[Animals] Dinosaur extinction began long before astroid hit Earth, study suggests

[-𝓣𝓐𝓚𝓘]

An investigation of 5,500 geological samples maintains that the dinosaurs were in decline before their extinction
The extinction of the dinosaurs is still a subject full of questions. Specialists have spent years trying to reconstruct what exactly happened at that time. The matter is, to date, the subject of scientific debate.

Thanks to previous discoveries, it is now known that the extinction of the dinosaurs took place 66 million years ago. This occurred as a result of an asteroid that hit the earth, specifically, northwest of the Yucatan Peninsula, Mexico. The devastation was progressive, due to the multiple effects that the shock brought with it. 75% of the planet's species disappeared.

Among the living beings that became extinct due to this cataclysm are the dinosaurs, animals that dominated the earth for 175 million years. That incredible amount of time and other factors of interest have managed to raise several questions in scientists about when these beings really were at the time of their extinction.

It may interest you: The impact of a second asteroid could be linked to the mass extinction of the dinosaurs

A new study, published in the scientific journal, (Proceedings of the National Academy of Sciences (PNAS), indicates that the diversity of dinosaurs was in decline towards the end of the Cretaceous, the period in which the asteroid fell. This research was carried out by scientists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences Here's what we know.

Before extinction, dinosaurs were already in decline
Much of the information we have regarding the last million years of the dinosaurs comes from finds made in North America. Curiously, in short, these discoveries have shown that, in that region of the world, the diversity of these animals was quite wide, towards the end of their times. However, other areas of the Earth have not had the same wealth of data on this time. This gave rise to the hypothesis that the dinosaurs were already in decline in the period prior to their extinction.

In order to better understand what was happening during this time, the IVPP researchers studied more than 1,000 eggs and eggshells that were found in Shanyang, central China. The purpose of the analysis was 5,500 geological samples that, thanks to the study, were placed within the last 2 million years of the Cretaceous. In essence, the work of this group was aimed at determining, through the application of computer models, how old the samples were. Part of the remarkable thing was finding a date so close to the extinction of the dinosaurs.

Little diversity towards the end of the Cretaceous
Something else to note about what was found in China is that the fossils they worked with only belonged to three species of dinosaurs (Macroolithus yaotunensis, Elongatoolithus elongatus and Stromatoolithus pinglingensis). As if that were not enough, before the study in this case, dinosaur bones had already been discovered that, curiously, coincided with those of the fossils analyzed in this latest investigation. This led scientists to conclude that, at least in that part of the planet, the diversity of these animals was already declining at the time mentioned.

It may interest you: Serious drought in the United States reveals dinosaur footprints in a state park

Despite what this study proposes, Alfio Alessandro Chiarenza, a researcher at the University of Vigo, mentions to CNN that these works should not yet be taken as conclusive on the subject. The reason for this, according to the specialist, is that it is very likely that other species of dinosaurs had soft-shelled eggs, which is why they would not fossilize. This possible fact would explain the reason for so little information on the biological diversity of this last period.

https://www.ngenespanol.com/animales/la-extincion-de-los-dinosaurios-comenzo-antes-del-impacto-del-asteroide/