Questedti and talampayensis. What are these two fossils? It has something to do with turtles. Ask for help.

The answer is as follows: Please read it carefully. Don't waste my painstaking translation.

Progressivism? Quentin: Protojaw turtle.

A fossil accidentally discovered in Guizhou Province, China, holds the key to a long-term scientific mystery-how did tortoise shells evolve? The evolutionary history of turtle shell has always been a mystery, and the skeleton fossil of this animal named "half-toothed turtle" finally provides scientists with enough clues. Its discoverer, Mason Lee, an associate researcher at the Institute of vertebrate paleontology and Paleoanthropology, Chinese Academy of Sciences, happens to be a senior turtle fan. Let's explore the wonderful history of turtle evolution with his enthusiastic talk.

1 found it? Turtle shell is a big mystery.

Mason Lee said that he only made a field investigation in GUANLING, Guizhou, and didn't want to look for tortoise fossils-although he predicted in his report to the National Natural Science Foundation of China two years ago that the earliest tortoise fossils might be found in this area. By chance, Mason Lee saw the first specimen on a stone pile where a fellow villager was going to build a house. At that time, it looked like an ordinary stone. Back in the laboratory of vertebrate paleontology Research Institute, he began to clean up this fossil step by step. At the moment when the bone shape began to be exposed, he immediately realized that it was the oldest turtle fossil ever discovered.

It turns out that Mason Lee was a "turtle fan" from a very young age. In the third grade of primary school, Mason Lee raised his first pet turtle, the yellow-edged turtle. This pet turtle, usually called "golden head", is quite common now, and it was still a rarity at that time. Later, in the early 1990s, he bought a turtle in Beijing Guanyuan Flower and Bird Market. He suspected that it was a legendary concave tortoise that had been extinct in China, so he tried his best to find the famous turtle expert Huang in China at that time. After Mr. Huang's identification, it is indeed a concave turtle, probably shipped from Vietnam. In addition, Mason Lee also raised Hainan closed-shell turtles, flower turtles and flower-throated water turtles.

No wonder Mason Lee immediately realized the value of this new discovery. The evolution of turtles has always been the biggest mystery in the evolutionary history of vertebrates. Mason Lee emphasized that this mystery is "the biggest one" without even adding "one".

He didn't say this completely out of his preference for turtles, because the oldest turtle fossil "Proganochelys" found before has a complete turtle shell, which is almost the same as the modern turtle shell, and the more modern turtle fossil also has a complete turtle shell, so it can be said that the turtle shell originated in without a clue. In addition, a series of strange characteristics derived from crustacean structure make turtles have completely different body patterns from other quadrupeds.

2 research? Fossils prove that the bellybutton was the first.

Mason Lee's research team named this ancient turtle "Toothed Turtle"? Semitestacea) means a tortoise with teeth and only half a shell. By measuring the age of strata, it can be determined that the "half-toothed turtle" fossil discovered this time was formed 220 million years ago, which advanced the history of turtles by more than 65.438+million years. This turtle still has teeth, which means it is still primitive. In addition, turtles of all fossil species and living species only have beaks as hard as birds, but no teeth.

More importantly, this fossil proves that there are two major steps in the evolution of turtle shells. The first step is to form the abdominal nail, then connect the specialized spine with the widened ribs, and then form the back nail. The upper abdomen evolved from the abdominal ribs. Abdominal rib is not a rib, but a long ossified tissue in reptile skin, especially in aquatic reptiles. Living reptiles such as crocodiles and cuneiform lizards also have abdominal ribs.

The tortoise's bellybutton has been fully formed, but only a part of its shell extends from its spine and shows widened ribs, which shows that its carapace is only half formed, which also proves that the tortoise's bellybutton was formed first.

This discovery makes the previous hypothesis of "small deck healing" about the formation process of turtle shell questioned. Previously, the popular theory in paleontology believed that there were a large number of small bone plates in the back skin of turtle ancestors, and then these dermal bone plates healed and sank under the skin, and healed with the spine and ribs, forming the tortoise shell we see today.

So, why did the tortoise advance into the abdominal armor? This leads to another important conclusion of the research team: turtles originated from water.

3 speculation? The ancestors of turtles came from water.

Reptiles living on land do not need the protection of abdominal armour, because most of their bodies are close to the ground, and it is almost impossible for the enemy to attack them from this position.

Mason Lee and others believe that animals in aquatic environment, especially when swimming, are more vulnerable to attacks from below than from above. This is also obvious in fish, most of which have white bellies, which is called "white bellies". This is because they are vulnerable to attacks from below. If the abdomen is white, it can be integrated with the sky above and become a "protective color". The ancestors of turtles solved problems in a slightly different way from fish. They won't try to fool dangerous attackers-after all, it's not that easy to fool. They turned to active defense and developed abdominal armor to provide protection for fasting. After comparing with the living turtles, the researchers think that the aquatic degree of the half-toothed turtle is similar to that of the living turtles.

