Tag Archives: dinosaurs

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.

– – –

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.

– – –

*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.

Leave a comment

Filed under Evolution, Extinction, Paleontology, Systematics

New Species: September 11 to 20

by Piter Kehoma Boll

Here is a list of species described from September 11 to September 20. It certainly does not include all described species. Most information comes from the journals Mycokeys, Phytokeys, Zookeys, Phytotaxa, Zootaxa, International Journal of Systematic and Evolutionary Microbiology, and Systematic and Applied Microbiology, as well as journals restricted to certain taxa.


Petrolisthes paulayi is a new crab described in the past 10 days.














Cartilaginous fishes

Ray-finned fishes




Leave a comment

Filed under Systematics, taxonomy

Review: The Paleoart of Julius Csotonyi

By Carlos Augusto Chamarelli

Hi everybody! PK here and it’s book-reviewing time! As you probably know by now, Titan Books has released another tome of paleoart earlier this year in May 20, and once again Earthling Nature was offered a chance to get a copy and review it for everyone’s delight. What happened, however, is that the timing was a much unfortunate one with the World Cup messing absolutely everything in Rio, so I haven’t actually received my copy yet (at the time of this writing), but I did receive things that were posted in May these days, so I’m still hopeful.

Fortunately, I have a PDF version which I could read while waiting, so my impressions written here are based on that; it just means I can’t praise the paper and illustration quality and such as much as I did previously, but bear with me anyways.

Dinosaur attacks are mandatory for paleoart covers.

Dinosaur attacks are mandatory for paleoart covers.

The new book in question, entitled The Paleoart of Julius Csotonyi, is a little reminiscent of Titan’s previous book on paleoart, Dinosaur Art – The World’s Greatest Paleoart, released in 2012 (and which you can view our critique right here), the difference being that instead of being a collection of works from 10 paleoartists, this time it focuses solely on the art – and some biography – of one of them: the Hungarian-born, Canadian-raised artist Julius Csotonyi. You know, like it’s said in the title.

I’ll start right off the bat saying that Csotonyi’s work is much impressive and definitely was one of the highlights of Dinosaur Art, so I think he is indeed one of the prime choices for a book solely focused on his work, and the text also provide interesting insights on these works as well as rather inspirational accounts of his rise to paleoartistic success. I mean, creating dinosaur murals for a museum? That’s some paleoart-nirvana right there.

Also, this picture. Nothing else needs to be said.

Also, this picture. Nothing else needs to be said.

Like Dinosaur Art, the book is full with beautiful artworks depicting prehistoric life from many time periods, some small and some spreading though pages as they should be to enjoy the details, plus there are examples of the usual start in childhood at dinosaur drawing in the beginning of it all, but what caught my attention the most was the presence of step-by-step pictures, showing the process of making a bunch of confusing lines like those of sketches become the saurian-masterpiece everyone loves. For those unfamiliar with Csotonyi ‘s style, he uses mostly digital tools, like a good modern paleoartist usually does; sometimes he uses brushes for a more traditional look, sometimes photomanipulation to achieve more realism, but the resulting picture always have that particular look and can be instantly recognized.

Mostly the reconstructed creatures possess striking patterns, but not striking colors; that, to me, is a key difference when dealing with realism with dinosaurs, and usually the more an artist make huge dinosaur colorful the less I’m inclined to judge their work as a reliable window to prehistoric life*. In this respect, Csotonyi achieves a good balance in the tone of colors, so the animals are neither boring nor garish to behold. The scenes depicted throughout the book vary, with some in the school of “dramatic prehistoric conflict”, others are more neutral and peaceful, and there are some which are anatomy and bones studies, so there’s something for every taste. It’s also worth noting that Csotonyi actually revisits older pictures and update their looks, as it was the case of the Anchiornis, which is important as depictions of dinosaurs will invariably change,and editing then as such is a good manner to make your picture still relevant.

Reenactment of Jaws Included.

Reenactment of Jaws Included.

