People who often watch fantasy**, or know a little bit about ancient Chinese culture, should know it"Xuanwu".The name of the Mighty One. Xuanwu, also known as "Xuanming", has the form of a turtle and a snake, and was considered by the ancients to be one of the four sacred beasts, ruling the north, and is also regarded as the god of the north and the god of water.
And because the ancient people believed that the underworld was in the north, Xuanwu was also believed to be able to ask the underworld for divination, and in later generations became the Zhenwu Emperor who was enshrined in Taoism, and the turtle with the same characteristics was therefore considered to be the human incarnation of Xuanwu, and its turtle shell was also used by people as a tool for divination and fortune-telling.
And because of the status of Xuanwu and the effect of calming houses and attracting wealth in feng shui, turtles are often kept at home by people to settle down and prosper their fortunes. In addition, the dorsal and abdominal carapaces of the turtle are also used in medicine, mainly for yin deficiency, hot flashes, heart deficiency and forgetfulness and other diseases.
So how did the tortoise evolve its tortoise shell, and how did it develop in the history of the Earth? In fact, scientists have had several headaches studying the evolution of tortoisesThis ancient Chinese mythical beast once became a "nightmare" for scientists
The turtle belongs to the turtle family, a reptile of the genus Hydrochloroise, and it has a tortoise shell, and the dorsal and ventral carapaces wrap its body in a clump, leaving only 6 holes so that its limbs and head and tail can be retracted. Turtles are omnivorous animals, can eat anything, such as insects, fish and shrimp, melons and fruits, weed seeds, etc., but also very hungry, mainly live near the water, half water and half habitat, at the same time is also half land, generally soaked in water during the day.
Turtles have been living on Earth for a very long timeIt has existed here almost since the Triassic, which is also the earliest era of the Mesozoic era in geological historyIt's about 240 million to 200 million years from now, in the middle of the Permian and Jurassic periods, coincided with the beginning of the rise of gymnosperms and reptiles.
Scientists have found that the turtle's shell is actually itThe ribs in the body grow outward, wrapping around the shoulder blades and fusing with the vertebrae to form one, which can act as a protective shell, and when the turtle encounters danger, it can shrink the outer limbs into the shell to avoid being injured by predators or attackers.
However, not all turtles are able to stretch their limbs, such as sea turtles, which choose to come to the ocean in order to adapt to the environment, but in order to survive well in the ocean, their shells have become more and more flattened in order to reduce resistance and maintain the speed of movement in the water, but because of this, the turtle has lost its role in retracting its shell.
In 1887, German scientists discovered a fossil of an ancient creature with the biological characteristics of turtles and turtlesIt is considered to be the original ancestor of all turtles today。It is not particularly different from modern turtles, except that it cannot retract its head into its shell, and the proto-jaw tortoiseshell is surrounded by a ring of bony plates, which and the nasal bones have small tooth-like teeth, the teeth disappear, and the two jaws become, protruding beaks forward.
The Mesozoic protojawed turtle has evolved into the morphology of the modern tortoiseSo what kind of creature did the protojawed turtle evolve from? With such doubts, scientists believe that it is a life of 2900 million years ago, the sawtooth dragon further evolved into the protojawed turtle.
This is because as early as the Permian, when reptiles had not yet risen, it was the sharp-toothed beasts that dominated the earth, with very sharp fangs, and often relied on this "big steel tooth" to bite and kill prey. In order to survive, like:On its back, the dragon grew a shield that spread from its neck to its tail, relying on his own armor to "go head-to-head" with these hunters.
At the same time,Serrats were large quadrupeds that walked in a similar way to turtles, with a body length of about 25 meters, the legs are as thick as an elephant's legs。So at the end of the last century, scientists thought that the ancestor of the turtle was a type of serratosaurus, and that it was at that time that evolved a thick tortoise shell to fight against predators with sharp teeth, thus becoming a protojawed turtle.
However, in 2008, China discovered the fossil of a semi-carapace-toothed turtle in Guizhou, which directly overturned the theory of the original scientists. After research and analysis, this newly discovered creature is about 10 million years earlier than the protojawed turtle, at this time they did not have a dorsal carapace, only developed an abdominal carapace, and their teeth did not degenerate, just like a turtle that has evolved halfway, which is also the origin of its nameThat is, "half a carapace" and "toothed".
If, according to previous scientists' deductions, the ancestor of the turtle was a sawtooth dragon, then in order to defend against natural predators, it should be the dorsal carapace that was advanced instead of the ventral carapace.
And the serratosaurs were herbivores, with short and thick teeth, just like the teeth of horses, cattle and sheep that we see now, while the teeth of the semi-carapace-toothed turtle were obviously small and sharp teeth, which were obviously the teeth of small carnivores. Hence the conclusion:The sawtooth dragons were not the ancestors of the tortoise
In order to continue to study the evolutionary path of the turtle, scientists have found the ancient fossils of the Zhengnan turtle, which were originally discovered in the early 20th century. In fact, the southern turtle has been thought not to be related to the modern turtle earlier, and it has been divided into the evolutionary clade of parareptiles, but in 2010,Phylogenetic studies suggest that the southern turtle is the ancestor of the modern tortoise
The Truenan turtle is probably in the Middle Permian of South Africa, about 2At 800 million years, it had a smaller number of dorsal vertebrae, and its ribs were significantly wider and thicker in order to dig caverns, but it had not yet evolved dorsal and ventral armors. But because of these changes,The southern's spine also becomes stiffer, making it difficult for it to escape predators. So in order to survive, the Zhengnan turtle began to "arm" itself and fold its armor.
And in 2015 Germany discovered a life in 2The 400 million-year-old turtle fossil, scientists call it the ancestral tortoise, although it is still not fully developed tortoise shell, but the ribs are wider than the south tortoise, and the abdomen has also formed a hard wall composed of multiple bones, and there is a trend of developing called the abdominal carapace.
And because of this,Scientists speculate that the evolution of the turtle was from the southern-type turtle to the ancestral turtle, and then developed into the proto-jawed turtle, which was the beginning of the modern turtle
However, molecular biologists have studied and analyzed the genes of reptiles and found that the ancestors of turtles and crocodiles and birds may be the same kind of creatures, and they have some of their characteristics.
Further evidence is the tempotemporal foramenIn order to increase the bite force, reptiles will have one or two temporal orifice on their skull, and the turtle is the only reptile that does not have temporal orifice. Some believe that the common ancestor of the turtle and the crocodile was a superorder of the Scalysaurus, which came to land from one branch of the water and evolved into a lizard-like ancestor, and the other evolved into an avoidora and a dipret.
Some people believe that their ancestors were bicellular reptiles from the beginning, but the turtles "deviated" and evolved into non-porous species. And when this ancestor existed, the South Turtle also existed, so the South Turtle was not the ancestor of the turtle.
However, these issues have not yet been sorted outIn 2018, another fossil of a protobeaked turtle was discovered in ChinaIt is a completely different form from the ancestral turtle and the semi-carapaceed tooth turtle, which has evolved a form with a partial beak but no tortoiseshell. This also makes the evolution of the turtle more confusingIt's like the ultimate "bug" in evolution, unpredictable, but even more intoxicating to indulge in the mystery.
The development of living beings is so mysterious and wonderful, we believeWith the future more fossils about paleontology unearthed, we can also know more about the ancestors of the turtle and know more about its evolution. **10,000 Fans Incentive Plan