Strange fossils discovered in the middle of the twentieth century. on the territory of the US state of Illinois, became the beginning of one of the most interesting mysteries of paleontology

This mystery haunted paleontologists for 150 years. Something called Prototaxites could not be confidently assigned not only to a family or genus, but to any biological kingdom. Only in our days has the analysis of fossils made it possible, it seems, to decide on this gigantic creation of the ancient Earth, which, however, has not ceased to be extremely surprising.

The history of Prototaxites is a great example of what to see and understand - what do you see, as they say, two big differences. The American scientist J.W. Dawson, who first described this mysterious creature (in 1859), believed that these were fossils of rotten wood, somehow related to the current yews (Taxus), and therefore gave them the name Prototaxites. Only now, before real yews, this creature had to "stomp and stomp", because Prototaxites was distributed, though throughout the Earth, but only 420-350 million years ago.

At the end of the nineteenth century, scientists began to think that it was a seaweed, more precisely, a brown seaweed, and this opinion was strengthened, getting into encyclopedias and textbooks for a long time. Although it is difficult to imagine something similar to an algae (or a colony of algae?), which has grown in the form of a "trunk" of six, and sometimes nine meters in height, is difficult.

By the way, Prototaxites was the largest organism on land at that time: vertebrates had just begun to appear, so wingless insects, centipedes, and worms crawled around the strange high "pillar".

The very first vascular plants, the distant ancestors of conifers and ferns, although they appeared 40 million years earlier, nevertheless, at the time when Prototaxites settled on Earth (in the early Devonian), they did not yet rise above a meter.

By the way, about the size. AT Saudi Arabia a specimen of Prototaxites was found 5.3 meters long, which has a diameter of 1.37 meters at the base and 1.02 meters at the other end. In the state of New York, they dug up a trunk 8.83 meters long with a diameter of 34 centimeters at one end and 21 centimeters at the other. Dawson himself described a specimen from Canada - 2.13 meters long and with a maximum diameter of 91 centimeters.

What else is important to note regarding the structure of Prototaxites. It doesn't have cells like plants have. But there are very thin capillaries (tubes) with a diameter of 2 to 50 micrometers.

Nowadays, scientists, based on the results of many years of research on this representative of the ancient living world, have put forward new versions. Some specialists, starting with Francis Hueber from the American national museum natural sciences (Smithsonian Institution, National Museum of Natural History), inclined to believe that Prototaxites is a fruiting body huge mushroom; others - to the fact that it is a huge lichen. latest version, with his arguments, put forward Marc-Andre Selosse from the University of Montpellier (Universite de Montpellier II).

One of the ardent proponents of the mushroom version is Charles Kevin Boyce, now at the University of Chicago. He published several works devoted to the detailed study of Prototaxites

Boyce never ceases to be amazed by this creature. “No matter what arguments you put forward, something crazy still comes out,” says the researcher. “A mushroom 20 feet tall does not make any sense. No seaweed will give 20 feet tall. us".

Francis Hueber recently completed a titanic task: he collected many copies of Prototaxites from different countries and made hundreds of the finest cuts, taking thousands of photographs of them. Analysis of the internal structure showed that it is a mushroom. However, the scientist was disappointed that he could not find characteristic reproductive structures that would clearly indicate to everyone that, they say, this is really a mushroom (which gave confidence to Huber's opponents from the "lichen camp").

The latest (in time, but clearly not the last in the history of Prototaxites) proof of the fungal nature of the strange organism of the Devonian period is an article by Hueber, Beuys and their colleagues in the journal Geology.

"The large range of isotopes found is difficult to reconcile with autotrophic metabolism, but it is consistent with anatomy indicating a fungus and with the assumption that Prototaxites was a heterotrophic organism that lived on a substrate rich in various isotopes," the authors of the article write.

Simply put, plants get their carbon from the air (from carbon dioxide), and mushrooms from the soil. And if all plants of the same species and of the same era show the same isotope ratio, in mushrooms it will depend on the place where they grow, that is, on the diet.

By the way, the analysis of the ratio of carbon isotopes in different specimens of Prototaxites is now helping scientists to recreate the native ecosystems of this ancient creature. Since some of its specimens seem to "ate" plants, others used the microbial community of the soil as food, others may have received nutrients from mosses.

