Through known common sense, it is known that the oldest sea turtle in the world is the semi-carapaceed turtle that appeared in the Cretaceous era, and is the first progenitor turtle among the known turtles. Superstitious scientists investigated the fossils of the semi-carapace-toothed turtle and found that it lived in 2The Cretaceous period, 200 million years ago, became the freshest species of sea turtle in the world, and it also provides a key role for experts to delve into the history of turtles.
1. How big is the oldest sea turtle in the world?
The Archaeopteryx is actually a semi-carapace-toothed turtle, which is called the Archaeopteryx because it is found to be the oldest sea turtle in the world. Like the dragon shark, the semi-carapace-toothed turtle survived in the Cretaceous period, and archaeologists have found that the length of the half-carapace-toothed turtle reached 34 meters, width 3At 7 meters, it is also the largest.
Even though it appeared 2 years ago200 million years old, but the body structure and dorsal carapace** of the semi-carapace turtle are very similar to those of the leatherfish turtles that still exist today, and the structure of the abdominal carapace and ribs contained in the abdomen are very similar to those of modern turtles. However, it is much larger and unbeatable in age, and it is also through the semi-carapace-toothed turtle that people understand that the turtle originally originated in fresh water.
2. The characteristics of the world's oldest sea turtle.
Originally, in human cognition, it was thought that turtles were born with turtle shells and abdominal armor, and their purpose was to be able to shrink out and wrap themselves when they perceived the proximity of risk, but in practice, the role of turtle shells was to burrow and dig soil. However, the world's oldest sea turtle, the half-carapace-toothed turtle, does not have this trait because the half-carapace turtle does not have a shell on its back.
After the fossil investigation of the semi-carapace-toothed turtle, archaeologists found that in practice, the world's oldest sea turtle is a transitional body, which is a product of the turtle in the degradation link, and with the degradation and environmental changes, it gradually grows a dorsal carapace.
In addition, there are many characteristics of the turtle that are different from modern turtles, such as the contact surface of the vertebrae and the proportions of the skull, which are different from today's turtles. The eyes of the semi-carapaced turtle are relatively long in the front half, there is no acromion process in the body part, and there are sharp and very fine teeth in the high and low jaws, and the whole turtle is more like a transitional embryo of a modern turtle.
At present, it seems that the formation of turtle carapace did not change from the small bony plates on the back, but should have evolved from the bony plates of the ribs and abdomen.
Turtles and turtles, including turtles and turtles, are the most primitive groups of living reptiles and are also witnesses of the age of dinosaurs.
They survived the mass extinction at the end of the Cretaceous period, beginning in the Mesozoic Era and continuing to the present.
Regarding the origin of turtles and turtles, there has been a long debate in the field of paleontology.
The reason why this problem has become an unsolved problem is mainly because the body structure of turtles is too peculiar, and there is a lack of reliable fossil records for those who want to study this strange structure.
Turtle and turtle fossils are not uncommon, but all of these fossil groups exhibit almost identical body structures to living turtles.
Even the German Triassic (2.) was once considered to be the oldest fossil of a turtle (2100 million years ago), it looks like an ordinary turtle.
Not only do they have a carapace structure that closely resembles that of living turtles, but like the latter, the upper and lower jaws have no teeth, only a beak that wraps around the shell like that of birds.
In 2008, Chinese paleontologists were in Guanling, Guizhou ProvinceOlder primitive turtle fossils have been found in 200-million-year-old strata.
The body structure of this turtle is very different from that of all living or fossil turtles known.
It also has fine teeth on its upper and lower jaws.
What is even more strange is that the carapace of this turtle is very special, its ventral carapace is very similar to that of living turtles, but the dorsal carapace is almost invisible, only a few pairs of broad ribs on both sides of the spine that resemble willow leaves.
Paleontologists believe that this represents a rudimentary state in the early stages of dorsal carapace formation.
For turtles, the presence of teeth and unformed dorsal carapace are very primitive and rare features.
The oldest fossil turtle to date is known as a half-carapace, meaning a turtle with teeth and only half a carapace (ventral carapace).
