Dreadnoughtus was thought to be the largest dinosaur ever discovered, but a new study suggests the animal was not as large as believed. Researchers originally believed the creatures weighed around 66 tons, but a new investigation suggests the actual weight was between 33 and 44 tons.

Dreadnoughtus schrani fossils were first discovered in Patagonia during 2005. The giant sauropod measured 85 feet long, and the specimens recovered in South America during 2014 were nearly complete. Because of the condition of the fossils, researchers felt confident releasing their estimate of the record-breaking weight of the ancient creature. Analysis of the fossil suggested the specimen was from a young individual who may have grown longer if it had not perished. If this is true, Dreadnoughtus would have been the largest dinosaur ever known to walk the face of the Earth. New research, however, suggests the dinosaur was not as heavy as originally estimated.

"Using digital modeling and a dataset that took in species, alive and dead, we were able to see that the creature couldn't be as large as originally estimated. Our analysis suggests that only the lower estimates produced by previous methods are plausible. Estimates of 60 tons and above do not fit with our current understanding of the mass characteristics of living land animals," Karl Bates from the Institute of Ageing and Chronic Disease at Liverpool University in England said.

The original estimates of weight were based on a traditional method of determining body mass based on the size of thigh and arm bones. However, the estimate of body weight was significantly higher than the masses of other sauropod dinosaurs that were just slightly smaller in length. This suggested to some researchers that the original estimates of weight were too high, prompting this latest study.

Computer modeling was utilized to develop a virtual model of the ancient animal. A digital representation of the animal was used to form a virtual skin around the bones. This shell was then filled in by representations of muscles, organs and connective tissue. Information for this stage in the project was largely obtained from a study of contemporary species. From this, the investigators were able to formulate the new lower weight estimate for the gargantuan dinosaur.

Despite the massive size of the dinosaurs, Dreadnoughtus was an herbivore, eating vast quantities of plants to support its massive body. Future research could further examine living species in an effort to understand the physiology and behavior of dinosaurs.

Analysis of the body mass of Dreadnoughtus, based on 3D modeling, was published in the journal Biology Letters.