Now, researchers studying fossils from southern Argentina have identified a new member of this iconic group. The dinosaur, named Bicharracosaurus dionidei, was smaller than the largest sauropods but still measured an estimated 65 feet (20 meters) long.

Giant Dinosaur Fossil Found in Patagonia

Scientists recovered parts of the dinosaur's spine, including more than 30 vertebrae from the neck, back, and tail, along with several ribs and part of the pelvis. The bone structure showed that the remains belonged to an adult animal that lived about 155 million years ago on Gondwana, the ancient southern supercontinent.

What makes the fossil especially intriguing is its unusual mix of features. Some parts of the skeleton closely resemble those of Giraffatitan, a brachiosaurid dinosaur discovered in Tanzania. Other traits, especially in the back vertebrae, are more similar to Diplodocus and related species from North America.

"Our phylogenetic analyses of the skeleton indicate that Bicharracosaurus dionidei was related to the Brachiosauridae, which would make it the first Brachiosauridae from the Jurassic of South America," says LMU doctoral student Alexandra Reutter, the study's first author. The paleontologist examined the fossils as part of her doctoral research.

New Clues About Jurassic Dinosaur Evolution

The discovery could help scientists better understand how giant sauropods evolved across the Southern Hemisphere during the Late Jurassic period.

"Our knowledge of the evolution of sauropods from the Late Jurassic has so far been based almost entirely on numerous fossil findings from North America and other sites in the Northern Hemisphere. For a long time, there was only a single significant site on the southern continents, in Tanzania. The fossil site in the Argentine province of Chubut, from which Bicharracosaurus dionidei originates, provides us with important comparative material, allowing us to continuously supplement and reevaluate our understanding of the evolutionary history of these animals, particularly in the Southern Hemisphere," says leader of the study and dinosaur expert Prof. Oliver Rauhut of the Bavarian State Collections of Natural History (SNSB).

Dinosaur Named After Local Shepherd

The first fossils of Bicharracosaurus dionidei were discovered on a farm by shepherd Dionide Mesa. Researchers honored him by using his name for the species designation. The genus name comes from "bicharraco," a colloquial Spanish term meaning "big animal."

The fossils were uncovered in the Cañadón Calcáreo rock formation in Patagonia's Chubut province. Today, the remains are housed at the Museo Paleontológico Egidio Feruglio in Trelew, Argentina.