When in 1861 a nondescript stone slab with the imprint of some ancient animal found in the west of Bavaria fell into the hands of scientists, one glance was enough to understand the significance of the find. The creature imprinted in the stone had clear signs of a reptile and a bird at the same time.
Clawed Hoatzin Loose fingers with claws on the wings, which, apparently, helped Archeopteryx to climb tree trunks, are found only in one of the modern bird species, the hoatzin. But, perhaps, in this case, the fingers on the wings are the result of adaptation to life in a dense equatorial forest, because in all other respects the hoatzin is a typical bird, and reptilian features are not found in it either by anatomical or genetic methods.
Igor Lukyanov
Charles Darwin, in publishing The Origin of Species, self-critically pointed out that if some species evolved from others, sometimes dissimilar, then for some time there must have been transitional forms that combined the characteristics of ancestors and descendants. The absence of such forms was an argument against Darwin. The discovery of Archeopteryx, a transitional form between reptiles and birds, became the strongest argument in favor. "Argument" fluttered into all textbooks and lived there as an exemplary life. A century and a half has passed. It has long become indecent to doubt evolution. But the place of Archeopteryx in its history is increasingly being questioned.
The backbone of the theory
Relatives soon joined the first "praptice" - several specimens found in the same Bavaria. One of them was discovered ... right in the museum: found back in 1855, it was incorrectly described and identified as Archeopteryx only in 1870. The second copy accidentally fell into the hands of a certain Johan Dorr, who exchanged it for a cow by a scientist - both parties were satisfied.
Free fingers with claws on the wings, which apparently helped Archeopteryx to climb tree trunks, are found only in one of the modern bird species - the hoatzin. But, perhaps, in this case, the fingers on the wings are the result of adaptation to life in the dense equatorial forest, because otherwise the hoatzin is a typical bird, and reptilian features are not found in it either by anatomical or genetic methods.
To date, ten specimens of Archeopteryx are known, and one of them has not yet been described in detail, and another one has either been secretly sold or stolen. All finds come from the south of Germany, which 150 million years ago was an archipelago of small islands in a warm tropical sea. In the Jurassic era of gigantism, our hero was distinguished by its modest size - about the size of a modern magpie.
Described as a transitional link between two classes - cold-blooded reptiles and warm-blooded birds, Archeopteryx had features of both the first and second. He had crocodile-like teeth, a long bony tail, three free fingers with claws on his wings, and at the same time was covered with feathers and had a "bird" brain size (in reptiles it is more modest). The feather played a decisive role in the recognition of the bird. A hundred years later, it became the cause of a fierce dispute.
Parallel result
One of the most amazing birds that inhabited the planet were toothy birds that lived in the Cretaceous period.
They all belonged to two groups, which, however, had more differences between themselves than any living birds. Representatives of the first group, odontotorms, had teeth sitting in separate holes, and when changing teeth, the new one grew right under the old one. Their most striking feature is their double-curved vertebrae, which distinguish them from all known living and fossil birds. Odontotorms were the size of a dove. The tail, limbs, the structure of the sternum resemble modern birds, and the structure of the pelvis resembles reptiles.
The second group - odonto withers - large, sometimes exceeding two meters in length, swimming and diving birds with well-developed hind limbs and underdeveloped wings. In terms of lifestyle, most likely, they most resembled penguins or Galapagos flightless cormorants. The teeth of these birds were located in a common groove; new teeth, replacing the old ones, grew next to them. In its structure, the spine was very similar to the modern bird, but the tail vertebrae were not fused, as in the current birds, but resembled the tail vertebrae of dinosaurs, the pelvis also resembled reptiles.
Both groups died out along with the dinosaurs, leaving no descendants, and their origin is not entirely clear. There is an assumption that they were also the result of parallel evolution and have nothing to do with modern birds.
Tutankhamun in feathers
Archeopteryx is to paleontology what Tutankhamen is to archeology. This is one of the icons of our science,” says Phil Manning, a paleontologist at the University of Manchester. However, there have always been iconoclasts, and our “miracle in feathers” was no exception. In the mid-1980s, a prominent British astrophysicist and writer, proponent of the theory of panspermia, Fred Hoyle, and several colleagues launched a rather noisy campaign, arguing that Archeopteryx was a grandiose falsification. It came to a direct discussion round table between Hoyle's group and paleontologists, which was broadcast by the BBC. "Debunkers" believed that the print of feathers on a copy stored in London was forged in the 19th century. Even the name of the suspect was called - Karl Haberlein, a well-known dealer in South German fossils in those years, who allegedly "equipped" the remains of some small reptile with the imprint of chicken feathers. The accusation was based on examining the print under a modern scanning microscope and photographing it from various angles. An additional argument was the presence of microdroplets of some modern organic matter on the prints, taken by the astrophysicist Hoyle for traces of glue, as well as the fact that on most other specimens of Archeopteryx, traces of plumage are determined extremely uncertainly. It is for this reason that some of the fossils found were not immediately identified, sometimes decades later. Without feathers, the creature's skeleton looks more like a reptile than a bird.
