In addition to teeth and bones, some animal droppings can be fossilized. For example, when some carnivores eat meat, they swallow it together with broken bones. There are many undigested broken bones in feces, which are not easy to rot, so they can also become fossils. Footprints can also become fossils. People or animals step on the sand, causing footprints. After the sediment dries, the footprints are filled with other substances. Both substances are preserved after being petrified by the minerals that later infiltrated, but the properties of the two substances are different, the hardness is different, and the degree of weathering or destruction is different. After one substance is weathered or destroyed, another substance appears as footprint fossils.
Animals and plants are buried in the sand after they die. With the passage of time, the bodies of animals and plants will be gradually buried in the depths of the earth with the deposition of sediment. Because of the high pressure and humidity here, the deposited sediment gradually turned into a layer of rock, which is called stratum in geology. The hard parts of animals and plants-bones, shells, etc.-are as hard as rocks as the sediment gradually turns into strata; Those soft parts of animals and plants, such as leaves, may also leave marks in the stratum. This kind of stone with original movement and plant imprint formed with the formation of stratum is called fossil.
Basic knowledge and the concept of fossils
Fossil The remains of animals or plants that remain in rocks. Usually, soft parts such as muscles or epidermis have been corroded before preservation, leaving only parts with greater resistance, such as bones or shells. They are then replaced by minerals from the surrounding sediments. Many fossils have also been flattened by the weight of the rocks covering them.
Fossils, through the action of nature, are the remains of paleontology, remains and their living relics preserved in the stratum.
Simply put, a fossil is a stone turned from the remains or remains of creatures living in the distant past. In the long geological age, there have been countless creatures living on the earth, and many of their bodies after death or traces left over from their lives were buried by the sediment at that time. In the following years, the organic matter in the remains of these creatures was completely decomposed, and the hard parts such as shells, bones, branches and leaves were petrified into stones together with the surrounding sediments, but their original forms and structures (even some subtle internal structures) remained; Similarly, the traces left by those creatures when they live can be preserved in this way. We call these fossilized biological remains and remains fossils. From the fossils, we can see the appearance of ancient animals and plants, from which we can infer the living conditions and living environment of ancient animals and plants, infer the formation age and historical changes of the strata where fossils are buried, and see the changes of organisms from ancient times to the present.
Etymology
The word Fossil comes from the Latin word "fossilis", which means to dig out. Most fossils are hard parts of prehistoric creatures that can be preserved, and these creatures live in fossil collection areas.
Formation condition
Although whether an organism can form fossils depends on many factors, three factors are basic:
(1) Organic matter must have hard parts, such as shells, bones, teeth or woody tissues. However, even very fragile creatures, such as insects or jellyfish, can become fossils under very favorable conditions.
(2) Living things must avoid being destroyed immediately after death. If an organism's body parts are crushed, rotted or severely weathered, it may change or cancel the possibility of this organism becoming a fossil.
(3) living things must be quickly buried by something that can hinder decomposition. The type of this buried material usually depends on the living environment of the organism. The remains of marine animals can usually become fossils, because marine animals sink to the bottom of the sea after death and are covered with mud. Mud turned into shale or limestone in later geological times. Fine-grained sediments are not easy to damage biological remains. In some fine-grained sedimentary rocks of Jurassic in Germany, the fossils of some fragile creatures such as birds, insects and jellyfish are well preserved.
Evolution process
It has been known that volcanic ash falling from nearby volcanoes once covered the whole forest, and sometimes standing trees can be seen in forest fossils, which have been preserved in a good posture. Quicksand and tar pitch can usually bury animals quickly. Tar asphalt acts like a trap to catch wild animals, and like a preservative to prevent the decomposition of hard parts of animals. Rancho in Los Angeles? Pull? Rancho laBrea asphalt lake is famous for finding many bone fossils in it, including wild boar with sharp teeth, giant land sloths and other extinct animals. The remains of some animals that survived during the ice age were frozen in ice or frozen soil. Obviously, some frozen animals can be preserved.
Although there have been many unknown creatures on the earth, only a few have left fossils. However, even if the conditions for turning organisms into fossils are met, there are still other reasons why some fossils have never been discovered. For example, many fossils are destroyed by ground erosion, or its hard parts are decomposed by groundwater. Some fossils may be preserved in rocks, but because rocks have undergone strong physical changes, such as folding, fracture or melting, this change can turn marine limestone containing fossils into marble, and any traces of organisms that originally existed in limestone will disappear completely or almost completely. There are still many fossils in sedimentary rocks that cannot be obtained for research, and there are also fossils-containing rocks that are well exposed on the surface of the earth, but they have not been studied in geology. Another very common problem is that the situation of the organism may not be fully displayed because the remains of the organism have become fragments or are poorly preserved.
