Chronological Dating of Archaeopteryx and Its Fossils

If you want to perform a study in paleontology or paleozoology, you should have the findings in your hand. Because the main thing that advances these branches of science is discovery, any fossil that can be found can completely disprove your hypothesis or move it toward a different area. So, the topic of this article will also be a creature that has entirely changed our perspective on feathered dinosaurs.

The concept of evolution in the world before the discovery of Archaeopteryx

Now, let’s examine the concept of ongoing evolution in the world before the discovery of Archaeopteryx. The Theory of Evolution was officially put forward by the English biologist and natural historian Charles Darwin in 1859 in “On the Origin of Species.” As a result of his travels on the ship HMS Beagle, Darwin put forward a crucial theory for understanding nature by looking at the hundreds of samples he found. The theory of evolution has gone over with a bang since it was put forward. Because it has changed over the way we “Sapiens” view nature. In 1860, the evolution debate reached a new stage at Oxford, one of the most respected universities in the world. Thomas Henry Huxley, a respected scientist who supported Darwin’s work the whole time, was one of the rare people at Oxford who stood up to the opponents of evolution and did not hesitate to express what he knew.

At that time, of course, an insignificant number of people opposed this theory, which changed our view. This is why Huxley did not hesitate to express his belief in the Theory of Evolution every time and was engaged in discussions. Meanwhile, some debates were going on at Oxford that went far beyond scientific ethics. Extreme creationists such as Bishop Samuel Wilberforce did not hesitate to say whatever came into their mouths, and in this case, we can hardly say that they cared about scientific ethics.

One of the debates at Oxford has become iconic. Wilberforce ended with a sarcastic jab, asking Huxley if he considered himself descended from an ape through his grandmother or grandfather. Huxley, on the other hand, gave an iconic answer to this. Huxley’s reply was:

[A] man has no reason to be ashamed of having an ape for his grandfather. If there were an ancestor whom I should feel shame in recalling, it would be a MAN, a man of restless and versatile intellect, who, not content with an success in his own sphere of activity, plunges into scientific questions with which he has no real acquaintance, only to obscure them by an aimless rhetoric, and distract the attention of his hearers from the real point at issue by eloquent digressions, and skilled appeals to religious prejudice.

Thomas Henry Huxley – Darwin Day

In summary, while people found it difficult to understand many scientific developments in the world, they also found it difficult to understand the Theory of Evolution at first. Even if this happens at the most respected universities in the world.

During that period, the discussions about the Theory of Evolution were on this scale. Now we can get a little closer to the main topic of our article. The question that opponents of evolution generally posed to Charles Darwin was: “If there is a gradual transition between species, where are the specimens of it?” Darwin’s answer to this question was based on the inadequacy of records. Indeed, there was very little organic material supporting Darwin at that time. He even wrote a chapter about this topic in the book ”On the Origin of Species.”

While things were going like this in the UK, a Jurassic upper-aged feather specimen was found in Germany. With your current knowledge, “What’s wrong with it? Is this a perfectly normal thing?” you may say. However, we should not forget that we are in the 1800s. At that time, it was believed that birds appeared and spread throughout the world in the Cenozoic Era, and this discovery was revolutionary.

Chronological dating of Archaeopteryx fossils

Archaeopteryx lived about 150.8–148.5 million years ago in the late Jurassic Period in the shallow coastal areas of today’s southern Germany and is a clear example of the transition from non-avian dinosaurs to birds. Its name is a combination of the words “Archaeos” and ”Pteron.” In ancient Greek, “Archaeos” means “Ancient” and “Primitive”, while “Pteron” can be translated as “Feather” or “Wing.”

If we examine the history of Archaeopteryx‘s discovery, the first fossil of Archaeopteryx was found in January 1855 in a quarry in the Altmühl Valley near Jachenhausen in southern Germany. Since Hermann von Mayer, a banker and amateur paleontologist, found the fossil to consist only of fragments of hind legs and feather marks—a faint hand remnant—it was not understood at that time that it was a bird remnant.

But five years later, in 1860, when the vane of a feather fossil, 60 mm long and 11 mm wide, was found at the same limestone level in the Kohler Quarry in Solnhofen, Von Mayer realized that it belonged to a bird for the third time and described this fossil, which had both internal and external patterns, as a “Wing feather.” Later, Von Mayer could not make a definite inference about what kind of creature this fossil belonged to; he thought that it was not a bird because it had a tail or a reptile because it had feathers. He claimed that these complex features contradict Cuvier’s “Rule of compatibility of organs.” Johann Andreas Wagner, on the other hand, based on the recommendations of his assistant Opel, reported this fossil at a meeting of the Bavarian Academy of Sciences on November 9, 1861.