For a long time before the discovery of the semi-carapace, paleontologists could not find a direct clue to the origin of the turtle, especially how the turtle carapace was formed, so they proposed two hypotheses and imagined two possible appearances of the turtle's ancestors.
The first is that the turtle ancestors had a large number of tiny bone plates in their backs**, which slowly fused with each other during later evolution, and at the same time sank under the skin, and finally healed with the spine and ribs, thus forming the carapace of the turtle.
The second is that the hypothetical small bony plates did not exist in the dorsal ** of the turtle ancestors, and the carapace was formed by their ribs gradually widening over a long period of evolution, and then connecting with each other, healing, and finally closing.
The semi-carapace-toothed turtle is the perfect embodiment of the second hypothesis, does it mean that it represents the form of the turtle's ancestor? More than a century ago, European paleontologists discovered another exotic reptile fossil in the Triassic strata.
It is difficult to paint a complete picture of the animal due to the fragmentation of the specimen, but it is certain that the animal had a wide rib cage and a carapace-like body made up of many small carapace pieces.
This carapace is different from the carapace of ordinary turtles, but it resembles the carapace of a living sea turtle called a leatherback turtle.
In light of this, paleontologists named the fossil saurophagis, sauro for reptile and phagis for young leatherback turtle.
Chinese scientists translated it as the dragon tortoise.
For a long time, fossils of dragon turtles were extremely rare, and a small number of specimens were found in Europe, but some important materials were lost in World War II.
It wasn't until 2011 that Chinese scholars found relatively intact bones in Yunnan and Guizhou that they were able to get a glimpse of the animal.
The fossil specimen in China was named the Yunnan-Guizhou Chinese dragon tortoise.
The situation of the Yunnan-Guizhou Chinese dragon tortoise is very much in line with the situation described in the first hypothesis mentioned earlier, the hypothesis of the origin of the dorsal bony plates of the tortoise carapace.
Stratigraphic data show that the survival age of the Chinese dragon turtle is about 20 million years earlier than that of the semi-carapaceed tooth turtle.
Chinese dragon turtle and semi-carapace-toothed turtle, who is the form of the ancestor of today's turtle and turtle? According to the existing materials and through complex paleontological methods, scientists believe that the Chinese dragon turtle has nothing to do with the ancestor of the turtle, and the semi-carapace-toothed turtle represents the most reliable primitive turtle at present.
Therefore, it seems that the formation of turtle carapace is not from the small bony plates on the back, but from the bony plates of the ribs and abdomen.
It is worth mentioning that the odontosaurus of the Triassic era, which had a wide body and a bony plate covering its back and abdomen, looked a lot like today's sea turtles.
They live in shallow water and, like turtles and turtles, have no teeth and beaks, which they use to eat shells.
But they have long been extinct and have nothing to do with living turtles and turtles.
Paleontologists from all over the world still have different opinions about the origin of turtles, and most of them are only speculations based on fossils, but it is not clear in one or two sentences to really say who the ancestors of turtles are.
According to records, the earliest reptiles that appeared on the earth were called "cup dragons".
Paleontologists compared the skulls of modern turtles with those of cupysaurs and found that their shapes were similar, so they believed that the ancestors of turtles were cupysaurs.
Whereas, the turtle evolved gradually from a branch of the cup dragon family.
The Cupysaurus, now called the Big-Nosed Dragon, is a biphyletic group of early reptiles, the earliest and most primitive reptiles.
In fact, we can understand it this way, the cup dragon is a prototype of all reptiles, the turtle is naturally evolved from the cup dragon, and then the prototype of the turtle appears, this is evidenced by the fossils unearthed in Germany and Thailand, the turtle body length of this period can reach more than two or three meters, the head and limbs can not be retracted into the body, and there are no teeth in the mouth, but there is a pair of large ear holes, so in order to protect themselves, they are covered with thorns and sharp thorns, look at this shape is a bit big snapping turtle meaning, It seems that the snapping turtle still retains some of its original taste, but the difference is that the "original snapping turtle" is mainly terrestrial, mainly infested in rivers, lakes and swamp areas.
