It is generally difficult to identify the exact proportions of fossil animals that are mined from the rock. A fossilized skeleton is rarely discovered in its entirety. Instead, the bones that make them tend to be disarticulated, entangled, and generally dispersed by factors such as weather conditions, water movement, and scavenger activity.

This was the case when the first specimen of a Supersaurus was discovered in 1972 in a bed of bones at Dry Mesa Dinosaur Quarry in Colorado. Brian Curtice, currently a paleontologist at the Arizona Museum of Natural History, describes the accumulation of tightly packed fossils originally found in the bone bed as a “bone salad” which made it very difficult to know which ones bones to allocate to newly discovered bones. Supersaurus.

Field worker Jim Jensen, who collected and prepared fossils for Brigham Young University in Utah, excavated this bone salad and published his findings a few years later. Among the bones he discovered was an 8-foot-long scapulocoracoid – two fused bones that make up the shoulder girdle in adult dinosaurs and other reptiles. The size of this identified bone Supersaurus as potentially one of the longest dinosaurs ever discovered. The public was intrigued at the time that a dinosaur larger than brachiosaurus, then considered the longest dinosaur, could have existed.

Jensen also unearthed other large bones that he said belonged to two other species of sauropod dinosaurs. When he published his findings in 1985 in the journal Naturalist of the Grand Bassin, he announced the discovery of three new sauropod dinosaurs from the quarry – besides Supersaurus (who had been named by a reporter in the initial post-discovery media frenzy), he named Ultrasaur and Dystylosaurus from bone evidence found in the bone bed.

However, Jensen was not a paleontologist by training and he made a few mistakes in his analysis. This has led to many debates among paleontologists over the years, which have questioned the validity of the other two new genera. Some, like Curtice, believe the bones were misidentified and all belong to one Supersaurus skeleton.

Curtice said Jensen’s theory that the bones belonged to three different dinosaurs had never been verified. “He was caught in the moment,” Curtice said. “He had no classical training.

Today, some 50 years after the initial discovery, Curtice has reassessed some of the original bones, as well as the bones that were subsequently excavated from the large boulders and fossils that were transferred at the time. from the quarry to the laboratory. He also compared all the bones with those of two other fossilized skeletons from Supersaurus (nicknamed Jimbo and Goliath) which were later discovered in Wyoming.

He thinks there are good reasons to reclassify all three Jensen species into one, namely Supersaurus.

Among the yet-to-be-studied bones of boulders, Curtice identified five new cervical vertebrae, one new dorsal vertebra, two new caudal vertebrae, and a left pubic bone. This gave him a more complete picture of the skeleton of Supersaurus and helped him to more accurately estimate the total length of the beast.

However, many bones have still not been excavated or are missing from the deposit, so it is still difficult to determine the total length.

“He should have 15 or 16 neck bones and we have six,” Curtice said. “So the big challenge is ‘Wait, what six do we have?’ They don’t come with numbers on them.

Curtice found that the vertebrae became smaller by a certain percentage as they moved away from the body, which allowed him to estimate the length of the missing bones. He calculated that, depending on the placement of a cervical vertebrae nearly 4.5 feet (1.3 m) long, Supersaurus measured either 128 feet or 137 feet in total length.

“It’s crazy length – longer than three yellow school buses, nose to tail,” Curtice said. “And given that we never find the largest individual in the fossil record, how long could these animals have taken?” “

The other more recent fossil Supersaurus findings, Jimbo and Goliath, supported Curtice’s length estimates. “What shocks me is how close Goliath and Jimbo are,” Curtice said. “If you have three animals within a few feet of each other, we now know, ‘OK, that’s the average. “”

Unfortunately, researchers have yet to formally identify Goliath as a Supersaurus in a peer-reviewed journal and, until then, the inclusion of its measurements for comparison purposes can only be provisional.

The findings from the new research “seem reasonable,” said Matt Lamanna, a vertebrate paleontologist at the Carnegie Museum of Natural History in Pittsburgh, who was not involved in the research. “I can’t really comment on the exact length estimate, but it is clear that there is a very, very large diplodocided sauropod in this quarry.”

Research would be stepped up if the dinosaur nicknamed Goliath was formally identified as a Supersaurus, mostly because Curtice uses it to inform his analysis, Lamanna said. “I think the final verdict will come when this specimen from Goliath is released, when this additional material from Dry Mesa is released. I want to see it go through a formal peer review.

“I think it will be pretty exciting when he does [publish]Lamanna added. “I think he’s most likely right.”

Pending publication of Goliath’s identity and peer review of his own research, Curtice presented his findings at the Society of Vertebrate Paleontology’s annual meeting earlier this month. Even the estimate of the “shorter” size of Supersaurus breaks records; at 128 feet (39 m), the dinosaur would have been longer than other contenders for this record. And with a neck at least 50 feet long (15 m), Supersaurus already holds the record for the longest-necked dinosaur. One thing is certain though, when Supersaurus roamed the plains of Colorado and Wyoming some 150 million years ago, it was an unusually large animal.

In conclusion, Curtice states that Supersaurus may be the longest dinosaur on record, but it’s not the heaviest. This honor probably goes to the superheavy titanosaur argentinosaurus, which weighed over 90 tons (82 metric tons) and was almost twice as heavy as Supersaurus was.

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Through Alison bosman, Terre.com Editor-in-chief