Ancient prints on stones. How the world's oldest fossils were discovered. Finding Martian fossils changes our understanding of Earth
1. After the animal dies, decomposition begins |
2. Over time, bones end up deeper and deeper into the layers of the earth. |
3. As the layers of the Earth slowly move, the rocky layers in which the fossilized remains of the animal lie rise to the surface. |
4. The fossilized remains, now lying close to the surface of the Earth, are brought to the surface either as a result of the movement of strata, or are discovered during paleontological excavations. |
Fossil remains are traces of ancient life that have survived to this day, preserved in the depths of the layers of the Earth. Fossils can contain both parts of organisms that once lived on Earth and traces left by these organisms during their lives (so-called presence traces). A dead animal or plant, which finds itself under the reliable shelter of sedimentary rocks, eventually becomes part of the earth's crust and, as a result of a number of chemical processes, acquires the properties of stone, that is, it petrifies. In order for the process of fossilization, that is, petrification, to occur, the animal or plant must be instantly covered with a layer of silt or sedimentary rock; Thus, covered with a layer of silt or other rock, the animal or plant avoids contact with air and the process of petrification of this creature begins, when the minerals found in the Earth displace the organic molecules contained in the hard tissues of the deceased organism and take their place.
Fossils are the most important evidence for the history of the origin of life on Earth. To date, paleontologists have discovered hundreds of millions of fossilized remains of ancient life forms in all corners of the Earth, which allow us to draw factual conclusions about the history and formation of life. All fossilized remains found to this day indicate that life on Earth appeared suddenly, in a highly developed form, without any flaws or shortcomings, and over hundreds of millions of years of the existence of life, not a single living creature has undergone a single change, and still exists in the form and form in which it was created on Earth by the Almighty Creator.
This circumstance is an important and irrefutable proof of the creation of life. Among hundreds of millions of remains, not a single one was found that would demonstrate the gradual formation of life forms, that is, the evolutionary scenario is not confirmed by a single example. There are only a few fossils that evolutionists have tried to present as transitional forms, however, the specimens that Darwinists have shown as examples of transitional forms have later turned out to be fakes, which once again shows the desperate situation that supporters of Darwin's theory find themselves in when they are forced to resort to methods so unworthy of scientists for lack of factual evidence.
Paleontological excavations, which have been ongoing in all corners of the world for more than 150 years, show that fish have always been fish since their creation on Earth, beetles have been beetles, birds have been the same as now, reptiles have always been reptiles. Let us repeat once again, there is not a single remains that would demonstrate the transitional forms of living beings, for example, the process of transformation of fish into reptiles or reptiles into birds (!). In other words, the data from the found fossilized remains crushed the main assertion of the theory of evolution about the gradual, millions of years, process of evolution of species of life as a result of multiple changes in the structure or functions of the body.
Along with information about the stages of the creation of life, fossils provide science with important information about changes in the Earth's surface as a result of the movement of continents and climate changes on the planet. It is noteworthy that fossilized remains have attracted the attention of researchers since the times of Ancient Greece, but paleontology emerged as a separate branch of science only in the mid-17th century. The first scientific studies devoted to the study of fossilized remains were the works of Robert Hook Micrography(Micrographia, 1665); Discussion about earthquakes(Discourse of Earthquakes, 1668) and the works of Niels Stensen (Nicholas Steno). At the time of Hook and Steno, scientists did not believe that the fossilized images of living beings found in the ground were fossilized traces of animals that once really lived, but believed that this was an amazing creation of nature, which miraculously copied living beings in such stone drawings. The reason for such fantastic explanations was the lack of information about the geological history of the Earth. For example, scientists could not believe that the fossilized traces of fish found in the mountains could really belong to a fish, because they physically did not understand how fish living in the seas could rise to such a height. It is believed that Nicholas Steno was the first who, like Leonardo da Vinci, took geology to a new level of development, putting forward the revolutionary assertion that the water level apparently dropped and receded over time. Robert Hook, in turn, was the first to state that mountains could be formed as a result of earthquakes that occurred in the layers of oceanic mountains or the collision of continents.
After Hook and Steno's conclusions that the remains found could be fossilized traces of ancient life forms gained scientific acceptance, geology began to develop rapidly, with the systematic collection of fossil remains and their study beginning in the 18th and 19th centuries. Thus, paleontology began to emerge as a separate field of science. The principles established by Nicholas Steno were adopted in the classification and identification of fossil remains. The rapid development of mineralogy, ore mining and the construction of railways, which began at the end of the 18th century, made it possible to make many new, detailed discoveries in the bowels of the Earth.
Modern geology has established that the Earth is composed of layers called “strata”, these strata are in motion and move continents and the ocean platform with them. As strata move, changes occur in the Earth's geography, and mountains arise from the movement and collision of large strata. Changes in the geography of the Earth, which occurred over a long period of time, showed that the territories that are now mountains were in ancient times covered with water or located at the bottom of seas and oceans.
Thus, fossilized remains found in mountain rocks have become the most important source of information about the various stages of the formation of the Earth. Geological information showed that the fossilized remains of living beings, preserved in sedimentary rocks after death, over a long period of time during the formation of mountains and the movement of strata, were pushed out and rose up to the surface of the Earth.
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The fossilized remains of a starfish, 490-443 million years old, testifies to the persistence of this form of life over hundreds of millions of years and to the absence in nature of the process of evolution of life forms. | FOSSIL IN AMBER THE REMAIN OF A FLYING ANT 20-15 MILLION YEARS OLD | There are not even a few differences between the shrimp that lived in the seas 250-70 million years ago and their modern relatives. Shrimp, living in the seas for hundreds of millions of years, indicate the absence of evolutionary mechanisms in nature. |
During research, it was noticed that certain types of fossils are found only in certain strata and certain types of rocks. In each of the rock layers there were special groups of fossilized remains of certain types of living beings, as a kind of signature of this layer. These “signature” remains showed multiple variations depending on time period and region. For example, two different environments or sedimentary rocks occurred in the same fossil layer, such as an ancient lake bed or ancient coral reefs. Or, conversely, in the depths of two different rocks, hundreds of kilometers apart, one and the same “signature” fossil could be found. Based on the fossils found, a unified geochronological table of the Earth was compiled, which is still used today.
| Darwinists argue that the great variety of life forms arose randomly from some proto-being. All living beings, supposedly over hundreds of millions of years, gradually developed, evolved and gave birth to new species. |
With the death of a living creature, the soft tissues of its body, under the influence of bacteria and the environment, begin to rot and decompose. (Very rarely there are cases when soft tissues were not subject to decay). More durable body tissues (bones, teeth, shell containing minerals) are more resistant to environmental influences and chemical processes without being destroyed. These processes provide the beginning of the fossilization process. Thus, the fossilized parts include the bones and teeth of vertebrates, the shells of brachypods and mollusks, the exoskeleton of trilobites and some armored organisms, coral and sponge structures, and woody parts of plants.
Typically, fossils refer to hard parts of a skeleton that have been petrified. However, remains are formed not only as a result of fossilization. Mammoths frozen in an ice mass, insects and small reptiles frozen in amber resin have also been perfectly preserved to this day.