It was not until the middle of the Jurassic period 160 million years ago that the first sea turtle evolved, and at the same time, turtles also evolved into two different types, one is a crypto-necked turtle that can retract its head directly into the shell, and the other is a side-necked turtle whose head cannot be retracted into the shell and can only bend its neck sideways to the side of the body.
These two types of turtles have obvious characteristics in modern turtles, and I think everyone should already know it.
Although there is no direct evidence, this is the most powerful statement of the origin of the turtle for a long time, but in November 08, that is, recently, the Chinese Academy of Sciences in China has a new insight according to the most primitive turtle fossils recently found in Guizhou: it is believed that the turtle does not originate from the land but from the water, because the ancient turtles of this fossil only have ventral carapace and no dorsal carapace, which shows that in the water they attack more from the lower part, and then to the land, due to the increase in attacks from above, So they evolved back armor, which sounds quite reasonable, but this has not yet reached the consensus of paleontological scientists in the world, and needs to be further verified.
Regardless of whether the ancestors of turtles came from water or land, they can indeed be called "living fossils", and they appeared at the same time as the dinosaurs but have survived until now, even the chalk that most creatures are extinct, they have survived, and they are surviving at a very slow evolutionary rate, perhaps this is why turtles have such a long lifespan and are so adaptable.
On the weekend, I took the baby to the Shuangyue Bay Turtle Base in Huizhou to see the turtles.
The history of the evolution of sea turtles actually gave me a little more knowledge.
Siberian Slong : Words, 2In the Permian period 600 million years ago, the primitive reptile Cupsaurus appeared.
Some of the cup dragons slowly evolved into Siberian dragons.
It is the ancestor of sea turtles.
At this time it does not have a turtle shell.
Semi-carapace-toothed turtle : Another 10 million years, about 2During the Triassic period 500 million years ago, a semi-carapace-toothed turtle appeared.
This half armor refers to having abdominal armor without back armor, and having teeth.
This suggests that the semi-carapace-toothed turtle evolved from the water, and because the abdomen of an animal that lives in the water is more vulnerable to attack, the abdominal carapace grows first.
Former Turtle : Another 30 million years have passed, about 2200 million years ago, the proto-jawtoise appeared.
It really has most of the characteristics of a turtle.
Because they began to live in the jungle near land rivers, they grew hard tortoiseshells to defend themselves against predators.
But it doesn't have the ability to shrink the head.
It is the common ancestor of turtles and turtles.
Amphibian tortoises : About 100 million years ago, during the transition period between the Jurassic and Cretaceous periods, due to crustal movements and climate change, the survival of the fittest turtles began to show their powers.
At this time, there are two kinds of curved turtles and side turtles, the difference is that the way of shrinking the head is different.
The shrunken-headed turtle appeared.
At this time, there are also three types of freshwater turtles, tortoises, and sea turtles.
Archaeopauchis: 70 million years ago, in the Cretaceous sea, the Archaeopaucus appeared.
It was huge, up to four meters long and weighing up to 2 tons, and was the ancestor of the current sea turtle.
It can be seen that its four legs have smooth lines, much like a paddle sliding in the water.
All in all, the turtle evolved from the Siberian dragon more than 200 million years ago.
After that, the vicissitudes of the sea, the earth's crust, climate, etc., changed, and the ancestors of the turtle slowly adapted to evolution.
Turtles first evolved in water, because turtle shells appeared first to defend against enemies in the water.
After that, the tortoiseshell appears.
Then the turtle slowly learns to shrink its head and evolves into an amphibian adapted to seawater, freshwater, and land.
These are the results of the turtle's adaptation to nature and its struggle against nature.
ps: The wind and the sun are beautiful, and the seaside scenery is very good.
At this stage, the production of turtle carapace is not transformed from the small bony plate of the back, but should be evolved from the bone plate of the rib bone and abdominal cavity.
