Wherefore Art Thou, PaleoArtist?

Duria Antiquior, By Henry De le Beche

As long as there has been paleontology (or maybe longer), there have been artistic interpretations. Naturally, these have evolved with our knowledge of the creatures of the past.

Actually, artistic depictions are a great way to trace our understanding of various creatures. On that note, one example stands out.

First up, Iguanodon, first discovered in 1822. We can use various works of art to trace the progression of not only our understanding of Iguanodon, but also the progression of our understanding of Paleontology in general. early depictions of Iguanodon were basically Iguanas blown up to massive proportions. Here is a set of statues that stand today on Sydenham Hill, but were commissioned for the Crystal Palace, and unveiled in 1854.

by Benjamin Waterhouse Hawkins

Moving Forward to the 1895, we can see that a great deal has changed in the depiction of Iguanodon. In this depiction, it is far more upright, and less Iguana-like.

by Alice B. Woodward

Now we'll jump forward about sixty years, and see how far we've come. Iguanodon is more refined than before, and the anatomy is understood better.

by Neave Parker

Now we'll move to a recent picture. Look at the huge difference from the early depictions!

by Chris Srnka and Jeff Poling

So let this be a lesson to PaleoArtists, myself included. Don't get too attached to the current "incarnation" of any dinosaur!

Announcing... Avian Evolution!

www.cafepress.com/trilobite

Hey Fossil Fans,

I actually meant to add this to the end of Part 3 of the avian evolution series, but I couldn't bear to make the post even longer. The idea for this one came while writing the series, and is based partly on the famous human evolution design. But you'll notice that the dinosaurs seem pretty keen on squabbling with each other. In fact, the little bird at the end seems a little ticked off about the whole thing, and is averting his eyes. Check out the design at Trilobite Clothing.

Ostrom, Deinonychus, and the Dinosaurs of Yixian (Part 3 of 3)

Even if you despise science, and hate palaeontology with special fervour, you have probably noticed that these days, pretty much everyone accepts that birds descended from dinosaurs. You may have also noticed that a large number of theropods are now regularly depicted with feathers. You probably looked at your calendar realized that it wasn’t April Fools Day, and wondered what was going on. How did this epiphany come about?

In the last post, I went over the Thecodont hypothesis, its inherent weakness as a scientific theory, and its wide and unquestioned acceptance. Well, in science, the status quo is never safe forever. Enter John H. Ostrom.

Ostrom was a paleontologist working at Yale University. In 1969, he published a groundbreaking description of Deinonychus antirrhopus (Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana ), a Cretaceous dromeosaur first discovered in Montana in 1931. In Osteology of Deinonychus, Ostrom noted 22 similarities between Deinonychus and Archaeopteryx, the “first bird.” This served to re-ignite the debate on bird origins, and Ostrom followed up his work with several more publications during the 1970’s, culminating in another major work in 1976 (Archaeopteryx and the origin of birds).

There were other theories emerging at the same time to challenge Ostrom’s hypothesis. In 1972, Alick Walker, published an article proposing the crocodylomorph hypothesis (New light on the origin of birds and crocodiles) , connecting birds with Crocodylomorphs, a group of crocodiles and reptiles closely related to them. However, Walker was only ever able to find 15-20 similarities between Crocodylomorphs and birds, compared to an eventual 70 or more similarities with theropod dinosaurs.

The road to acceptance of the newly re-emerging theory of bird origins proved to be rocky. In 1985, Astronomer Sir Fred Hoyle claimed that the discovery of Archaeopteryx in Germany had actually been an elaborate hoax, with feathers having been imprinted in the rock around real reptilian skeletons after their discovery. However, further discoveries and testing of the Berlin and London specimens proved Hoyle’s claim groundless.

The floodgates having been opened, research into the connection between birds and dinosaurs began. In 1986, Jacques Gauthier, a curator of the Peabody museum at Yale, published a detailed cladistic analysis of theropod dinosaurs. His results upheld John Ostrom’s earlier work. He concluded that, while crocodiles were the closest living relative of birds, extinct theropod dinosaurs were, in fact, much more closely related. This helped sink Alick Walker’s Crocodylomorph hypothesis.

Although evidence for the bird dinosaur link was mounting, it was not until the mid to late 1990’s that acceptance of the hypothesis became widespread in the public. In 1996, rumours began to spread about a dinosaur named sinosauropteryx, discovered in the Yixian fossil formation, in northeastern China. Then, at the 1996 meeting of Vertebrate Palaeontologists at the American Museum of Natural History, the secret was revealed.