Environmental conditions are very important factors in the formation of a fossil. For example, the formation of a fossil located in the depths of the sea will begin faster and will survive for a longer period than a fossil formed on land.
The most common process for fossilizing remains is permineralization or mineralization. During this process, minerals found in the sediment covering the deceased creature begin to replace the organic cells of the animal's bones. If an animal dies in water, the minerals dissolved in the water begin to push out the organic molecules in the bones over time and take their place. The permineralization process occurs in several stages:
First of all, the body of a deceased animal must be instantly covered with a layer of earth, mud, silt, volcanic rock or sand, that is, air access to the body must be stopped. In subsequent months, the thickness of the earth covering the animal’s body continues to increase, and new layers are formed. The layers of the earth act as a shield, protecting the animal’s body from external influences and physical decay. Gradually, the thickness of the layers of earth increases and within several hundred years the body of the animal is covered with a multi-meter layer of earth or seabed. Over time, solid parts of the body, such as bones, shell, scales, cartilage, gradually begin to undergo chemical breakdown. Water begins to seep into the tissues in which the process of chemical decomposition has begun, and the minerals contained in the water gradually settle in the tissues, filling the voids formed by the breakdown of organic substances. Minerals deposited in tissues are much stronger than destroyed organic components, and more resistant to temporary destruction (calcium, pyrite, silicon, iron, that is, the main minerals that make up rocks). Thus, over millions of years, minerals displace the destroyed particles of bone structures, cartilage and shells, and fill these voids, resulting in an exact stone copy of the once living creature, that is, its shapes and outlines are exactly the same as those inherent in it during life , but the material they are made of is stone.
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1. Corals: marine coelenterates, mainly from coral polyps, partly from the hydroid class. Most corals form a calcareous or horny skeleton of various shapes. Coral thickets form the basis of coral reefs. 2. Radiolarians (rays): a subclass of protozoa of the Sarcodidae class. A large group of microscopic marine planktonic, predominantly warm-water organisms whose skeleton is formed from silica. 3. Bivalves (Bivalvia): a class of bilaterally symmetrical aquatic invertebrate animals such as mollusks. The shell consists of 2 valves, covering the body of the mollusk from the sides. The calcium structure of the shells of these living creatures has been preserved for hundreds of millions of years without the slightest change. 4. Grabtolites: sea creatures with an organic skeleton that lived primarily in colonies. They are usually found in layers of iron pyrites. 5. Shark teeth: teeth and bones contain phosphates in their structure, due to which their remains are preserved in the Earth much better than other tissues. 6. Moss Track Fossils: Moss track fossils found in sedimentary layers 7. Ammonoid? and (ammonites) - extinct shells of a subclass of cephalopods. The photo shows a sample of ammonite, petrified as a result of the replacement of calcareous shell particles with particles of iron pyrite contained in the layers of the Earth. 8. Petrified Wood: Tree cells trapped in layers of sediment were eventually replaced by silica cells and thus became fossilized. 9. Amber: insects and small living organisms, trapped in amber resin and petrified along with it, have survived unchanged to this day. 10. Fossilized remains of leaves: plants trapped in layers of sedimentary rocks gradually petrify and turn into coal fibers. |
As a result of the permineralization process, various forms of the process occur:
1. If the skeleton was completely immersed in sedimentary rock and only after that the process of its destruction began, then the internal form of the creature mineralizes, that is, acquires a stone structure.
2. If the organic cells of the skeleton are completely replaced by minerals, then we get an exact copy of the skeleton and all the bones.
3. If the body of an animal is crushed by a mass of sedimentary rock, then the exact shapes and outlines of the creature and sometimes even the outer cover remain on the rock.
As for plant fossils, there is a chemical process of tissue charring, which is also caused by bacteria. Charring is a chemical process in which parts of plants turn into coal when the supply of oxygen ceases and the temperature rises and the accumulation of carbon increases. In the process of charring the wood structure, oxygen and nitrogen molecules give way to carbon and hydrogen. Carbonization bacteria, depending on pressure, temperature differences or other chemical processes, destroy the molecules of wood tissue, usually fiber, and the process of displacing proteins and cellulose from the structure of the tree begins, the place of which is taken by carbon fibers. All other organic materials such as carbon, methane, hydrogen sulfate and water vapor are displaced. Thanks to this process, during the Carboniferous period (354-290 million years ago), the formation of coal deposits began in swampy areas.
Sometimes fossils were formed in other ways. Organisms buried in high-calcium waters found themselves covered by minerals such as travertene. As the organism decayed, traces of it remained on the minerals.
It is very rare for an animal's soft tissue, fur, hair, or skin to be preserved as fossils. However, the remains of organisms from the Precambrian era (4.6 billion - 543 million years), which had an exceptionally soft structure, have also reached us in fossilized remains in the form of well-preserved traces. Along with bone structures and skeletons, we have also received well-preserved remains of soft tissues and internal organs of animals that lived in the Cambrian period (543 - 490 million years), which allow us to study the structure of the internal organs of the most ancient inhabitants of the Earth. In addition, soft tissue, animal hair and insect hairs are also preserved in amber, the age of the remains is about 150 million years, which also makes it possible to conduct a detailed analysis of life forms of that period. Mammoths, preserved unchanged in captivity in ice in Siberia, or insects, small reptiles, captured by amber resin in the forests of the Baltic, were petrified and perfectly preserved along with soft tissues.
The sizes of the fossils also show great diversity. Paleontologists have found fossils of both microorganisms and huge fossils of entire groups of animals living in communities. A unique assemblage of fossils is the sponge reefs preserved as a large mountain in Italy. This highest "living elevation" is made up of 145-million-year-old calcium sponge reefs. These sponge reefs, which developed on the bottom of the ancient Tethys Sea, were pushed higher and higher out of the sea as a result of the movement of tectonic layers. The elevation also preserves organisms that lived on sponge reefs during the Triassic period. Burgess Shale in Canada and Chenjiang in China, which contain hundreds of thousands of fossilized remains of animals, are the most famous and well-studied formations. Amber deposits in the Dominican Republic and on the western coasts of the Baltic Sea are sources of important fossils that reveal to science a picture of life since ancient times. Special mention should also be made of the Green River Formation in Wyoming (USA), the White River Formation (USA), the Eichstatt region in Germany and Hajula in Lebanon, which revealed to the world the richest deposits of fossils, on the basis of which paleontologists were able to see what life was like on Earth for hundreds of millions of years ago.
Classification of fossil remains
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A unique assemblage of fossils is the sponge reefs preserved as a large mountain in Italy. This highest "living elevation" is made up of 145-million-year-old calcium sponge reefs. These sponge reefs, which developed on the bottom of the ancient Tethys Sea, were pushed higher and higher out of the sea as a result of the movement of tectonic layers. The elevation also preserves organisms that lived on sponge reefs during the Triassic period. The remains of sponge organisms also indicate the absence of evolutionary changes; they are completely identical to modern sponge organisms. |
Fossil remains, just like the world of living organisms, are divided into several groups, which are usually called “kingdoms”. In the 19th century and early 20th century, fossil remains were divided into 2 main groups - plant and animal. However, the diversity of fossils found led to the need to create several more main groups, which would include such life forms as fungi and bacteria. According to the classification developed and adopted in 1963, fossils were divided into five kingdom groups; The life forms included in each of them began to be considered separately:
1. Kingdom Animalia - fossils of the animal world. The oldest samples are 600 million years old.
2. Kingdom of plantai - fossils of the plant world. The oldest samples are 500 million years old.
3. Kingdom Monera - Fossils of small bacterial cells that do not have a nucleus or organelles. The oldest samples reach an age of 3.9 billion years.
