Presumably, many friends have caught dragonflies in childhood, watching a small and beautiful dragonflies flying in the air, is absolutely a great pleasure of childhood. But if there is a dragonfly with a wingspan of 75 centimeters, would you dare to catch it? If you think I’m flying in the sky, I can tell you clearly that such a dragonfly did exist. It’s called Giant Vein Dragonfly.
Giant Vein Dragonfly, also known as Giant Tail Dragonfly or Big Tail Dragonfly, survived in the Paleozoic Carboniferous 300 million years ago. Compared with modern dragonflies, Giant Vein Dragonflies have nothing special in appearance, but they are surprisingly large in size. The length of their bare wings reaches 75 centimeters, making them the largest known insect ever to appear.
Friends familiar with insects must know that there are two reasons why modern insects do not grow up very well, besides the fact that the body structure of the muscles in the skeleton can not support the body too large, the other is that the breath of insects enters the body cells directly through the trachea, rather than through the medium of blood as vertebrates do, so once the body shape changes. Large, the respiratory tract will be lengthened, which will inevitably affect the speed of oxygen into the body, thus affecting breathing. To sum up, according to the evolutionary view of “survival of the fittest”, large insects are obviously not suitable for living in the modern world.
So how do giant vein dragonflies come into being? So we have to talk about the oxygen content in the atmosphere at that time. Relevant researchers have found that during the Carboniferous period, the Earth’s oxygen content was 20 percentage points higher than it is now, and deduced that the 20 percentage points are enough to sustain dragonflies’breathing. As for how such large dragonflies survive, scientists have also given corresponding analysis, believing that they mainly feed on relatively small insects of the same generation, and even capture some small amphibians.
Fossil dragonflies were first discovered in France in 1880. In 1885, Charles Brongniart, a French paleontologist, described and named the fossil and classified it into the order Primitive Dragonflies of Insecta. According to the fossils unearthed, the objective is characterized by a spherical head, a toothed jaw on the head, a long thoracic segment, a long and soft abdomen, similar veins on the front and back wings, slightly longer front wings than rear wings, and strong and spiny feet.
Although giant vein dragonflies once occupied the sky by virtue of their huge size, their prosperity was not long. With the change of climate, the oxygen content in the atmosphere decreased, and the giant vein dragonflies declined gradually, and finally all disappeared in the Permian Period. Only fossil specimens are now stored in the French National Museum of Natural History in Paris, quietly telling visitors about its former glory.