Discovered a tiny ancestor of the dinosaurs
In the Triassic deposits of Madagascar have found a small fossil reptile. Animal of no more than ten centimeters refers to the group, that led to the giant dinosaurs and pterosaurs. Detailed description of the findings given in the journal Proceedings of the National Academy of Sciences.
Dinosaurs and flying reptiles, the pterosaurs are famous for their huge size. It is therefore surprising that their immediate ancestors were very small. In the Triassic sediments age 237 million years in the South-West of Madagascar found the bones of reptiles, called Kongonaphon kely, or "tiny killer bugs".
"There is a General perception of dinosaurs as giants. This new animal is very close to the time of life to the place of divergence of the branches of dinosaurs and pterosaurs, and it's amazing little" — presented in a press release from the American Museum of natural history in the words of one of the study's authors, Christian Kammerer (Kammerer Christian), curator of research in the field of paleontology at the Museum of natural Sciences North Carolina in the United States.
And dinosaurs, and pterosaurs belong to the group Ornithodira — priceladies, the origin of which is not very well known, as found a few samples related to the beginning of the line. Description of coronatine will help scientists to explain how the pterosaurs began to fly, as well as the origin of down and feathers from representatives of both branches.
Before this it was considered that all early archosaurs — a larger group of reptiles, which included birds, crocodiles, naticia dinosaurs and pterosaurs, including pitseleh, body size at first was about the same, and then began increasing in size. It is now clear that along with the consolidation, some members have evolved to decrease.
"Analyzing changes in body size during the evolution of archosaurs, we found irrefutable evidence that it dramatically decreased at the beginning of a line of dinosaurs and pterosaurs," says Kammerer.
Triassic deposits of the South-West of Madagascar is unique in that it has previously been found several fossils, which has allowed the closure of many white spots in the evolutionary history. Now is the time of coronation, which was lying neglected in a Museum since 1988.
"The opening of this tiny relative of the dinosaurs and pterosaurs emphasizes the importance of fossils Madagascar to improve the knowledge about the history of vertebrates in General", — said the head of the project with local actors, Professor and Director of the laboratory of vertebrate paleontology at the University of Antananarivo Lovasoa Radiokhimiya (Lovasoa Ranivoharimanana).
For example, wear of the teeth of coronatine suggests that it ate insects. Perhaps the "miniaturization" and avoiding meat food, competition for which is among the larger contemporaries were very high, let the small ancestors of dinosaurs and pterosaurs to take a comfortable for the evolution of the niche.
Another advantage could be the skin of a reptile covered with feathers, which may later developed feathers. According to researchers, the fluff was used for thermoregulation. The body of the animal was very small, and internal resources to maintain a stable temperature is likely not enough. And the middle-late Triassic was a period of very extreme climate, the huge diurnal temperature swings between hot days and cold nights.
The authors believe that all these features physiology, slojivshuyusya small early ancestors of the dinosaurs, then helped their larger descendants to occupy a dominant position on the planet.