Researchers from Argentina, USA and South Africa have found evidence that indicate the existence of heldness at the steeringomorph – one of the groups of dinosaurs – even at the beginning of the Jurassic period, about 193 million years ago. The article of scientists has been published in the journal Scientific Reports.
Since 2013, Paleontologists have discovered during the excavations of the formation of the Coloranda lagoon in the south of the Patagonia more than 100 eggs and about 80 skeletons of young and adults and herbivorous vesselsomorph, the far ancestor of such a velvet, as a diplodok and argentino zero. Most of the first were grouped by masonry from eight to 30 eggs. X-ray visualization on the ESRF synchrotron in Grenoble showed that all eggs contained moszavrov embosites. Moreover, it turned out that all of them are grouped into two or three rows inside specially broken “tranches”, which indicates the presence of the nest.
Paleontologists analyzed the size and age of bone tissues of moszavrov skeletons in order to determine their age. In addition, they analyzed the formation itself: the fossils were found in different horizons at the same place, which indicates that the Muszavras came to the same point for many during many seasons of mating. It turned out that the fossils were grouped by age – in one place there were eggs and just hatched individuals, the skeletons of young people – the other. Researchers managed to highlight the accumulation of 11 individuals age less than a year – which indicates the existence of “schools”. Skeletons of adult individuals – alone or pairwise – found separately, but within the same area the size of a square kilometer. All this forced the researchers to assume that Muszavras lived herds, but they tried to group by age.
In order to determine the age of fossils, the researchers analyzed samples of volcanic ash. They were zirkons – minerals, in the ratio in which uranium and lead isotopes, scientists were able to determine that the age of fossil Muszavra is 193 million years ago. Most likely, the herd died during a flood, and then covered with ashes from the eruption. This is the most ancient testimony of complicated social behavior in dinosaurs – by 40 million years older previously discovered.