I do have one or two points that I personally have mixed feelings about : the pictures where he uses actual photos for the landscape aren’t as good as those where he actually makes the scenery, and I understand it’s easier to do that than making the entire scene, but in some of these cases the shadows of the animals get a little in the eye, and it looks too much like the creature was in fact inserted into the scene rather than being part of it. On another point, some of the skins used in the photo manipulations can be a little jarring; the Edaphosaurus with a tuatara’s scaly skin and face being a good example of this. Then again, those can be regarded as very minor points as they don’t detract of the overall quality, so I’m not one bit bothered, and neither should you, as the book remains a incredible piece.

"Alright, alright! You can keep it! Geez."

“Alright, alright! You can keep it! Geez.”

In closing thoughts, The Paleoart of Julius Csotonyi is yet another excellent book for everyone interested in dinosaurs and prehistoric life, depicted here in an evocative but not in a “dinosaurs are monsters” light, and it’s definitely worth checking. I promise that when (if) I get my copy I’ll update this review. Also, you can click here to go to his website give him a good ol’ Iguanodon thumbs-up.


*And don’t give me the “oh, but birds are dinosaurs, and they’re colorful, so dinosaurs must have been ALL colorful!” BS. It’s just embarrassing.

1 Comment

Filed under Paleoart, Paleontology, Reviews

Earthling Bulletin #17

by Piter Kehoma Boll

Skull of Jianchangosaurus yixianensis, a new therizinosaur from China with an unusual dentition. Photo extracted from Pu et al. 2013. doi:10.1371/journal.pone.0063423.g003

Skull of Jianchangosaurus yixianensis, a new therizinosaur from China with an unusual dentition. Photo extracted from Pu et al. 2013. doi:10.1371/journal.pone.0063423.g003




Scientific Articles

Leave a comment

Filed under Bulletins

Earthling Bulletin #12

by Piter Kehoma Boll and Rafael Nascimento

The new venomous primate species Nycticebus kayan. Photo by Chi'en C. Lee. Extracted from .wildborneo.com.my

The new venomous primate species Nycticebus kayan. Photo by Chi’en C. Lee. Extracted from wildborneo.com.my




Scientific Articles

1 Comment

Filed under Bulletins

The Dos and Don’ts of the Aspiring Paleoartist – part 2

By Carlos Augusto Chamarelli

Hi everybody, it’s me again with some more paleoartistic tips mixed with ranting since the first one was quite well received by our readers. Long overdue, as usual. Last time we saw examples of plagiarism and why it’s bad to do it, emaciated reconstructions by taking skeleton references too literal and the perils of overloading details.

Actually, before we move on to new tips I’d like to elaborate a bit more on the skeleton reference topic since I felt I didn’t talk enough about it. After all it is a vital part of paleoart since without them we’d be still stuck with draconian monsters (or worse: creationism) so it deserves to be further discussed. So let me put it right off the bat, short and simple: skeletons are a good way to know about the creature, but they’re a terrible way to know what the creature looks like.

Sure they allow us to know their overall size and shape, but they can only reveal so much on their own because skeletons hardly resemble the animal they’re supposed to be on the outside.

If that’s how nature worked, we would’ve have to rename our planet as “Hell”. Various “GSP style” cenozoic animals, pictures by TheMacronian (Cat & Horse), yoult (chicken) and nemo-ramjet (human).

Don’t get me wrong, I’m not being unfair because we know what these  animals look like in real life, while dinosaurs and other prehistoric animals, not. The path of reconstructing things we only have bones to work with is a rocky one and involves a lot of guessing, true, but what the heck, I think we can afford to have better guesses than just add skin over bones and call it a day.

I know those pictures are actually intended to be just humorous, but they also remind us of how far off we probably are of knowing what dinosaurs truly looked like. Trust me on this one: in the future, as out knowledge on dinosaurs advance,  many of the pictures we love to label as accurate will join the ranks of laughably outdated reconstructions.

In the meantime we might as well try and improve it the best we can, so let’s move on to the tips properly, such as…

– Slit pupils are Okay!

Long ago you’d see many pictures where dinosaurs had eyes with slit pupils, a feature that’s easily identifiable as a reptilian characteristic. Of course, that was before the feathered dinosaur revolution came into scene and their relationship with birds was settled for good; the slit-pupil eyes gradually fell in favor to the round-pupil eyes of the likes of birds. Nowadays it’s considerably harder to find pictures of slit-pupil dinosaurs, even if there’s no good reason to think they didn’t had them.

