What’s the first image that comes to mind when someone says the word “dinosaur?” Maybe a menacing T. rex with huge, gnashing teeth and comically short arms, or a stegosaurus with its tail spikes and bony, distinctive plates or perhaps even a triceratops with its three large horns and frill of bone.
Now imagine another set of dinosaurs — those that weigh seven times that of our well-known T. rex, or those that eat thousands of calories by the hour or even stretch longer than a short course Olympic pool. Combine all these traits into one organism, and you have Dreadnoughtus: an enormous, herbivorous dinosaur with a skeleton so complete and a body mass index so high that scientists suspect that it may just be the largest dinosaur that has ever lived.
Dreadnoughtus, whose skeleton was recently uncovered and reported on in the journal Nature, was discovered in Patagonia, Argentina. It was excavated over a period of four years by a team led by Kenneth Lacovara, an assistant professor in Drexel University’s Department of Biodiversity, Earth and Environmental Science. The discovery of Dreadnoughtus was particularly significant because of how complete the skeleton was; 70 percent of the dinosaur’s skeleton beyond its head was found including the entire femur and humerus.
These two bones were especially important to Lacovara’s team because they are crucial to calculate the body mass index of a four-legged animal. Because both were present, his team was able to calculate the weight of Dreadnoughtus to 65 tons or 59,300 kilograms. Their value is the highest weight calculated in recent history, for a titanosaurus, the family to which Dreadnoughtus belongs.
The most astounding discovery concerning Dreadnoughtus’ size, however, was not just that it was large, but that it could have been larger. The paper cited the bones as osteologically immature at the time of Dreadnoughtus’ death, with certain bones still remaining unfused and vascularized and fibrolamellar bone tissue still present between the cortex and surface of the bone. The humerus bone also did not have lines of arrested growth, and the dorsal ribs of the dinosaur still contained primary fibrolamellar tissue near the surface.
Though Lacovara’s primary research is on animals long extinct, the techniques he employs for analyzing Dreadnoughtus are anything but ancient. In the process of characterizing the properties of the bones, Lacovara and his team scanned each bone digitally, compiling them into a digital reconstruction of Dreadnoughtus available in their Nature publication. These scans were then sent to laboratories in other parts of the world for their own research and analysis. Lacovara believes digital scanning to be the future of dinosaur excavation and analysis, especially in the case of Titanosaurs, whose bones literally weigh tons.
After digital scanning and examination of the bones discovered by Lacovara’s lab, it was fittingly named Dreadnoughtus, meaning “fearing nothing,” due to the enormous size of its body and its weaponized tail. The name was also a subtle tribute to Dreadnoughtus’ Argentinean roots: two 20th-century battleships, the Rivadavia and Moreno, were called “dreadnoughts,” due to their impenetrability and vital position in the Argentinean navy. The species name of the dinosaur, Schrani, was a more modern tribute to Adam Schran, an entrepreneur and funder of Lacovara’s research.
To fuel its enormous, unfearful body, Dreadnoughtus had to spend many hours of its days eating. Its movement, however, was hindered by its sheer size — Dreadnoughtus possessed a 37-foot-long neck and a 30-foot-long tail. Thus, Lacovara speculates that Dreadnoughtus did not move around very much and rather, spent its time clearing patches of trees and fern leaves, and it likely died doing such. Luckily for us, the unfortunate death of this young dinosaur has led to one of the most important paleontological discoveries of the 21st century.
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