A new species of diplodocid – the family of sauropod dinosaurs which includes the iconic Diplodocus – has been described by a duo of European researchers who have dubbed it Galeamopus pabsti in a new paper published in PeerJ.
While the remains of this 150-million-year-old dinosaur were first excavated in 1995, the creature hadn’t been formally described until now, when palaeontologists Emanuel Tschopp and Octávio Mateus, from the University of Turin, Italy, the Nova University of Lisbon and the Museum of Lourinhã in Portugal, took on the Jurassic giant.
The specimen was discovered on the Howe Ranch, located in the US state of Wyoming. Described by the researchers as a “diplodocid El Dorado”, the site is a gold mine for prehistoric discoveries, and is famed for harbouring a significant number of almost complete dinosaur skeletons.
The researchers analysed the skeleton’s autapomorphies – distinctive features unique to a given group of organisms – to help differentiate their dinosaur from others. This allowed them to conclude that the specimen had belonged to the diplodocid sauropods, the family of dinosaurs which included the longest creatures to ever walk our Earth.
Similar in shape to the long-necked Diplodocus, the newly identified Galeamopus pabsti boasts comparatively bigger legs and a more triangular skull than its well-known relative.
The researchers are still stumped by the exact age of the dinosaur when it died. Studying its bone histology – the microscopic structure of its bone tissue – they found that the dinosaur had reached sexual maturity, but that parts of its spinal column weren’t fused, as would be expected in a fully grown organism.
Digging deeper, the researchers identified a similar phenomenon in three other dinosaurs, leading them to conclude that “that neurocentral closure was delayed and only partially completed by sexual maturity in sauropods, as is the case in some crocodiles and lizards”.
The dinosaur was discovered in the Morrison Formation, a layer of sedimentary rock across the western USA. While diplodocid species have also been found in Europe, South America, and Africa, the highest diversity has been discovered in the US, where more than fifteen species of the giant herbivores have been uncovered to date.
Palaeontologist Steven Salisbury from the University of Queensland, Australia, was unsurprised by the identification of the new sauropod. “Discoveries of new dinosaurs are only going to continue,” he said. “The more people that are looking and working on it, exploring and searching areas, the more that’s going to be unearthed.”