Now when everyone mentions arthropods, they will think of those millimeter-level to centimeter-level small bugs, but in the history of the earth, there is a huge insect era, that is, the Paleozoic Carboniferous, and the ancient centipede worm is in this era.
Ancient martial arts ~ arthropod
A giant of the insect world
The Carboniferous period dates back 359 million to 299 million years and lasted about 60 million years, during which the climate was warm and humid, with large areas of tropical rainforest and marshland, and the fossil fuels and coal we use today were mainly formed during this period, hence the name Carboniferous gas.
At that time, the atmospheric oxygen content reached a peak of 35%, which was very suitable for arthropods to thrive, thus giving birth to a large number of huge insects, and diving animals are the landing pioneers of the biological world, they began to migrate from the sea to the land as early as about 450 million years ago in the late Ordovician period, compared with other phyla, the basic structure of arthropods is very suitable for landing.
Their hard exoskeletons prevent water dispersion, strong legs allow them to support their weight and move around, crossing obstacles, polypods landed on land in the late Ordovician, are one of the first organisms to land, the living members of this group include centipedes and horses, the giant centipede known as the well-known giant centipede, is actually a creature called arthropods, they flourished in the Carboniferous period, they look more like the demons of the insect world.
Ancient centipede
Arthropods belong to the polypod suborder Shellfish, centipedes belong to the Zoopoda, they are not a species, although they are similar, but very far related, so arthropods are not giant centipedes, but and Maru is a large class, the body of arthropods is sectional, there are about 30 segments, the tail segment is covered by two side plates and a central plate, the ratio of the logarithm to volume of the foot is eight to six, there are many types of this number, the small one is only 30 centimeters, the large one is 2.5 meters long.
Among the footprint fossils of giant arthropods found in New Mexico, there are two similar parallel tire traces, which show that this arthropod is at least half a meter wide and 2.4 meters long, which is the longest land arthropod in the Carboniferous period, but you don't need to be afraid, because from the fossils, the arthrothoracic does not have a strengthened mouth and nose, and the intestinal fossils are also some stone pine debris and fern spores, indicating that arthropods feed on plant debris and are purely vegetarian.
There are also fossils of arthropod footprints found in many places, these fossils are a row of small parallel footprints, it can be seen that they can walk quickly, through the forest, when walking fast, their bodies will elongate, and at the same time lengthen the step distance, so that they can walk faster, arthropods can help spread pollen and spores when walking, they may also walk in water, lakes and rivers shed their shells,
At this time, they are very vulnerable to fish and amphibians, but they basically have no natural enemies on land, why did these arthropods evolve more and more in the Carboniferous period? This is related to the atmospheric environment at that time, marine arthropods originally breathed with gills, and insects landed to form a unique way of breathing.
They bypassed their own circulatory system, formed a series of tiny trachea on the surface of the hard exoskeleton, injected oxygen directly into the tissue, and in this diffusion breathing mode, the atmospheric oxygen content directly determines how much oxygen the insect tissue can get, the land plants of the Carboniferous period are very luxuriant, the atmospheric oxygen content rises sharply, and insects have grown amazingly in an environment with excess oxygen.
The end of the insect giant
But once the superior environment changes, they will be destroyed, 300 million years ago, at the end of the Carboniferous period, the earth entered a brief and intense ice age, the sea level dropped 100 meters, glaciers covered the southern part of the gammana continent, the climate was warm and humid, and it changed to cool and dry.
With the gradual formation of the Pangea supercontinent, the inland areas are becoming more and more arid, the primeval forests have withered into isolated plates, confined to the ice-water area, and are more and more far apart, large areas of land are desertified, atmospheric oxygen content has dropped sharply from 35% to 15%, and arthropods have gradually gone extinct due to insufficient oxygen.
The Carboniferous period is both the era of giant insects and amphibians, and the era of joint rule by land arthropods and amphibians.
If you put it now, such a large invertebrate will soon suffocate and it will not be possible to survive, so this very large arthropod can only appear on our models and imaginations.