When it comes to aquatic turtles, turtles are probably the easiest thing to think of. So, what is the relationship between the half-toothed turtle and the tortoise? Mason Lee said that although paleontologists can't fully determine the evolutionary history of turtles at present, it is certain that today's turtles are completely different from those with half teeth. Turtles have flippers suitable for "flying" in water, while half-toed turtles have claws similar to turtles.

■? interconnection

Ancient giant tortoise

The history of turtles is even older than dinosaurs. In more than 200 million years, many kinds of turtles have been produced, and now a large number of turtle fossils have been unearthed. Let's take a look at two famous prehistoric turtles.

How's the Protojaw Turtle progressing? Kunstetti

Protojaw turtle is the oldest turtle fossil discovered by human beings before the discovery of half-toothed turtle fossil.

It lived in the late Triassic period 200 million years ago. Except that the head can't be retracted into the shell, it is not much different from modern turtles. Its teeth have disappeared, its jaw has formed a horny beak, and its body has been protected by tortoise shells. Protojaw was first discovered in Germany, and also found in northern Thailand 1980 to 198 1. So far, protognathus has not been found in China.

Archelon, an ancient giant turtle? Iskilos

The biggest turtle in history.

The first ancient giant tortoise fossil was found in 1895. This fossil is very famous, on the one hand, because it is huge, on the other hand, because it lacks the right hind foot, and it is likely to be bitten off by some huge carnivore. The ancient giant tortoise fossil in the 1970s is the largest turtle fossil ever discovered, with a length of over 4m and a flipper width of over 4.87m.,

Ancient giant turtles are very similar in appearance to today's turtles. They have biting beaks and may feed on animals such as squid.

Paleontology? Taranpais? Ancient tortoise? Fossil size: 70 cm in length?

Location: Upper Triassic strata in northwest Argentina, Los Angeles, Colorado, Caracas.

The story of the tortoise

In the second of three articles written by Gallas, Dawkins believes that another extraordinary animal of Richard has helped Darwin's theory of evolution.

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Richard Dawkins's mail.

Guardian, Saturday, February 26th, 2005

Last week's "The Story of the Giant Tortoise" described the mistake of ancestors' turtles floating unintentionally in the colony of South America × Galapagos Islands, and then the local differences and large sizes of the islands evolved for all of them. But why are the so-called colonists turtles? It may be a simple guess that turtles that have settled in the sea have been dragged to the beach on the island. If they lay eggs, what they like to see will stay on land and evolve into turtles? I don't like the girl who happened in the Galapagos Islands, only a few million years later.

I really like that this did happen, however, before all the ancestral turtles grew up. However, the climax of expectation came to the story of the turtle-the second of my three new stories. By the way, the word turtle is an example of Bernard Shaw's observation that Britain and America are two countries separated by the same language. Used in Britain, turtles live in water and turtles live on land. For Americans, it's turtles that live on land.

There is ample evidence that all the recent ancestors of turtles today, including the United States, Australia, Africa and Eurasia, as well as Galapagos, Al Dabboura Giant, Seychelles and other marine islands, are turtles themselves. Its recent ancestor, Stephen Hawking, who went astray, was a turtle that fell all the way. All kinds of giant turtles in the Galapagos Islands are tortoises from South America.

If you go back to your alma mater, you will live in the sea all your life. In different periods of evolutionary history, many different animal groups migrated to the land of enterprising people, even the driest desert, to their own private seawater, and blood and cell fluid were also with them. In addition, reptiles, birds, mammals and insects, we see everything around us and have succeeded in getting water from other groups, including scorpions, snails, crustaceans such as tide worms and land crabs, millipedes, centipedes, spidels and their relatives and various worms. We must never forget plants if they have not invaded the land of other immigrants.

From water to land, all aspects of life have been greatly adjusted, from breathing to reproduction: this is a journey through a large biological space. However, it almost looks like an abnormal and thorough land animal turned around after numbering, gave up the hard-won land as a tool and returned to the water in droves. Seals and sea lions (amazing taming of Galapagos sea lions, etc. ) only participated in the way. The intermediates they show us may be, in extreme cases, whales and manatees. Whales (including small whales, which we call dolphins) and their close relatives, the manatee dugong, are no longer the habit of land animals to completely restore the complete ocean of ancient ancestors. They don't even go ashore to breed. However, when they do this, they still breathe the air and have not developed any gills equivalent to their early ocean incarnations.

