Date: 10 months ago   Category: Studies

Paleontologists have found remains of yaytsekladushchy "great-grandfather" of mammals - RIA Novosti, 8/30/2018

MOSCOW, 30 Aug – RIA Novosti. Scientists have found in Arizona remains of extremely unusual ancient zveroyashcher who continued to lay eggs, like reptiles, but at the same time had difficult teeth as mammals. His opening will help to understand when the most ancient ancestors of people have appeared, scientists write in article published in the Nature.© magazine of the Photo: April Neander, University of Chicago Scientists have found in Yakutia remains of two mammal times of dinosaurs "Opening of this animal and his posterity is especially important from the point of view of evolution. They have many lines which are making related them with modern mammals whose studying will help us to understand how our ancestors developed" — EVA Hoffman from the university of Texas in Austin (USA) has said. The first mammals have appeared on our planet about 220-225 million years ago, towards the end of the Triassic Period, along with the first primitive dinosaurs. After the emergence, ancient warm-blooded animals have very quickly extended on all Earth. The first primitive representatives of our class were rather small sizes. Judging by structure of their teeth, they ate a monotonous diet, generally insects. The main boom of their evolution has begun only after the dinosaurs who weren't allowing them to occupy new ecological niches have died out. Scientists, as Hoffman notes, argue long ago on when our ancestors have learned to bear posterity in the womb, having refused postponement of eggs, both when and why part of them "has lost a bag" and I have passed to placentary development. The analysis of genomes of modern marsupials and yaytsekladushchy animals specifies that it has occurred in the Jurassic Period and that the retroviruses which have changed structure of DNA of our ancestors were "responsible" for all this. © Photo: Paleontologists have found Misaki Ouchida a marsupial of the "badger" eating динозавровХоффман and her colleagues have taken the first step to disclosure of these secrets, carrying out excavation at the end of the last century in the northeast of Arizona where breeds of the Kayentsky formation lie. They were created at the very beginning of the Jurassic Period, about 190 million years ago when the first large dinosaurs have begun to appear. Here they managed to find extremely unusual fossil – remains of the Kayentatherium wellesi tsinodont, a zveroyashcher of the size of a dog and also 36 of his eggs buried together with mother under a dirt layer during some cataclysm. As scientists tell, initially they assumed that in a fossil only remains of a female of the tsinodont disappear and didn't suspect that at her there is also her brood. One of graduate students has accidentally found their traces during unpacking of a fossil in 2009 then scientists have spent several years for obtaining their three-dimensional photos by means of the computer tomograph. These efforts were repaid – paleontologists managed to find not only traces of teeth of cubs of Kayentatherium wellesi, but also their skull, bone and traces of the fact that they were in eggs, but haven't been given rise to them by mother. © Photo: Mark A. Mlekopit Klinger/Carnegie Museum of Natural History



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