About 200 million years ago during the Triassic period, when the horizon began to take shape now the demise of the dinosaurs long empire, there were already 'the armored beings whose line and whose shapes were then proved sufficiently perfect to allow them to travel to the present day with a few changes: they were the first turtles.
Their fossil 'old have been found in Triassic deposits of Germany and have allowed us to demonstrate how some of the key features of these animals, such as the skull very robust and consists of a small number of bones or the imposing protective armor, specimens are also common today.
Despite the numerous fossils studied and several theories set out by paleontologists over the past one hundred years, the origin of turtles and the appearance of their ancestors' continue to the next is still a mystery.
During the Mesozoic, ie from 65 to 225 million years ago, reptiles ruled the Earth. They had made their appearance in the Carboniferous period, evolving from amphibians and becoming the first vertebrates adapted to life in arid environments. Their eggs, unlike those of amphibians, did not need to be laid in the water and were wrapped in a protective casing that isolated dampness '(or the legacy' of the environment). Their well-developed lungs, the efficiency of their circulatory system and internal fertilization by the male copulatory organs (double in lizards and snakes) were some of the features that facilitated the survival of these animals.
had appeared during the Carboniferous period some small reptiles on Earth (about 50 cm in length) called Cotilosauri (Order of Cotilosauria), which are probably the ancestors 'primitive of our turtles and including the gender Seymouria is likely the most' primitive at all. These animals were characterized by a troncogrosso and slightly compressed, with a short tail, very wide at the base and narrow tip, 'and legs too short and fitted with five fingers. It is believed that the Cotilosauri presented its side, a factor which shows their amphibious existence. Currently
and 'was universally accepted that the most' ancient representative of the order Chelonia (Chelonia) is the kind Eunotosaurus, although between them and remains a significant gap Cotilosauri nellambito the fossil record. Some Eunotosaurus africanus fossils were found in southern Africa in various strata of Permian average (this was the remains belonging to specimens in poor condition): despite being fornt of teeth and possessed a number of other features common to reptiles' primitives, we have the reason to believe that they are to be considered more 'close to the turtles that current forms comosciute still primitive. The search of the 'missing link' of turtles in the chain of evolution continues today.
0 comments:
Post a Comment