As a result, the reputation of the ancestor survived. Paleontologists pointed out that in addition to the London specimen, the plumage was clearly imprinted on the Berlin one, the circumstances of the find of which are not in doubt. In addition, the imprints of some feathers go deep into the shale strata - it is impossible to fake this plausibly. Droplets of "glue" turned out to be traces of taking numerous casts. Finally, microscopic examination showed that the imprints of bones and feathers in many places cross the thinnest dendritic deposits invisible to the eye. Formed over millions of years, "watermarks" are completely symmetrical on both sides of the print, their forgery is impossible even now.
The most interesting thing turned out when it came to feathers. In the second half of the 1990s, the English paleontologist Alik Walker, using a scanning microscope, established that the feather of Archeopteryx is fundamentally different from modern birds. His fan is solid, it is not divided into beards and beards. The transverse structures on them are simply ridges that increase mechanical strength. In other words, feathers are not bird feathers. So the "chicken" version fell completely, and the scientific world stood before new problem. Archeopteryx was considered a bird mainly for its feathers. If they are not avian, then what is he?
The problem of ancestors
To understand the question of who Archeopteryx is, the establishment of his ancestors would help. In the 20th century, a variety of reptiles were considered the predecessors of the "first bird". Up to crocodiles - what if in ancient times they really could fly? Over time, therapods, a group of carnivorous dinosaurs, the most famous of which were the famous tyrannosaurs, began to be considered the most likely candidates for the predecessors of Archeopteryx. But it was not possible to finally shed light on the mystery, although more and more creatures fell into the hands of scientists, seemingly suitable for Archeopteryx as parents, grandfathers, or, at worst, cousins.
In 1997, the remains of a creature were found in China that could very well be the required original form. They named it Protarcheopteryx. The slender animal, which in life slightly resembled an ostrich, was certainly a reptile, could not fly, but had plumage on its limbs and tail, as well as a number of "Archaeopteryx" features of the skeleton. Why not an ancestor? But, alas, he lived 20-30 million years later. Microraptor looks even more exotic and, perhaps, archaic - a small feathered lizard that lived 120-130 million years ago had a completely "bird" set of contour feathers on both the front and hind limbs. There were many publications with colorful pictures of four-winged animals soaring in the sky, vaguely resembling a flying squirrel. However, the device of the hip girdle of this reptile hardly allowed it to push the “hind wings” apart. (By the way, modern birds acquire this ability only in a frying pan.)
Thing in itself
Being an exemplary transitional form included in all textbooks, the first bird remained a kind of artifact for a long time.
Neither her immediate ancestors nor descendants were known. It is a little easier with ancestors - it is obvious that Archeopteryx in any case descended from some kind of reptiles, there is simply no one else. It was more difficult with the descendants - the skeleton of modern birds is quite different from the creature that scientists identified in their forerunners. Over time, this circumstance alarmed scientists more and more.
In addition to plumage and wings, Archeopteryx had a number of other features that related it to birds. The clavicle-fork, the posterior circulation of the first toe, the location of the pelvic bones, the lunate bone in the wrist - in the 19th century, all these signs were avian. In the 20th century, their assessment slowly changed, since over and over again they, in different combinations, were found in obvious reptiles, as a rule, which did not have even a hint of the ability to fly, and sometimes lived much later than Archeopteryx. In the 1980s, speculation began to surface that flightless dinosaurs might have had feathers. In 2007, characteristic traces of large feathers were found on the bones of Velociraptor, a small Jurassic predator made posthumously famous by a Steven Spielberg film.
Although the last two decades of the discovery of bird-like reptiles (or vice versa) followed several times a year, Archeopteryx remained an "orphan" - new finds were younger. The missing link (or something similar to it) was only found in 2009 in northeast China. The creature, named Anchiornis huxleyi, lived 155-151 million years ago - not much earlier than Archeopteryx in geological terms. But the find did not solve the problem of origin: Anchiornis turned out to be too advanced a form to name its ancestors by looking at it. It is only clear that the evolutionary paths of some ancient group of reptiles diverged approximately in the middle of the Jurassic period.
Either grandfather, or a vision
In 1981, the Englishman Cyril Walker described new group birds that lived 100-65 million years ago. He called them enanciornis, that is, "opposite birds", or "anti-birds". The remains of various enantiornithes were found in China and Mongolia, Uzbekistan, North and South America. They differed quite a lot from each other in size, lifestyle and anatomy, but, as a rule, they were all excellent flyers. The main feature of this completely extinct group was that their skeleton, with external resemblance, resembled the skeleton of not modern birds, but Archeopteryx. Functionally, all skeletal structures corresponded to analogues of modern, fan-tailed birds, but their different forms indicate that this is a product of parallel evolution. Yes, and the feathers of the "opposite" were more like the feathers of Archeopteryx. Then Archeopteryx, no matter in what status - reptiles or still the first "opposite bird" - can be their ancestor. But who then is the ancestor of modern birds?