However, he named it “Griphosaurus problematicus,” that is, “Problematic riddle-lizard,” saying that it was a reptile covered with feathers. Wagner realized that this finding could be used by Darwin and his parties as proof of the Theory of Evolution; however, he opposed this interpretation due to his theological beliefs and defined the fossil only as “A reptile”. In 1862, the fossil was sold to the Natural History Museum of London for 750 pounds, along with its entire collection, which held 1703 pieces.

Sir Richard Owen, a very prestigious anatomist, depicted the fossil in detail, emphasizing that it was a bird, and changed its name to ”Archaeopteryx macrura.” The fossil has entered textbooks under this name.

This fossil, which is still a valuable part of the collections of the Natural History Museum of London, is known in the literature as the “London Specimen.” The skeleton known as the London Specimen (BMNH 37001) constitutes the first “Holotype.” There were some doubts that the feather sample might not belong to the same animal as the body fossils of the creature. To prove this claim, a laser scan was performed on the feather sample in 2019, and the structure of the feather was revealed. Later, the feather structure found was compared with those of other Archaeopteryx specimens, and it was reported that the morphology of the feather was different from those of other specimens. However, another study conducted in 2020 stated that the previous study was inconsistent and that the feather was essentially an upper main primary covering feather belonging to Archaeopteryx.

Sixteen years after the first Archaeopteryx skeleton was found, a second skeleton was found by farmer Jakob Niemeyer in January 1874 or 1875 in the quarry belonging to Johann Dörr, which was found in lithographed limestones in Blumenberg, near Eichstätt. Johann Dörr bought the fossil and sold it to Ernest Otto Häberlein. The skull of this skeleton, which was much better preserved than the first one, showed that the animal had teeth.

By taking a lesson from the smuggling of the first find out of the country, the smuggling of the second find out of the country was prevented and purchased by the Berlin Museum of Natural History for 20,000 gold marks. The fossil is still part of the collection of the aforementioned museum.

This find, which has passed into history as a Berlin Specimen, was examined by paleontologist Wilhelm Dames and classified as a representative of the same species as the London Specimen named “Archaeopteryx macrura” in 1884.

Harry Govier Seeley, the author of the book ”Dragons of the Air” and a respected vertebrate paleontologist, put forward the thesis in 1881 that the Berlin and London specimens of Archaeopteryx may be different in terms of species, if not in terms of genus.

Dames later decided that the marked difference between the hip bones of the two specimens was a marked enough difference to classify the Berlin Specimen as a separate species from the London Specimen, and described the Berlin Specimen as a new species named “Archaeopteryx siemensii” in honor of Werner von Siemens, who helped purchase it.

In 1917, Yugoslav zoologist Branislav Petronijević and another zoologist, Henry Woodward, proposed that the Berlin Specimen should be named “Archaeornis siemensii,” arguing that the Berlin Specimen should be different from the London Specimen not only as a species but also as a genus in an article published on the shoulder girdle and hip girdle of the London Specimen of Archaeopteryx.

The fragments, consisting of a feather and two skeletons, remained fossils that formed the basis of what we knew about Archaeopteryx until 1950. In 1956, a new Archaeopteryx fossil consisting of a trunk was discovered in Langenaltheim, just 250 meters from the location of the London Specimen. This fossil has taken its place in history as the Maxberg Specimen, bringing the number of Archaeopteryx specimens known up to three. The Maxberg Specimen was formally described by Florian Heller in 1959. Heller, for example, took his images through an X-ray and a UV filter. The fossil was formed on two opposite rock slabs. Mainly, a body with some feather traces and both a head and a tail can be examined on these plates.

On September 8, 1970, he was appointed as a faculty member of the Department of Geology of Yale University and the Peabody Museum of Paleontology by Prof. Dr. John Ostrom was studying flying reptiles at the Teylers Museum in the city of Haarlem in the Netherlands. Later, Prof. Dr. John Ostrom began to study a Solnhofen fossil that had been purchased by Hermann von Mayer.

It had been found in January 1855 in a quarry in the Altmüln Valley, near Ridenburg, and described by von Mayer as a “Flying reptile” in 1857 under the name “Pterodactylus crassipes.”

Prof. Ostrom determined that the fossil is actually an undetected Archaeopteryx fossil and increased the number of known Archaeopteryx fossils to 5. In 2017, it was named a separate genus of Ostromia, which is thought to be more closely related to Anchiornis. This specimen is known as the Haarlem Specimen (TM 6428/29).