Turtles and turtles, including small turtles and turtles, are the first group of living reptiles, and they are the guardians of the age of dinosaurs.
They survived the extinction of cluster servers at the end of the Cretaceous period, from the beginning of the Mesozoic Era to the present day.
Regarding the origin of turtles and turtles, the paleontological industry has been controversial.
This problem often becomes a mystery for many years, and the root cause is that the body structure of turtles is too novel, and the willingness to study such novel structures is the lack of reliable fossil records.
Turtle and turtle fossils are not common, but the main body structure of all these fossil groups is basically the same as that of living turtles.
Even once considered to be the oldest turtle fossil - French Triassic 2The 100-million-year-old protopalatine turtle looks like this ordinary turtle.
Not only do they have a carapace structure very similar to that of living turtles, but they also have the same crustacean structure as the latter, and they have no incisors in their upper and lower jaws, and can only encapsulate the beak of a cuticle shell like a bird.
In 2008, Chinese paleontologists have been in Guanling, Guizhou Province for 2200 million-year-old geological formations have found more historic fossils of the first turtles.
The body structure of these turtles is very different from that of all living or fossil turtles known.
It also has delicate incisors on its upper and lower jaws.
What is even more puzzling is that the carapace of this turtle is very unique, its ventral carapace is already very similar to that of living turtles, while the dorsal carapace is basically invisible, only a few groups of spacious rib bones on both sides of the spine shaped near willow leaves.
Paleontologists believe that this means a prototype of the initial stage of the dorsal armor.
For turtles, the unformed dorsal armor of a high monk with front teeth is a very initial and rare feature.
The oldest fossil turtle is called a half-carapace turtle, which means that it has incisors and can only be half a carapace and belly carapace.
For a long time before the discovery of the turtle, paleontologists could not find any immediate clues to the origin of the turtle, and they were very confused about how the turtle carapace was created, so they clearly put forward two hypotheses and conceived what the two turtle ancestors would look like.
The first type is that the skin on the back of the turtle ancestors affects many subtle bone plates, which gradually combine with each other in the subsequent evolutionary process, move down to the subcutaneous tissue, and finally heal with the spine and rib bones, and then produce the carapace of the turtle.
The second type is that these hypothetical small bony plates are not found in the dorsal skin of the turtle ancestors, and the carapace is produced by the gradual widening of their rib bones over a long period of evolution, then docking with each other, healing, and finally closed.
The semi-carapace-toothed turtle is the ultimate reflection of the second type of hypothesis, does it mean the shape of the turtle's ancestor? A century ago, European paleontologists had discovered this strange reptile fossil in the Triassic geological formations.
Because the specimen collection is very crushed, it is impossible to sketch the panorama of this small animal, but there is no doubt that this animal has a wide rib bone and a body structure composed of many small carapaces of similar carapaces.
This type of carapace is different from the carapace of a normal turtle, but it resembles the carapace of a living sea turtle called a leatherback turtle.
For this reason, paleontologists named these fossils saurophagis, sauro means reptile, and phagis means small leatherback turtle.
Chinese scientists translated it as the dragon turtle.
Fossils of dragon turtles have long been extremely rare, and Europe has found that a small number of specimens have been collected, and some of the key raw materials were lost in World War II.
It was not until 2011 that Chinese scientists found the relatively detailed human skeleton of this small animal in Yunnan Province and Guizhou Province, which was enough to fully appreciate its original appearance.
The collection of fossil specimens in China was named Yungui and China's dragon turtle.
The condition of the dragon turtle in Yunnan and Guizhou is very consistent with the first hypothesis mentioned above, that is, the hypothesis of the origin of the dorsal bony plate of the tortoise carapace.
The geological structure materials show that the survival age of the dragon turtle in China is about 20 million years earlier than that of the semi-carapaced tooth turtle.
China's dragon turtle and semi-carapace-toothed turtle, who is the shape of today's turtle and turtle ancestors? According to the current raw materials, according to the complicated paleontological methods of qualification, biologists feel that the dragon turtle in China has nothing to do with the ancestors of the turtles, and the semi-carapace-toothed turtle means that the initial turtle is more reliable at this stage.
