Why can dinosaurs be warm-blooded animals with wings?

In 1860, it was nearly a hundred years since the beginning of the Industrial Revolution. With the continuous wars in Eurasia, machinery, steel, and coal seem to be dragging the whole world forward, and half of the human society has been uprooted.

Yet all this does not seem to disturb a place in southern Germany called Solnhofen, which was then part of the Bavarian kingdom. Because it is rich in limestone formed by deposits, one of Sorenhofen's traditional industries is quarrying. Sorenhoven's workers carefully chiseled the limestone along the bedding and often found unexpected gifts: the limestone was sandwiched with fossilized animals, as exquisite as printmaking. One day of this year, a quarry worker chiseled out a "printmaking" and found a fossil made of feathers inside.

Feather imprint fossils discovered in 1860. Sorenhofen's limestone is flat and delicate and is often used as a printing plate. The limestone strata in this area were formed in the late Jurassic about 150 million years ago, when Europe was much closer to the equator than it is today, and the low oxygen environment and carbonate sand layers at the bottom of shallow seas and lakes easily preserved paleontological remains to form fossils. Photo: H. Raab / wikimedia

There is no way to know how German paleontologist Hermann von Meyer felt when he saw the 150 million-year-old feather-the earliest known bird fossils existed only in the much later Cenozoic Eocene. Meyer published the scientific name for the feather in 1861: Archaeopteryx lithographica--Archaeopteryx means "ancient wings or feathers", the real name lithographica means "printing plate stone painting", and the Chinese translation is "Archaeopteryx".

The restoration picture of Archaeopteryx chasing Xiujaw dragon. Picture: Durbed / wikimedia

What did the Germans miss?

No one expected that just a few months after the name was published, a fossilized Archaeopteryx skeleton was found in nearby Langenaltheim. The fossilized skeleton is missing the head and cervical vertebrae, while clearly retaining a feather-like structure.

The quarry owner who owned the specimen paid it as a medical fee to Karl H?berlein, a local doctor and fossil collector. Habern plans to sell specimens in order to collect the dowry for his daughter, which has attracted all parties' attention.

A skeleton fossil of Archaeopteryx found in Germany in 1861, later known as the "London specimen". The following article will talk about the origin of the name. Photo: H. Zell / wikimedia

In the middle of the 19th century, there was always an open and secret struggle between the countries of continental Europe and Britain in terms of national strength, science and technology, and scholarship. A large number of natural discoveries made by the British in the colonies put great pressure on the European scientific community, and Germany naturally did not want its major discoveries to fall into the hands of others. The dark tide on the other side comes from the masterpiece Origin of species published by the British naturalist Darwin in 1859.

Darwin and the first evolutionary tree he painted. Picture: Charles Darwin & Julia Margaret Cameron / wikimedia

The idea of evolution and the theory of natural selection put forward in the Origin of species are epoch-making, but in the middle of the 19th century, religion still occupies a dominant position in the field of thought. Once published, this book is bound to be attacked by many parties. One side's firepower came from another Englishman, Richard Richard Owen, paleontologist and founder of the natural history department of the British Museum.

Irving is well aware of what this bone means to Darwin-if birds evolved from reptiles, then this specimen with the characteristics of both birds and reptiles is the transitional fossil Darwin pursued and solid evidence of evolution. Although Irving was a famous dinosaur and an outstanding naturalist, he himself adhered to creationism and catastrophe. As a devout Catholic, he hated Darwin and always attacked Darwin and "the origin of species". Determined to occupy the study of Archaeopteryx specimens.