4. Kingdom Protoctista – Fossils of single-celled organisms. The oldest samples are 1.7 billion years old.
5. Kingdom Fungi - Fossils of multicellular organisms. The oldest samples are 550 million years old.
Part of the beauty of films like Jurassic Park is that they are based on fact. Wait, are they based? Of course, in the film the director tries to show dinosaurs and other ancient life forms as accurately as possible. But the fact is that scientists do not know exactly what ancient life looked like, although they are trying to reconstruct it. New discoveries are constantly being made that shed light on what we don't know about Earth's earliest life forms - and this sometimes forces us to rewrite textbooks.
Most of us think that when the Earth was formed, life appeared in the seas. This is partly true, but no one knows exactly how the first life appeared. And having appeared, life immediately began to influence the surface of the planet. Without the plants that crush rocks into sediment, for example, there would not be enough materials to form tectonic plates and therefore continents. Without plants, the Earth could become just a water world.
Believe it or not, more complex life may even change the structure of global ice ages, making them less severe, through "regulatory feedback." The discontinuous pattern of freezing and thawing goes back billions of years to a time when Earth did not have the complex web of life that exists today. Then the glaciers stretched from the poles to the equator, disrupting the entire planetary foundation.
Since then, as more and more life has filled the surface and seas, the glacial Earth has formed huge glaciers at both poles, stretching out several fingers in terms of latitudes that never reach the equator.
542 million years ago something mysterious happened on Earth
Experts call the sudden increase in the diversity and richness of Earth's fossil record, which began 542 million years ago, the "Cambrian explosion." He puzzled Charles Darwin. Why did all the ancestors of modern animals appear literally overnight, in a geological sense?
One expert opinion is that there was life before the Cambrian period, but it didn't have any hard parts. The scientists analyzed soft-bodied Precambrian fossils, some of which have no connection whatsoever with any form of modern life today, as well as young Cambrian soft-bodied fossils from Canada. It turned out that at least 50 million years before the Cambrian “explosion,” multicellular life developed. Scientists don't understand where the hard parts came from, but perhaps a genetic mutation caused a cascading effect that led to the sudden development of shells and skeletons. However, not everyone agrees with this theory. There is still no exact answer to the question of what happened to life on Earth 542 million years ago.
The first land plants may have caused a mass extinction
During the Devonian period, which was 150 million years after the Cambrian, it was good to be born a fish at the top of the food chain. Apart from a few stray plants and animals exploring the land, all life lived in the sea. After tens of millions of years, everyone came out of the sea onto land, where tall forests of ferns, mosses and mushrooms appeared.
And then the sea creatures began to die. At least 70% of all invertebrates in the sea have gradually disappeared. The Devonian extinction was one of the ten largest mass extinctions in Earth's history.
Many experts believe that land plants were to blame. They say the first forests created soil that broke rocks into minerals that eventually flowed into the ocean, causing algae blooms. This algae consumed all the oxygen, and the sea creatures suffocated. Even worse, the algae was then eaten by other organisms and became hydrogen sulfide. It turned sea waters into acid. The plants couldn't escape either. They sucked enough carbon dioxide out of the air to cause an ice age, which wiped out many of them too.
Fortunately, there are a few species left that have survived even these hellish conditions at sea or on land.
Ancient life knew how to adapt
There has never been a complete extinction of species, even when the planet was hit by a massive asteroid. For example, back in Earth's youth, the oxygen produced by newfangled cyanobacteria was toxic to many early life forms. While many oxygen haters died, others adapted and became more sophisticated. Extinctions have happened from time to time, but Jurassic Park's Ian Malcolm was right when he said that life will always find a way to keep going.
According to the fossil record, survival and extinction had a greater influence on demography. If a large group of species were scattered around the world, there was a chance that at least one or two individuals would survive extinction. Other conditions include environmental conditions and genetic factors that make species vulnerable or allow adaptation.
Horseshoe crabs turned out to be the best - they survived four major mass extinctions and countless smaller ones.
Finding Martian fossils changes our understanding of Earth
What is a fossil? At first glance, this is all that has been dug out of the ground, but this approach can be misleading when we are trying to understand ancient life.
Fossils are difficult to identify. It can sometimes be difficult to tell whether a bubble on a Precambrian rock is a fossilized bacterium or just a rock. What is life and how can we identify its fossils? The most interesting thing is that space exploration can help us in this matter.
At the moment, attention is focused on Mars, since besides Earth, this planet offers the friendliest planetary climate for life. Once upon a time there were even rivers and lakes. If life existed in these ancient waters, fossils may have remained. This raises an obvious question. If we're trying to understand what life was like on Earth 542 million years ago, how do we define 4 billion-year-old Martian remains?
Astrobiologists are working on this, not disdaining the help of paleontologists. Understanding what ancient fossils on Mars might be like allows scientists to sharpen their understanding of what isn't fossils on Earth.
Fossil sites
Most of the fossils we saw probably formed in water. Water is good for creating fossils. The land is not very good. In shallow waters close to the beach, for example, lots of sediment from rivers and streams quickly buries shellfish and other sea creatures, preserving them.
Tropical forest rain can be as rich and rich as shallow sea shelf, but it will not form many fossils. Plants and animals that die in it will quickly decompose due to the moisture. In addition, predators will quickly carry away the corpses, and the rest will be destroyed by wind and rain.
Standing water in low-lying areas such as swamps and lagoons is also suitable because it does not contain much oxygen and does not support many decomposing organisms. In addition, there is also a shift in fossils toward bodies with hard parts, as well as groups of animals and plants that are large, long-lived, and dispersed over a wide geographic area. Time also affects. Geological processes like mountain building and plate subduction tend to wear away fossils, which is why the oldest ones are so hard to find.
Fossils rarely resemble living things
The physical processes after a plant or animal dies are complex and messy. There is a separate field of science that studies these processes. While it certainly helps in many ways, it does not provide a perfect map of the original living being. Some solid fossils, such as insects and carnivorous plants, trapped in amber are the exception, but they are all relatively young. For the most part, only a small part of the organism is preserved. And as far as we know, fossilization only occurs in the hard, tough parts of a plant or animal, so experts must reconstruct animals from a couple of teeth and, if they're lucky, a few bones.
Paleoartists use fossil evidence to reconstruct ancient living things, but they fill in the gaps with details taken from modern descendants of a plant or animal. Often new discoveries confirm reconstructions. Sometimes - more often in the case of feathered dinosaurs - the first reconstructions turn out to be inaccurate.
Not all fossils are petrified
Scientists love to stick to words. A paleontologist describing a 200-million-year-old tree that has turned to stone might call it "mineralized" or "replaced" rather than petrified.
