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In New Zealand we have a lot of interest in birds- this probably reflects both the uniqueness of our avifauna and it’s extinction pressures. Also, there’s not a lot of charismatic mammals to distract us. New Zealand is also a good place to understand the modern evolution of some bird groups. Many birds are secondarily flightless, none more so than the ratites (of which we have many moa and kiwi species).

In terms of ancient evolution of birds however, it is the fossil discoveries in China (western Liaoning) and Spain (La Hoyas) that are becoming quite exciting. Since the discovery of Archaeopteryx in 1861, the number of fossils with avian and reptilian features has expanded. These families all occur in the late Jurassic and early Cretaceous periods. The timing of the evolution of modern birds has been fairly well-established. (Albeit the long evolutionary history of this group does not rule out an earlier- perhaps even Triassic- origin).

Last year Nature[1] published the description of a new fossil from the late Jurassic in China. The species has been named Anchiornis huxleyi and more significantly, is the oldest troodonitid fossil that has been found. The troodontids are part of a small group of families that map out the reptile-bird transition. This group is known as the Paraves- it consists of the troodontids, the dromaeosaurs and the avialae (of which the most famous fossil example is Archaeopteryx).

The Fossil
(Link to Nature website)

Anchiornis is another feathered dinosaur. For paleontologists, it also solves a temporal paradox. It’s appearance in the fossil record before Archaeopteryx means the evidence that feathers predate the evolution of flight has been discovered. Many of our other feathered dinosaur fossils (e.g. Microraptor) date to after Archaeopteryx.

Anchiornis is essentially a small, bipedal theropod. It’s long limbs indicate an active, agile animal. The early bird like features of this fossil are its deathers and elongated forelimbs. The most intriguing aspect of the fossil however, is that the feathers are present on all four limbs. This also is the case with Microraptor. Hence, these fossils are pointing towards a more complicated evolution of flight. It appears that the evolution might have gone through a four winged stage until the flight feathers were lost on their legs and feet.

The transition between theropod reptiles and birds has been well-established. There are many new fossil species and families that now map out this evolution. We have transition fossils now that date before and after Archaeopteryx. Creationists should take note.

Theropod Phylogeny
(Link to Nature Website)

What is going to be of even more interest is the new fossil discoveries that are still being made in these western Chinese Jurassic stratas.



[1] Hu, D., Hou, L., Zhang, L. and Xu, X. (2009). A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus. Nature 461, 640-643.