Sinosauropteryx wasn’t actually on the agenda, but Phil Currie, then of the Royal Tyrell Museum in Drumheller Alberta, had brought pictures. The palaeontology community was on fire. In 1998, Ji Qiang, Phil Currie, Mark Norrell and Ji Shu-An published their findings in Two feathered dinosaurs from northeastern China. Phil Currie called the China finds “the most important dinosaur discovery of this century," and continued, "the credibility of the dinosaur-to-birds theory takes a gigantic leap ahead with these specimens."

As the flow of new specimens from Yixian continued, other research further reinforced the dinosaur-bird connection. In 1999, a group of researchers published a paper (Beta-keratin specific immunological reactivity in feather-like structures of the Cretaceous Alvarezsaurid, Shuvuuia deserti) announcing that, through chemical analysis, they had determined that the feather-like structures on Shuvuuia deserti, a Cretaceous theropod, were similar in composition to the feathers of modern birds. They had found the decay products of the protein Beta-Keratin, a major component of modern feathers, in the fossilized feathers of Shuvuuia deserti. Further strengthening the find was the lack of Alpha-Keratin, found in reptile skin, but not in the feathers of modern birds.

In 2005, Mary Higby Schweitzer of North Carolina State University announced that she and her team had recovered preserved soft tissue from the femur of a Tyrannosaurus recovered from the Hell Creek formation in Montana. In 2007 Schweitzer‘s team announced that they had sequenced a protein from the soft tissue. Analysis showed that it most closely resembled chicken collagen, followed by proteins found in frogs and newts. The team also found medullary tissue, grown inside the bones of female birds as a source of calcium for eggshell production.

The theory that birds are descended from theropod dinosaurs is now widely accepted in the world of palaeontology. That isn’t to say that there is no dissent. Alan Feduccia, a paleornithologist from the University of North Carolina. Feduccia claims that birds and theropods evolved from the same, common ancestor. One particular element of dinosaur-bird evolution he is critical of is the ground-up development of flight.

However, let us reflect back for a moment on the evidence we have seem supporting the hypothesis. The inherent similarities between birds and theropods are backed up by a growing mountain of physical and chemical evidence. The debate on bird origins is not really over, but perhaps somewhere, a fat lady is warming up for an upcoming performance.

This is part two of a three part series on the history of research into the link between birds and theropod dinosaurs. This is by far the longest section, dealing with the re-emergence of the theropod origin hypothesis.

Sources:

Dino-Birds - The Evolution of Birds from Dinosaurs - http://www.surfbirds.com/mb/Features/dinosaurs/dino-birds-arch.html
Yale Bulletin - http://www.yale.edu/opa/v32.n16/story5.html
The origin and evolution of birds - http://www.geologyrocks.co.uk/tutorials/origin_and_early_evolution_birds
Wikipedia: Tyrannosaurus - http://en.wikipedia.org/wiki/Tyrannosaurus#_note-3
Wikipedia: Alick Walker - http://en.wikipedia.org/wiki/Alick_Walker
The Life of Birds - http://www.pbs.org/lifeofbirds/evolution/index.html
Welcome to Dinotopia - http://technology.newscientist.com/article/mg18625001.900
NYT: Reptiles’ Link to Birds May be Settled - http://query.nytimes.com/gst/fullpage.html?res=940DE1D9163DF937A15755C0A96E948260&sec=&spon=&pagewanted=1
Wikipedia: Jacques Gauthier - http://en.wikipedia.org/wiki/Jacques_Gauthier#_note-1
T.Rex Soft Tissue Preserved - http://news.nationalgeographic.com/news/2005/03/0324_050324_trexsofttissue.html
Review of Ostrom’s Studies of Archaeopteryx - http://elibrary.unm.edu/sora/Wilson/v089n03/p0488-p0492.pdf
Wikipedia: Shuvuuia - http://en.wikipedia.org/wiki/Shuvuuia_deserti#_note-schweitzer1999
Wikipedia: Feathered Dinosaurs - http://en.wikipedia.org/wiki/Feathered_dinosaurs
Did Birds Evolve from Dinosaurs? - http://8e.devbio.com/article.php?ch=16&id=161
John H. Ostrom, Influential Paleontologist, Is Dead at 77 - http://www.nytimes.com/2005/07/21/nyregion/21OSTROM.html
EvoWiki: J. Alan Feduccia - http://wiki.cotch.net/index.php/Alan_Feduccia

Dinosaurs Aren’t Birds, Clavicles Don't Lie! (Part 2 of 3)

Even if you despise science, and hate palaeontology with special fervour, you have probably noticed that these days, pretty much everyone accepts that birds descended from dinosaurs. You may have also noticed that a large number of theropods are now regularly depicted with feathers. You probably looked at your calendar realized that it wasn’t April Fools Day, and wondered what was going on. How did this epiphany come about?