Mineralization occurs because there are empty cavities in the wood. Let's say a tree falls into a lake that contains a lot of dissolved minerals from a nearby volcano that released its ash stuff into the water. These minerals, especially silicates, enter the wood and fill the pores and other cavities, so parts of the wood become encased in the stone and are preserved.
The tree can also be replaced. This is a longer process. Suppose our tree did not fall into the lake when it fell, but went into the soil. Groundwater began to seep in and after a certain geological time, minerals replaced the entire tree, all woody parts, molecule by molecule. All "petrified" trees are good, but paleontologists extract more information from a tree that has undergone molecular replacement than from a mineralized tree.
It turns out that the saber-toothed “tiger” was not the only ancient creature with long teeth. Sabretooths are an example of convergent evolution, where unrelated species independently evolve the same useful function. Sabretooths were useful for all types of predators that had to hunt animals larger than themselves.
There are many other examples of convergent evolution. Modern giraffes, for example, are not related to dinosaurs, but have the same long necks as brachiosaurs and other dinosaurs. The long-extinct mammal Castorocauda looked and behaved similar to the modern beaver, although the two species are unrelated.
One of the strangest cases of convergent evolution involves us. Koalas have fingerprints that look just like ours, even though they are marsupials (they have pouches on their bellies) and we are placentals (our unborn young feed through the placenta). Scientists think koalas may have evolved tiny curls on their toes to make it easier for them to climb trees, just as we and our closest ape relatives did in the past.
Ancient Animals Live and Thrive Today
It often happens that some strange species of animal or plant, which everyone already thought had disappeared, turns out to be alive and well. We think of them as relics, not suspecting that there are still many ancient organisms on Earth that have undergone virtually no changes.
As we have already noted, horseshoe crabs have survived many mass extinctions. But they are not the only ones. The same cyanobacteria that once killed off much life on Earth by starving them of oxygen billions of years ago are also alive and well. Insects also make an excellent case for ancient life. For example, rove beetles date back to the Triassic period (more than 200 million years ago). Today, this family of beetles probably contains the largest number of living organisms in the world. And their ancestors were probably familiar with Triassic water bugs, like those that sometimes appear in ponds and scare people.
Most amazingly, some species of sulfur-producing anaerobic bacteria, which were among the first living organisms on Earth, live with us today. Moreover, these are one of those microbes that inhabit our digestive tract. Fortunately for us, the Earth's atmosphere has been improving significantly over the years. Or most of them, at least.
In the distant past, many of the organisms that inhabited the Earth were much larger than modern animals. There were also monstrous millipedes and giant sharks. The parade of giants was presented by a BBC Earth correspondent.
The heaviest animal that has ever lived on Earth is the blue whale, weighing more than 150 tons. As far as we know, no living organism in history has had a similar mass. But some creatures could boast larger sizes.
Sarcosuchus imperialis may well have eaten small dinosaurs
Dinosaurs enjoy, perhaps, the undeserved attention of the public, because besides them, many other animals of enormous size lived on Earth, which we will never see in the flesh.
Some of them are giant ancestors of living creatures, while others did not leave offspring, and therefore seem especially amazing.
The remains of prehistoric giants can shed light on the gradual changes in living conditions on Earth, since the size of animals often directly depends on the environment.
In addition, there is something fascinating about extinct giants, whose appearance we can only imagine.
We offer our readers the ten most amazing creatures that we are no longer destined to meet in nature.
Aegirocassis benmoulae
Aegirokassida filtered seawater, absorbing plankton
What might the fruit of love between a whale and a lobster look like? If such a creature existed in the world, it is possible that it would resemble an aegirocassid.
This two-meter-long prehistoric shrimp lived on Earth about 480 million years ago. She belonged to the now extinct genus Anomalocaris.
The animal looked like a space alien. Using mesh processes on its head, it filtered plankton from sea water.
The life of aegirocassids occurred during a period of increasing species diversity of plankton. As a result, these animals did not compete in the search for food with most other anomalocaris - carnivorous predators with sharp teeth.
It is possible that aegirocassida will help us figure out how the limbs of arthropods, represented by modern spiders, insects and crustaceans, developed.
Fossil remains of Aegirocassida
Studying the fossilized remains of Aegirocassida, scientists came to the conclusion that it had paired lobes
Until recently, based on the findings of incompletely preserved fossils, scientists believed that Anomalocaris had only one pair of flexible lateral lobes for each body segment. However, analysis of the remains of Aegirocassida indicates that each segment of these creatures had two pairs of blades used for swimming.
Scientists once again studied previously found fossils of other species of the genus Anomalocaris and came to the conclusion that they also had paired lobes. They concluded that in some species fusion of the lobes occurred during evolution.
This led scientists to the conclusion that Anomalocaris were prehistoric arthropods. This idea has previously been criticized due to the strange body structure of representatives of this genus.
Until 1985, paleontologists believed that the appendages on the heads of Anomalocaris were shrimp, their tooth-strewn mouthparts belonged to jellyfish, and their bodies belonged to sea cucumbers.
Rakoscorpion (Jaekelopterus rhenaniae)
This is what a prehistoric crustacean scorpion probably looked like
Cancerscorpio is the worst nightmare of an arachnophobe (a person who has a pathological fear of spiders). This giant, 2.5 meters long, claims to be the largest arthropod to ever inhabit the Earth.
In English the creature is known as the "sea scorpion".
This title is inaccurate. Rakoscorpio was not a scorpion in the literal sense of the word, and, most likely, it was found not at the bottom of the seas, but in rivers and lakes. He lived about 390 million years ago and ate fish.
This species was first described in 2008: a fossilized claw 46 cm long was found in a quarry near the German city of Prüm - all that remained of the animal. However, the ratio between the size of the claw and the entire body in crayfish is very constant, so the researchers concluded that J. rhenaniae reached a length of 233 to 259 cm.
This find is further evidence that prehistoric scorpions were very large.
No one knows for sure why scorpion cancers grew to such gigantic sizes.
Some scientists suggest that the answer lies in the composition of the Earth's atmosphere: in some periods of the past, the level of oxygen in it was much higher than now.
Others point to the relatively small diversity of vertebrate predators that lived then, including fish.
Arthropleura
Millipede
The modern millipede fits in the palm of your hand; now imagine the same one 2.6 m long - it will be like an arthropleura
Another contender for the title of the largest arthropod in history is Arthropleura from the genus of millipedes, reaching 2.6 m in length.
Arthropleura lived from 340 to 280 million years ago and it is possible that they owed their gigantic size to the high oxygen content in the atmosphere.
No one has yet managed to find the entire fossilized arthropleura. Skeletal fragments up to 90cm in length have been discovered in southwest Germany, and traces believed to have been made by these millipedes have been found in Scotland, the USA and Canada.
Researchers believe that the body of Arthropleura consisted of approximately 30 segments, covered on top and sides with protective plates.
Since no fossil remains of Arthropleura jaws have yet been discovered, it is difficult to say for sure what it ate.
Paleontologists who studied the fossilized excrement of this creature identified fern spores in them, indicating the likelihood of the presence of plant foods in their diet.
Arthropleura was popularized by filmmakers - it is mentioned in the BBC popular science series Walking with Monsters (2005) and First Life (2010).
