In a Flap over Archaeopteryx
Palaeontology is a fascinating subject, it is an ever changing branch of the Earth sciences. New fossils are found which challenge existing theories and scientific assumptions. New research techniques such as computer modelling and high resolution X-ray scans reveal exciting new information about organisms preserved in the fossil record. Times they are a changing and even one of the most iconic creatures from the field of palaeontology is in danger of being knocked off its lofty perch.
Archaeopteryx (ancient wing) could perhaps be one of the most famous fossilised creatures ever discovered. Truth is, this Late Jurassic, feathered creature is known from at least ten specimens, although one of these fossils, the first ever found consists of just a single feather! Most scientists think that this crow-sized animal which lived in a warm, tropical, coastal environment in what was to become southern Germany, was one of the earliest ancestors of modern birds. However, new discoveries in China coupled with extensive research from the Chinese Academy of Sciences suggests that Archaeopteryx may just be another small Theropod dinosaur and not such a significant discovery after all.
The Story of Archaeopteryx
The first fossils of Archaeopteryx were found in 1860 near Solnhofen in Bavaria (the single feather). The fine-grained limestone in which the fossils have been found is used in the lithographic printing process and this explains the formal scientific name for this creature Archaeopteryx lithographica. This part of southern Germany was populated by a number of ardent Catholics who vehemently denied the theories postulated by Charles Darwin in his book "The Origin of Species", that was first published in 1859. The discovery of the feather and a year later by an articulated almost complete specimen of Archaeopteryx provided powerful evidence to support Darwin's idea that organisms evolved over time through a process called natural selection.
Archaeopteryx was named and described by the German palaeontologist Hermann von Meyer in 1861, after the discovery of the near complete fossil. In total only a handful of Archaeopteryx fossils have been found (nine specimens and one fossil feather). The first Archaeopteryx fossil was found several years before the feather specimen was discovered, but at the time it was wrongly classified as a flying reptile, it was finally classified as a fossil of Archaeopteryx in the early 1970s.
Archaeopteryx shows characteristics of birds and reptiles. It is sometimes called a "missing link", but the term transitional fossil is more appropriate. Archaeopteryx had feathers, a breast bone (called a furcula) and was lightly built - thought to be adaptations for powered flight. However, it also had conical teeth in the jaws and a long, reptilian tail.
New Research Suggests Archaeopteryx may be Just "Another Theropod Dinosaur"
Despite the rarity of the fossils and their delicate state of preservation, the fossils attributed to Archaeopteryx have been extensively studied over the last 150 years or so. Recent studies have concentrated on determining the structure and composition of the feathers. Other studies have focused on the brain case in a bid to determine how well co-ordinated and equipped for flying this little animal was. The assumption has been, a belief held by most palaeontologists, is that Archaeopteryx represents an ancestor of true birds. However, a team of palaeontologists from the Chinese Academy of Sciences are challenging this long held theory.
The Chinese researchers having identified a new species of Archaeopteryx-like dinosaur, classified as a member of the Theropoda, from lake deposits formed about 160 million years ago in the north of China are challenging these assumptions. According to their research findings published online in the scientific publication "Nature", the new dinosaur species, named Xiaotingia zhengi is a close relative of Archaeopteryx, which is widely accepted as the most primitive bird, known from the fossil record. However, a phylogenetic analysis incorporating this new research suggests that Archaeopteryx was not a bird. This has some very significant implications for our understanding of bird origins and the relationship between reptiles and birds. Could Archaeopteryx be in danger of being knocked of its lofty perch?
One of the smallest non-avian dinosaurs discovered to date; X. zhengi weighed about the same as a bag of flour.The fossil shows evidence of conical teeth, set in a long pointed jaw, as well as long, robust arms that are similar to those of primitive birds. Its modified feet have the highly extensible second toe, a characteristic of a group of dinosaurs known as the Deinonychosauria, These were very bird-like, cursorial dinosaurs, fierce predators such as Velociraptor, made famous from the "Jurassic Park" movie trilogy.
Lead author of the scientific paper on this new discovery, Dr.Xu Xing of the Institute of Vertebrate Palaeontology and Palaeoanthropology, Chinese Academy of Sciences, has expressed his excitement regarding the discovery but insists that Archaeopteryx is just another type of Theropod,perhaps an ancestor of Velociraptor but not a direct ancestor of the Aves (birds).
This new study is going to challenge long held views about the significance of Archaeopteryx, the feathers (excuse the pun) are certainly going to fly. It is widely accepted that birds are descendants from dinosaurs. Like dinosaurs, birds are members of the Archosauria. However, when examining the phylogenetic relationship between fossils, the picture becomes less clear. The Chinese Academy of Sciences has made a number of very important discoveries related to this important issue in palaeontology. It is now widely accepted that birds are descended from dinosaurs, but scientists are still working put together a fossil family tree to demonstrate how all the fossils found to date are related to each other and how the dinosaur-bird transition occurred.
The Chinese based team have a number of very well preserved fossils to study, most of which date from around 160 million years ago,making these specimens about ten million years older than the Archaeopteryx material. Genera such as Archaeopteryx from Germany and Xiaotingia and the recently discovered Anchiornis (China) are claimed to be more similar to other Deinonychosaurs. So Archaeopteryx may not actually be a bird at all. Certainly, not the first bird to evolve - an assumption made by many people.
Just because Archaeopteryx was the first feathered fossil indicating a bird/reptile link found, it does not mean it was the first bird to evolve. We explain this by using the following illustration:
Imagine that you have a pillow case, take a note pad and rip all the pages into small squares. On each square write a number from one to ten thousand, then fold these pieces of paper and drop them into the pillow case. Then once mixed all around pull out a single number. It is extremely unlikely that this number will be the digit number one. In fact the odds for this happening are 10,000 to 1. We won't go into the semantics of the chances of fossil preservation potential between a common established species and a newly evolved species, but the point is just because Archaeopteryx was the first bird-like fossil found, it does not mean that it was the first bird to evolve.
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