Archaeopteryx

About Archaeopteryx

The 'Missing Link' of Evolution and the Oldest Feathers

Archaeopteryx is one of the most iconic animals in the history of paleontology, living during the Late Jurassic period, about 150 million years ago. It has played a role as the evolutionary 'missing link' connecting bipedal carnivorous dinosaurs (theropods) and modern birds.

The first fossil that gave rise to this name was not a skeleton, but a fossil of a 'single feather' discovered near Solnhofen in Germany in the summer of 1860 or 1861. German paleontologist Hermann von Meyer named this unprecedented feather fossil Archaeopteryx, meaning "ancient wing" in Greek.

Shortly after the discovery of that feather, an almost complete full-body skeletal fossil (the London Specimen) with distinct feather impressions was found. The year was 1861, just two years after Charles Darwin published On the Origin of Species and introduced the theory of evolution. This fossil sent shockwaves through the scientific community of the time as definitive evidence that birds branched off and evolved from reptiles (dinosaurs).

Butterfly-style Flapping and Complete Wing Surface

Whether Archaeopteryx could actually fly was a major point of debate for over 150 years. It was once thought that its skeletal structure prevented the powerful flapping of modern birds, restricting it to merely gliding from tree to tree.

However, in 2018, an international research team examined the internal structure of its wing bones using cutting-edge "synchrotron" X-ray technology, revealing an astonishing fact. The bone strength of Archaeopteryx was very similar to that of modern pheasants and quails, which fly by flapping over short distances. It was concluded that instead of moving its wings up and down like modern birds, it performed "powered flight," lifting itself into the air through a unique stroke—throwing its wings powerfully forward to catch the air, similar to the "butterfly" stroke in swimming.

Features Connecting Dinosaurs and Birds

Archaeopteryx has a mixture of dinosaur (reptile) and bird characteristics. Its jaw is lined with sharp teeth, its forelimbs have three fingers with claws, and it has a long, bony tail. These are clearly features of carnivorous dinosaurs known as theropods. On the other hand, it also possesses bird-specific structures such as asymmetrical flight feathers and a furcula (wishbone).

Furthermore, recent research has revealed that not only its "appearance" for flying, but also its unseen "inside the mouth" had evolved highly. As a result of examining the aforementioned Chicago Specimen with ultraviolet light and CT scans, it was found that a "hyoid bone" existed deep in its mouth to support muscles. This suggests they had a flexible tongue that could freely manipulate prey.

In addition, traces of fleshy projections called "oral papillae" on the roof of the mouth (palate) to push food into the esophagus and prevent regurgitation, as well as a network of sensory organs at the tip of the beak to grope for prey, were also discovered. Since the physical act of flying consumes an enormous amount of energy, they had simultaneously developed an advanced digestion and foraging mechanism to efficiently intake calories to compensate for it.

Miraculous Preservation - The Environment of Solnhofen

About 150 million years ago, the Solnhofen region of Germany, where Archaeopteryx fossils were discovered, was an archipelago scattered across a vast, shallow tropical sea. Around these islands, "lagoons" with poor water circulation were formed.

In the dry climate, the seawater evaporated, and water with an extremely high salt concentration and no oxygen accumulated at the bottom of the lagoons. In this highly toxic environment, neither scavenging animals nor decomposing bacteria could survive.

When Archaeopteryx, flying overhead or living on nearby islands, died and fell into these lagoons, they sank quietly into the fine mud without decomposing. Thanks to this process, not only were the skeletons preserved without being scattered, but even the feathers and extremely delicate tissues inside the mouth were left behind as vivid fossils, almost like lithographs, for the modern age.
The limestone in this region has been mined as a material for lithography since ancient times, and it was this industrial quarrying activity that brought about the discovery of the century, Archaeopteryx.

Diverse Specimens of "Archaeopteryx"

Since the discovery of the feather in 1861, 14 skeletal specimens and one feather have been scientifically reported to date. For many years, these were all considered to be the same Archaeopteryx, but recent detailed analyses have shown that some specimens belong to a different dinosaur called Ostromia, or a different species called Albersdoerferi, revealing that there was a diverse group of bird relatives in the Solnhofen region at the time.

London Specimen (Specimen Number BMNH 37001)

The first skeletal fossil, discovered in 1861. Beautiful feather impressions remain, providing crucial evidence supporting Darwin's theory of evolution. At the time, Richard Owen of the British Museum of Natural History purchased it for the colossal sum of £700—an extraordinary amount for a single research institution—and it is still housed in London today.

Berlin Specimen (Specimen Number HMN 1880/81)

Discovered in 1874 or 1875, this is the most complete and beautiful specimen. Almost the entire body, including a skull lined with teeth, is intact, and it is sometimes called "the most beautiful fossil in the world." The image we conjure up when we hear "Archaeopteryx" is mostly based on this specimen.

Haarlem Specimen (Teylers Specimen) (Specimen Number TM 6428/29)

Discovered in 1855, this is a partial fossil found even before the first feather fossil. Initially misidentified as a pterosaur. Later identified as Archaeopteryx, but the latest research in 2017 revealed it to be a different genus, Ostromia, more closely related to Chinese dinosaurs.

Daiting Specimen (8th Specimen)

Discovered in 1990 and long kept hidden as a private collection, but scientifically investigated in 2018. Found in slightly newer strata than other specimens, it was described as a new species, Archaeopteryx albersdoerferi, possessing features closer to modern birds, such as a fused skull and hollowed (pneumatized) bones.

Solnhofen Specimen (Specimen Number BMMS 500)

Discovered in 1987, this specimen is characterized by being larger than others. Initially described as a different genus, the mainstream view now considers it a species of Archaeopteryx.

Eichstätt Specimen (Specimen Number JM 2257)

Discovered in 1951. It is considered a male and female pair specimen, and is presumed to have been a juvenile.

Chicago Specimen (14th Specimen)

The newest specimen, housed at the Field Museum of Natural History in the U.S. in 2022. It is only about the size of a pigeon, making it the smallest known individual. An extremely delicate skeleton is preserved three-dimensionally, leading to numerous major discoveries that unravel the mysteries of Archaeopteryx's flight and diet, such as the aforementioned "tertial feathers," "hyoid bone," and "oral papillae."

Archaeopteryx Stamp and Fossil Gallery