Meganeura
Imagine an insect similar to a dragonfly, with a wingspan of 65 cm - Meganeura could be something like this
Gigantism among arthropods was first associated with high oxygen levels in the atmosphere in 1880 after the discovery of Meganeura remains in France.
These dragonfly-like creatures lived about 300 million years ago and fed on amphibians and insects.
Their wingspan reached 65 cm. We are talking about one of the largest species of flying insects that ever inhabited the Earth.
Strictly speaking, meganeuras belonged to the genus of dragonfly-like insects. They were distinguished from the dragonflies known to us by certain structural features of the body.
Limitations on the size of insects are imposed by the method of delivering oxygen from the air to the internal organs. The role of the lungs is performed by the tubular tracheal system.
During the Carboniferous period, 359-299 million years ago, the oxygen content in the air reached at least 35%. Perhaps thanks to this circumstance, Meganeura was able to extract more energy from the air and retain the ability to fly even as it increased in size.
The same hypothesis explains why meganeura did not survive in later periods, when the oxygen content in the air decreased.
Sarcosuchus imperator
Sarcosuchus imperial skeleton Sarcosuchus imperial is also called the “super crocodile”
In the process of evolution, not only insects were crushed. Paleontologists searching for dinosaur remains in Niger in 1997 were surprised to discover fossilized crocodile jawbones that were as long as an adult human.
It later turned out that scientists had found the best-preserved specimen of Sarcosuchus imperator to date, a prehistoric giant crocodile that lived in the deep rivers of northern tropical Africa 110 million years ago.
The animal, which is informally called a super crocodile, reached 12 meters in length and weighed about eight tons, that is, it was twice as long and four times heavier than the largest living crocodiles.
It is quite possible that in addition to fish, Sarcosuchus also fed on small dinosaurs.
Its narrow jaws reached 1.8 m in length and were studded with more than a hundred teeth. There was a massive bone growth at the tip of the upper jaw.
The eyes of Sarcosuchus moved vertically in their sockets. Apparently, this monster looked like the Ghanaian gharial living in India and Nepal, which is listed in the Red Book.
Despite its unofficial name, Sarcosuchus imperatoris was not the direct ancestor of the 23 species of modern representatives of the crocodile order. It belonged to an extinct family of reptiles called Pholidosaurus.
Other, no less large fossil remains of prehistoric crocodile-like reptiles were found, including those belonging to the extinct genus of Deinosuchus.
They were related to modern alligators and may have reached a length of 10 meters.
Crocodiles could grow to such sizes because they lived primarily in water, which supported their weight - something that would have been impossible on land.
In addition, the crocodile skull is very strong. Accordingly, the force of compression of the jaws is also great, which allows the reptile to hunt large prey.
Metoposaurus
The two-meter metoposaur had a wide, flat head with a mouth studded with hundreds of teeth.
It wasn't just crocodiles that prehistoric fish had to fear. In ancient times, there were also giant carnivorous amphibians on Earth, which looked like huge salamanders.
Fossilized remains of Metoposaurus have been found in Germany, Poland, North America, Africa and India.
Metoposaurus was very distantly related to modern salamanders
Most prehistoric species disappeared from the face of the Earth about 201 million years ago. Then many vertebrates, including large amphibians, became extinct, which gave dinosaurs the opportunity to establish their dominance on the planet.
Metoposaurus was described in March 2005 by Stephen Brushett of the University of Edinburgh and his colleagues. It was named Metoposaurus algarvensis after the Algarve region in southern Portugal where the remains were found.
The two-meter metoposaur had a wide, flat head with a mouth lined with hundreds of teeth. Small, poorly developed limbs indicate that it did not spend much time on land.
Metoposaurus was the ancestor of modern amphibians such as frogs and newts. Despite its appearance, Metoposaurus was very distantly related to modern salamanders.
Megatherium
Megatheriums are considered the ancestors of modern sloths, armadillos and anteaters
What would an elephant-sized cross between a bear and a hamster be like? Possibly Megatherium.
This extinct genus of giant sloths lived primarily in North America between 5 million and 11,000 years ago.
Although Megatherium was smaller than dinosaurs and woolly mammoths, it was one of the largest land animals. Their length reached six meters.
Megatheriums were relatives of modern sloths, armadillos and anteaters.
The Megatherium skeleton was extremely strong. The animal probably had great strength, but did not differ in its speed of movement.
Many scientists believe that megatheriums used their long forelimbs, equipped with large claws, to tear leaves from trees and strip bark at heights inaccessible to smaller animals.
However, it has also been suggested that megatheriums could also feed on meat. The shape of their ulna bones suggests the ability to move their forelimbs quickly. It is possible that megatheriums killed their prey with a wave of their paws.
“Terrible Birds” (Phorusrhacidae)
Flightless birds could swallow a medium-sized dog or similar animal in one fell swoop
In recent years, scientists have been attempting to clone extinct animal species, including the Iberian ibex, the marsupial wolf, the passenger pigeon and even the woolly mammoth.
Let's hope that they will not think of experimenting with the DNA of representatives of the Fororacoceae family - or, as they are also called, “terrible birds” from the order Craniformes.
These flightless birds reached three meters in height, ran at speeds of up to 50 km/h and could swallow a medium-sized dog in one fell swoop.
Thanks to its height and long neck, such a “terrible bird” could detect prey at a great distance, and its long, powerful legs allowed them to develop the high speed necessary for hunting.
With their downward-curving beaks, forarokos tore at prey in much the same way as modern birds of prey do.
The "Terrible Birds" lived between 60 and two million years ago. Most of the fossil remains known to us were found in South America, and some in North America.
At one time, some scientists claimed, based on finds in Florida, that these birds became extinct only 10,000 years ago, but later it turned out that the age of the remains found was much older.
It is believed that the closest living bird relatives of the Forarocosidae are the cariamidae family, native to South America, whose representatives reach 80 cm in height.
Megalodon (Carcharodon megalodon or Carcharocles megalodon)
Fossil megalodon was much larger than a modern white shark
You may have heard stories about basking sharks that are three times longer than the great white shark and 30 times heavier. Don't worry: such monsters haven't existed for a long time.
They are called megalodons, and no one knows exactly how large they really were. Like all sharks, the megalodon's skeleton consisted of cartilage rather than bone, so almost no fossils have survived to this day.
As a result, we have to draw conclusions about the size of this fish only on the basis of the discovered teeth, from which the Greek name for the monsters comes, meaning “huge tooth” in translation, and individual fragments of vertebrae.
Megalodon gets its name from its giant teeth
According to the latest estimates by scientists, the length of the megalodon was 16-20 m. For comparison, the length of the largest modern fish - the great white shark - does not exceed 12.6 m.
In the giant jaws of the megalodon there were over 200 jagged teeth, each up to 18 cm long. The force of compression of the jaws was 11-18 tons - 4-6 times higher than that of the tyrannosaurus.
The idea that megalodon has survived to this day was made in the film “Monster Shark: Megalodon Lives,” shown in 2013 on the Discovery Channel.
The film received scathing criticism due to the fact that it used falsified video footage and comments from actors posing as scientists.
Real scientists believe that megalodon lived from 15.9 to 2.6 million years ago. After that, according to a scientific paper published in 2014, whales became the largest inhabitants of the oceans.
