In the kingdom of the dinosaurs, size definitely matters, and when measuring up to other prehistoric creatures the group of long-necked, plant-eating sauropods known as titanosaurs were the biggest beasts ever to plod across primeval Earth.
Titanosaur fossils as a whole have been well-established since the late nineteenth century, and discoveries include the largest terrestrial species in history such as the Argentinosaurus located in Neuquén, the Patagotitan from the province of Chubut, and the Notocolossus from the area of Mendoza.
Now to add to its notoriety, paleontologists in Argentina have identified the oldest known species of titanosaur that they've officially named Ninjatitan zapatai. This massive animal lived nearly 140 million years ago during the Early Cretaceous in the territory of what is now modern day Patagonia, Argentina. Details of the discovery were delivered in a new research paper submitted to the online scientific journal Ameghiniana.
“There were large animals towards the end of the Jurassic period, such as Apatosaurus and Brachiosaurus," Dr. Pablo Ariel Gallina, a paleontologist at the Fundación Azara in Maimonides University and CONICET, told Agencia CTyS. "And, already in the line of titanosaurs, the pulse with the largest giants occurs towards the middle of the Cretaceous period, with species such as Patagotitan, Argentinosaurus or Notocolossus.”
According to the study, the presence of a basal titanosaurian sauropod in the lowermost Cretaceous of Patagonia helps supports the theory that the diverse group was well established in the southern hemisphere and highlights the notion of a Gondwanan origin (the supercontinent made up of what's now South America, Africa, India, Australia and Antarctica) for Titanosauria.
The prehistoric postcranial remains of Ninjatitan zapatai were first discovered back in 2014 in the Bajada Colorada Formation in the Neuquén province of Patagonia. Ninjatitan zapatai measured in at approximately 66 feet in length, and had an extremely long neck and thick tail. Its name was given in honor of the Argentine paleontologist Sebastián Apesteguía, who is affectionately nicknamed "The Ninja."
“In the following campaign, three vertebrae and some bones of its hind legs appeared; a part of the femur and what would be its fibula," Dr. Juan Ignacio Canale told Agencia CTyS. “There began the preparation of the materials in the Museum of Villa El Chocón. Until that moment, we knew that it was a sauropod, but when we carried out the detailed study of the phylogenetic relationships, of the kinship relationships of this animal with other known species, we realized that it belonged to the group of titanosaurs, for so the importance of this discovery was even greater than we had imagined at the beginning.”
The most surprising fact to emerge in the research into its origins was the conclusion that Ninjatitan zapatai was munching on trees and leaves over 130 million years ago, giving it the distinction of being the oldest known member of the colossal Titanosauria lineage, though not exactly the largest.
"The Bajada Colorada dinosaur fauna represents one of the most diverse and unique associations not previously documented, from the lowermost Cretaceous deposits worldwide; a moment in dinosaur evolution little explored," Dr. Gallina tells SYFY WIRE.