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Shaking dinosaur hips and messing with their heads

by Piter Kehoma Boll

This week brought astonishing news regarding the phylogeny of dinosaurus, as you perhaps have heard or read. New anatomical evidences have completely rebuilt the basis of the dinosaur family tree and I’m here to explain a little bit of what happened.

As we all know, Dinosaurs include a great variety of beasts, from the meat-eating theropods to the long-necked sauropods and from the horned ceratopsians to the armored ankylosaurs, among many others.


Silhouette of a human compared to the largest known dinosaurs of each major group. Picture by Matt Martyniuk.*

For more than a century now, dinosaurus have been divided into two groups, called Ornithischia and Saurischia. Ornithischia (“bird-hipped”) includes dinosaurus whose pelvic bones are more similar to what is found in birds, with a pubis directed backward. Saurischia (“lizard-hipped”), on the other hand, have a pubis directed forward, as in reptiles in general. This grouped the theropods and the sauropods in the same group as Saurischia while other dinosaurus were grouped as Ornithischia. But birds are actually theropods, thus being lizard-hipped dinosaurus and not bird-hipped dinosaurus! Confusing, isn’t it? So let’s take a look at their hips:


Comparison of the hips of a crocodile (Crocodylus), a sauropod (Diplodocus), a non-avian theropod (Tyrannosaurus), a bird (Apteryx), a thyreophoran (Stegosaurus), and an ornithopod (Iguanodon). Red = pubis; Blue = ischium; Yellow = ilium. Picture by myself, Piter K. Boll.**

As you can see, the primitive state, found in crocodiles, sauropods and early theropods, is a pubis pointing forward. A backward-pointing pubis evolved at least twice independently, both in more advanced theropods (such as birds) and the ornithischian dinosaurus. But could we be so certain that Tyrannosaurus and Diplodocus are more closely related to each other (forming a clade Saurischia) just because of their hips? Afterall, this is a primitive hip, so it is very unlikely to be a synapomorphy (a shared derived character). Nevertheless, it continued to be used as a character uniting sauropods and theropods.

A new paper published by Nature this week, however, showed new evidences that point to a different relationship of the groups. After a detailed analysis of the bone anatomy, Matthew G. Baron, David B. Norman and Paul M. Barrett have found 20 characters that unite theropods with ornithischians and not with sauropods. Among those we can mention the presence of a foramen (a hole) at the anterior region of the premaxillary bone that is inside the narial fossa (the depression of the bone that surrounds the nostril’s opening) and a sharp longitudinal ridge along the maxilla.


The skulls of both ornithischians and theropods (above) show an anterior premaxillary foramen in the narial fossa (shown in yellow) and and a sharp ridge on the maxilla (shown in green), as well as other characters that are not present in sauropodomorphs and herrerasaurids (below). Composition using original pictures by Carol Abraczinskas and Paul C. Sereno (Heterodontosaurus), Wikimedia user Ghedoghedo (Eoraptor and Herrerasaurus), and flickr user philosophygeek (Plateosaurus).**

In his blog Tetrapod Zoology, Dr. Darren Naish comments the new classification and points out some problems that arise with this new view. One of them is the fact that both theropods and sauropodomorphs have pneumatic (hollow) bones, while ornithischians do not. If the new phylogeny is closer to the truth, that means that pneumacity evolved twice independently or evolved once and was lost in ornithischians.

He also mentions that both ornithischians and theropods had hair-like or quill-like structures on their skin. In theropods this eventually led to feathers. Could this be another synapomorphy uniting these groups? Maybe… but when we think that pterosaurs also had “hairs”, one could also conclude that a “hairy” integumentary structure was already presented in the common ancestor of dinosaurus. In this case, perhaps, we only had not found it yet on sauropods. Now imagine a giant Argentinosaurus covered with feathers!

One concern that appeared with this new organization is whether sauropodomorphs would still be considered dinosaurs. The term “dinosaur” was coined by Richard Owen in 1842 to refer to the remains of the three genera known at the time, Iguanodon, Hylaeosaurus and Megalosaurus, the first two being ornithischians and the latter a theropod. As a consequence, the original definition of dinosaur did not include sauropods. Similarly, the modern phylogenetic definition of dinosaur was “the least inclusive clade containing Passer domesticus (the house sparrow) and Triceratops horridus“. In order to allow Brachiosaurus and his friends to continue sitting  with the dinosaurs, Baron et al. suggested to expand the definition to include Diplodocus carnegii. So, dinosaurus would be the least inclusive clade containing P. domesticusT. horridus and D. carnegii.