Vertebra of Titanoboa and modern middle snake
This colossal snake looked like a modern boa constrictor, but acted more like today's Amazon jungle anaconda. It was a slimy swamp dweller and a huge predator that was able to eat any animal it hunted. The diameter of his body was close to the waist size of a man of our time.
In the swampy jungle, the Titanoboa's life was surprisingly long due to the constant, incessant rain, abundant vegetation and living creatures. Deep-water rivers allowed the snake to both go deep and crawl around palm trees and hilly jungles.
The river basin in which Titanoboa fed was filled with giant turtles and crocodiles of at least three different species. It was also home to a giant fish, three times larger than the current inhabitants of the Amazon.
On March 22, 2012, a 14-meter reconstruction of the titanoboa skeleton, created for the Smithsonian Channel's popular science program Titanoboa: Monster Snake dedicated to titanoboa, was presented at Grand Central Station in New York.
Ecology
When we find common fossils of ancient shells on the beach, they are very easy to recognize. However, there are fossils of very ancient living creatures that are difficult to recognize even for specialists.
The problem also lies in the fact that many of them are poorly preserved or have come to us in incomplete form. It's not surprising that until better specimens are found, fossils of long-extinct creatures will often be mistaken for completely different species. We invite you to learn about these mysterious fossils, which have been mistaken for mysterious things at various times.
1) Ammonites
Ammonites are common in fossils, but have been misidentified for a long time. Even in Ancient Greece they believed that these were ram horns. They were named after the Egyptian god Amon, who wore such horns. In ancient China they were called horn-stones for the same reason. In Nepal, they were considered as holy relics left by the god Vishnu. The Vikings believed that ammonites were the sacred offspring of the serpent Jormungandr, who turned into stone.
In the Middle Ages in Europe they were called snake stones, were believed to be the fossilized bodies of coiled snakes that were turned into stones by Christian saints. Some enterprising traders even carved snake heads from ammonite fossils and sold them as souvenirs.
Today we know that these are just fossilized shells of squid-like creatures that lived on our planet 400 million years ago and lived until the death of the dinosaurs. More complex fossils include more than just shells. Fossil shells can be found along with protruding tentacles and misshapen heads that resemble modern nautilus mollusks.
2) Fish teeth
The fossilized remains of fish teeth have been interpreted in different ways. Some ancient fish had hard, flat molars that allowed them to crush mollusk shells. In Greece and later in Europe, these fossils were considered magical jewelry and were often called toad stones, since people believed that large toads wore them as decorations on their heads. The teeth were used to make talismans; it was believed that they could cure epilepsy and poisoning.
In Japan, fossils of flat shark teeth have been identified as claws shed by the terrible Tengu monsters. In Europe, shark teeth were seen as hardened tongues of the devil.
It was only in the 17th century that the Danish anatomist Niels Stensen seriously studied these fossils and concluded that most of the "devil's tongues" found were just shark teeth. He also realized that fossils did not appear spontaneously in the earth and that they were located next to the remains of ancient animals long dead.
3) Trees
Lepidodendron- an ancient tree-like plant with bark resembling a pine cone, which has long been extinct. The leaves of this plant looked like grass stems and lepidodendron was still closer to herbs than to modern trees. Most of the European coal deposits are the remains of these ancient plants. Lepidodendron fossils are very interesting. Long tree trunks were often preserved entirely in fossils; such a trunk could reach 30 meters in height and about a meter in width.
At fairgrounds in the 19th century, these fossils were often displayed as the bodies of scaly snakes and dragons. People could pay a small fee to admire the ancient "monsters" and listen to fictional tales of their dramatic fate. Various Christian saints could also appear in the stories. More complete fossils might include not only trunks, but also branches, roots, leaves and cones, which provided evidence that these were once trees and not mysterious fairy-tale creatures.
4) Foraminifera
On the Pacific coast of southern Japan you can sometimes find unusual grains of sand. Many of them are shaped like tiny stars, less than 1 millimeter in size. Local legends say that these are the remains of unfortunate children from the divine union of two stars. These “children” died because they fell to Earth or were killed by sea monsters living off the coast of the Japanese island of Okinawa. Their fragile skeletons wash up on the shore, and this is all that remains of the poor creatures.
In fact, these are the remains of various forms of earthly life, creatures similar to amoebas, which are called foraminifera. These creatures and their modern descendants are single-celled creatures that build themselves a protective shell. When they die, their needle-like shells remain, and if you look through a microscope, you can see the tiny chambers and structures in great detail.
5) Protoceratops
Dinosaurs called protoceratops were relatives of more famous Triceratops. They walked on 4 legs and were comparable in size to a large dog, although they were somewhat heavier. They definitely had a large skull with a bird's beak, in the back of which there was a bony outgrowth with holes.
Protoceratops lived in large herds, so they left behind a large number of fossils. For many people who were not yet familiar with dinosaurs, the found skulls seemed like the remains of fantastic and strange creatures. Because of their size, it was believed that Protoceratops were small lions. However, the distinctive feature of the skulls of these animals suggested that they were lions with curved beaks, like those of eagles. The animals' feet resembled the paws of eagles with claws rather than the paws of lions. People thought the creature was a mixture of a lion and an eagle. Apparently, legends about these creatures most likely appeared after people found fossils of Protoceratops.
6) Belemnites
Belemnites are extinct ancient animals that resemble modern squids. Unlike squids, belemnites had 10 “arms” of equal length, which were covered with tiny hooks, and, remarkably, these sea creatures had a skeleton. Belemnites lived during the age of dinosaurs and are well preserved in fossils.
The most commonly found fossilized remains of their skeletons are cylindrical objects with a tapered end without any structures such as tentacles. These fossilized skeletons are shaped like a bullet.
In Europe, they were believed to be "thunderbolts" - objects that fell to earth from the heavens, producing the sound of thunder when they struck the surface of the earth. They were associated with various thunder gods. Many people kept them in different parts of their homes in order to divert lightning. Others believed that belemnites were associated with elves, not gods. They believed that these were the fingers of elves. People used them in various superstitious medicinal practices, such as to treat snake bites or relieve headaches. They applied the fossils to the affected area of the body and cast various spells.
7) Ankisaurs
Ankysaurs were one of the groups of early dinosaurs. These herbivores had long necks and tails and were relatives of the more familiar ones brontosaurus And diplodocus. Ankysaurs were smaller in size than their later ancestors and grew no more than 2 meters in length. They evolved from bipedal ancestors and did not stand entirely on 4 legs, although their front legs were well adapted for locomotion. They stood up on their hind legs when needed and used their front paws to grasp things.
Ankysaurs have attracted particular interest because they were initially misidentified. They were confused with the creature that would seem to be the least like a dinosaur: a human. Strangely, the long neck and tail, lizard-like body, reptile-like skull, and other features were simply ignored! Just the fact that the creature was the size of a man helped make everyone believe that these were the remains of our ancestor.
After other fossils of these creatures were found over several decades, the name "dinosaur" was coined and people recognized that these fossils were not of humans at all, but of reptiles. The fact that you can confuse a lizard with a person shows how people can be mistaken.