Furthermore, the older we go back to the past, the longer the interval of missing fossil records. The older the rock is, the more opportunities it will be subjected to destructive forces, and the more unrecognizable the fossils will be. Moreover, because older organisms are different from today's organisms, it is difficult to classify them, which further complicates the problem. However, despite this, a large number of preserved biological fossils still provide a good record for us to understand the past.
Animals and plants can turn into fossils through many different ways, but which way depends on:
(1) The original composition of organisms
(2) the place where it lives
(3) the force that affects the remains of living things after their death.
Most paleontologists believe that there are four forms of preservation of biological remains, each of which depends on the composition of biological remains or the changes they have undergone.
The original soft part of a living thing can only be preserved when it is buried in a medium that can prevent its soft part from decomposing. This medium includes frozen soil or ice, oil-rich soil and amber. When a creature becomes a mummy under very dry conditions, it can also preserve the original soft part of its body. This situation generally only occurs in arid areas or desert areas, and the remains are not eaten by wild animals.
Perhaps the most famous examples of fossils of soft parts of animals have been preserved in Alaska and Siberia. A large number of frozen hairy mammoth remains-an extinct elephant-were found on the tundra in these two areas. Some of these behemoths have been buried for 25,000 years. When the frozen soil melts, the mammoth's remains are exposed. There are also some bodies that are badly preserved. When they are exposed, their meat is eaten by dogs and their tusks are resold by ivory traders. Mammoths' fur is now exhibited in many museums, and some of them preserve mammoths' flesh or muscles in ethanol.
The soft part of the biological body is also found in the oily soil in eastern Poland, where there is a well-preserved extinct rhinoceros's nose horn, front legs and part of its skin. Natural mummies of ground sloths were found in caves and craters in New Mexico and Arizona. The extremely dry desert climate here can dehydrate all the soft tissues of animals before they rot, and can preserve some skins, hairs, tendons, claws and so on.
A more interesting and unusual way for organisms to become fossils is to preserve them in amber. Ancient insects can be captured by mucilage secreted by some conifers. When turpentine hardens and further turns into amber, insects stay in it. Some insects and spiders are so well preserved that they can even study their fine hair and muscle tissue under a microscope.
Although the preservation of soft tissues of organisms has formed some interesting and amazing fossils, the fossils formed in this way are relatively rare. Paleontologists often study fossils preserved in rocks.
Hard tissues on organisms can also be preserved. Almost all plants and animals have some hard parts, such as clams, oysters or snails; Teeth and bones of vertebrates; The shells of crabs and the woody tissues of plants that can become fossils. Because the hard parts of organisms are made of substances that can resist weathering and chemical action, such fossils are widely distributed. The shells of invertebrates such as clams, snails and corals are made of calcite (calcium carbonate), and many of them have been preserved with little or no physical changes. The bones and teeth of vertebrates and the exoskeletons of many invertebrates contain calcium phosphate. Because this compound is very resistant to weathering, many substances composed of phosphate can also be preserved, such as a well-preserved fish tooth. Bones made of silica also have this property. The siliceous part of microfossils and some sponges become fossils through silicification. Other organisms have chitin (a kind of substance similar to nails), and the chitin exoskeleton of arthropods and other organisms can become fossils. Because of its chemical composition and burial method, this substance is preserved in the form of carbon films. Carbonization (or distillation) occurs in the process of slow decay after biological burial. In the process of decomposition, organic matter gradually loses its gas and liquid components, leaving only carbonaceous films. This carbonization is the same as the formation of coal. A large number of carbonized plant fossils can be seen in many coal seams.
In many places, plants, fish and invertebrates have preserved their fossils in this way.
Some carbon films accurately record the finest structures of these creatures.
Fossils can also be preserved through mineralization and fossilization. When the mineralized groundwater deposits minerals in the space where the hard part of the organism is located, the hard part of the organism becomes harder and more resistant to weathering. The common minerals are calcite, silica and various iron compounds. The so-called displacement or mineralization is a process in which the hard part of the organism is dissolved by groundwater, while other substances are precipitated in the vacated position. The original structure of some displaced fossils was destroyed by the displaced minerals.