In this new family tree, the name Saurischia would still be used, but to refer only to the sauropodomorphs and some primitive carnivores, the herrerasaurids. The new clade formed by uniting theropods and ornithischians was proposed to be called Ornithoscelida (“bird-legged”), a name coined in 1870 to refer to the bird-like hindlimbs of both theropods and ornithopods (the subgroup of ornithischians that includes dinosaurs such as Iguanodon and the duck-billed dinosaurs).

What can we conclude with all that? Nothing will change if you are just a dinosaur enthusiast and do not care about what’s an ornithischian and a saurischian. Now if you are a phylogeny fan, as I am, you are used to sudden changes in the branches. Most fossils of basal dinosaurs are incomplete, thus increasing the problem to know how they are related to each other. Perhaps this new view will last, perhaps new evidence will change all over again the next week.

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ResearchBlogging.orgReferences and further reading:

Baron, M., Norman, D., & Barrett, P. (2017). A new hypothesis of dinosaur relationships and early dinosaur evolution Nature, 543 (7646), 501-506 DOI: 10.1038/nature21700

Naish, D. (2017). Ornithoscelida Rises: A New Family Tree for DinosaursTetrapod Zoology.

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*Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

**Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.


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Filed under Evolution, Extinction, Paleontology, Systematics

Send in the Chickenosaurus! or: Why I do trust Jack Horner

By Carlos Augusto Chamarelli

Oh just look who decided to make an article. Things have been pretty slow on my side due to a lot of recent troubles, but I finally gathered enough willpower to post about something I’ve been meaning to write about: Jack Horner’s greatest ambition of creating dinosaurs.

Yes, that might be confusing/shocking for those who remember my previous statement that I’m against some of his theories (and contrary to my friends’ skepticism, I do intend in making more posts about them), but this time I’ll write about him in a positive light because even myself have to admit that I’m looking forward for the results of his experiment.

But first I’d like to point out how amusing and slightly hypocritical it is for Jack Horner try to recreate dinosaurs in the first place, since, you know, he was one of the advisors for the movie adaptations of Jurassic Park. Heck, he was the inspiration for the Alan Grant character. And if you remember well – looking past the astonishing CGI that puts Avatar to shame; and the book is not as good as some led me to believe – the moral of the entire thing was that reviving dinosaurs and making zoos with them is a bad thing.

Ok, that’s not true. The real moral of Jurassic Park is that you shouldn’t stiff a fat man you heavily (haw) rely upon.

Operation Genesis is an awesome game though. Screencap from Jurassic Park ,extracted from jurassicpark.wikia.com.

That aside, what Jack Horner is trying is actually a little different from the model of Michael Crichton’s novel, although his initial approach was just that. The plan was to extract real DNA from fossil material, in this case real bones, back when Mary Schweitzer (one of Horner’s students and lab scientists) developed a process that could retrieve living tissue out of dinosaur bones such as blood vessels, with the downside that the bone had to be destroyed. It worked spectacularly well in the sense that for the first time one could look at real, living tissues of an animal extinct for millions of years.

Unfortunately, it didn’t contain DNA. Maybe because the specimens in were kept stored for so long? So the next step was to create a mobile lab to make this same process in dinosaurs that were just dug up from the field.

Mary and a rather tiny-headed Horner in front of the mobile lab. Extracted from http://www.montana.edu.

Still, no intact DNA could be recovered, so they just concluded that it’s impossible for extinct DNA to survive for so long. In other words, we won’t be able to clone dinosaurs. Ever.

But I could say that maybe he was just being unlucky. I’m sure that if he tried it long enough he would eventually hit the jackpot and find the prized DNA, so he shouldn’t abandon the idea of the mobile lab so easily. Alas, his gaze is now directed at chickens.

Yes, chickens. Putting it bluntly, the theory is that you can make a dinosaur out of a chicken. More elaborately: since birds are living descendants of dinosaurs*, they still posses in their genes the code for saurian traits, but they are “dormant”; so if you could locate those genes and “turn them on”, you can make a bird (in this case, the chicken) grow clawed arms, teeth and a long tail. The resulting creature is, as named by Horner himself, a Chickenosaurus.

He might want to consider making the torso longer, bids are too compact. Extracted from thesavoia.com.

From what his TED lecture, concisely entitled “Building a dinosaur from a chicken”, was able to show, so far they managed to create chickens with teeth and a decently elongated tail, but in embryos only. And since the embryo has to be extracted from the egg in order to study their development… Well, no toothed or long-tailed chicken walking around just yet.

Anyway, I’m not here really to write about the process of creating the chickenosaurus itself – I’m, sure there are more insightful explanations elsewhere, or in Horner’s own book about the project “How to Build a Dinosaur”;  rather, its a contemplation and speculation of what it means if the Chickenosaurus succeeds to be created.

