In Argentina, the fossil of a dinosaur lay in wait for nearly 100 million years until paleontologists finally found it. This fossil is a special find, as after identifying it as a rebbachisaur, it was discovered to be the oldest one ever found.
Rebbachisaurs were long-neck herbivorous dinosaurs and were unearthed in the Neuquén Province in the Huincul Formation. This area is a known hotspot for dinosaur fossils but it is still a breakthrough, given how old the find is.
The Rebbachisaur
Rebbachisaurids were a part of sauropods and featured iconic long necks and unique teeth and vertebrae. Their cousins are the more famous Diplodocus, which is one of the best-understood sauropods in North America.
Rebbachisaurids had strange teeth that looked like rows of batteries in extreme cases. This trait was not shared by other sauropods but was shared with other groups like hadrosaurs.
Finding The Rebbachisaur
The rebbachisaur that was found at the base of the Huincul Formation was a Cienciargentina sanchezi that lived in the Late Cretaceous era. The best estimate of its age is 94 million years and the geological layer in Neuquén Basin aided in its preservation.
Paleontologists have found some of the world’s most surprising and important dinosaur fossils, making it a popular place for excavation and paleontological research.
Its Anatomy
The Cienciargentina sanchezi that was uncovered was found to be a primitive rebbachissaurid due to its unique vertebrae traits, including amphicoelous (curved inward) to opisthocoelous (bulging outward) shapes. These unique shapes in the vertebrae set it apart from other species in its lineage.
The fossils that were preserved showcased a long, flexible neck and weight-bearing hind legs.
An Important Discovery
This discovery marks the earliest known rebbachisaurid ever to be found, moving back to previous notions of when this group existed. It is also the most complete example ever excavated and helps to fill out unknown variables in dinosaur lineages.
Through research, the fossil could provide a window into an ancient world and show us how sauropods evolved, and their genetic diversity spread as the environment around them changed.
Prehistoric Ecosystems
The region where the fossil was found was drastically different during the Late Cretaceous period. The environment was full of thick vegetation, and the dinosaur would have lived near streams and floodplains that are non-existent today.
Its massive size would have been its first defense against predators of the time, and its diet adapted to the readily available vegetation in the area. The fossil alone helps to paint a picture of what life during this time would have been like.
Evolution
With the fossil being significantly older than other specimens, this pushes the timeline of rebbachisaurids back. They were also more widespread across the continent than previously believed. With unique vertebrae and teeth, this group of sauropods faced different conditions, fueling a divergent evolutionary path.
Other sauropods could have faced unique shifts in climate, vegetation scarcity, or competition that didn’t affect this rebbachisaur group.
Studying The Fossil
Fossils can be accurately dated by carbon dating and digital modeling techniques that do not disturb or damage the fossil. This cutting-edge science also allows scientists to reconstruct what would have been around the bone, such as muscles, and ultimately, how they would have moved.
This gives new insights into how they would have behaved throughout their lives.
A Global Collaboration
Paleontological work is often a multi-faceted endeavor, with collaboration between multiple fields. The study of this rebbachisaur was led by Leonaro Salgado and Maria Edith Simon from the Universidad Nacional de Río Negro-Conicet.
Their hard work studying the fossil highlights how international cooperation in paleontology can refine the way we think of evolution and previous hypotheses.
The Future For Cienciargentina Sanchezi
Cienciargentina sanchezi isn’t the first fascinating fossil to be found in the Huilcul Formation, and it won’t be the last. The Neuquén Province is full of undiscovered fossils waiting to be found and studied.
Some may not challenge previous hypotheses but fuel scientific intrigue and future endeavors that can lead to amazing breakthroughs.