Owen and a bird skeleton. Irving's main contribution in the academic circle was to promote the establishment of the branch of natural history of the British Museum. However, he was narrow-minded and spared no effort to eliminate dissent. In addition, in his later years, he was expelled from the Royal Society because of his other evil deeds that destroyed the research of others. Picture: John van Voorst / wikimedia

After lengthy negotiations, Owen finally shipped the Archaeopteryx fossil, along with more than 1000 specimens of other creatures, back to the British Museum for £700. Ironically, the Germans lost this priceless treasure in part because another opponent of Darwin, the German paleontologist J. Andreas Wagner, claimed everywhere in Germany that the specimen was not a transitional fossil of birds and had no significant value, so people in Germany did not try their best to recover it.

Owen has already lost.

Irving obtained the fossil Archaeopteryx, which was later called the "London specimen", and immediately began to study it, and published a detailed research report in 1863, naming it the Great Archaeopteryx A. macrura, identifying it as a special kind of bird. Although Owen deliberately concealed, for example, he ignored the existence of teeth in fragments of the London specimen's jawbone, insisting that Archaeopteryx's beak would be found in the future. But he still can't avoid that there are a lot of dinosaur features in the specimens.

Comparison between the forelimb of Archaeopteryx (left) and Archaeopteryx (right). Picture: John Conway / wikimedia

In 1866, in the fourth edition of the Origin of species, Darwin could not hide his excitement and wrote something like this--

All birds were once thought to have appeared suddenly after the Eocene; but we now know that Professor Irving, with his authority, confirmed that birds were active in the "upper green sand" deposition period (about 75 million years ago); recently, however, strange Archaeopteryx was found in the limestone of Sorenhoven, dragging a lizard-like tail with feathered joints and wings with free-moving claws. Nothing is more convincing than this discovery that our understanding of the past inhabitants of the world is still poor.

In any case, Owen, who clung to the wrong point of view, lost in this game.

The story is told by Archaeopteryx

However, the Germans still own the limestone site of Sorenhoven. In 1874, the second Archaeopteryx bone fossil was found by farmer Jakob Niemeyer in Blumenberg. This specimen is extremely complete and retains the skull with teeth. In order to get the money for the cow, Jakob changed hands twice in 1876 and sold the specimen to Ernst Otto H?berlein, the son of Carl Haboren.

O. C. Marsh, a researcher at Yale University in the United States, coveted this for a long time, but in the end, German industrialist Ernst Werner von Siemens bought the specimen for 20, 000 marks and gave it to the Berlin Museum of Nature. This specimen finally did not leave Germany, so it was also called "Berlin specimen" by later generations.

The Berlin specimen is the first specimen of Archaeopteryx with an entire skull. Photo: H. Raab / wikimedia

In 1884, a study by Wilhelm Dames found that there was a difference between this more complete specimen and the London specimen, and in honor of Siemens' contribution, it was named Siemens Archaeopteryx A. siemensii.

In the more than 100 years since then, with the vicissitudes of life, new Archaeopteryx fossils have been discovered in the limestone area of Sorenhofen, but they are still extremely rare. A total of 12 pieces have been published by 2018, and there has been no shortage of interesting stories about the discovery of each specimen. For example, in 1970, J. Ostrom, a famous American paleontologist who studied ancient birds, found that there was a fuzzy feather mark on a specimen identified by Meyer as a pterodactyl in 1857. He determined that it was actually the earliest Archaeopteryx fossil found. The third bone specimen found in 1958, the Maxberg specimen (Maxberg specimen), was found lost after its owner, Eduard Opitsch, died in 1991, possibly by theft, and his whereabouts are still unknown.

Some specimens of Archaeopteryx were compared with human size after restoration. Picture: Jaime Headden & F. Spindler / wikimedia; Chinese: species Calendar

Do you remember that feather at first? It used to be the main type specimen of the scientific name of Archaeopteryx A. lithographica. In taxonomic research, it is necessary for the publisher of the name to designate a specimen as the "representative" corresponding to this name, which is the main pattern.

In 1996, however, researchers thought that the first feather specimen was probably not Archaeopteryx A. lithographica, but from another undiscovered theropod dinosaur or bird. After a long debate, the London specimen was redesignated as the new type specimen (neotype) of the name Archaeopteryx A. lithographica on October 3, 2011, and the Archaeopteryx A. macrura identified by Owen became a synonym and was no longer recognized.