The skeleton of Archeopteryx combined features of birds (fork-shaped collarbone, sublunar bone, pelvic structure) and reptiles (“crocodile” teeth, long tail, three free fingers with claws).
Published in 1991, the data of the American scientist Shankar Chatteji shocked fellow paleontologists: he claimed to have found the remains of a bird that lived 225-210 million years ago in Texas. That is, it is older than Archeopteryx by 60-75 million years! The animal, called protoavis, had in its skeleton much more similarities to modern birds than the textbook Archeopteryx. Its body length was about 35 cm, it had a toothy beak, free fingers with claws on the forelimbs, and the size of the eye sockets and their location indicated that it was active at dusk and at night. Feather attachment points were found on the bones of the hand.
Most paleontologists were skeptical about the find: the bones were found separately and may belong to different animals, there is no direct evidence that Protoavis could fly, and the forelimbs are too small for wings. But there are indirect ones: a large volume of the brain and large kidneys. Birds require a lot of energy to fly, so their metabolic rate is high. With the speed of metabolism, the capabilities of the excretory system, that is, the kidneys, also grow. In protoavis, in the pelvic bones, like in modern birds, there are three deep recesses in which these large kidneys are located.
Many publications of recent years actually ignore Protoavis. Their authors are easy to understand: his scientific recognition will greatly change ideas about the origin of this part of the animal kingdom. Archeo-pteryx from a respected ancestor will become an extinct relative of someone who is not clear. "Sorry for the bird."
All sisters on earrings
The evolution of birds is one of the most intriguing and confusing pages in the annals of our planet. And new discoveries bring additional confusion to the already seemingly existing harmonious picture. Here, for example, is a bird found in China, named Confuciusornis (in honor of Confucius), which lived in the Early Cretaceous period (after Archeopteryx). The find had a beak without teeth and fused tail vertebrae, like in modern birds, obviously, it could fly, but in terms of the structure of the skull it was more primitive than Archeopteryx. Another fossil "orphan" without ancestors and descendants?
The assumption of some scientists looks reasonable that they “tried to turn into birds” various groups dinosaurs, and more than once. If the supporters of protoavis are right and no errors have crept into their study, then this particular animal should be considered the ancestral form for modern birds. But what about Archeopteryx? The famous Chinese paleontologist Xu Xing, who described the reptilian counterpart of Archeopteryx, Xiaotingia, believes that Archeopteryx is also a reptile. But he, apparently, has not sunk into oblivion, his probable descendants are not modern fan-tailed birds, but birds of the Cretaceous period that have not survived to this day, enanciornis. At least, the fossil finds that exist today allow us to draw such conclusions. But who knows, maybe at some point new finds will completely change our ideas about the past, confirming some new bold theory, as Archeopteryx found in a Bavarian adit did 150 years ago.
Structure The structure of the skeleton of Archeopteryx is compared with the structure of the skeleton of modern birds and deinonychosaurs - theropod dinosaurs, which, according to most paleontologists, are the closest relatives of birds. Unlike modern birds, which do not have teeth, the premaxillary, maxillary, and dentary bones of Archeopteryx bore teeth. The conical teeth of Archeopteryx are most similar in morphology to those of crocodilians. The premaxillae of Archeopteryx were not fused together, in contrast to modern birds. The upper and lower jaws were devoid of a horn sheath (ramphothecus), thus, Archeopteryx did not have a beak. The large occipital foramen, which connects the cranial cavity with the spinal canal, is located behind the skull in Archeopteryx, similar to the position in Deinonychosaurs, while in modern birds it is displaced to the bottom of the skull. The cervical vertebrae of Archeopteryx are biconcave in front and behind, like in Deinonychosaurs; while in modern birds, the cervical vertebrae are heterocoelous - they have saddle-shaped articular surfaces. The sacral vertebrae of Archeopteryx did not fuse with each other, while in modern birds the lumbar, sacral and part of the caudal vertebrae fuse into a single bone - a complex sacrum. The sacral spine of Archeopteryx consists of 5 vertebrae, which is comparable to the number of sacral vertebrae of deinonychosaurs - 5-6. The sacral spine of modern birds includes 1 vertebra, which is part of the complex sacrum. 