Not only the remains of animals and plants can form fossils, but also the evidence or traces that show that they once existed can form fossils. Trace fossils can provide considerable information about the characteristics of this creature. Many shells, bones, leaves and other parts of living things can be preserved in the form of male molds and female die. If a shell is pressed into the sea floor before the sediment hardens and rocks, its external features will be impressed (female die). If female die is later filled with another substance, a male mold is formed. The male mold can show the original external characteristics of the shell. The external female die shows the external characteristics of the hard part of the organism, while the internal female die shows the internal characteristics of the hard part of the organism.
Some animals have left evidence of their existence in the form of marks, prints, footprints, holes and holes.
Footprints, for example, can not only indicate the types of animals, but also provide information about the environment. The dinosaur's footprint fossils not only reveal the size and shape of its feet, but also provide clues about its length and weight. The rocks with footprints can also help determine the environmental conditions for dinosaurs to survive. The most famous dinosaur footprint fossils in the world were found in the late Cretaceous limestone in the Palusi river bed near Ross Town, Somerville County, Texas, about 1. 1 billion years ago. Large limestone slabs with dinosaur footprints have been transported to museums all over the world, becoming dumb evidence of this huge reptile. Invertebrates can also leave traces. They can be found on the surface of many sandstone and limestone deposits. The traces of invertebrates range from simple traces to caves of crabs and other reptiles.
These tracks provide evidence about the way these creatures move and their living environment. A cave is a tubular or round hole made by animals in the ground, wood, stone and other substances that can make holes for hiding and foraging. If it is filled with fine substances later, it may be preserved. Occasionally, the remains of the animals that broke out of the cave can be found in the sediments that filled the cave. Worms, arthropods, mollusks and other animals can stay in caves on the soft seabed. Some mollusks, such as shipwrecker, a clam that drills wood, and Litho-domus, a clam that drills diamonds, can often find their cave fossils and borehole fossils. Among the oldest known fossils, there is a tubular structure, which is thought to be a worm's cave. This tubular structure is found in many of the oldest sandstones.
Boreholes are holes made by some animals for foraging, attachment and hiding. Boreholes often appear on fossilized shells, wood and fossils of other organisms. Borehole is also a kind of fossil. Endophagous animals such as the drilling snail can drill holes through the shells of other animals to eat their soft parts. Many ancient mollusks can see neat holes in their shells that look like drilling snails.
Fossils are useful for tracing the development and evolution of animals and plants, because fossils in older rocks are usually primitive and simple, while fossils of similar species in newer rocks are complex and advanced.
Some fossils are valuable as indicators of the environment. For example, reef-building corals always seem to live in conditions similar to today. Therefore, if geologists find coral reef fossils-where corals were originally buried, it is reasonable to think that these rocks containing corals were formed in a warm and quite shallow sea. This makes it possible to outline the location and scope of the sea in prehistoric times. The existence of coral reef fossils can also indicate the depth, temperature, bottom conditions and salinity of ancient water bodies.
A more important use of fossils is for comparison-to determine the close relationship between several rock layers. By comparing or comparing the characteristic fossils contained in various strata, geologists can determine the distribution of some geological structures in a specific area. Some fossils exist for a short time in geological history, but they are widely distributed in geography. This kind of fossil is called indicator fossil. Because this kind of fossil is usually only born with rocks of a certain era, it is particularly useful in comparison.
The fossils of microfossils are particularly useful as indicator fossils for petroleum geologists. Micro-paleontologists (scholars who study micro-paleontology) separate tiny fossils by washing the cores obtained from drilling holes, and then study them under the microscope. The data obtained through the study of these tiny paleontological remains are very valuable for judging the age of underground rock formations and the possibility of oil storage. The importance of microfossils to the world oil fields can be seen from the fact that some oil-bearing strata are named after some key foraminifera genera. Other microfossils, such as ostracods, spores and pollen, are also used to identify underground rock formations in many other parts of the world.
Although plant fossils are very useful for indicating climate, they are not very reliable for stratigraphic correlation. Plant fossils provide a lot of information about the evolution of plants throughout the geological era.
[Edit this paragraph] Classification
Fossils in strata can be roughly divided into four categories according to their preservation characteristics: solid fossils, die-casting fossils, trace fossils and chemical fossils.
