An article published in the journal “Proceedings of the Royal Society B” describes the study of the most massive titanosaurus discovered so far. Called Patagotitan mayorum, it was about 37 meters long (122 feet), about 6 meters (20 feet) tall and its weight was estimated at 69 metric tons, which make it the largest animal that ever lived on the mainland. It lived in the late Cretaceous, between 95 and 100 million years ago, in today’s Patagonia, Argentina.
The first fossils of Patagotitan mayorum were discovered in 2011 in the Chubut province, Patagonia, and in subsequent years about 150 bones belonging to at least 6 specimens were uncovered in the same site. The excavations made the news very quickly for the size of the bones found and the paleontologists of the Museum of Paleontology Egidio Feruglio who conducted them, led by Jose Luis Carballido and Diego Pol, subsequently prepared the fossils so that they could study them.
In order to estimate Patagotitan mayorum’s weight, the paleontologists were forced to resort to indirect methods because they only had their bones available so they needed another way to establish their body’s volume. This was achieved by comparing the new species with others it might be related to and others that lived at the time or had some characteristics in common with the new titanosaur.
The comparison with genera that were already known such as Argentinosaurus, Puertasaurus, and Futalognkosaurus, other titanosaurs that lived in Argentina, showed similarities but also important differences. An interesting conclusion is that, according to the paleontologists, Patagotitan mayorum was closely related to the Rinconsauria group, which includes the Rinconsaurus and Muyelensaurus genera, which include some of the least massive titanosaurs.
Diego Pol explained that the study conducted with his colleagues indicates that most of the giant titanosaurs discovered in Patagonia belong to a single group. The consequence is that the evolution of that extreme gigantism took place only once and not in separate events. Other cases of evolution into larger species from less massive titanosaurs show a much lesser growth than the group Patagotitan mayorum is part of.
Patagotitan mayorum could be the largest animal that ever lived on the mainland. However, its size is similar to that of the other largest titanosaurs known so it’s possible that they came close to the maximum possible limits for those animals. That’s another reason for interest in these giant dinosaurs.