21-23 unfused caudal vertebrae of Archeopteryx formed a long bony tail. In modern birds, the tail vertebrae are fused into a single bone - the pygostyle, which serves as a support for the tail feathers. The ribs of Archeopteryx were devoid of the hook-shaped processes that provide strength in modern birds. chest fastening the ribs. In contrast, the skeleton of Archeopteryx contained ventral ribs (gastralia), typical of many reptiles, including deinonychosaurs, but not found in modern birds. [edit] Shoulder and pelvic girdle Like modern birds and deinonychosaurs, Archeopteryx's clavicles fused to form a fork. The bones of the pelvic girdle (ilium, ischium, and pubis) in Archeopteryx did not fuse into a single bone, in contrast to the condition in modern birds. The pubic bones of Archeopteryx are slightly posterior, as in deinonychosaurs, but not in modern birds. Also unlike modern birds, Archeopteryx's pubic bones ended in a "boot-shaped" extension, which is typical of Deinonychosaurs. Also, as in Deinonychosaurs, the distal ends of the pubic bones joined to form a large pubic symphysis; in modern birds, the pubic symphysis is absent. The long forelimbs of Archeopteryx ended in three fully developed fingers. The three fingers of Archeopteryx are formed by two, three and four phalanges, respectively. The same phalangeal formula (2-3-4) is typical of deinonychosaurs. In contrast, the three-toed fingers of modern birds are greatly reduced, the number of modified phalanges of fingers is 1-2-1. Archeopteryx's fingers bore large, strongly curved claws. The wrist of Archeopteryx contained a lunate bone, characteristic of the skeleton of modern birds, also known from Deinonychosaurs. The other bones of the carpus and the bones of the metacarpus did not fuse into a common bone (buckle), unlike modern birds.Detachment - extinct birds
Family - firstbirds
Genus/Species - Archeopteryx lithophraphica. Archeopteryx
Basic data:
DIMENSIONS
Length: 35 cm
Weight: around 300-400
BREEDING
Nesting period: probably throughout the year.
Incubation period: modern birds of the same size incubate the eggs for about 4 weeks.
LIFESTYLE
Habitat: tropical jungle.
Food: possibly insects, mostly beetles and butterflies.
Habits: Archeopteryx (see picture / photo) lived on the ground, possibly on trees, flew poorly or did not fly at all.
Archeopteryx lived 150 million years ago. He is the oldest animal that most closely resembles modern birds. Fossils of this bird show that its body was covered with feathers, and its long legs were similar to those of a bird.
WHAT YOU EAT
The large jaws of Archeopteryx were studded with numerous sharp teeth. They weren't meant to be crushed plant food. But Archeopteryx could not have been predators either, since most of the animals of that period were very large and could not be prey for them. The diet of Archeopteryx was probably based on insects. In the Mesozoic era, there were many insects that they could eat. Most likely, the Archeopteryx used wings to knock down dragonflies or, with the help of long legs, collected beetles and other insects on the ground.
LIFESTYLE
Archeopteryx had fused collarbones and a body covered in feathers. It is believed that he could, if not fly, then at least plan. It is likely that on his long legs he ran along the ground while the ascending air current picked him up.
The plumage of Archeopteryx helped to maintain the temperature rather than fly. Wings could serve as nets for catching insects. It is believed that Archeopteryx could climb trees using claws on its wings. He spent most of his life in the trees.
BREEDING
The body of Archeopteryx was covered with a thick layer of feathers. There is no doubt that Archeopteryx was a warm-blooded animal. Therefore, the researchers suggest that, like modern birds, it incubated eggs, unlike its closest dinosaur relatives from the Coelurosauria group, which probably did not.
Archeopteryx most likely laid its eggs in self-made nests, which it placed on rocks and trees to protect them and the chicks from predators. The cubs that hatched from the eggs of these dinosaurs were similar to their parents, only smaller in size. Scientists believe that Archeopteryx chicks, like the offspring of modern birds, were born unfeathered. Consequently, in the first weeks of life, they were probably not independent and needed the care of their parents. This means that Archeopteryx must have some form of parental instinct, among other things - and provide food for the chicks.
NATURAL ENEMIES
In a world that was home to many dangerous predatory dinosaur species, Archeopteryx must have had quite a few natural enemies. With the ability to run fast, climb trees and glide, and possibly fly, Archeopteryx were not easy prey. The main enemies of modern small birds are large predator birds such as hawks and falcons. In the era of Archeopteryx, flying predators most likely did not yet exist. True, pterosaurs lived in the same period - flying pangolins with membrane wings, but they did not fly very well and could not pursue other animals in the air.
LIVING FOSSIL?
Of modern birds, Archeopteryx is most reminiscent of hoatzins that live in the northeast. South America. Hoatzin chicks have claws on their wings that are used for climbing trees. Their muscles intended for flight are poorly developed, so hoatzins more often climb trees than fly.
INTERESTING INFORMATION. DO YOU KNOW WHAT...
- Some scientists believe that modern birds are the only living descendants of dinosaurs.
- The name Archeopteryx means "ancient wing" in Greek.
- Today, researchers believe that Archeopteryx evolved from small dinosaurs that, clinging to the claws, began to climb trees.
- To date, no bird fossils have been found that have lived 30 million years after Archeopteryx.
