A display featuring the Titanosaur—a 122-foot-long, 70-ton sauropod—opened to the public Friday at the American Museum of Natural History in New York, reports the Wall Street Journal. It's the biggest dinosaur ever discovered, as far as many paleontologists are concerned. But, writing for fivethirtyeight.com, David Goldenberg recalls the tale of one that was supposedly larger: Amphicoelias fragillimus. Based on the reported 1877 discovery of a nearly 5-foot-tall piece of vertebra by a schoolteacher outside of Cañon City, Colo., Amphicoelias would have been 190 feet long. But that piece of vertebra—the sole evidence that Amphicoelias existed—has been missing for more than a century. After its discovery, the bone was shipped to Philadelphia (it was on a freight train manifest), and renowned paleontologist Edward Drinker Cope published a paper about it.
When Cope died in 1897, his collection was sent to the American Museum of Natural History. Upon cataloging the collection, the museum couldn't find the vertebra. Some have claimed that Cope made it up to outshine a rival. (This Slate piece has details on that famous feud.) One skeptic, Cary Woodruff, tells Goldenberg he thinks the estimate of Amphicoelias' huge size is based on a typo: Cope wrote that the vertebra was 1500mm when he meant 1050mm. Cope realized the error, Woodruff believes, but kept quiet about it to avoid humiliation. In an earlier report, Motherboard notes that studying the dinosaur based on Cope's notes alone is unsatisfactory, so Amphicoelias doesn't get counted among the biggest dinosaurs. But the matter is far from settled. "Large-dinosaur sleuths," Goldenberg writes, still make their way to the American Museum of Natural History in search of clues about the elusive Amphicoelias. (An excavation at a school in Scotland turned up remains believed to belong to a pirate.)