Owner Comments:
Every story has a beginning, and the story being told with this set, that of the dinosaurian ancestry and identity of modern birds, is no exception. The first chapter of this story starts with the animal whose fossilized remains are shown on this coin: Archaeopteryx lithographica.
In 1859, Charles Darwin’s groundbreaking work, On the Origin of Species, was first published. This work was the first scientific work that worked to address the true origin of all of the various and varied life forms on Earth. The most important thing that Darwin’s work did was to propose the Theory of Evolution through natural selection. Until Darwin’s work, the origins of life and different life forms were explained by various non-scientific creation myths, which varied by population, society and religious affiliation. On the Origin of Species changed all of that by finding the real, scientific answer to the question of the origins of life and its various forms, which was that existing life forms evolved from earlier forms by evolving new and novel features, and that natural forces would either favor or disfavor different life forms. As we know today, Darwin was absolutely correct in his assessment. Evolution is indeed how different life forms arise and how the great diversity of life on our planet came to be and continues to change. But in 1859, one thing was lacking and that was a transitional fossil, a fossil of a life form showing characteristics of two different life forms. Then, in 1861, everything changed.
In 1861, a German quarry worker discovered the fossil of a single feather. Later that year, the first skeleton of an Archaeopteryx was discovered. Dinosaurs were known at the time, and this new skeleton showed just what Darwin stated would eventually be found: skeletally, it was virtually indistinguishable from several small theropods which had already been discovered and described but the fossil also preserved feather imprints, showing that this dinosaur had feathered wings, feathered legs and a long, feathered tail. In 1875, the specimen shown on the coin was discovered. Known as the Berlin Specimen, this fossil remains the most complete specimen of Archaeopteryx ever found.
To scientists in the 1860’s, who did not understand the nature of theropod dinosaurs as we do today, Archaeopteryx appeared to be a transitional form showing the emergence of birds from reptiles. Indeed, most of Archaeopteryx’s features match up to other small terrestrial theropods. It had jaws lined with razor sharp teeth, a long, bony tail and a sickle-shaped killing claw on its second toes……but then there were those feathers, forming wings. For many years, Archaeopteryx was considered to be the first known bird as it was the very first dinosaur fossil found with preserved feather imprints. Archaeopteryx, at the time, was seen as important proof of evolution and may still be the most scientifically significant dinosaur fossil ever found because of the proof of evolution it provided at a critical phase in the study of natural evolution. If it wasn’t for Archaeopteryx, those archaic and highly incorrect creation myths may have taken back over and crippled the studies of biology and Earth history for years, decades or centuries more.
Today, Archaeopteryx’s status is somewhat changed. First off, the feathers that Archaeopteryx shows are not transitional features in and of themselves. As more fossils of Theropods with preserved feathers and quill knobs have been discovered and even Ornithischian dinosaurs have been discovered with “feather-like structures”, it now appears that feathers were ancestral traits of at least the theropods, if not of the Dinosauria as a whole. Secondly, as birds are a kind of dinosaur and we now know it, birds did not actually “emerge” from reptiles as they still are reptiles. So, that begs the question: Is Archaeopteryx still considered a transitional fossil?
Actually, yes, it is. Archaeopteryx shows two important trends leading to the emergence of true birds within the theropod family which occurred in the Early Cretaceous. Archaeopteryx is from the Late Jurassic period, existing from 150.8–148.5 million years ago. The first important thing about Archaeopteryx in a modern transitional sense is that it was small. It was the size of a modern raven, and it was likely black in coloration so it probably looked a lot like one as well, long, bony tail aside. While Ornithischians and Sauropods, the other two types of dinosaurs, kept getting larger and larger over the course of the Jurassic and Cretaceous Periods, Theropods went in the opposite direction. In spite of the presence of giant Theropods such as the Tyrannosaurs and Carnosaurs, most Theropods got continually smaller over the course of the Mesozoic. This decrease in size was key in the evolution of flight, which is only known among Theropods within the Dinosauria. Secondly, while Archaeopteryx’s feathers are not transitional in and of themselves, they are transitional in that they are more similar to the stiff, asymmetrical flight feathers found on modern birds and later dromaeosaurs than the “dinofluff” found on Tyrannosaurs and other, larger and more primitive Theropods.
Relating to this transition is the aforementioned long tail. While the tail structurally similar to many other dinosaur tails, the feathering on the tail was arranged in a palm frond like pattern. This was a key step in the evolution of the aerodynamically sound tail fans found in flighted Enantiornithes during the Cretaceous and flighted Euornithes from the Cretaceous up to the modern day. So, Archaeopteryx is still a transitional fossil in the evolution of flight among Theropods and is a key chapter in that larger overall story. Recently, scientists have determined that Archaeopteryx was capable of fully powered flight, but that its fight style was quite different than that seen in later, more advanced Mesozoic and Cenozoic flying dinosaurs.
About Archaeopteryx itself, we actually know little. Only 12 fossils of Archaeopteryx are currently known, and most of those are highly incomplete. We know that it was likely black in coloration and that it was definitely carnivorous and likely predatory animal of small prey. During its lifetime, Europe was a series of islands as the sea levels were much higher due to the lack of polar ice caps at that time. By comparing its scleral rings to modern reptiles, we can theorize that Archaeopteryx was likely diurnal. We also know that its brain was advanced and complex, but not as advanced as those found in later Cretaceous Coelurosaurs. So, we know that Archaeopteryx was an intelligent animal as well, but how it used that intelligence we do not know, nor will we likely ever know. Fossils tell us very little about behavior. However, what can be said for certain that in this chapter of the story of life on Earth, Archaeopteryx is one of the most important players and served to be the first silent storyteller of the true story of avians.