- The remains of Archeopteryx found in Bavaria are so well preserved (these are whole skeletons with feather prints) that at first scientists had doubts about their authenticity.
STRUCTURE OF THE SKELETON OF ARCHEOPTERYX
Archeopteryx basically resembles small dinosaurs, but it also has features inherent in birds, compare for example with the skeleton of a dove.
Jaws: Archeopteryx resembled a bird's beak, but they had sharp teeth.
The skeleton of Archeopteryx resembles that of small dinosaurs: it has the same long tail and a similar skull structure. However, there is a difference in the structure of the facial bones.
Clavicles: fused, which is characteristic only of birds. But there is no evidence that Archeopteryx flew.
Three fingers with claws: on every wing. Archeopteryx claws, like bats, were needed for climbing trees.
Typical paws birds with one finger pointing backwards.
- Archeopteryx fossil finds
WHERE AND WHEN LIVED
So far, 6 Archeopteryx fossils have been found. All are in Bavaria. At the time when the Archeopteryx lived, the territory of Germany was part of a continent that looked completely different, and was in the tropics. Based on the determination of the geological age of the slates in which the fossils were found, it became known that Archeopteryx lived in the Upper Jurassic period, that is, about 150 million years ago.
The discovery of the first Archeopteryx fossils in 1860 shocked the scientific world. For the first time, a person saw a creature resembling a half-bird, half-reptile.
Detachment - extinct birdsFamily - firstbirds
Genus/Species - Archaeopteryx lithophraphica
Basic data:
DIMENSIONS
Length: 35 cm
Weight: around 300-400
BREEDING
Nesting period: most likely throughout the year.
Incubation period: modern birds of the same size incubate the eggs for about 4 weeks.
LIFESTYLE
Habitat: tropical jungle.
Food: possibly insects, mostly beetles and pasterns.
Habits: lived on the ground, possibly in trees, flew poorly or did not fly at all.
CLASSIFICATION
Class: Birds.
Subclass: Lizard-tailed.
Squad: Extinct birds.
Genus/Species: Archeopteryx lithographica.
Archeopteryx lived 150,000,000 years ago. He is the oldest animal, most reminiscent of modern birds. Fossils of this first bird show that its body was covered with feathers, and its long legs were similar to those of a bird.
FOOD
The large jaws of Archeopteryx were sown with numerous sharp teeth. They were not designed to grind plant food. But Archeopteryx could not have been predators either, since most of the animals of that period were very large and could not be prey for them. The diet of Archeopteryx most likely consisted of insects. In the Mesozoic era, there were many insects that they could eat. Most likely, the Archeopteryx used wings to knock down dragonflies or, with the help of long legs, collected beetles and other insects on the ground.LIFESTYLE
Archeopteryx had fused clavicles and a body covered with feathers. It is believed that he could, if not fly, then at least plan. It is likely that on his long legs he ran along the ground until the ascending air current picked him up. The plumage of Archeopteryx was more likely to help maintain the temperature than to fly. Wings could serve as nets for catching insects. It is believed that Archeopteryx could climb trees using claws on its wings. He spent most of his life in the trees.
BREEDING
The body of Archeopteryx was covered with a thick layer of feathers. There is no doubt that Archeopteryx was a warm-blooded animal. Therefore, the researchers suggest that, like modern birds, it incubated eggs, unlike its closest relatives, dinosaurs from the Coelurosauria group, which probably did not. Archeopteryx most likely laid eggs in its arranged nests, which it placed on rocks and trees to protect them and their chicks from predators. The babies that hatched from dinosaur eggs could take care of themselves right away. They looked like their parents, only smaller. Scientists believe that Archeopteryx chicks, like the offspring of modern birds, were born without plumage. Consequently, in the first weeks of life, they were probably not independent and required parental care. This means that the Archiopteryx must have had some form of parental instinct, including providing food for the chicks.
NATURAL ENEMIES
In a world where many dangerous predatory dinosaur species lived, the Archeopteryx must have had many natural enemies. With the ability to run fast, climb trees and glide, and possibly fly, Archeopteryx were not easy prey. The main enemies of modern small birds were birds of prey, such as hawks and falcons. In the era of Archeopteryx, predators that fly, most likely, did not yet exist. True, pterosaurs lived in the same period - flying pangolins with membrane wings, but they did not fly very well and could not pursue other animals in the air.LIVING FOSSIL?
Hoatzins living in the northeast of South America are most similar to Archeopteryx from modern birds. Hoatzin chicks have claws on their wings that are used for climbing trees. The muscles intended for flight are poorly developed, so hoatzins often climb trees. DO YOU KNOW WHAT...
- Some scientists believe that modern birds are the only living descendants of dinosaurs.
- The name Archeopteryx in translation from ancient Greek means "ancient wing".
- Today, researchers believe that Archeopteryx evolved from small dinosaurs that, clinging to the claws, began to climb trees.
- To date, no fossils have been found of birds that lived 30,000,000 years after Archeopteryx.