Most importantly: Why do that?

Both RSN and I agree he’s the most obnoxious character in the book. Screencap of Jurassic Park. Extracted from konaskorner.com.

Unfortunately, the answer can’t be a simple “because it’s awesome”, even if it indeed is.  With great technological advancement there’s the  fear it will eventually get out of hand and have disastrous consequences; genetic engineering isn’t anything new, but it certainly still raises a lot of questions about morality and criticisms against it, and the Chickenosaurus, bringing it to a whole new level, certainly raise those points up to the max. But humanity values tend to shift with time, after all there was once a time electronics where thought to be satanic machinations, so in the future our opinion on genetics could be more open-minded and less pessimistic and consider this paranoia a bit of laughable. But even in this scenario, there’s still the question “what for?”.

One could say it’s only natural for the advance of science, even if it’s something that can be regarded as unimportant for humanity immediate needs or completely useless, but in all fairness, it’s not like there were many discoveries out there that are far closer to imbecility. In comparison, the Chickenosaurus is just a mild example, because surely he won’t revert global warming or famine or unify Korea (allegedly), but that doesn’t mean it isn’t worth the investment. For all I know it could be the first step toward a much bigger discovery in the future.

Apparently, Horner himself is well aware of this problem: close to the end of his lecture he tries to justify what use his project could possibly have once done, which seemed to make him have a really hard time because the best he could come up with is that the Chickenosaurus would be “a great way to teach kids about evolutionary biology”. In my opinion, that’s a lame excuse, but that’s bound to happen when you try to rationalize something that is inherently cool. It just sounded very ineffective.

The other use Horner (humorously) exemplifies is that “Colonel Sanders could advertize another piece”. In a way, I can totally see people ordering Chickenosaurus, especially in, you know, Asia (no offense for our Asian readers). It could be one of those exotic dishes that people spend absurd amounts of money to taste, it just has that appropriated  level of crazy, but it’s worthy for them because, hey, they have the chance to eat a true dino!


…. Right?

But on the other hand, by the time chickenosaurus can be created in large scale, in vitro technology might as well have evolved enough to allow anyone eat meat without killing animals (also, please note I wish to avoid debates about that here, ok? Thanks).

Lest we forget, it would still taste like effing chicken…

But the way I see it, the Chickenosaurus has the potential of exploring a particular soft spot of humanity: pets.

You can simply say “oh, just get a dog then, or a cat… or a dog” since that’s about all the pets people I met have, but just name an animal, any wild animal. Chances are that whatever you chose is or was a pet for someone, even if it’s something DEFINITELY not meant to be kept as one.

Let me guess… Russia? Extracted from evilsushi.com.

Needless to say, sometimes things can go… Wrong. But hey, it’s not like that minor downside called “death” or “gruesome mauling” has stopped anyone of having animals like bears, lions, tigers, hyenas, crocodiles or even poisonous snakes as their companion.

But apart of these most extreme examples, there are other, less dangerous exotic animals more commonly (or not) kept as pets, ranging from the now widely known hedgehog to things I would never guess people would keep as pets, like capybaras. With the proper documentation (and depending of the country where you live), you might have about any kind of animal as long you are sure of the commitment and do so legally. I say that because, unfortunately, animal trafficking is still a major issue in this respect.

In other words, people anywhere seem to have a need for pets, usually the more exotic the best, especially for bragging rights. Can you imagine the frenzy allowing Chickenosaurus to be sold as pets would create?

Robots just aren’t futuristic enough anymore. Extracted from science.howstuffworks.com

Truth is, genetic engineered pets are anything but new, the GloFish being the most iconic example, which is also banned in certain countries, though I really fail to see how a fish that glows in the dark could present any kind of danger. It does, whoever, proves that there is place for a mutant chicken in pet stores if they have the guts to try.

In a way, the Chickenosaurus would make a darn good pet, and not because of his dinosaur appeal, but of its advantage of coming from animals that already prone to be kept as pets. It’s already a growing trend even in big cities to keep chickens as pets as long you have enough space (and a diaper. And yes, that’s a real thing). Although it’s impossible to say for certain what kind of change in behavior the tail, arms or teeth might bring, rest assured that you won’t be the victim of a sci-fi terror movie plot where the cuddly dinopets suddenly turn violent and kills their owner (but I have to admit I would love a movie like this).

Which brings us to another important point: what if the owner (for whatever out-of-world reason) decides he no longer wants his pet dinosaur?

Once again, you won’t fall victim of the sci-fi terror movie plot, since chances are that even if you abandon them in the wild – which is in no way advisable to do with any pet, but some people just don’t care… – they’ll act like normal feral chickens, which, despite what the name might suggest, probably aren’t prone to leap at you and slash your throat, nor they are prone to be responsible for a disastrous environmental impact.