8) Mastodons and mammoths
Just a few thousand years ago, mastodons and mammoths roamed the icy land. They looked like elephants, but had warm fur and tusks several meters long. Mass species extinction, climate change and hunting have led to their extinction. Like modern elephants, these animals had very strong muscles in their trunks that were stronger than other muscles in their body.
The trunk of mammoths and mastodons required that there be a hole in the middle of the animal's skull. Modern elephants have the same feature. People who live in areas where elephants live have seen animal skulls more than once, so they know this feature. Others who found skulls of ancient relatives of elephants with giant holes in the middle imagined this creature as a huge humanoid giant with one eye socket. The legend of the Cyclops seems to have its roots in the days when people found skulls of ancient animals outside of Africa.
9) Sea urchins
Sea urchins are spiny, round-shaped creatures whose fossils are commonly found off the coast. They belong to a group of animals called echinoderms. These creatures have lived on our planet for hundreds of millions of years, and their distant ancestors left behind a lot of fossils. Although ancient sea urchins have many similarities with modern species, their fossils have long been mistaken for completely different creatures.
In England, they were believed to be supernatural crowns, loaves of sacred bread, or magical snake eggs. In Denmark, they were believed to be “thunderstorm” stones: it was believed that they began to release moisture before storms, which helped people predict inclement weather.
The five lines found on many sea urchin fossils were considered a good omen and were kept as a good luck charm in India. The magical powers associated with sea urchins reflected how each culture interpreted them. They were believed to be able to cure snake bites, help prepare bread, protect against storms, and bring good luck.
10) Hominids
Many of man's relatives, the apes, left behind fossils. These fossils were often misinterpreted before people began to think about human evolution. Fossils that were found in Europe and America sometimes “proved” the existence of various mythical characters mentioned in the same Bible, such as giants or demons. Others said that these were the ancestors of apes, although modern apes have very different features.
Some are sure that these skeletons belong to aliens, and not fairy-tale monsters. Apparently, fossils found in Asia inspired people to create legends about the Yeti. Some believe that some hominids could coexist with humans, so the legend-makers were inspired not by their fossils, but by these living creatures themselves.
The living creatures presented in this article arose at the beginning of the Paleozoic - the era of ancient life. This era began 541 million years ago with the so-called Cambrian evolutionary explosion: in a relatively short (by paleontological standards) period of time - about 100 million years - a wide variety of living organisms arose on Earth.
Entirely new types of animals appeared, such as chordates and arthropods. For comparison, it took more than 3 billion years for the simplest cells to develop into multicellular organisms. The skeletal revolution is considered part of the Cambrian evolutionary explosion (many creatures acquired a mineral skeleton).
Animals have noticeably developed sensory organs and brains. A clear structure of the “prey-predator” relationship has emerged. The former developed along the path of improving defense mechanisms, the latter learned to run and swim faster, and honed their means of attack.
Many of the earliest living creatures of the Cambrian period were so unusual that scientists cannot place them in any known group of animals.
Anomalocaris - a large shrimp-like predator
This unusual sea creature is possibly the ancestor of all modern arthropods or is closely related to them. Anomalocaris had an elongated body, consisting of no less than 11 segments, lateral swimming lobes and a fan-shaped tail - with their help the animal could swim quickly. It is assumed that the creature was diurnal.
These were one of the largest organisms known from Cambrian deposits: their body length could reach 60 cm (there is evidence that some could grow up to 1.8 m in length). Outwardly, this predator resembled a shrimp.
Anomalocaris had excellent vision. The eyes were faceted, each with at least 16 thousand hexagonal lenses (most modern arthropods have much fewer: a fly has about 4 thousand lenses per eye, and an ant has 100).
The most unusual part of Anomalocaris is its disc-shaped mouth. It consisted of 28 small and 4 large segments, resembling a pineapple circle in appearance. In the central hole were sharp, hard teeth. This structure of the oral apparatus is uncharacteristic of arthropods.
In front of the mouth there were two grasping tentacles with which the animal caught the prey. Anomalocaris chewed, squeezing and unclenching its mouth, but never closing it completely. The head, jaws and grasping tentacles were covered with a chitinous shell.
Fossil remains of Anomalocaris
Who did he eat?
Australian researchers analyzed the teeth of Anomalocaris and concluded: their composition is similar to the chitinous shell of the animal - it would not be able to bite through even the softest shell of a trilobite. In addition, scientists did not find any damage on the teeth of this unusual shrimp, which should remain from interaction with the shells of victims.
Scientists decided that the animal either hunted soft-bodied inhabitants of ancient reservoirs or ate plants.
Opponents of this point of view believe that the accumulated fossils of Anomalocaris are still not enough to draw clear conclusions. In addition, the remains of trilobites were found with bite marks on their shells, which could have been left by Anomalocaris.
Anomalocaris translated from Latin means “unusual shrimp.” Scattered remains of the animal have been found since the end of the 19th century, but they were mistaken for other creatures: the grasping tentacle was considered an ancient relative of the shrimp, and the imprint of the mouth was considered a jellyfish. Only in the 1980s, when a whole Anomalocaris was discovered in Canada, did scientists realize that the individual parts found earlier were its remains.
Where did he live
Fossil remains of Anomalocaris are now found in the northern United States, Canada, China and Australia. However, scientists believe that the animal had a cosmopolitan distribution (it lived wherever conditions allowed, and at that time they favored its wide distribution).
Most of the Earth was occupied by water spaces, which were everywhere populated by trilobites, which may have formed the basis of the diet of Anomalocaris. A rather monotonous climate contributed to maintaining suitable conditions for life in the seas and oceans in different parts of the planet.
Trilobites
Trilobites are marine arthropods that became completely extinct by the end of the Paleozoic. Nowadays, these creatures can only be found in the form of fossils. The oldest of them is 530 million years old, but it is possible that trilobites appeared even earlier. Modern insects, centipedes, arachnids and crustaceans are also arthropods. Today they make up up to two-thirds of all species of living organisms on our planet.
The size of trilobites varied greatly from a few millimeters to 70-90 cm.
Trilobites organized their life in different ways. Most of the creatures lived at the bottom of reservoirs, eating algae, small organisms and organic remains. Some species were free-swimming (eating plankton), others were burrowers (eating mud). There were also predators among the trilobites. These arthropods had no jaws; the creatures grabbed and ground food with modified forelimbs.
The trilobites themselves also served as food for marine life, such as cephalopods and the first fish.
Incredible variety of shapes
Over 10 thousand fossil species of trilobites and 5 thousand genera are known, united in 150 families and 9 orders. Because of this, trilobites varied greatly in size and appearance. Some had wide and flat shells, others narrow and convex, decorated with grooves.
Some types of trilobites had eyes that were located on processes, others were blind.
It is believed that these creatures were bisexual and reproduced by laying eggs, from which small larvae emerged. For some time, the newborns swam passively, thanks to which they were quickly carried away by currents over long distances.
Appearance
The body consisted of a head protected by a shell with two eyes, a segmented torso (thorax) and a tail (pygidium). The eyes of trilobites, like those of many modern insects, were faceted and consisted of a mass of lenses. The eyes were set on stalks in those animals that buried themselves in the mud. Many species of ancient arthropods could see 360°. The eye color was different.