1, solid fossils
Refers to fossils that are almost completely or partially preserved by paleontological remains themselves. The original organism has avoided the oxidation of air and the corrosion of bacteria under particularly suitable conditions, and its hardware and software can be completely preserved without significant changes. For example, the mammoth (discovered in the frozen soil of Siberia in the Quaternary Glacial Period in 190 1 year, before 25,000 years, not only the bones were intact, but also the skin, hair, flesh and blood, and even the food in the stomach were preserved intact).
2. Moulded fossils
It is the impression or recast left by biological remains in strata or surrounding rocks. One kind is imprint, that is, the imprint left by the biological remains falling to the bottom, and the remains are often destroyed, but this imprint reflects the main characteristics of the organism. Creatures without hard shells can also preserve their soft imprints under certain geological conditions, the most common being the imprints of plant leaves. The second type is impression fossils, including external model and internal model. The external model is the trace of the hard part of the remains (such as shells) printed on the surrounding rock, which can reflect the original biological appearance and structure; Internal model refers to the trace of the inner contour structure of the shell printed on the surrounding rock, which can reflect the internal morphology and structural characteristics of the biological hardware. For example, when a shell is buried in sandstone, its internal cavity is also filled with sediment. When the sediment solidifies into rock and the shell is dissolved by groundwater, the outer mold of the shell is left on the contact surface between the surrounding rock and the shell surface, and the inner mold is left on the contact surface between the surrounding rock and the shell surface. The third type is called the core, and the sediment filling in the shell mentioned above is called the core. Its surface is the internal model. The shape and size of the core are equal to the size of the space inside the shell, and it is an entity that reflects the inner structure of the shell. If there is no sediment in the shell, when the shell is dissolved, it will leave a space with the same shape and size as the shell. If this space is filled again, it will form an entity with the same shape, equal size and uniform composition as the original shell, which is called the outer core. The shape of the outer core surface is the same as that of the original shell, which is printed by the outer mold, while its interior is solid and does not reflect the internal characteristics of the shell. The fourth type is the casting mold. When the shell is buried in the sediment and the outer mold and the inner core have been formed, the shell is completely dissolved and filled with another mineral, so that the filling keeps the original shape and size of the shell, just like the casting process, thus forming the casting mold. Its surface is the same as that of the original shell, and there is a core inside them, but the subtle structure of the shell itself has not been preserved.
Generally speaking, the concave and convex patterns of the outer mold and the inner mold are just the opposite of the original. The external shape of the outer core and the mold is completely consistent with the original, but the internal structure of the original is destroyed and disappeared, and its material composition is also different from the original. As for the difference between the outer core and the mold, the former has no inner core, while the latter also contains an inner core.
3. Trace fossils
Refers to the traces and relics of paleontological life activities preserved in rock formations. The most important trace fossils are footprints. Besides, there are crawling marks, burrows, boreholes of arthropods and hidden caves formed by tongue-shaped shellfish living in coastal areas, which can form trace fossils. In terms of relic fossils, it often refers to animal excrement or eggs (egg fossils); The dung balls and granules of various animals can form dung fossils. Dinosaur eggs in Cretaceous strata in China are world-famous. In the past, dinosaur egg was found in Laiyang, Shandong Province and Nanxiong, Guangdong Province in recent years.
4. Chemical fossils
Although some remains of ancient creatures have been destroyed and not preserved, various organic substances such as amino acids and fatty acids formed by the decomposition of organic components that make up the creatures can still remain in the rock strata. This kind of fossil is invisible, but it has a certain chemical molecular structure enough to prove the existence of past creatures, which is called chemical fossil. With the progress of modern chemical research and the improvement of science and technology, the organic molecules of ancient organisms (referring to amino acids, etc.) can be separated from rock formations for identification and research, and a new discipline-paleontology has emerged.
5. Special fossils
Amber-a large amount of resin secreted by ancient plants, with strong viscosity and high concentration, was sticky when insects or other creatures flew on it. After sticking, the resin continues to flow out, and the insect body may be completely wrapped by resin. In this case, the outside air can't penetrate, and the whole creature has been preserved without any obvious changes, which is amber.
The keel of Chinese medicine shop-used as the keel of Chinese medicine, is actually mainly the bones and dental stones of many vertebrates that have not been completely fossilized in the late Cenozoic, and most of them are Pliocene and Pleistocene mammals, such as rhinoceros, Hipparion spp., deer, Cervidae and Proboscidae. As for the five-flowered keel or five-flowered dragon tooth, the color is not monotonous white, gray or yellow-white, but red-brown or blue-gray patterns are mixed between yellow and white. It is an elephant's front teeth.
