacuate excess body heat by increasing their surface area, much like the ears of elephants.