The Eichstätt Specimen (JM 2257) was found near Workerszell, Germany, in 1951 and described by Peter Wellnhofer. It is the specimen with the smallest known head. It was once described as a separate genus under the name Jurapteryx recurva. In 1987, it was noticed that an Archaeopteryx skeleton was found in the personal collection of Friedrich Müller, the former president of Solnhofen.

Mr. Müller bought this fossil years ago, but the detailed cleaning of the fossil had not yet been done. That’s why he thought of it as a fossil Compsognathus. However, when it was cleaned in detail, it became clear that this was an Archaeopteryx that had been preserved along with its feathers. This specimen was probably the largest ever found.

On August 3, 1992, the sixth Archaeopteryx fossil was found near Solnhofen. This skeleton had one important difference from the others: it was the smallest specimen after the Eichstätt Specimen, which was the fifth fossil ever found. The sixth fossil specimen has been named the Solnhofen Specimen in reference to the location where it was unearthed. As for the date of discovery of the Solnhofen Specimen, some sources point to the 1960s and some to the 1970s. The identification of the fossil was carried out in 1988.

It was impossible that this fossil, which was 30 cm long from the skull to the tail tip, belonged to a young animal, because Peter Wellnhofer had proved that there was an ossified (Fused) breastbone in this skeleton. However, in the Berlin Sample, which is larger than this, the sternum had not yet fused. The fact that the feet and tibia are longer than those of other Archaeopteryx fossils compared to the body indicates that the find should be classified in a different species.

Dr. Peter Wellnhofer named this new species “Archaeopteryx bavarica” due to its presence in the state of Bavaria. Thus, a second species has been described within the genus Archaeopteryx for the first time.

Discovered on August 3, 1992, in Langenaltheim and described by Peter Wellnhofer, the fossil is known as the Munich Specimen (BSP 1999 I 50). It was purchased by the Munich Museum of Paleontology for 1.9 million marks, and it is still in that museum. The fossil was initially thought to be the basis of Archaeopteryx bavarica; however, subsequent studies have suggested that it may belong to Archaeopteryx siemensii.

The eighth specimen was discovered in a fragmentary state in the Mörnsheim Formation in Daiting in 1990. For this reason, it is also called the Daiting Specimen. In 2009, paleontologist Raimund Albertsdörfer acquired the fossil. It was later named ”Archaeopteryx albersdoerferi.”

In 2000, another fossil was found in different pieces. It was loaned to the Bürgermeister-Müller Museum in 2004, and the fossil remains there. For this reason, it is called the Bürgermeister-Müller Example.

It was found in Bavaria in 2005 and described by Mayr Pohl and Peters. It has been in a private collection in Switzerland for a long time. The sample was named Thermopolis Sample (WDC CSG 100). It was donated to the Wyoming Dinosaur Center. It is thought to have the best-preserved head and feet. The majority of the neck and lower jaw have not been preserved. The Thermopolis Specimen was described as “A well-preserved specimen of Archaeopteryx with theropod characteristics” in a December 2, 2005 “Science” journal article. This fossil shows that Archaeopteryx did not have an inverted toe, one of the general characteristics of birds, which meant that Archaeopteryx adopted a climbing lifestyle rather than perching in trees. The Thermopolis Specimen was classified as “Archaeopteryx siemensii” in 2007.

The eleventh discovery was made in 2011 and could be examined in 2014. It is in a state of private ownership, so it does not have a specific name. Although most of the skull and one forelimb of this fossil are missing, the tail section has been preserved up to the tail tip, and the rear members are also well-preserved.

The twelfth specimen was found by an amateur collector in 2010; however, it was announced in 2014, while its scientific identification took place in 2018. It is an incomplete specimen whose feathers are not well-preserved. It has been found in the Painten Formation. ^[1]

Although all the fossils of Archaeopteryx came from the Solnhofen region of southern Germany, the twelfth specimen is not only the oldest but also the newest fossil discovered. The layers in which this fossil was found are at least 200,000 years old, probably 300,000 years older than the lithographic rocks in which other Archaeopteryx remains have been found.

Transitional features found in Archaeopteryx

The most crucial feature of Archaeopteryx fossils is that they are a pivotal transitional example due to the combination of many bird and reptile features. It is especially noticeable that the nasal and temporal cavities resemble those of a reptile. In addition, Archaeopteryx has a series of cylindrical, hooked teeth with the ends facing backward in its mouth.

For example, there are twenty-two teeth in the lower jaw of Archaeopteryx bavarica. Plates between the teeth, one of the characteristics of Thecodontia reptiles, the ancestors of dinosaurs, are also seen.