1. standard fossil
This refers to fossils with obvious characteristics, short duration but wide distribution, and a large number of fossils that are easy to find. People usually use them as an important basis for dividing the correlation strata. Belongs to one of the landmark fossils.
2. facies fossil
In different organisms or combinations of organisms, some have strict requirements on living environment and natural geographical conditions for survival. The fossil formed by such organisms is facies fossil. People usually infer the environmental conditions of various places at that time from the fossils formed by these organisms, and the data is quite accurate. Belongs to one of the landmark fossils.
3. Fossils
This refers to fossils that can be used as the basis for dividing the biological zone of the smallest stratigraphic unit in stratigraphy.
4. Persistent fossils
Some creatures with extremely slow evolution have a long time span, and their fossils last for a long time. People call these fossils persistent fossils.
5. Fossil clock (ancient biological clock)
Ma Tingying, a Chinese scholar, first proposed in 1933 that there were growth lines reflecting the seasonal changes of climate on the outer wall of Paleozoic four-coral. Thirty years later, American paleontologists calculated the number of months and hours per day when studying ancient corals. People call these fossils that can calculate the revolution speed and rotation speed of the ancient earth ancient biological clock or fossil clock.
From the form of fossils, they can be divided into stone fossils, coal fossils, frozen fossils, amber and so on.
There are many stone fossils, dinosaur eggs are the most typical example. Leaves on coal are the most common coal fossils, and amber fossils containing insects are very many, which are very easy to see in well-preserved virgin forests. Frozen fossils are rare, and the bodies of famous mammoths and well-preserved snowmen are the most attractive examples.
[Edit this paragraph] Research situation
The age of the earth is about 4.6 billion years. Cambrian is a period of 540 million to 5. 1 100 million years ago. It is 400 million years earlier than the "Jurassic" of the dinosaur era that we are familiar with. 1909, the Burgis faunal fossils discovered in Canada in the middle CAMBRIAN period caused a sensation all over the world, and now this fossil group has been listed as a scientific site by the United Nations. 1947, the late Precambrian Ediacaran fossil fauna was discovered in Australia. The time interval between these two fossil groups is 1. 1 100 million years, so it is difficult to prove the sudden change between the two species. The Chengjiang animal fossil group is just in the middle of the time span of the above two fossil groups, which is the most important link of the Cambrian life explosion.
The whole story of the discovery of biochemical rocks in Chengjiang, Yunnan.
Perhaps, there is no discovery process of paleontological fossil group in the world, which is as legendary as the Chengjiang biochemical fossil group in Yunnan.
1In mid-June, 984, Hou Xianguang, who just graduated from Nanjing Institute of Paleontology, China Academy of Sciences, came to Maotianshan Mountain in Chengjiang County, Yunnan Province to look for the fossils of high muscle insects that once lived in Cambrian. He lives in the shed of the field geological exploration staff, goes out early and comes back late every day, climbs the rugged mountain road and searches for paleontological fossils at selected sites. The stones chopped down every day often weigh two or three tons. However, hard work has not yielded the desired harvest. After working for more than a week, Hou Xianguang is still empty-handed, and he is inevitably disappointed.
At about 3 pm on July 1 day, Hou Xianguang, who was in the process of intense excavation, lifted his foot and accidentally cut off a loose rock stratum, and a strange but well-preserved fossil was exposed. He was ecstatic and judged with his knowledge that it was an early Cambrian invertebrate fossil. He made persistent efforts and found three important fossils on the same day. Later, he further identified and found that the fossils were Naluo worm, gill shrimp worm and spike worm.
It was like opening the door to a treasure trove of paleontology. In the following days, Hou Xianguang discovered many paleontological fossils of the same period, such as arthropods, jellyfish and worms. After returning to Nanjing, he and his tutor, Professor Zhang Wentang, wrote "Discovery of Nalox in the Asian continent", and named the animal fossils of Chengjiang as "Chengjiang Fauna" in the paper.
Since then, in Maotian Mountain, many strange ancient creatures that scientists have never seen before have been rediscovered one after another. Professor Chen Junyuan from Nanjing Institute of Paleontology, Chinese Academy of Sciences, and Professor Shu Degan from Northwest University successively joined the research ranks. A series of articles published in international authoritative academic journals such as Nature and Science described to the world the spectacular scene that life on earth broke out collectively in Chengjiang, Yunnan 530 million years ago.