We ended part one with Thomas Huxley crushing Richard Owen’s reputation, and riding high with his cohorts on a wave of dinosaur-bird theories. However, trouble was appearing on the horizon, in the form of Gerhard Heilmann, a Danish doctor-turned-artist-turned-palaeontologist.


Heilmann became interested in birds, and between 1913 and 1916, published a series of articles on the evolution of birds in Dansk Ornitologisk Forenings Tidskrift (Journal of the Danish Ornithological Society). These were collected, and Vor Nuværende Viden om Fuglenes Afstamning was published in 1916. In 1926, an English version was published, under the name Origin of Birds.

Heilmann agreed with earlier work that demonstrated striking similarities between theropods and modern birds, but threw the proverbial wrench into the works. He asserted (incorrectly), that theropods did not have clavicles, the bones that fuse together in birds to form the wishbone. Since earlier reptiles had possessed clavicles, Heilmann assumed that theropods had lost them through evolution, and, according to Dollo’s Law, would not be able to re-evolve them.

Therefore, he concluded, birds must have evolved from earlier reptiles. He declared them descendants of Thecodont reptiles, a “Wastebasket Taxon” that existed mainly for reptiles that didn’t fit neatly into any of the categories palaeontologists had established. For Heilmann, it was clavicles or bust. The number of striking similarities between birds and theropods were chalked up to evolutionary convergence.

Scientists loved Heilmann’s work. It was detailed, and methodical. The hypothesis laid out in Origin of Birds formed the basis of the next five decades of thought on the origin of birds. This period was apparently not the height of scientific thought. For instance, the discovery in 1936 of clavicles on Segisaurus, a theropod, didn’t put a dent in the Thecodont hypothesis.

In fact, no compelling evidence existed for the Thecodont hypothesis, but it was very difficult to disprove, because of the nature of the Thecodont group. Because it is a “Wastebasket Taxon,” its members are not bound together by a set of similarities, but simply by the fact that they don’t fit into any other group. Therefore, there are no reasonable criteria to use in comparing modern birds and Thecondonts.

This made the Thecodont hypothesis a good fallback as soon as any doubts were raised about a different, more testable, theory. It was a very safe position to have, and for almost fifty years, palaeontologists largely stuck with it.

This is part two of a three part series on the history of research into the link between birds and theropod dinosaurs. Part three will be posted tomorrow.

Sources:

Wikipedia: Dollo’s Law - http://en.wikipedia.org/wiki/Dollo's_law
Dino-Bird Relationships - http://www.ucmp.berkeley.edu/diapsids/avians.html
The Origin and Early Evolution of Birds - http://www.ucmp.berkeley.edu/diapsids/avians.html
Wikipedia: Thecodont - http://en.wikipedia.org/wiki/Thecodont

Good Gracious, My Meal is a Theropod! (Part 1 of 3)

Even if you despise science, and hate palaeontology with special fervour, you have probably noticed that these days, pretty much everyone accepts that birds descended from dinosaurs. You may have also noticed that a large number of theropods are now regularly depicted with feathers. You probably looked at your calendar realized that it wasn’t April Fools Day, and wondered what was going on. How did this epiphany come about?

Our story starts very close to Darwin, as these stories have a nasty habit of doing. It starts with Thomas Huxley, Darwin’s famous “Bulldog,” who, after a long day of puzzling over a strange dinosaur bone (located under the tibia), went home to a dinner of tender, delectable quail.

Take a moment to imagine his shock when he noticed that his repast had the same, strange bone underneath the tibia as the dinosaur he’d been studying, which turned out to be the anklebone. Huxley then theorized that birds descended from dinosaurs.

It is a great story, but like most great stories, it probably isn’t true. Archaeopteryx, the famous “first bird,” was discovered in 1861, and was immediately suspected to be a link between birds and dinosaurs. However, it was purchased in 1862 by the British Museum of Natural History. Richard Owen, superintendent of the museum, and fervent opponent of evolution, was keen to get his hands on it and put his own, anti-Darwinist spin on the find. He concluded it was simply an “ancient, long-tailed bird.”