As a result of the evolution from reptiles to birds, the skull has undergone some changes. These are the formation of the beak from the jaw by elongation of the premaxilla bones and the loss of teeth (Lat. Premaxillae), the formation of a beak from the jaw with the loss of teeth by elongation, the growth of the eyes and eye sockets, the growth of the brain and brain cavity, and the jawbone (Lat. Quadratum), where the lower part of it is connected with a joint to allow movement to the skull. All these findings prove that Archaeopteryx is an intermediate transitional specimen.

The vertebrae of Archaeopteryx are also more similar to those of reptiles than birds. The spine of Archaeopteryx forms a long tail, a feature not seen in birds. Another vital element of the Archaeopteryx skeletons that resemble reptiles is the abdominal ribs, which are unrelated to other elements. On the other hand, the front elements of Archaeopteryx turned into wings. All three fingers have nails. One finger is bonded to the wing, while the other two are free and not covered with feathers. ^[2]

This is the case of Ophisthocomus hoazins (EN: Gypsy chicken), an endemic species of South American birds today and a condition that can be observed in the vestigial wings of adult ostriches ^[3]

As is seen in the image, Ophisthocomus hoazin chicks cling to trees with their nails. The nails of Archaeopteryx are thought to have had a similar function. ^[7]

The structure in the Archaeopteryx skeletons, which is the same as that of birds, is the lades bone. However, in some theropod dinosaurs, the collarbones can fuse to form the lades bone. This is one of the considerable similarities between dinosaurs and birds. Celal Şengör expressed the leg structure of Archaeopteryx as follows in his article:

The head of the thighbone (Femur) has turned inward from the hind leg bones, and the calf bone (Fibula) has shrunk. The knees and ankles form simple hinge joints. The tip of the tibia is united with the wrist bones (Tarsalia), and the near ends of the comb bones (Metatarsalia) are fused with the wrist bones. The comb bones are long and partially fused. Three fingers look forward; one is turned upside down. Since all these features resemble both those of birds and ‘lizard-hipped’ dinosaurs that moved on two legs, it constitutes another piece of evidence of Archaeopteryx‘s place between dinosaurs and modern birds.

A.M. Celal Şengör – Cumhuriyet Bilim Teknik Gazetesi

All these features are findings that prove that Archaeopteryx is an example of an intermediate transition between non-avian dinosaurs and birds, and these findings provide strong evidence for Darwin’s Theory of Evolution. These features indicate that Archaeopteryx‘s body was covered with feathers and that it was warm-blooded.

Archaeopteryx shows feathering in a structure similar to modern birds. On the wings, small covering feathers on the wing (PC), hand and arm covering feathers on the wing, and hand-arm feathers are seen fully developed. Because the fingers are fully developed, the fingers that develop on the thumb in modern birds and are called alula fibers (Protrusions on the front part of the wings of modern birds and some non-avian dinosaurs) are not seen in Archaeopteryx.

On the tail, the feathers differ from those of modern birds because they come out of the spine. Feathers take on the task of maintaining body temperature in modern birds and give them the property of being warm-blooded; it is estimated that feathers reveal the same situation in Archaeopteryx.

From which ancestor did Archaeopteryx evolve?

There are different theories about which ancestor Archaeopteryx descended from. Theories on this subject can be collected under three different headings.

1. Comments made based on tail similarities proposed by R. E. E. Wiedersheim in the twentieth century and Petronievics in the twenty-first century, when examined at this scale, argued that Archaeopteryx is descended from lizards.
2. It is the thesis that Archaeopteryx is descended from flying reptiles, supported by Sir Richard Owen, Harry Govier Seeley, and Wiedersheim.
3. It is the theory that birds evolved from dinosaurs, advocated by Othniel Charles Marsh, a respected vertebrate paleontologist, of which Huxley was one of the leading proponents. The period known as the “Dinosaur Renaissance” was initiated by John Ostrom and has become accepted as modern. ^[4]

According to this theory, the “Coelurosauria” of birds is a clade that includes other theropod dinosaurs, which are more closely related to birds than Carnosauria. It is suggested that they are descended from the clade, and their closest relative among dinosaurs is Compsognathus. It was thought that birds descended from theropods in the Coelurosauria included the Compsognathidae, Tyrannosaurus, Ornithomimosaurs, and Maniraptorans. Maniraptorans also include birds, which are dinosaurs living today. Currently, birds are accepted in the Aves class. In the past, the definition of Coelurosauria was used to cover all small theropods, but current studies have invalidated this classification. When the differences between non-avian dinosaurs and birds, which were previously thought to be sharp, became less apparent over time, Thomas Henry Huxley quoted this:

We have had to stretch the definition of the class of birds so as to include birds with teeth and birds with paw-like fore limbs and long tails. There is no evidence that Compsognathus possessed feathers; but, if it did, it would be hard indeed to say whether it should be called a reptilian bird or an avian reptile.