- The remains of Archeopteryx found in Bavaria are so well preserved (these are whole skeletons with feather prints) that at first scientists had doubts about their authenticity.
STRUCTURE OF THE SKELETON OF ARCHEOPTERYX
Archeopteryx mostly resembles small dinosaurs, but it also has bird-like features. For comparison - the skeleton of a dove.Jaws: resemble a bird's beak, but they had sharp teeth.
The skeleton of Archeopteryx resembles that of small dinosaurs: it has the same long tail and a similar skull structure. However, there is a difference in the structure of the facial bones.
Clavicles: fused, which is peculiar only to birds. But there is no evidence that Archeopteryx flew.
Three fingers with claws: on every wing. Archeopteryx, like bats, needed claws to climb trees.
Typical paws birds with one finger pointing backwards.
- Archeopteryx fossil finds WHERE AND WHEN LIVED
So far, 6 Archeopteryx fossils have been found. All are in Bavaria. At the time when the Archeopteryx lived, the territory of Germany was part of a continent that looked completely different, and was in the tropics. Based on the geological age determination of the slates in which the fossils were found, it became known that Archeopteryx lived in the Upper Jurassic period, that is, about 150,000,000 years ago.
). Maxberg specimen(S5).
Only the torso. Found in 1956 or 1958 near Langenaltheim, described in 1959 by Heller. Detailed study by John Ostrom in the 1970s. For some time it was shown in the Maxberg Museum, after which it was returned to the owner. After the death of the collector in 1991, the copy could not be found. It is believed that it was secretly sold by the owner or stolen.
Haarlem copy(TM 6428, also known as the Theler specimen). Undescribed instance.In 1997, Mauser reported the discovery of a fragmentary specimen in a private collection. The name of the owner and the location of the fossil have not been released. Until now, the specimen has not been formally classified, its assignment to Archeopteryx remains provisional.
Thermopolis specimen
Thermopolis specimen(WDC-CSG-100).Discovered in Germany. For a long time it was in a private collection, described in 2005 in the journal Science. Located at the Wyoming Dinosaur Center, Thermopolis, Wyoming, USA. Has the best preserved head and feet. More detailed in 2007.
Skeleton
This section provides short review osteology of Archeopteryx: only the basic details of the skeletal anatomy are described. The structure of the skeleton of Archeopteryx is compared with the structure of the skeleton of modern birds and deinonychosaurs - theropod dinosaurs, which, according to most paleontologists, are the closest relatives of birds (see below).
Scull
Unlike modern birds, which are toothless, the premaxillary, maxillary, and dentary bones of Archeopteryx bore teeth. The conical teeth of Archeopteryx are most similar in morphology to those of crocodilians.
The premaxillae of Archeopteryx were not fused together, in contrast to modern birds. The upper and lower jaws were devoid of a horn sheath (ramphothecus), thus Archeopteryx did not possess a beak.
The large occipital foramen, which connects the cranial cavity with the spinal canal, is located behind the skull in Archeopteryx, similar to the position in Deinonychosaurs, while in modern birds it is displaced to the bottom of the skull.
Spine
Based on the study of the London and Eisstadt specimens, paleontologists concluded that the thumb of the hind limb of Archeopteryx was completely opposed to other fingers, which is characteristic of modern birds. However, analysis of a better-preserved thermopolis specimen has shown that, in reality, the orientation of the thumb of Archeopteryx is more similar to that of Deinonychosaurus than that of modern birds. However, this interpretation has been disputed.
In addition, the thermopolis specimen supported the suggestion that Archeopteryx had a hyperelongated second toe of the hindlimb bearing a large claw. The hyperelongated second finger, equipped with a large predatory claw, is typical of deinonychosaurs.
Plumage
The first drawing of the Berlin copy, made by an unknown illustrator in 1878-1879. The author noted the presence of feather prints in the specimen.
The flight feathers of Archeopteryx are characterized by the asymmetry of the webs, which is typical for modern birds capable of flight. The tail feathers were less asymmetrical. The difference from modern birds was observed in the absence of a winglet - a separate mobile tuft of feathers on the thumb of the forelimbs.
The body plumage of Archeopteryx is less well described, having only been properly examined in the well-preserved Berlin specimen. This specimen wore “pants” of well-developed feathers on its legs, the structure of some of them had some differences (for example, there were no beards, like in ratites), while others were strong enough, allowing for the possibility of flight.
Along the back was a patch of contour feathers, symmetrical and strong (although not stiff enough compared to flight feathers), very similar to the contour feathers on the body of modern birds.
The remaining feathers of the Berlin specimen are of the "pseudo-down" type and are indistinguishable from the integumentary fibers of the dinosaur. Sinosauropteryx: soft, scattered and perhaps even outwardly more like fur - they covered all the remaining parts of the body (where preserved), as well as the lower part of the neck.
