A new study shows that diplodoxids can move their tails like stalks at speeds comparable to a fast car.
The researchers created a computerized 3D model of a diploid tail based on five diploid fossil specimens.
Diodes are a group of herbivorous sauropods, famous for their long necks and long tails, which reached an impressive 40 feet in length.
According to the results, the creatures could have whipped their tails at speeds of up to 73 miles per hour (33 meters per second), but nowhere near the speed of sound (760 miles per hour), as an earlier study suggested.
Diplodocid is a species of herbivorous long-necked sauropod, known for its massive sizes and long necks and tails
What are diplodosides?
Diplodocides were a group of sauropod dinosaurs and included some of the tallest creatures that ever walked the Earth.
Some of the large, long-necked creatures, which count Diplodocus and Supersaurus as members of the family, were up to 112 feet (34 meters) long.
And while their necks were long, their legs were definitely not.
Described by some as the “dachshund” of giant dinosaurs, it had short bipedal legs, with its hind legs longer than its front.
This gave their backs a distinctive slope towards the neck.
Their diet is thought to have included grazing on ferns and horsetails.
The study was led by Simone Conte at the Nova School of Science and Technology in Caparica, Portugal, and Politecnico de Milano, Milan.
Such an elongated and slender structure would allow terminal velocities to be achieved on the order of 30 m/s, or 100 km/h, much slower than the speed of sound, due to the combined effect of muscular and joint friction, as well as aerodynamic drag.
The physical properties of the skin, tendons, and ligaments also support such evidence, proving that in life, the tail would not withstand the stresses imposed by traveling at the speed of sound.
Interestingly, the new study, published today in the journal Scientific Reports, contradicts previous research by University of Alberta paleontologist Philip Corey and Nathan Myhrvold, inventor, photographer and former Microsoft chief technology officer.
This older study, based on more rudimentary computer simulations, suggested that the dicotyledonous tail has a structure attached to the end of its tail – similar to a tuft at the end of a flagellum, commonly known as a “cracker”.
When the tail was whipped, the cracker could travel faster than the speed of sound (340 meters per second or 760 miles per hour) and create a small sonic boom, they said at the time.
However, several paleontologists have criticized the research, including Dr. Kenneth Carpenter of the Denver Museum of Natural History.
Diplodoxids may have been able to flap their tails like a whip at speeds of up to 33 meters per second (over 100 kilometers per hour).
The researchers refuted the findings of Nathan Myhrvold (pictured), inventor, photographer and former chief technical officer of Microsoft.
The bullion runs from the handle to the tip of the whip known as the “cracker” or “popper”.
When the whip is swung, energy is transmitted from the handle through the whip to the tapering end.
As mass decreases, velocity increases causing the “cracker” to move faster than the speed of sound.
Breaking this barrier is what causes sonic booms in whiplashes, but also in supersonic aircraft.
“To be honest, computer simulations are another case of rubbish, take out rubbish,” he said at the time, adding that such speeds were painful and could damage the tail.
The purpose of a diplodocid tail is debated, although there are many explanations from scientists.
Some suggest that it may have acted as a counterweight to the long neck or as a “third leg” when the dinosaur was standing upright on its hind legs.
Alternatively, it could be a defensive weapon, a noise-making structure, or a “spatial awareness haptic device”—or it could have a combination of multiple uses.
For the new study, Conti and colleagues simulated the movements of the bipedal tail using a model based on five bipedal fossil specimens.
The model’s tail is about 40 feet long, weighs 1,446 kilograms, and consists of 82 cylinders – representing vertebrae – attached to the base of immobile hip bones.
They found that when the base of the tail moved in an arc, it generated a whip-like motion at a maximum speed of 33 meters per second (73.8 miles per hour).
This is more than 10 times slower than the speed of sound in standard air and too slow to create a supersonic boom.
For the study, the researchers created a computerized model of a diplodocid tail based on five fossil diplodocid specimens.
The tail model produced a whip-like motion at a maximum speed of 33 meters per second (73.8 mph).
The authors also found that the thin, whip-like tail could not move at 340 meters per second (760 mph) without breaking.
They then looked at whether adding three different three-foot-long structures—imitating the end of a whip—to the model’s tail end could allow it to travel at the speed of sound without rupturing.
The first structure consists of three parts made of skin and keratin, the second consists of braided keratin strands, and the third has a flail-like structure formed by soft tissues.
Again, none of the hulls was able to withstand the pressure of moving at 340 meters per second without breaking the tail.
Pictured is the anatomy of the flagellum compared to the tail model. c) The cross-section of the animal’s vertebrae is shown
While the results suggest that the bisexual tails could not create a sonic boom as suggested by Corey and Myhrvold, they were still fast enough to be used as defensive weapons or to fight with other bisexual tails.
Conti told MailOnline that Currie and Myhrvold’s past study “didn’t make any mistakes” and that his team had built on their work.
His new study made use of a more sophisticated program, called MBDyn, which divided the tail into 82 elements, he said, yielding more reliable results.
“Thanks to advances in computer technology and software development, such as MBDyn, is the main difference between the two studies,” Conti told MailOnline.
“In short, we can say that we were able to achieve the results we obtained thanks to the work previously done by others.”
SAUROPODS: Long-necked and small dinosaurs
Sauropods were the first successful group of herbivorous dinosaurs, dominating most terrestrial ecosystems for more than 140 million years, from the late Triassic to the late Cretaceous period.
They had long necks, tails, and relatively small skulls and brains.
It stretched to 130 feet (40 m) long and weighed up to 80 tons (80,000 kg) – 14 times the weight of an African elephant.
They were widespread – their remains are found on all continents except Antarctica.
They had nostrils high on their skulls – instead of being at the end of the snout like many other terrestrial vertebrates.
Some fossils show that these nostrils were so far from the skull that they were very close to the eye holes.
Sauropods like Diplodocus began diversifying in the middle Jurassic period, about 180 million years ago.
Source: University of California Fossil Museum