Thomas Henry Huxley – Clark University

For a long time, it was assumed that Archaeopteryx lithography, a small theropod dinosaur that lived during the Late Jurassic period and which we examined earlier in the article, was the oldest bird. However, there have been some studies suggesting that Aurornis xui may be the most basal avian that has ever lived. So much so that it has been discovered that this creature lived about 10 million years before Archaeopteryx lithography. This also throws the dates back a lot. Gregory Paul had put forward a pro-avian model, and according to the suggestions made, Aurornis was an example of this pro-avian classification. In his predictions, he suggested that the direct ancestors of birds could not have lived in trees. According to him, feathers, which were originally for the task of keeping the body warm, evolved to form wings. ^[5]

How did Archaeopteryx fly?

So, how did Archaeopteryx fly? There are different theories about this. These theories are, respectively:

1. Archaeopteryx, hence birds, is a reptile that glides over short distances by jumping from tree to tree.
2. It is derived from a reptile running on the ground.

It has been suggested that the claws on the wings of Archaeopteryx assumed the function of clinging from tree to tree, just like in the offspring of the Hoatzin.

Hungarian geologist Franz Nopcsa put forward a hypothesis in 1974, accepting that Archaeopteryx evolved from ground-dwelling and insect-eating dinosaurs and accordingly arguing that wings initially evolved not to fly but to catch insects. Feathers that initially assumed functions such as controlling body temperature provided a net-like structure by creating large surfaces, and thus wings were an advanced mechanism for catching insects.

Archaeopteryx first began to fly by jumping between short distances and then became a key living example in the process of moving towards birds by developing strong wings due to the benefits of flying in catching insects and protecting from enemies. According to a study by Philip Senter in 2006, Archaeopteryx did not fly by flapping its wings like modern birds but instead adopted the downward wing-assisted gliding technique. In a study conducted by scientists in March 2018, it was stated that Archaeopteryx could fly, but it differed significantly from that of modern birds. When the bone histology of Archaeopteryx is examined, it is seen that they had developed a flight mechanism similar to that of pheasants in our modern world.

Peter Wellnhofer argues that the feature of flight occurs as a result of a joint function of the mechanisms of gliding from tree to tree and chasing insects on the ground, which are revealed by current theories.

The flight feature accelerated the metabolism and reduced the mass of the creature by creating air sacs in the bones. Even the feature of flight itself was a powerful example of Darwin’s evolutionary mechanism. ^[6]

The author’s opinion

As can be seen, time has vindicated Charles Darwin. The example of Archaeopteryx has been a slap in the face to those who brutally attacked and demanded evidence about transitional examples to his theory for a while.

Today, some speculators have still produced disinformation (False information), such as the claim that an explicit transitional fossil such as Archaeopteryx is fake. This article is written as a response to people who claim that fossils are unreal and who are in the field of scientific thinking. If anyone asks about the power of evolution or wants a striking and important example of a missing link, you can tell him about Archaeopteryx. For those who progress in the light of science and those who want to progress…

Resources

1. ^{WIKIPEDIA ENTRY} Archaeopteryx. (2023, June 25). In Wikipedia. [Wikipedia English]
2. ^{DICTIONARY ENTRY} Britannica, T. Editors of Encyclopaedia (2023, June 9). Archaeopteryx. Encyclopedia Britannica. [Britannica]
3. ^NEWSPAPER Şengör, A. M. C. (1995, December 16). İlk Kuş Archaeopteryx. Cumhuriyet Bilim Teknik Gazetesi, no. 456, 6–9.
4. ^WEBSITE Marshall, M. (2019, June 3). The evolution of Archaeopteryx is stranger than anyone imagined. New Scientist. [New Scientist]
5. ^WEBSITE Castro, J. (2018, March 14). Archaeopteryx: The Transitional Fossil. Live Science. [Live Science]
6. ^WEBSITE Bakırcı, Ç. M., & Kartal, E. C. (2019). Dinozorlardan Kuşlara Evrimin En Net Örneklerinden Birisi: Archaeopteryx. Evrim Ağacı. [Evrim Ağacı]
7. ^WEBSITE Selçukoğlu, A. K. (2022). Hoatzin (Ophisthocomus hoazin). Evrim Ağacı. [Evrim Ağacı]