There are no signs of feathering on the upper neck and head. Although they may have been absent, as with many feathered dinosaurs, this may also be a lack of preservation of the specimens: it appears that most specimens of Archeopteryx entered the sediment after some time at the sea surface, swimming on their backs. The head, neck, and tail are usually curved downwards, suggesting that the specimens were just beginning to decompose when they were buried. The tendons and muscles relaxed and the bodies took on the shape characteristic of the discovered specimens. It would also mean that the skin had softened and sagged by that time. This assumption is supported by the fact that in some specimens the flight feathers began to fall off by the time they plunged into the sedimentary rock. Thus, the head and neck feathers may have simply fallen off, while the more tightly held tail feathers remained.
Brain and inner ear
A distinctive feature of the skulls of pterosaurs, some theropods and birds are thin meninges and small venous sinuses, which makes it possible to accurately estimate the surface morphology, volume and mass of the brain of extinct representatives of these taxa. The best brain reconstruction to date of Archeopteryx was made in 2004 at the University of Texas using X-ray tomography.
paleoecology
In the late Jurassic period, the territory of modern Europe was an archipelago of islands in a shallow warm tropical sea, located much closer to the equator than at present. The Solnhofen limestones, to which all discovered specimens of Archeopteryx belong, make it possible to reconstruct the picture of the late Jurassic period. Traces of flora, although rather sparse, include cycads and conifers. There are more animal remains, many insects, small lizards, pterosaurs and compsognathans have been found.
The excellent preservation of the remains of Archeopteryx and other terrestrial animals found in the Solnhofen limestone indicates that the remains could not have been transported from afar to the site of fossilization. That is, the discovered Archeopteryx specimens rather lived on these low islands surrounding the Solnhofen lagoon, and were not brought here after death from somewhere else.
Populations of Archeopteryx were small in number. In deposits near Solnhofen, Archeopteryx skeletons are much rarer than those of Rhamphorhynchus, a group of pterosaurs that dominated the ecological niche currently occupied by seabirds.
The low islands surrounding the Solnhofen lagoon were dominated by a semi-arid subtropical climate with a long dry period and little rainfall. The flora adapted to such a climate consisted mainly of low (up to 3 meters) shrubs. Contrary to the common reconstruction of Archeopteryx climbing a large tree, tall trees appear to have been almost absent from the islands. Very few tree trunks have been found in the sediments and no fossilized tree pollen has been found.
It is difficult to reconstruct the way of life of Archeopteryx. There are several theories regarding this. Some researchers have suggested that Archeopteryx were primarily terrestrial adapted, while others suggest that Archeopteryx was primarily arboreal. The absence of trees does not contradict this assumption - some modern views birds live exclusively in low bushes. Miscellaneous aspects the morphologies of Archeopteryx indicate both a terrestrial and arboreal existence. The length of the legs and elongated feet allowed some authors to come to the conclusion about the universality of Archeopteryx, which could feed both in thickets and on the ground, and even along the coast of the lagoon. Most likely, the prey was small, Archeopteryx grabbed very small victims with its jaws, those who were larger - with claws.
Based on the analysis of the structure of the eye sockets, it is suggested that Archeopteryx led a nocturnal lifestyle.
Ability to fly
The asymmetry of the flight feathers indicates that Archeopteryx was aerodynamically adapted for flight. But Archeopteryx did not possess a number of other adaptive features characteristic of birds capable of flight, modern and extinct, so the mechanics of its flight and the flight itself were more primitive compared to later birds.
There is no consensus among researchers on the question of whether Archeopteryx was capable of flapping (active) flight or only gliding (passive) flight.
The absence of a keel and supracoracoid tendon in Archeopteryx, as well as a small angle of the shoulder joint, and estimated, according to some researchers, indicate that Archeopteryx was only capable of gliding flight. The lateral orientation of the joint between the scapula, coracoid and humerus shows that Archeopteryx was not able to raise the wings above the level of the back - necessary condition for the wing-swing of modern birds. It has been hypothesized that its gliding flight was accompanied by small, non-swinging wing movements.
Other researchers note that Archeopteryx differs from typical predominantly gliding birds in body shape as well as wing size. In addition, they indicate that the bony sternum or the boomerang-shaped fork, or the lamellar coracoid of Archeopteryx, could serve as an attachment site for the muscles that moved the wing. Proponents of such arguments conclude that Archeopteryx was capable of some form of primitive flapping flight.
Since the reconstruction of the functional anatomy of an extinct animal at an intermediate evolutionary stage of development is problematic, it is unlikely that one or another point of view will prevail in the discussion about the ability of Archeopteryx to fly in the near future.
Taxonomy
Historically, the first name of Archeopteryx is Pterodactylus crassipes Van Meyer. Name Archeopteryx lithographica was originally given to a single pen described by Van Meyer. The Swinton suggested that the name A. lithographica was officially assigned to the London copy. The International Commission on Zoological Nomenclature has eliminated many alternative titles in favor A. lithographica .
