Lost in sedimentary mudstone, conglomerate, sandstone and tuff masonry was made 98-91 million years ago, which was confirmed by the uranium-lead method of dating.
The first thing you notice specialists of the Institute of Paleontology and Anthropology vertebrates (IVPP), – almost perfectly spherical shape of the eggs.
Even more surprising were the results of the analysis of the structure of the shell. With an overall width of 2,4-4 mm, the thickness of the so-called inner cone layer was 0.18-0.25 mm, which is part of the 1/20-1/4 shell. The study revealed the presence of a columnar layer of horizontal lines of growth, as well as dark and light bands of varying thickness and length.
In an article published in the journal Chinese Science Bulletin, researchers from China wrote that these characteristics are not met at the previously found instances, so for the classification to create a separate family (oofamily), called Stalicoolithidae.
The scientists found the most eggs are similar in their characteristics to the family Spheroolithidae, that makes them belong to dinosaurs.
“This discovery is extremely important not only for understanding the structure of the local fauna of the Cretaceous period, but also to study the evolution of dinosaurs in general,” – says Professor Xiaolin Wang (Wang Xiaolin) of IVPP.
With eggs, scientists also hope to clarify the evolution of the amniotes, a group of vertebrates, with blastoderm – amnion. They are of interest to scientists because of amniotes are and mammals.