Therefore, at this stage, the production of turtle carapace is not transformed from the small bone plate of the back, but from the bone plate of the rib bone and abdominal cavity.
It is worth mentioning that the odontosaurus of the Triassic period had a wide human body and a bony plate covering the back and abdomen, which looked very similar to today's sea turtles.
They live in shallow water, the same as turtles and turtles, have no front teeth and rich beaks, and are used to eat coconut shells.
However, they have long been extinct, and have nothing to do with living turtles and turtles.
In the first epoch of the Paleozoic Era. The end of the Cambrian period is about 52 to 5500 million years ago, a seemingly weak and powerless animal Haikou worm appeared on the earth, the scientific name of the ear material village Haikou worm.
It was the second great moment in the history of the earth since the emergence of life 3.8 billion years ago, when invertebrates evolved vertebrates for the first time, and it is also our common ancestor with turtles, and its descendants include all existing vertebrates.
In the Cambrian period, the sea was full of dangerous creatures.
Tens of millions of years have passed, and the pace of evolution has not stopped.
Our common ancestors with turtles lived in water and evolved until the Ordovician.
The Ordovician period is the second epoch of the Paleozoic Era.
The petite Haikou worm evolved its first gigantic shell to defend against predators such as the Aurora hornstone, and in the Ordovician period, jawless fish with carapace evolved for the first time.
Fish that have no osprey and only round mouthparts can only prey on small plankton.
Countless tides, sunrises and sunsets.
The ancient ocean roars.
Unconsciously, tens of millions of years have passed to reach 43.8 billion years of the Silurian period.
For the first time, small ferns began to grow on the earth, and turtles and our ancestors began to evolve into echinoculus with carapace and upper and lower jaws, and our ancestors' opponents arthropods such as sea scorpions, horseshoe crabs, and giant winged horseshoe crabs.
It has been fighting like this for tens of millions of years.
Arrived in the Devonian period about 3700 million years ago, fish began to dominate. The Devonian period was the age of fish.
In the Late Devonian period, a branch of total-finned fishes evolved into quadrupeds and began to land on land, and in the early days quadrupeds could not completely leave the waters, also known as amphibians, and the known early amphibians called ichthalds lived in 3700 million years ago in the Late Devonian.
The larvae live in water and survive in a terrestrial environment, and cannot completely leave moist swamps and freshwater waters.
As some amphibians explored the land, some went further and further until the Carboniferous. More than 280 million years ago, the first reptiles were born, which is another epoch-making sign in the history of biological evolution.
Vertebrates can now lay eggs with amniotic membranes on land.
Four-legged vertebrates can go farther, and the earliest reptile known to lay eggs on land is called the carboniferous lizard.
After the Carboniferous period passed, the primitive reptile Cuposaurus appeared in the Permian period 260 million years ago.
Part of the cupsaurus specialized evolved the body parts from the Siberian cupsaurus.
But it's still far from the turtle's form.
Until it was discovered that the Triassic era semi-carapace turtle was found in Guizhou, the half-carapace tooth turtle is a special and strange species, proving that the turtle evolved in the water and the ventral carapace evolved first than the dorsal carapace.
Because the abdomen of animals living in water is more susceptible to attacks such as cup ichthyosaurs and phantom dragons, the turtle fills the gap in the evolution of the turtle, which only has an abdominal carapace without a dorsal carapace, and also has teeth.
It is a very primitive characteristic.
Time passed, tens of millions of years ago, and at the end of the Triassic period, primitive turtles that really had most of the characteristics of turtles appeared, also called protojaw turtles.
Because they began to live in the jungle near land rivers to defend against enemies, they evolved a strong back armor, which is the rib plate of the turtle, and only by thickening and widening did they evolve the back carapace to defend against enemies.
However, the protojawed turtle does not have the ability to shrink its head, and it is the common ancestor of the existing turtles and turtles.
Gradually, through the Jurassic to the Cretaceous. The suborder Curvature and Side-necked Turtle suborder evolved.