Among them, the love-hate entanglement of taxonomists is difficult to sum up.

From dinosaurs to birds

Thomas Henry Huxley, known as Darwin's fighting dog, was not idle when Irving was picking on Darwin with lanterns. After carefully studying the London specimen, he not only refuted Owen's concealment and omission, but also put forward a startling view at the time: birds probably originated from dinosaurs. This means that dinosaurs are not completely extinct, at least one has been living around human beings.

Huxley, known as Darwin's Bulldog, argued against Irving's theory that the anatomical structures of the brains of humans and gorillas are similar. Photo: Lock & Whitfield / wikimedia

Huxley, of course, is not without proof. Although Archaeopteryx bones share the same or similar characteristics as birds-feathers and wishbones, partial carpal healing, opposite first toe and other toes of the hindlimb (easy to grasp but not long enough), but most of the characteristics, such as extremely long tail vertebrae, tongue-shaped shoulder blades, beakless, dentate, metatarsal separation, etc., are more similar to theropod dinosaurs. In fact, the "Sorenhofen specimen" of Archaeopteryx described in 1988 was considered by amateur collectors to belong to the genus Compsognathus at the beginning of its discovery.

Compared with modern birds (right), Archaeopteryx (left) has much longer caudal vertebrae. Picture: wikimedia

Still, living birds look too different from dinosaurs and other reptiles. In 1926, Danish biologist Gerhard Hellman (Gerhard Heilmann) published the Origin of Birds, which demonstrated that birds had nothing to do with dinosaurs based on the lack of wishbones in dinosaurs, suggesting that the similarity between Archaeopteryx and dinosaurs originated from convergent evolution, while birds originated from slotted teeth.

This book influenced the idea of the origin of birds throughout the first half of the 20th century, and Huxley's view fell silent. Until 1964, the aforementioned paleontologist Ostrom once again carried the view of bird-dinosaur origin based on the newly discovered balanced dinosaur (Deinonychus antirrhopus), reconnecting the relationship between birds and dinosaurs by using morphological phylogenetic trees.

The revolutionary discovery came from the east. Since 1994, a large number of fossils of ancient birds and feathered dinosaurs have been found in western Liaoning, China-Sinosauropteryx, Confucius Bird, Jehol Bird, Annithosaur, Microraptor, and Zheng Shixiaotinosaurus.

Sinosauropteryx fossil and its restoration map. Photo: Laikayiu / Inner Mongolia Museum; Robert Nicholls / wikimedia

These discoveries have not only completely changed the academic understanding of the origin of birds, but also updated people's concept of dinosaurs-dinosaurs can have feathers, can be warm-blooded, can build nests, can raise young, flexible, running dinosaurs, replacing the image of monsters lying on the ground with stiff tails in old sci-fi movies. To some extent, this is a continuation of the "dinosaur literary renaissance" led by American paleontologist Robert Thomas Bakker in the 1960s.

Today, we can finally regard birds as a branch of dinosaurs. Traditionally, extinct "dinosaurs" have become amalgamated groups, more appropriately called "non-bird dinosaurs". The definition of bird has also been updated to "include the most recent common ancestor of Archaeopteryx and sparrow, as well as all its descendants".

From dinosaurs to birds. Picture: uga.edu

In the more than 150 years since the discovery of Archaeopteryx feather fossils, human society has undergone several drastic changes. In 1867, a boy named Wilbur Wright was born in Indiana. In 1903, the Wright brothers invented the airplane, and man achieved power flight for the first time.

150 million years after Archaeopteryx grew asymmetrical feathers and swept across the lagoon, another terrestrial vertebrate took the first step toward the blue sky and the starry sky.

This article is the 242nd article in the fourth year of the species calendar, from the author of the species calendar @ Zhong Mi.