The mystery of the great growth of the Paleozoic fungus is discussed by the co-author of this study, Carol Hotton (Carol Hotton), from the Smithsonian Museum of Natural History: she believes that big sizes helped the fungus further spread its spores - through scattered swamps, randomly scattered across the landscape.

Well, when asked how this mushroom grew to such a monstrous size, scientists simply answer: "Slowly." After all, there was no one to eat this mushroom at that time.

But what to do? Sections of fossils stubbornly "did not want" to resemble sections of trees, and in general - they did not look like a plant. Rings on sections, by the way, are observed there, but these are not annual rings of trees.

In the book "Reptiles and Amphibians" by the publishing house "World of Books" for 2007, you can see a spread with a "remarkable" in its informativeness genealogical tree of modern and prehistoric amphibians and reptiles.

To begin with, the fossil fish Eustenopteron is called "coelacanth", although it is completely different in shape. In addition, coelacanth is a modern genus of lobe-finned fish, which, if only for this reason, could not stand at the base of the family tree of prehistoric tetrapods. In addition, it belongs to a completely different order of fish, which has an extremely indirect relationship to the ancestors of vertebrates.
By “labyrinth toothed” they clearly mean labyrinthodonts (this is “tracing paper”, the literal translation of the name), but the names of other groups of amphibians cannot be comprehended by a simple mind.

Here is a page from the original German edition.
Hulsenwirbler- so called in German thin vertebral, or lepospondyls (representative - diplocaulus);
Schnittwirbler- temnospondyls (representative - mastodonsaurus).
And instead of the translated coelacanth at the base of the evolutionary tree of vertebrates there are lobe-finned fish - Quastenflosser.

In the same way, the names of the orders of dinosaurs belong to the "verbal freaks" - lizard and ornithischian. Why the clarification “living in water bodies” is completely incomprehensible, if only because most dinosaurs were frankly land animals. Also, the name of the beakhead detachment was subjected to “scandal” - the term “lizards” was outdated long ago, it was still in the dictionary of Brockhaus and Efron for 1907.
And to publish in our century a book with outdated images of dinosaurs dragging their tails, without correction, is simply a shame.

Again, the original text brings clarity.
On the German pelvis (part of the skeleton) is called Becken. But this word also has another meaning, for example, a pool or a sink in which they wash their hands. So the translator got water "pool" dinosaurs.

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Since their discovery in Patagonia in 1891, Necrolestes have been a mystery.

An international team of researchers, including scientist John Wible of the Museum natural history Carnegie made an incredible discovery about Necrolestes patagonensis, whose name translates to "tomb raider" because of its underground lifestyle. This most talked about fossil mammal from South America has been a paleontological mystery for over 100 years.

Persistence in research, recent fossil discoveries, and comparative anatomy have helped researchers correctly place the 16-million-year-old strange Necrolestes, with its high-turned snout and large burrowing limbs, in the mammalian evolutionary tree. This discovery has shifted the bottom of the benchmark evolutionary origin fossils 45 million years ago, proving that the family of mammals survived the extinction that ended the age of the dinosaurs. This fact is an example of the Lazarus effect, where a group of organisms is found to have lived much longer than expected. The assignment of Necrolestes to their relatives in the fossil record answers one long-standing question, but raises new questions, reminding us that there is still much we don't know about the global implications. mass extinction 65 million years ago, the discovery challenges the assumption that the well-studied and documented phenomena that occurred in the western North America have taken place all over the world. Research Article on the discovery of the Necrolestes mystery will appear in the Proceedings of the National Academy of Sciences.

Paleontological mysteries

Since their discovery in Patagonia in 1891, Necrolestes have been a mystery. "Necrolestes is one of those animals whose photos, if they appeared in textbooks, would be accompanied by the caption: 'We don't know what it is,'" says co-author John Wible of the Carnegie Museum of Natural History, a mammologist and member of the scientific team that also includes researchers from Australia and Argentina. Weebl is known for his work on the origins and evolutionary relationships between three groups of modern mammals: placentals (viviparous mammals such as humans), marsupials ( marsupials, such as opossums) and egg-laying mammals (such as platypuses).