Among them, the Manchurian turtle in the Late Jurassic and Early Cretaceous curved neck turtles evolved from the post-Cenozoic snapping turtles.
In the Cretaceous Ocean, the world's largest turtle ever lived, the dinosaur tortoise, also known as the giant ancient turtle, can reach 4 meters, and the offspring that survive now are marine leatherback turtles that can reach 2 meters.
The suborder Curve-necked Turtle includes many extant phyla, such as the Tortoise family.
Freshwater turtles, hawksbill turtles and so on.
There is also the Maoming turtle in Maoming, Guangdong in the Miocene of the Cenozoic.
Over the next 100 million years, many phyla evolved into the Side-necked Turtle family, but they were far less extensive than the suborder Curve-necked Turtles.
Types such as snake-necked turtles and side-necked turtles have evolved.
In Australia, the Cenozoic Miocene has been excavated for 2A 7-meter giant side-necked turtle fossil.
China's famous tortoise fossils were unearthed in Gansu Hezheng, also called Hezheng tortoise.
The carapace is similar to that of today's continental and other species. The primitive type of tortoise belongs to the southern male turtle produced in China, which lived in the Late Jurassic and Early Cretaceous.
The carapace was not as high and bulging as the modern tortoise, but relatively flat, and the body length could reach 14-1.About 6 meters.
It also shows the primitiveness of the living concave tortoise and the boot-footed tortoise, which are more similar to the modern tortoise than the southern male tortoise and the political tortoise.
1. Spiral tooth shark.
As many of you know, sharks are one of the oldest species on Earth, and their ancestor, the Spiral Tooth Shark, is far more shocking. The structure of its impressive jaw caused many problems for scientists, as they could not find 2A complete replica of this animal that disappeared 200 million years ago.
It is speculated that this animal would use this bizarre tooth to catch a mollusk with a shell. For centuries it was thought that the saws on their mouths were in the nose of this creature, but the discovery of similar species led to the conclusion that it was located in the lower jaw.
2. Shovel-toothed elephant.
You may wonder how elephants develop their distinctive long trunks. Judging by the fossils of this creature, millions of years ago, it was attached to its mouth, an animal with two large teeth in its jaw, through which it could dig lakes, break bark, build soil, and feed on the roots of plants.
The size of this creature is comparable to the current African elephants, and in those days they weren't very large, but their powerful incisors could scare away anyone who wanted to disturb it. Its discovery became the answer to the missing link in the evolution of this species to this day.
3. Pacific traveling whales (four-legged whales).
Fossils found from other eras suggest that these animals (whales and dolphins) evolved from amphibians similar to otters, but a discovery in Peru provides new data on these species.
In addition, research has shown that early whales migrated to the Pacific Ocean through the South Atlantic Ocean and around South America, so it received the name "whale traveler who came to the Pacific Ocean". The discovery and name greatly challenged the theory that cetaceans came from North America and opened the door to continue to dig into the history of these fascinating creatures.
4. Gerobatrachus Hottoni (frog salamander).
Popularly known as the "ranamandra" since its discovery, the creature is characterized by having a tail and legs, fused ankles like a salamander, and a skull as broad as a frog. On the other hand, its spine has the characteristics of two animals. This finding helps to settle the debate about whether the two species have a common ancestor.
5. Semi-carapace-toothed turtle (a half-shelled turtle).
It's hard to imagine turtles without their shells, but the discovery of this fossil reveals how turtle shells originated as a defense mechanism millions of years ago. The oldest known turtle half-carapaceed turtle has only the ventral carapace (a type of breastplate) on the front, and it took thousands of years for their back to become a hard shell that protects today's turtles. Another distinctive feature of this creature is its teeth, which do not resemble modern turtles, as they have an elongated neck and tail.
6. Decennatherium Rex (the oldest giraffe).
The oldest predecessor of the modern giraffe was found at the site of a mountain camp in Madrid. Interestingly, they have short necks and their diet seems to be more varied, feeding on trees and grasses.