Some time ago, the Institute of Southern Antiquology of the Chinese Academy of Sciences reported that our researchers found a new fossil in South China, which is a new genus of the mixed-winged horseshoe family, and named it: Xiushan phobia.
But the species was long extinct, living in the Silurian Period 430 million years ago, much earlier than the dinosaurs lived. According to the restoration map, the Hideyama phobia (hòu) is the following guy, which belongs to a kind of plate-footed horseshoe crab.
Ecological restoration map of the crab (Source: Nanjing Institute of Paleontology, painted by Yang Dinghua)
Because it looks very similar to a scorpion, it is also called: "sea scorpion". There are more than 300 species of plate-footed horseshoe crabs, which were born 470 million years ago, became extinct 250 million years ago, and lived for more than 220 million years.
The Hideyama horseshoe crab is marked in blue
Although the plate-footed horseshoe crab lives in the ocean, due to the very strong evolution of limbs, some species have the ability to move on land, these species of horseshoe crabs, in addition to the gills used to breathe in the ocean, also evolved a second set of gills, used to breathe on land, is a veritable amphibian.
This species also has a surprising feature: it is particularly large. In 2007, scientists discovered limbs up to 0.46 meters long and then extrapolated that the total length could reach 2.6 meters. In addition, 1.6 meters, 1.83 meters, close to 2 meters, etc.; the horseshoe crabs found in South China this time are considered small.
And now the existing arthropods in the world, like insects, crabs, shrimp, spiders, scorpions, are simply incomparable in size.
Extinct with modern arthropods
Near the head of the plate-footed horseshoe, there are two pairs of huge pairs of pliers, covered with hard spines, the tail is like a scorpion, and the whole body is covered with thick armor formed by exoskeletons to protect itself. As carnivores, they could easily kill all kinds of fish, enough to dominate the ocean, and were the top predators at that time.
Despite its mighty capabilities, it was hit hard by the late Devonian extinction event 370 million years ago, with most of the plate-footed horseshoe extinct and a small number of adaptable horseshoes completely extinct 250 million years ago.
This is the first time in history that arthropods have been at the top of the food chain, but also the last, so studying them can better help us understand the diversity and geographical distribution of prehistoric organisms.
Although our research on the plate foot crab has been going on for many years, in fact, the fossils of the plate foot crab have always been very scarce, and the fossils found so far are almost all from Europe and the United States, but China is very rare.
After years of field exploration by scientists, they are actually hidden in all corners, waiting for our excavation.
The newly discovered hybrid crab has not been reported for 80 years, and the previous discoveries have not been in China (prehistoric Gondwana), which makes the new discovery in South China particularly important.
The fossils of the Xiushan horseshoe crab have greatly filled the gap in the continent of Gondwana.
Both the horseshoe crab and the plate-footed horseshoe crab belong to the class of limbs, but the appearance of the horseshoe crab is very similar to that of trilobites. Horseshoe crabs are not close relatives to trilobites, and are subphylum trilobites and trilobites. Horseshoe crabs have been living in the world for more than 400 million years, and to this day, this ancient creature still retains its original appearance, and people also call it a "living fossil".
The "living fossil" horseshoe crab has survived for hundreds of millions of years, and after overcoming the ups and downs of the long years, it is now in a dilemma of survival. The main reason is because of their special and rare blue blood, which is of extremely high medical value and has been blessed by almost all of them.
We all know that the blood of most animals is bright red, which is because in the blood of most animals, the iron-based hemoglobin is used to transport oxygen, and the combination of iron and oxygen forms the common red blood.
But in the blood of the horseshoe crab, the iron becomes copper, and the color of the copper oxide is exactly blue-to-green, which is why the blood of the horseshoe crab is a dark blue visible to the naked eye, and the protein in their blood is also called "hemocyanin" in medicine.
The magic of these blue bloods lies in its powerful antibacterial ability. Horseshoe crabs do not have white blood cells in their blood, and in order to ensure that they are not swallowed up by bacterial infections, they have slowly evolved a protective mechanism that is different from other animals.
When bacteria come into contact with it, it does not phagocytosis like white blood cells, but rather chemicals that can locally coagulate the blood after atrophy and rupture, so that the bacteria coagulate and block the destruction of bacteria.
In 1956, biologist Fred Bang discovered that the dead form of a horseshoe crab was extremely strange, because the blood of the whole body of the horseshoe crab, which was infected with the gram-negative bacteria, was almost all coagulated and colloidal.
Using this finding, fred bang extracted a bacteriological detector from the blood of the horseshoe crab called the horseshoe reagent. The reaction of the horseshoe reagent to the bacteria is very rapid, and the sensitivity is higher than that of other drug reagents, even if the concentration of one hundred millionth of the bacteria detected cannot escape its detection.
Finally, each of us has been blessed with the blood of the horseshoe crab, such as injection drugs, plasma products and even some anti-cancer drugs, there are traces of the blood of the horseshoe crab, so the blood of the horseshoe crab has become one of the most precious blood in the world. It is hoped that human beings will not cross the river and tear down bridges because of this, and the survival of "living fossil" horseshoe crabs will not be affected because of their own selfish interests.