1992, Chengjiang animal fossil group site was listed as "the fourth priority in East Asia as a global address site" by UNESCO. At the end of 2005 1 1, the application of Chengjiang Fossil Group to declare World Heritage was formally submitted to the Ministry of Construction.
The reporter visited Chengjiang Animal Fossil Group Museum.
At the end of 2005, the reporter made a special trip to visit Maotianshan Mountain in Chengjiang, Yunnan Province, where the fossils were discovered. Chen Ailin, an academic member of Yunnan Provincial Key Laboratory of Paleontology and director of Chengjiang Animal Fossil Group Museum, told the reporter about the process of fossil discovery in that year, which was still very impressive.
According to curator Chen, after 22 years of unremitting research, paleontologists have discovered 180 kinds of animals in Chengjiang, 80% of which are new species unknown before, and there are more than 20 kinds of trace fossils and fecal fossils. Almost all kinds of living animals can find their distant ancestors in Chengjiang fossil group, and Yunnan worm, the "ancestor" of human beings, was found in Chengjiang for the first time.
Paleontological research shows that it has been 3.8 billion years since life appeared on earth, but before Cambrian 540 million years ago, life only existed in the ocean in the simple form of algae and fungi. After CAMBRIAN, a large number of metazoa suddenly appeared in the ocean, and the evolution from unicellular algae and fungi to multicellular metazoa was particularly rapid. It took only10 million years, and Chengjiang fauna recorded the whole picture of the biota in this special period. "Compared with 3.8 billion years,10 million years is equivalent to one minute in a day and night. Scientists call the rapid evolution of life an explosion of life." Director Chen explained.
Some experts once thought that the discovery of Chengjiang fauna challenged the theory of evolution. Does the explosion of life contradict Darwin's theory of evolution?
"Darwin did not have a comprehensive understanding of the history of biological evolution in his time due to the limitations of research conditions. He believed that evolution should be slow evolution. Therefore, when scientists discovered trilobites that suddenly appeared in CAMBRIAN, they thought it might shake the foundation of evolution. In the social environment at that time, anyone who proposed rapid evolution was considered creationism. "
"Since the 20th century, a lot of scientific evidence shows that evolution should be a rapid process, and Chengjiang fauna is typical. However, the research results of scientists on Chengjiang fauna only modify Darwin's gradual change theory, which is not a challenge, because even10 million years is not a very short time. "
When he came to Chengjiang Fossil Museum, curator Chen showed the latest achievements of Professor Chen Junyuan on fossil restoration in recent years. Those lost individuals who once only stayed in fossil specimens, the panoramic view of the ocean 530 million years ago that had already dissipated in geological changes, vividly appeared in front of reporters, and the strange postures and colorful colors of various creatures were amazing. Director Chen introduced the characteristics and significance of these magical creatures.
[Edit this paragraph] Typical fossils
Remote ancestor of insects: Fuxian Lake worm
Fuxian Lake worm is a unique fossil in Chengjiang fauna, belonging to the primitive type of true arthropod. The adult is10cm long and has 3 1 individual joints. The exoskeleton is divided into three parts: head, chest and abdomen. The number of its back and abdomen sections is different, which is similar to the Devonian straight shrimp fossils, and the straight shrimp is the ancestor of modern insects, which indirectly indicates that it is caressing. Hou Xianguang also found that the digestive tract of Fuxian Lake worm is full of sediment, which indicates that it is a mud-eating animal.
Nine-eyed Elf: Micronetworm
Micronetworms belong to the phylum Podopod, named after polygonal scaly bone fragments on their bodies. They can reach 8 cm in length and have 9 pairs of mineralized bone fragments and 10 pairs of feet. These bone fragments play the role of connecting legs and joints. At present, only in Chengjiang have such a complete fossil been found.
Some experts believe that these bone fragments are an egg storage device for breeding offspring, but referring to the characteristics that the reproductive organs of modern arthropods are mostly concentrated in one place, it is impossible for the egg storage device to be so dispersed. Some experts also believe that these bone fragments are multi-eyes with photosensitive effect, so they have the reputation of "nine-eye elves". However, the eyes of animals are generally concentrated on the head, and creatures similar to micro-webworms have not been found on earth.
Micronetworms once appeared on the cover of Nature magazine and became fossil stars. The New York Times once commented on micro-webworms: "Some Cambrian creatures can easily play the role of science fiction. The strangest guy is a vermicular animal with 10 pairs of feet and covered with scaly bones."