The durable chitinous shell did not allow the trilobites to grow. Growing up, these arthropods molt several times, shedding the old shell and acquiring a new one. While another shell was being formed, the body was actively developing. During molting, trilobites were very vulnerable, so they tried to stay in groups.
The official date of the discovery of trilobites is considered to be 1771, when the German scientist Johann Walch identified the class of animals of the same name. Trilobites were first reported, but under a different name, by the British archaeologist and museologist Edward Llwyde in 1698.
The word “trilobite” is translated from Latin as “three-lobed.” The name reflects the structural features of the creature. The arthropod's shell was conventionally divided lengthwise and crosswise into three segments: along the head (shield), trunk (thorax) and caudal (pygidium) sections; across - axial (rachis), left and right lateral parts (pleura). It is assumed that in addition to the brain, the shield contained a heart and stomach. On the shield and thorax there were legs that performed the functions of breathing, chewing and movement.
Where did they live?
Trilobites lived in large numbers throughout the planet, and their fossilized remains can be found almost anywhere. Particularly well-preserved remains of trilobites are found in Yunnan Province in China (Maotianshan Shale), in Alberta in Canada (Burgess Shale), in New York State in the USA, and in Rhineland-Palatinate in Germany (Hunsrück Shale). Also, stocks of trilobites are often found in the area of the Lena Pillars in Yakutia.
Opabinia
Opabinia is a very unusual sea creature that had an original appearance. Her body was elongated and divided into 15 segments. On the sides of each of them there was a pair of petal blades directed slightly downward. The body ended in a V-shaped tail, which was formed by three pairs of long processes directed upward. The animal led a quiet lifestyle most of the time, moving along the bottom in search of food - soft invertebrate bottom inhabitants.
Opabinia was a tiny creature, not exceeding 7 cm in length.
The discovery of opabinia has baffled scientists. They could not determine which modern animal species this creature could be the ancestor of. The research carried out, as well as the discovery of Anomalocaris (see above), made it possible to bring some clarity to this issue. Currently, there is a scientific opinion that Opabinia was related to the common ancestor of all modern arthropods and worms.
The study of the animal had another important scientific significance. Previously, it was believed that the appearance of a large variety of multicellular organisms about 540 million years ago occurred abruptly. The phenomenon itself was called the “Cambrian explosion.” But the presence of creatures such as Opabinia at the beginning of the Cambrian refutes this theory. Today, taking into account new data, it is believed that the first complex animals could have appeared 25-40 million years earlier than expected, that is, back in the Precambrian period.
There is a point of view that Opabinia could be the ancestor of modern tardigrades. The latter are invertebrates invisible to the human eye. Their body length is only 0.1-1.5 mm. In a minute they can cover a distance of no more than 3 mm! Tardigrades are ubiquitous and feed on the cell membranes of algae and mosses.
Appearance
The strange and surprising appearance of Opabinia was given by its proboscis with a peculiar claw at the end and a large number of eyes. The proboscis was hollow, its length was about one third of the body, in the largest individuals it was approximately 2 cm.
With the help of a claw, Opabinia captured food and sent it into the mouth opening located at the base of the proboscis. The animal's five eyes were placed in two lines. They were attached to the head with the help of small appendages. They may have had a facet structure like modern insects.
The most notable feature of Opabinia is its five eyes located on the back of its head. These eyes were probably used by the animal to find food. Due to its flexible body, it is unknown whether Opabinia led a pelagic (in the water column) or benthic (bottom-dwelling) lifestyle.
Scientists even debate whether Opabinia could swim at all. Perhaps, in moments of danger, by bending her whole body and helping herself with the blades, she was able to overcome some distance in the water column.
Where did you live?
Unlike trilobites, only one species of Opabinia is known so far, Opabinia regalis. Its representative was discovered in the Burgess Shale deposits in British Columbia, Canada.
In 1960, fossils of creatures that researchers described as a species of Opabinia were found near Norilsk in Russia. However, some scientists question the correctness of the identification, especially since the remains are very poorly preserved.
In 1997, news came from Australia that a species related to Opabinia had also been found there. But this version is also the subject of scientific controversy.
Over time, the statements of Russian and Australian scientists may receive additional confirmation. This would mean that Opabinia were distributed throughout the seas of the whole world.
Hallucigenia
Seemingly the product of hallucinations (hence the name), Hallucigenia lived in the depths of the sea and led a benthic lifestyle. Her vision was poorly developed. Most likely, the animal distinguished only between light and darkness. Hallucigenia had 10 pairs of limbs. The first three served as oral tentacles, the remaining seven served for walking.
In size, Hallucigenia was even smaller than Opabinia, its dimensions did not exceed 3.5 cm. It looked like a small worm with legs and long spines.
At the tip of each leg there were one or two small claws. There were seven pairs of spikes on the back, which could perform a protective function. The elongated head was equipped with a pair of simple eyes and a mouth, which was surrounded by a ring of hard plates. The latter acted as teeth.
Hallucigenia is an invertebrate, the relationship of which to certain types of animals is still under scientific debate. The discoverer of this creature, the American paleontologist Charles Doolittle Walcott, classified it as an annelid. In 1977, the English scientist Simon Conway Morris, having examined the remains available at that time, firstly gave the name itself - hallucigenia, and secondly, described it as an independent genus. The paleontologist believed that this animal was the ancestor of modern onychophorans. The latter are moisture-loving terrestrial invertebrates.
Additional research has shown that hallucigenia may have shared a common ancestor with modern arthropods.
There is another interesting point of view. According to her, the fossilized remains, which today are mistaken for hallucination, could be part of a larger creature still unknown to science. This was the case with Anomalocaris. For some time, its individual parts were attributed to three different animals.
The history of the study of hallucigenia is as unusual as its appearance. Simon Conway Morris, restoring the appearance of the animal, initially mistook the limbs for dorsal spines, and vice versa. Therefore, in his reconstruction, hallucigenia was turned upside down. It was only in 1991, after the discovery of a related Chinese species, that the scientist realized his mistake. Until 2015, the question of what the animal’s head looked like remained unresolved.
The latest discovery - a well-preserved imprint of an ancient creature - made it possible to completely recreate the appearance of the animal.
Appearance
Outwardly, the hallucigenia looked like a worm with two rows of stilted legs and dorsal spines.
Hallucigenia had pharyngeal teeth. Small but sharp, they were located in the upper part of the digestive tract at the entrance to the intestines. Apparently, with their help the animal could absorb food. Scientists suggested that the teeth in the throat prevented food from falling out of the mouth when the hallucigenia gained a new portion. Many species of modern fish have such teeth.
Relative
In 1991, the fossilized remains of an animal that resembled a hallucigenia in appearance were found in China. The body of the fossil was covered with hard plates, which is how it got its name - armored worm. The creature probably had several pairs of eyes located along the body. Like hallucigenia, the worm moved with the help of several pairs of flexible limbs.
Where did you live?
Fossil remains of Hallucigenia were first found in the Canadian province of British Columbia. Modern science knows of just over 100 specimens of varying degrees of preservation. In 1991, fossils of a related species were discovered in China. It can be assumed that different types of hallucigenia were quite widespread. Therefore, in the future, scientists hope to find traces of them in other parts of the world.