Study claims early dinosaurs were sociable, may have lived in herds

New research conducted on a massive archaeological fossil location in Patagonia, Argentina, reveals that some of the primitive dinosaurs used to reside in herds, and this particular behaviour might be one of the important factors in dinosaur survival. At the European Synchrotron Radiation Facility (ESRF), the discovery of embryos of the same species within some fossil eggs has led to the findings. The results of the research were issued in the journal Scientific Reports.  

Primitive dinosaurs were social 

According to previous research, certain dinosaurs used to live in herds during the latter stage of the dinosaur era such as the Cretaceous Period, but, from when and how they had developed this behaviour in their evolutionary past had been a huge unanswered mystery.  

A global group of scientists had discovered a 190-million-year-old dinosaur breeding site in Patagonia, during the early 2000s, which included juvenile bones of Mussaurus patagonicus, a primitive herbivorous sauropodomorph dinosaur. Diego Pol, a palaeontologist at CONICET who found the site, said, "Such a preserved site was bound to provide us with a lot of information about how early dinosaurs lived," ANI reported. 

The eggs discovered on the location were among one of the items that might give insight on how ancient dinosaurs existed, and Pol wanted to know if they were produced by Mussaurus or not. Pol went on to explain that it is difficult to locate fossil eggs, and getting fossil eggs with embryos within is also the rarest occasion since their fossilisation requires extremely specific circumstances. 

Citing Vincent Fernandez, a palaeontologist at the London Natural History Museum and former ESRF scientist, ANI reported, “We use high-energy X-rays to penetrate in the sample without destroying it and get a full view inside it,” in the ESRF facility.  

Finding on research of fossilised Mussaurus embryos

After the fossilised eggs were discovered in Argentina, they were brought to the ESRF, where Pol took 30 of the 100 discovered eggs to examine with strong X-rays. Fernandez described the procedure by saying that it took four days for scanning the eggs all around clock. Further, high-resolution computed tomography discovered fossilised Mussaurus embryos inside some of the eggs, indicating that all of the specimens came from a single dinosaur species' communal mating location. 

Simultaneously, the researchers investigated the location. The fossil remains were discovered in different rock layers at the same location, implying that Mussaurus returned to the same location for nesting colonies in subsequent seasons. The researchers were able to deduce from the sediments that the breeding area was on the lake's dry borders. 

One of the intriguing aspects was that dinosaur bones were not arbitrarily dispersed across the fossil site, but were instead clustered as per their age. The fossils of dinosaur newborns were discovered near the nesting area. One-year-old infants were discovered in close proximity to one another, such as a group of 11 bones in resting attitude, indicating that Mussaurus established schools of young dinosaurs. Adults and subadults were often seen in couples or alone, all within a one-square-kilometre region. 

Scientists used histology tests, which involved cutting a tiny slice of bones and examining the bone tissue underneath a microscope, to calculate the age of the juvenile fossils. All of the results indicate a well-organized herd system, and this is the first time such intricate social behaviour has been observed in an ancient dinosaur. 

While concluding, Pol said, "These are not the oldest dinosaurs, but they are the oldest dinosaurs for which a herd behaviour has been proposed. Mussaurus belongs to the first successful family of herbivorous dinosaurs, so we postulate that being social and protecting their young together as a herd may have been part of the reason these long-necked dinosaurs were so common in all continents".   

(Image: Pixabay/ Representative Image)