But another question arises: would it stop there?

If you can revert a chicken, so what about other animals?

Somewhere in the world there’s a girl who said “gosh I’d surely like a dog that’s also a purse; gives the word ‘pack animal’ a whole new meaning”. Pet Store, by Alexis Rockman. Extracter from http://www.spiritofspider.com/

By following logic, if birds can be reverted to dinosaurs by turning on “dormant” genes, then maybe the same is true to any other animal, perhaps even humans.

Wait, let me rephrase that: if birds have dormant ancestral characteristics, then so should every other animal. Not that I’m expecting anyone to do that in humans, at the risk of becoming the prequel for Man After Man. Nevertheless, it’s probably not going to happen anytime sooner than the Chickenosaurus, as doing so requires the genome to be sequenced, which not a lot of vertebrates have been; one of the reasons the chicken is the prime choice for Horner’s experiment (other than being readily available).

At some point in the future, strange manners of “de-evolved” genetically altered pets from more familiar stocks might pop up, but they are comparatively a very long way compared to the Chickenosaurus.

Of course, some people just can’t wait that much for their own freak of nature. Extracted from metro.co.uk

Somewhat more plausible to happen (and less deranged) would be the creation of different breeds of Chickenosaurus. It’s the same principle when mass-produced popular cars first appeared, with its wide variety of black colors. The Chickenosaurus will probably come from poultry stock whose feather coat is either brown or white, at first that won’t matter because of “golly! A real dinosaur for pet!”, but soon enough some will start to say “that’s nice, but can I have one bigger? Smaller? Green? Rainbow colored?”.

Just look at the vast list dog breeds for example: they range greatly from size, shape and fur pattern, all of them created by selective breeding. Depending of the breed, it took could take anywhere from a few decades to several hundred or more years to create them. Older breeds were created for working, such as hunting or herding, so these tend to be bigger and stronger or with the physical build of a runner, whereas more recent breeds were created just for show, being smaller and favoring a “cute” appearance.

What I mean is, despite their origins, some people feel that a certain breed of dog is more appealing than others, so it won’t be a surprise if there’s a demand for variety in the Chickenosaurus.

“The tiny one is obviously the baby”, says the future alien paleontologist. Extracted from economydogcare.com.

But fortunately for those who wish for a different kind of Chickenosaurus, they won’t need to wait thousands of years to receive their whatever-color-and-shape Chickenosaurus they want. We can’t be sure if selective breeding will be an option for them because we have no idea if they would be able to mate naturally in the first place (another reason it’s hard to imagine it would create an environmental disaster), but genetics could also provide a faster way to make those cosmetic alterations, but they might no be an immediate addition since A) the first time the Chickenosaurus becomes available he’ll be crazy expensive, and B) it will take some time to locate the genes responsible for them.

And then there would be those who still have a soft spot for dinosaurs with scales (such as myself), who would love to have a reptilian Chickenosaurus. It seems that no matter how much our understanding of dinosaurs increase and no matter how fluffy they get, dinosaurs with scales still hold a place in everyone’s hearts. It would be one gene-switching-on anyways.

A walk in the park. Picture by Rafael Silva do Nascimento.

So these are my thoughts in the possible future of Jack Horner’s Chickenosaurus; I have no idea if it sounds biased or overly ideal, because it’s hard to not be excited and really hard to sound serious when talking about chickens, and we can’t rule out the logic conclusion of certain things. I do hope Horner manage to successfully conclude his project; call me delusional all you want, but I’d rather live in a world where chickens can become dinosaurs than live in one where exploding them is considered art (I really wish I was making this up).

Thanks for reading!

* Just pretend you know that when I say “dinosaur” I’m referring to the extinct species and “birds” the modern ones.

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References & Further Reading:

TEDxVancouver – Jack Horner – Building a dinosaur from a chicken. 2009. Available on-line in: <http://www.youtube.com/watch?v=0QVXdEOiCw8&gt;.Acess on December 5, 2011.

DNA from T-Rex – Soft Tissue from Fossil?. Unknown year. Available on-line in: <http://www.youtube.com/watch?v=DB69zCwbBPY&gt;. Acess December 5, 2011.

Wired – How to Hatch a Dinosaur.2011. Avalable on-line in: http://www.wired.com/magazine/2011/09/ff_chickensaurus/all/1

LabSpaces – Dinosaur diggers bring mobile lab, new techniques to Eastern Montana. 2008. Available on-line in: http://www.labspaces.net/6484/Dinosaur_diggers_bring_mobile_lab__new_techniques_to_Eastern_Montana


Filed under Evolution, Paleontology