Thursday, February 2, 2012

Archaeopteryx: The Icon of Evolution

As with the museum posts(page) it really don't make sense search wise to name my book review posts book review # so I am going to go to naming them the title of the book for simplicities sake. Now on to the review.

It was a typical day in the Late Jurassic (Tithonian to be specific) on a small island located in the Tethys Ocean on what is currently the Bavarian region of Germany. The climate was warm and dry and the sun was beaming down on the small bush sized plants that covered the island. Out over the sea a group of pterosaurs (for me I will say Rhamphorhynchus muensteri) caught fish that swam to close to the surface near the reef while the breath of some of the marine reptiles (e.g. ichthyosaurs) broke the surface on occasion. On shore small theropod dinosaurs poked around in the bushes hoping to find a lizard or insect that they may be able to eat. The young Archaeopteryx had watched this scene play out plenty of times but only recently away from the safety of her mother's nest but at least now she could fly, well at least short distances and her flight wasn't very powerful due to her sternal keel still being cartilage. Her black feathers glistened in the sunlight and as a curious Compsognathus got too close she snapped her toothed jaw at it and flew slightly higher out of grasp for the dinosaur. She of course was a dinosaur too but there was something special about her she also had a lot of features that made her look more bird like than dinosaur like except for her long tail and her toothed "beak", and she certainly wasn't the first dinosaur to look bird-like but she would become when discovered one of the most important. As she looked out over the sea toward the dark black clouds that had been approaching for a while now she realized she was hungry it had been a while since she ate after all. Something hit her on the head and then more and more she wasn't quite sure what this was after all it hadn't rained, at least not much, her entire life. The rain drops also disturbed a dragonfly nearby from the branch it was sitting on and she took off after it. As she closed in a strong gust of wind blew her out over the reef, this was further out to sea than she had ever been. She looked toward shore and then the wind picked up even more. 150 million years later, in 1861, a slab of limestone is split from a quarry in the Solnhofen formation and she would again see the light of a new day but the world would be completely different than the one she lived in but she too would change it greatly.

While that story is clearly fictional the idea behind it is the vast amount of information that we have learned about Archaeopteryx lithographica since the first one was discovered in 1861. While most of this knowledge has been out there for years the first time that I truly saw it all compiled in one place was in a book I just finished called Archaeopteryx: The Icon of Evolution by Dr. Peter Wellnhofer (someone really needs to update and expand on his Wikipedia page). In this book we are taken to Solnhofen where we learn about the limestone that Archaeopteryx was deposited in and how this helps understand the environment that this animal lived in. We then learn about the animal itself and Dr. Wellnhofer tries to fit it into a phylogenetic location which includes a discussion on the different views of how birds evolved as well as the evolution of flight. While there have only been a total of ten (well eleven but the most recent one hasn't been published on yet and was just found late in 2011) body specimens and one isolated feather found we know so much about this animal. Part of the reason is how complete the specimens are with most being nearly complete but what I think the main reason for the amount we know about the animal is the just sheer amount of research that has been done on the specimens since it was the first animal found that truly showed the evolution of organisms in action, in this case the evolution of dinosaurs to birds.

This book is exceptionally well written and that is due to the sheer amount of knowledge that Dr. Wellnhofer has on paleontology and in particular the Solnhofen region. If you want to learn about Archaeopteryx or if you want to learn about Solnhofen geology or if you just want a book with really really nice pictures of really amazing fossils this is the book for you. Detailed images of all 10 of the specimens are included including pictures taken using infrared which really helps show off a lot of the soft tissue preserved in the specimen. There is a detailed description of the genus in general as well as where it fits evolutionarily which includes a very through description of the origin of birds including the many hypothesis of what the evolved from, and he, logically, leans toward them evolving from theropod dinosaurs. There is also a brief overview of the different ideas of how flight and feathers evolved and a basic overview of known, as of 2009, Mesozoic bird species.

If there is one fault in the book it is that it is too detailed. At times I felt like I was dredging through scientific papers, this is part of the reason it took me so long to finish, so if you aren't an expert in the field or haven't spent a lot of time reading scientific papers on dinosaur and bird evolution you might struggle a bit through parts. Most of the book is easily readable and the parts that are technical can be skipped or skimmed over without missing the overall point or theme of the section so don't let the technical nature scare you off. The price might scare you off but it is worth it for all the knowledge contained within.

The only other problem is that the book is dated which should say something about how fast the science has come since 2009. This is really that much of a problem after all how was Dr. Wellnhofer supposed to know that since I started reading the book early last year that phylogenetic studies would say that Archaeopteryx is not a bird (Naish et al., 2011; Xu et al. 2011), although at least one study disagrees (Lee & Worthy, 2011), that the color of the feathers would be determined (Carney et al., 2012), and that an even earlier feathered dinosaur would be discovered (Liu et al., 2012) (I got the e-mail about that last one as I was working on this review). So I will forgive the book seemingly being slightly dated since there are so many new specimens found in the paleontology world every year, there have been several new Mesozoic birds found in the past year (e.g. Xu et al., 2011).

This book is very interesting and worth picking up. It is a handy reference for the currently known specimens as well as about the evolution of birds in general. Oh and did I mention it has very awesome pictures, yeah they are very pretty. I will leave you, again, with a picture of the one specimen of Archaeopteryx that I have seen, the Thermopolis specimen, it was a great experience.


Book citation
Wellnhofer, P. 2009. Archaeopteryx: The Icon of Evolution. Verlag Dr. Friedrich Pfeil, Munchen, 208p.

References
Lee, M. S. Y., & T. H. Worthy. 2011. Likelihood reinstates Archaeopteryx as a primitive bird. Biology Letters doi: 10.1098/rsbl.2011.0884.

Liu, Y.-Q., Kuang, H.-W., Jiang, X.-J., Peng, N., Xu, H., & Sun, H.-Y. 2012. Timing of the earliest known feathered dinosaurs and transitional pterosaurs older than the Jehol Biota. Palaeogeography, Palaeoclimatology, Palaeoecology doi: 10.1016/j.palaeo.2012.01.017.

Naish, D., Dyke, G., Cau, A., Escuillié, F. & Godefroit, P. 2011. A gigantic bird from the Upper Cretaceous of Central Asia. Biology Letters doi: 10.1098/rsbl.2011.0683 (I should note that there is some doubt if this is actually a bird anymore but that shouldn't change the phylogentic tree published within)

Xu, X., You, H., Du, K. & Han, F. 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature 475, 465-470.

Book review page

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