Other animals, from land to water snails, water spiders, water beetles, cormorants that Galapagos penguins can't fly, (Galapagos is already in the northern hemisphere, only penguins), and sea iguanas (Galapagos turtles (everywhere) are abundant in the surrounding waters).

Iguanas are good at survival. Occasionally, the ocean passage is in driftwood (recorded in the West Indies). There is no doubt that the iguanas in the Galapagos Islands can be traced back to such a piece of domestic garbage from South America. Girls in the oldest surviving Galapagos Islands are no more than 3 years old. Since marine iguanas evolved here alone, you might think that this set is to make the best use of water resources. The story is complicated, but ...

Galapagos Islands, one after another, like Nazca Plate, move at a speed of about10cm/year, and are located in a specific volcanic hotspot in the Pacific Ocean. As the plate moves eastward, hot spots are hit from time to time along the production line, providing another island. This is why the smallest island is ancient in both the west and the east. However, while the Nazca plate continues to move eastward, it is also diving under the South American plate. The easternmost island sinks to the bottom of the sea at a rate of about one centimeter per year. At present, it is known that although the sunken island has moved eastward in this area for at least 17 million years. At any time during that period, this submerged island may have been the original port for the colonization and evolution of iguanas. I will sink under the waves of their primitive ancestral island, which is their long-term island.

Turtles return to the sea earlier. On the one hand, they are completely considered less likely to return to the water than whales and manatees, and turtles still lie on the beach to lay eggs. Like all vertebrate returnees, they breathe air, but in this part, they go to whales. Some turtles extract more oxygen from the water through the double chambers at the back end, which are rich in blood vessels. In fact, Australian river turtles breathe most of the oxygen. As an Australian, he will not hesitate to say it through his ass.

There is evidence that all modern turtles are terrestrial ancestors dinosaurs. There are two key fossils called hominids? Quentin and Guchesis? Talampayensis can be traced back to the early dinosaur era, and it seems to be the ancestor of all modern turtles. You may want to know what we know about animal fossils, especially if they are just fragments that live on land or in water. Sometimes it's obvious. Dinosaurs in the era of ichthyosaurs and reptiles, with radial fins and streamlined bodies. Fossils look like dolphins. They must be like dolphins in the water. The tortoise is not obvious at all. A simple method is to measure their forelimb bones.

Joyce and Jacques Gauthier of Yale University made three key measurements on the bones of the arms and hands of 765,438+0 living turtles and tortoises. They drew the size of 3 with a triangular drawing paper. Look, all tortoise species form a close gathering point at the upper part of the triangle; Triangle diagram of the lower part of all water turtles. There is no overlap unless they add some species and spend time on water and land. Of course, these amphibian species appear in the triangle, and half of them are between "wet clusters" and "dry clusters". So, the obvious next step is: where are the fossils? There is no doubt that the movement in the hands of Quinstetti and P. Taranpaines has left us. The points on the chart are correct in the thickness of the dry mass. These fossils are tortoises. They came from the time before our turtles returned to the water.

Therefore, you might think that modern turtles may have lived on land since early earth times, because most mammals returned to the sea after humans disappeared. But obviously not. If all modern turtle genealogies are drawn, almost all branches are water. Today's turtles form an independent branch, deeply nested among the branches of aquatic turtles. This shows that modern tortoises haven't stayed on land since the first continuous Kunstetti and p. Talampayensis. On the contrary, their ancestors got closer when they returned to the water, and then they returned to land.

Therefore, turtles show significant double circuits. Like all mammals, reptiles and birds, their ancestors were marine fish and more or less worm-like creatures, or in the ocean, they belonged to protobacteria. Later ancestors lived on land and lived there for several generations, and the number was very large. Later, ancestors evolved into backwater turtles. Finally, they returned to land. Some of them, but not Galapagos giants, now live in arid deserts.

I once described the inheritance of DNA as "death". Because of the way natural selection works, there is a feeling that an animal's DNA is a written description of the world and its ancestors are natural selection. A fish, the gene book of the dead ancestor describes the ocean. Like most mammals, the first few chapters of this book are all about the settings in the ocean and all the land after that. Whales, manatees, sea iguanas, penguins, seals, sea lions, turtles and turtles are all great. This book tells the story of their epic return to the ocean, the testing ground of one third of their distant past. But for the tortoise, it may be the only one, but is this book devoted to the last paragraph or the quarter paragraph? -reappear, but again and again. Will there be another animal book about the inheritance of human death? Is it a rewrite with many evolutionary reversals?

Richard Dawkins's new book The Story of Ancestors is an evolutionary history of Chaucer's pilgrimage. Pilgrims are creatures. Their stories illustrate some basic principles of evolution. If the author wrote it in a book when he went on a pilgrimage to his private island, this article would be.