The Miocene mammal Necrolestes patagonensis appeared in this world 16 million years ago in Patagonia, present-day Argentina. Necrolestes are currently classified as species that were thought to have become extinct shortly after their extinction. large dinosaurs at the end of the Cretaceous. Photo from phys.org

Despite excellent preservation, the mysterious fossils move from one institution to another and from explorer to explorer, and the classification of Necrolestes changes with each new move. As recently as a few years ago, Necrolestes still could not be definitively assigned to the group of mammals. A CAT scan of the ear area in 2008 led to a hypothesis put forward by another research group that classified Necrolestes as a marsupial. This discovery intrigued Weebl, co-author of the work, and Guillermo Rugier of the University of Louisville, Kentucky. As a specialist in South American mammals, Rougière was not convinced that "marsupial" identification was accurate and set about his own attempts to classify the animals. “This project scared me a little, because we had to challenge an interpretation that had existed for 100 years,” admits Rougière.

In the process of preparing the fossils for further study, Rougière uncovered skull characteristics and anatomical features that had not previously been seen. Based on these newly discovered facts research group concluded that Necrolestes belonged neither to the marsupials nor to the placentals, to which it has always been assigned. Most likely, in fact, the Necrolestes belonged to a completely unexpected branch of the evolutionary tree, which was believed to have become extinct 45 million years before the appearance of the Necrolestes.

Mysterious anatomy

Part of the mystery of the Necrolestes was the impossibility of attributing them anatomical features to any one type of classification. Given the body features in the form of a highly raised muzzle, a solid body structure and short, wide feet, researchers have always believed that they must be classified as burrowing mammals. Burrowing mammals have a broad humerus (upper arm bone) that is adapted for burrowing and tunneling. The humerus of Necrolestes is wider than that of any other burrowing mammal and indicates that Necrolestes are especially specialized in burrowing, perhaps even more so than any other known burrowing mammal, but this trait does not make the task of classification any easier. The simple triangular teeth of Necrolestes served it well for feeding on subterranean invertebrates. However, until recently, the features of the teeth have been of little help in classifying Necrolestes because their teeth are so simple that it is impossible to state their unambiguous resemblance to any other mammals.

The secret is revealed

In 2012 again open to the world the extinct mammal Necrolestes was the key that unlocked the mystery of the "earth diggers". Discovered by co-author Rougière in South America Necrolestes belongs to the Meridiolestida, a little-known group of extinct mammals that lived in the late Cretaceous and at the beginning of the Paleocene (100 million years ago) in South America.

Evolutionary Consequences

The mass extinction that ended the age of the dinosaurs wiped out thousands of animal species. Among those who disappeared were the Meridiolestida, a group of mammals to which the Necrolestes belong, interrupting their evolutionary line, as scientists used to think. Until the final identification of Necrolestes, only one member of Meridiolestida was known to have survived extinction, and this species also became extinct soon after, at the beginning of the Tertiary period (65.8 million years ago). Therefore, Necrolestes is the only remaining representative of supposedly extinct groups. "This is the most a prime example effect of the Lazarus, - comments Weebl. “Is it possible that a species has existed on Earth for so long without anyone knowing about it?”

Rougière says: “In some ways, Necrolestes are similar to modern platypuses, although apart from general characteristics they have nothing more in common. There are few platypuses, they are found only in Australia and occupy a certain niche among modern mammals, just like Necrolestes were an isolated line living only in South America, and there were few representatives of their genus compared to a large number of marsupials.

Herbivorous, armored ankylosaurs are famous for their massive "club" at the end of the tail, which apparently served as a defensive weapon. But experts also know their other intriguing feature: the vast majority of the discovered remains of these dinosaurs were buried with their belly up.

Discussions on this topic began as early as the 1930s, and so far there have been a lot of hypotheses, the most important of which have recently been tested by a group of paleontologists led by Jordan Mallon from the Canadian Museum of Natural History. But first, they made sure that the “ankylosaur orientation problem” is not a historical myth. Scientists reviewed 36 finds made in Canada and the reports of their authors, confirming that 26 of them were indeed upside down. It cannot be explained by chance.

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The authors then began testing the key theories that explain this phenomenon. The first of them suggests that the ankylosaurs were rather clumsy in their movements and, having fallen on their backs, could not roll back, and the predators knocked them over on their backs, reaching the belly, which was not protected by armored plates. Scientists did not find any evidence for this, and teeth marks were found only on one of the studied samples. “If the ankylosaurs were so sluggish, they would hardly have survived for about 100 million years,” adds Jordan Mallon.