Thomas Huxley, however, wasn’t convinced. Between 1862 and 1867, he researched living birds, and published, in 1867, a complete reclassification of birds, which alleged a reptile-bird link (On the Classification of Birds; and on the Taxonomic Value of the Modifications of Certain of the Cranial Bones Observable in That Class). We don’t know when (or if) the “quail” incident actually happened. But, it’s nice to think that the lowly quail had at least something to do with it.

What is clear is that, later on in 1867, Huxley was shown the misidentified hip bone of a Megalosaurus, and, upon correctly placing it, was struck by its similarities with living birds that he had studied. Any doubt about the tenuous connections he had drawn in On the Classification of Birds was washed away.

In 1868 Huxley gave a lecture at the Royal Institution about archaeopteryx. In a single talk, he demonstrated the link between dinosaurs and birds, and tore Richard Owen’s “ancient bird” theory to shreds.

It should be noted that Huxley was not alone in supporting this theory. Othniel Marsh, of Bone Wars fame, was also an early proponent of the dinosaur-bird connection. Marsh also was one of the earliest American intellectuals to adopt the theory of evolution. In fact, Marsh and Huxley were quite close and in writing an obituary of Huxley, Marsh described him as “a guide, philosopher, and friend.” Another supporter was Franz Nopcsa von Felső-Szilvás, an Albanian Baron and palaeontologist.

This is part one of a three part series on the history of research into the link between birds and theropod dinosaurs. Look for parts two and three, to be posted tomorrow and the day after.

Sources:

Wikipedia: Franz Nopcsa - http://en.wikipedia.org/wiki/Franz_Nopcsa_von_Fels%C5%91-Szilv%C3%A1s
Wikipedia: Origin of Birds - http://en.wikipedia.org/wiki/Origin_of_birds
Huxley’s Bibliography - http://aleph0.clarku.edu/huxley/bib1.html
Dinosaurs and Birds - http://www.abc.net.au/science/slab/dinobird/story.htm
Dino-Birds - The Evolution of Birds from Dinosaurs - http://www.surfbirds.com/mb/Features/dinosaurs/dino-birds-arch.html
Wikipedia: Thomas Huxley - http://www.surfbirds.com/mb/Features/dinosaurs/dino-birds-arch.html
Wikipedia: Othniel Marsh - http://en.wikipedia.org/wiki/Othniel_Marsh

Deus Ex... What?

After careful study of the ending of the original (and arguably the only good) Jurassic Park movie, I have decided that slapping it on the wrist by labelling it an obvious Deus Ex Machina is simply not enough. That velociraptor is in the air, when the massive T.Rex snatches it cleanly in mid-flight. Where the lumbering beast came from we aren't sure. I guess without glasses of water handy, nobody can feel its approach.

Anyways, I pronounce this scene a Deus Ex Tyrannosaur, which I think better describes the situation. As a general rule, in reality, T.Rexs don't appear inside buildings to snatch velociraptors mid leap, saving the heroes.

Needless to say though, it makes for compelling entertainment.

Trilobites and Me...

Hey Fossil Fans,

For those of you who are perhaps not as enamoured with trilobites as I am, it may seem odd that I run a blog and a clothing store about a creature that went extinct several million years ago. Well, I think it's really several things.

The first thing to understand is that I'm a paleontology nut in general, and I have been since a very young age. A lot of your probably wanted to be a movie star, or an astronaut, or something like that when you were young. For me, the first career I ever wanted was paleontology. Ironically, that's not really were I'm headed in life, but the fascination has remained.

So I'm a fossil nut in general, but what got me zoomed in on trilobites? Well, a few things. I had started Trilobite Clothing before I became really interested in Trilobites. I was checking out the features of Cafepress.com, and I needed a logo and a name for my store. I have absolutely no memory of why I chose the trilobite as my mascot. I'd always thought trilobites were cool, but maybe it was a deep subconcious longing that lead me to the name Trilobite Clothing.

Anyways, after setting up a free Cafepress store, I abandoned it for over a year, as I simplyy couldn't get my head around the marketing of it. Anyways, during the summer of 2007, I visited the Royal Tyrrel Museum in Drumheller Alberta. Everything in the Museum is stunning, but the most impressive thing I saw was a new display of stunning trilobite specimens, mainly from Morocco. This really got me interested, and as I evolved quickly into a rabid trilobite fan, I remembered my old store, Trilobite Clothing, just sitting there, ready to go.

The rest, as they say, is history.

Just as a note though, I marvel quite frequently at the level to which my love of trilobites is connected to my store. Running the store keeps me connected with like-minded people, and up on the latest news. You wouldn't really think that a business would define a person so much, but in my case, it has.

Long live the Trilobite!