It's big news, quite literally. New research indicates that the Brontosaurus really did exist, some 112 years after scientists declared the opposite was true. The backstory: Paleontologist Othniel Charles Marsh and his team discovered the fossils of two long-necked dinosaurs in the Western US in the 1870s and had them shipped to the Yale Peabody Museum. There, in 1877, Marsh described the first as Apatosaurus ajax; in 1879, he dubbed the second Brontosaurus excelsus. But then came the blow: In 1903, paleontologists, having found a third similar "intermediary" skeleton, asserted that the Brontosaurus and the Apatosaurus belonged to the same genus. Since the Apatosaurus was named first, it lived on, and the Brontosaurus became Apatosaurus excelsus. Until now.
After what a press release describes as an "exhaustive" study, British and Portuguese paleontologists say the Brontosaurus merits its own genus. Scientific American reports that in its quest to reconstruct the diplodocids' family tree (Apatosaurus is a diplodocid, which is in the sauropod family), the team analyzed 477 unique anatomical features of 81 sauropod specimens. Wired explains how nuanced the analysis was, describing a search for "a neck bone with a slightly different ratio of length to width, or a shoulder blade that’s a slightly more square [shape]." Explains researcher Emanuel Tschopp, "Our research would not have been possible at this level of detail 15 or more years ago." Those specimens who passed the 20% threshold in terms of differences were considered a unique genus, and Marsh's specimen qualified. Smithsonian reports most of the distinctions are "subtle" but quotes Tschopp as saying, "The most obvious and visual feature would be that Apatosaurus has a wider neck than Brontosaurus."