Another hypothesis believes that everything is connected with the shape of the armored body of ankylosaurs and with the location of their center of gravity. When an animal died and was decomposed by bacteria, its belly would have to swell, which could naturally turn it upside down. In favor of this hypothesis, it is usually indicated that this happens with modern armadillos. However, when Mallon's colleagues themselves examined 174 bodies of animals hit by cars, there was no confirmation of this. The authors also followed the decomposition of some dead armadillos, while not one of them "naturally" turned over on his back.

Another model explains the orientation of the remains by the fact that the bodies of dead animals could be in the reservoir, afloat, and easily turned over under their own weight. Subsequently, they found themselves at the bottom or aground and were brought in by sedimentary rocks already in such an inverted position. To test this version, Mallon and his co-authors developed three-dimensional computer models of the buoyancy of the bodies of the two main varieties of ankylosaurs (ankylosaurids and nodosaurids), taking into account their bone density, lung volume, etc.

By placing the models in a virtual river and "inflating" their bellies - as if by the action of gases that continue to release intestinal bacteria after death - the scientists monitored their behavior. In the case of the dinosaur, the hypothesis worked: even a small random deviation was enough for the body to turn upside down afloat. Ankylosaurids proved to be more stable, but with a strong enough wave, and they switched to a more stable inverted orientation. This, apparently, happened once in nature, leaving paleontologists one of the many, and now solved, mysteries of dinosaurs.

Recently, paleontologists, using the latest technology, discovered in the sediments, which are 95 million years old, a snake. Yes, not just a snake, but with ... hind legs. This discovery made it possible to establish the ancestor of snakes, as well as to find out how these reptiles lost their legs during evolution, which has so far been one of the mysteries of paleontology.

These fossils, which are 95 million years old, were found back in 2000 in the Lebanese village of Al Nammura. The remains belonged to the snake Eupodophis descouensi. This reptile reached 50 centimeters in length. The recovered remains were transferred to the Museum of Natural History (Paris) for further research.

And recently, a group of scientists led by Dr. Alexandra Usse, using X-rays, carried out layer-by-layer scanning of the sample and, based on its results, built computer model object under study in 3D format. It turned out that this snake had hind limbs, although very reduced.

The image quite clearly shows that the internal structure of the bones of the paws of ancient snakes largely resembles the structure of the legs of modern terrestrial lizards. True, thighs and shins Eupodophis descouensi very shortened, there are also ankle bones, but the foot and fingers are already missing. Moreover, the exhibit had only one leg free, and the second was hidden in stone, but an X-ray examination was able to show the scientists even her. Since both legs are arranged in the same way, we can safely assume that the absence of some parts of the limb is not the result of injury or deformity, but an indicator of the beginning of the reduction of the paws in snake ancestors.

"Discovery of the internal structure of the hind limbs Eupodophis allows you to explore the process of limb regression in the evolution of snakes. Currently, there are only three fossil snakes with preserved hind limbs and lost forelimbs. They are classified as three different groups- this is Haasiophis,Pachyophis and Eupodophis. Other known fossil groups of snakes have no limbs. However, based on their anatomical structure, it is believed that they still had limbs, but then disappeared.

Now we can even say how, most likely, such a reduction took place. These studies show that the loss of limbs by the ancestors of snakes is not the result of any anatomical changes in the structure of the bones, but, most likely, was associated with a reduction in the growth period. Due to some genetic changes, the paws did not have time to fully form in the embryonic period, so the snakes were born with a little “unfinished” legs, ”says the team leader, paleontologist Alexandra Usse.

By the way, this version is also confirmed by the studies of domestic embryologists. Not so long ago, studying the so-called Hox genes (these are the genes responsible for the formation of the body of the embryo in the early stages of development) of snakes and lizards, scientists found that the latter lack the Hox-12a gene, and also Hox-13a and Hox- 13b. It is known that these genes are responsible for the formation of the rear end of the body of reptiles, as well as for the appearance and development of the hind limbs. The mutation that occurred, as a result of which one of the genes disappeared completely, apparently led to the fact that the hind legs ceased to develop normally, and the change in its two "neighbors" - to complete disappearance these limbs.