- expansion of the lacrimal bone in the dorsal part;
- cranially directed medial condyle of the mandibular quadrate;
- large ectopterygoid;
- the same width of the neck and body of the scapula along the entire length;
- flat subsquare coracoid;
- prominent tubercle on coracoid cranio-ventrally from glenoid foramen;
- perpendicular position of the plane of the proximal epiphysis of the shoulder to the plane of the distal epiphysis of the shoulder;
- short forearm (shorter than the hand and humerus);
- preservation of the 1st-3rd fingers in the hand and reduction of the 4th-5th;
- contact of the semilunar carpal with 1 and 2 metacarpals;
- enlarged ungual phalanges of the hand with large tubercles for attachment of flexor tendons;
- development of a small trochanter in the proximal part of the thigh;
- the cranial part of the ilium is noticeably larger than the caudal part;
- development of a pedicle on the ilium for articulation with the pubis;
- forked caudal end of the ilium;
- large pubic symphysis.
Finally, their alleged motives for falsification were weak and inconsistent. They cited Richard Owen's desire to support Darwin's theory as one of the motives, which is unlikely given Owen's views on Darwin and his theory. Another motive is Owen's desire to set a trap for Darwin, in the hope that the latter will support the fossils, and Owen can then discredit him with a fake. This is also unlikely, since Owen himself wrote the detailed work on the London copy, and such discredit would have worked against him.
The arguments of the falsifiers were not taken seriously by paleontologists, since their evidence was based on a misunderstanding of geology, and never affected other fossils with feathers, the number of finds of which has increased significantly since that time.
see also
Notes
- In 1984, paleontologist Shancre Chatterjee discovered fossils between 225 and 210 million years old that he believes are the remains of a bird phylogenetically closer to modern birds than Archeopteryx. The genus of vertebrates was named protoavis. However, his relationship to birds has been questioned.
- Mäuser M. Der achte Archaeopteryx. Fossilien, 1997, v. 3, p. 156-157
- Mayr G, Pohl B & Peters DS. A well-preserved Archaeopteryx specimen with theropod features. Science, 2005, v. 310p. 1483-1486
- Mayr G. et al. The tenth specimen of Archaeopteryx. Zoological Journal of the Linnean Society, 2007, v. 149, p. 97-116
- Feduccia A. et al. Archeopteryx 2007: Quo Vadis? The Auk, v. 124, p. 373-380
- Christensen P, Bonde N. (2004). Body plumage in Archaeopteryx: a review, and new evidence from the Berlin specimen. Comptes Rendus Palevol. 3 : 99-118. PDF full text
- Longrich N. (2006): Structure and function of hindlimb feathers in Archaeopteryx lithographica. paleobiology. 32 (3): 417-431. DOI:10.1666/04014.1 (HTML abstract)
- Elżanowski A. (2002): Archaeopterygidae (Upper Jurassic of Germany). In: Chiappe, L. M. & Witmer, L. M (eds.), Mesozoic Birds: Above the Heads of Dinosaurs: 129-159. University of California Press, Berkeley.
- P. D. Alonso et al. The avian nature of the brain and inner ear of Archaeopteryx. Nature, 2004, v. 430, p. 666-669
- Chiappe, Luis M. (2007). Glorified Dinosaurs. Sydney: UNSW Press, 118-146. ISBN 0-471-24723-5.
- Davis, P.; and Briggs, D. (1998). "The impact of decay and disarticulation on the preservation of fossil birds". Palaios 13(1): 3-13. (English)
- Paul, Gregory S. (2002). Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore: Johns Hopkins University Press. ISBN 0-8018-6763-0.
- Ostrom, J.H. (1976). "Archaeopteryx and the origin of birds". Biological Journal of the Linnean Society 8: 91-182.
- Archaeopteryx may have hunted at night. New Scientist.
- Padian K., Chiappe L. The origin and early evolution of birds. Biol. Rev., 1998, v. 73, p. 1-42
- Senter, P. (2006). Scapular orientation in theropods and basal birds and the origin of flapping flight. Acta Palaeontologica Polonica. 51 (2): 305-313. PDF full text
- Swinton, W. E. Opinion 1084, Proposed addition of the generic name Archaeopteryx VON MEYER, 1861 and the specific name Lithographica, VON MEYER, 1861, as published in the binomen Archaeopteryx Lithographica to the official lists (Class Aves). Bulletin of Zoological Nomenclature, 1960, v. 17(6-8) p. 224-226.
- ICZN. Opinion 607, Archaeopteryx VON MEYER, 1861 (Aves); Addition to the official list. Bulletin of Zoological Nomenclature, 1961, v. 18(4), p. 260-261
- Huxley, T. H. On the classification of birds and on the taxonomic value of the modifications of certain of the cranial bones observable in that class. Proceedings of the Zoological Society of London, 1867, p. 415-472.
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