However, the question of the origin of snakes is still one of the most mysterious in paleontology. Scientists believe that these reptiles evolved about 150 million years ago from some group of lizards. It is still unclear what kind of group this was, as well as why the snakes became long and legless.

According to one point of view, the loss of limbs is associated with the transition to an aquatic lifestyle. In the water, paws are not needed, it is much more profitable to move there, bending the body in a snake-like manner. This version is confirmed by the fact that one of the ancient two-legged snakes, Pachyophis, was an aquatic animal.

The disadvantages of this version are the fact that among the primitive snakes there are no those who live exclusively in water, such appear only among the advanced representatives of the group, for example, sea ​​snakes (Hydrophiinae). In addition, in the fossil record, snakes are extremely rare in marine and freshwater deposits, which is rather strange, since the fauna in such burials is preserved several orders of magnitude better than in terrestrial ones, and they come across more often. Also against this version is also the fact that, apart from the absence of limbs, primitive snakes have no other adaptations for life in water.

According to another hypothesis, the ancestors of snakes were burrowing lizards that lost their limbs due to the fact that underground they do more harm than good. This version is confirmed by the fact that primitive snakes from the group of blind snakes ( Typhlopidae) are truly underground animals. The burrowing way of life, apparently, was also carried out by fossils Haasiophis and Eupodophis. It is also known that representatives of many groups of lizards, for example, skinks ( Scincidae), legless lizards (Anniellidae), spindles ( Anguidae) or scalefoot ( Pygopodidae), during the transition to a burrowing lifestyle, they also lost limbs (at the same time, not a single case of loss of legs in aquatic lizards is known).

So, most likely, the ancestors of snakes really led a burrowing lifestyle. That is why they needed a long body (it is easier to squeeze through the ground). Also in this regard, they gradually lost the outer openings of the ears (so that the earth would not clog), limbs and movable eyelids (there is no need for them underground, in wet soil eyes do not dry out), but in return they acquired a transparent film formed from fused eyelids that protects the eye (that's why it seems that the snake is hypnotizing us, its gaze is motionless).

For quite a long time, lizards from the group of monitor lizards were considered the ancestors of snakes ( Varanidae). These lizards, like snakes, have a long and movable tongue, a highly developed Jacobson's organ responsible for chemoreception, an additional movable articulation of the branches of the lower jaw, as well as a structure of vertebrae similar to snakes. In addition, earless monitor lizards living in Indonesia ( Lanthanotidae), as their name implies, like snakes, lack external ear openings. However, the details of the structure of the skull in monitor lizards and snakes are very different, and in addition, molecular analysis of DNA shows that the two groups are very far from each other. Also against this version is also evidenced by the fact that among monitor lizards there are no (and, apparently, there never were) representatives leading a completely underground lifestyle.

But with another group of modern lizards called geckos ( Gekkonidae), snakes have much more common features buildings (about who geckos are and what they are famous for, read the article "Secrets of night climbers"). In particular, the skulls of snakes and geckos are completely devoid of temporal arches (formed by the zygomatic bones) and have a movable articulation of the bones of the lower jaw. The eyelids of many geckos, as well as those of snakes, have grown together and formed a transparent outer shell of the eye. And, finally, among these lizards there are those who lead a burrowing lifestyle.

The most characteristic here are the representatives of the subfamily of the scalypods, which has already been mentioned above. Its representatives, living in Australia and New Guinea, have a snake-like elongated body and appearance extremely reminiscent of snakes. This similarity is also emphasized by the absence of the forelimbs and a significant reduction in the hind limbs, which usually have the appearance of short, scaly outgrowths sometimes ending in claws, as well as the absence of external openings of the ears. Of course, it is unlikely that squamopods were the direct ancestors of snakes, however, apparently, these are one of their closest relatives.

In addition, data from molecular studies also suggest that geckos are the closest relatives of snakes in terms of DNA structure.

According to these data, geckos and snakes separated from other scaly ones 180 million years ago, and the separation of these groups occurred a little later, about 150-165 million years ago. That is, approximately when, according to paleontologists, this group arose. So that's where it all comes together.

So, a new research methodology has helped scientists fill a gap in the history of reptiles and solve one of the most intriguing mysteries of evolution. It should be noted that paleontologists generally place great hopes on this technique. It allows you to get images with a resolution of a few microns - a thousand times less than a hospital tomograph.