It’s understandable that some like to hint the close relationship with birds by making all dinosaurs – specially feathered ones- have round pupils but first you have to consider that slit pupils aren’t exclusive to reptiles: fishes, amphibians, even some mammals, like that one obscure creature the internet knows nothing about, identified only as “cat”, have them.

As demonstrated by Branquinho. Picture by me.

But then again, we’re talking about dinosaurs here; are there any birds with slit pupils?

If you asked sometime ago I would have to answer “no” because I did search about it and couldn’t find anything at all. Because of that this rather minor tip was left out of the previous one. Then I re-searched and again nothing turned up, which made me think that maybe it was because slit pupils were somehow unsuitable for flight; either that or we are unfortunate to live in an epoch where no birds with such eyes exist.

But later I re-researched and I found out that indeed there’s one particular bird with slit pupils. It’s  the black skimmer (Rynchops niger) from the Americas.

It also has the standard sea bird colors. Extracted from bird-friends.com

Unfortunately for us the skimmer has very dark brown irises, which make it mighty difficult to see the slit pupils, but there are a few pictures over the internet where you can make out the details. Not only it proves that slit pupils aren’t a handicap for flying, birds aren’t an exception either:

Have you also noticed how hard it is to see dinosaur with brown eyes? Picture (cropped) by Dan Pancamo, extracted from wikipedia.org

In other words, you definitely shouldn’t be shy to make some of your dinosaurs have slit pupils when making dinosaur pictures for fearing it makes them somehow “inaccurate”. If anything, not giving some slit pupils is the inaccuracy.

– Movement does not equal to quality!

As much as the Dinosaur Renascence was a great breakthrough in our understanding of dinosaurs, even I have to recognize it also brought a lot of annoying trends. One in particular is the emphasis in movement.

Sorry, let me rephrase this: the extreme emphasis in extreme movement.

If you ever had the chance to see Bakker’s book “The Dinosaur Heresies”, the bible of the dinosaur renascence, you’ll know what I mean. The dinosaurs pictured have very dynamic poses, so dynamic in fact that they probably need a string attached to the ground so they don’t jump out of orbit.

Even the predator is confused by what the Psittacosaurus in the middle is doing. Picture by Robert Bakker, extracted from his book, The Dinosaur Heresies.

It wasn’t so bad at the time of its release; it was fresh and mind-blowing, but after years of nothing but marathonist dinosaurs, it kind of lost the appeal. It really did. I’m also not so sure if it can be taken as accurate, such as the galloping Chasmosaurus previously seen, and I do intend in talking about this in a later post.

Anyway, what I’m saying is that, while I understand it’s exciting to make and see dinosaurs as dynamic as possible, we’re not in the Brontosaurus Age anymore, or the nineties, we don’t need to prove anything. We already know dinosaurs weren’t lethargic, and we’re moving on to a new vision on these creatures. Making them appear running at 300 km/h with their jaws wide open all the time does as much harm for their image as the spiked and skinny reconstructions I pointed out last time.

The problem it seems is that dinosaurs to this day are labeled as “monsters”, so their actions need to be shown in an over-the-top fashion to highlight their monstrous monstrosity, thus perpetrating their monster status, and people accept this kind of image. As a consequence we often see dinosaur-centered documentaries that prefer to focus solely on the violence that such monstrous monsters provide, sometimes at the expense of accuracy. I swear I couldn’t bear to watch one episode of Jurassic Fight Club for the word “killer” was repeated incessantly in a span of less than 5 minutes.

Science is optional. Picture by “Jed”, extracted from earlsetchingemporium.blogspot

This reminds me of a conversation RSN had with his friend Rafael Albo (and I hope he’s okay with his mention here) about this issue, in which he said something along the lines of “well if a magazine like National Geographic were to show pictures of lions they definitely would prefer to show them fighting rather than sleeping”. Except that’s not necessarily true: a quick search for lion pictures by NG (or anyone else, really) will reveal that the majority of them are the animals being playful or resting. In other words, acting like real living things would.

“This KILLER is a heartless KILLER who likes to KILL his KILLS with KILLING efficience! KILL KILLING KILLER KILL!” Picture by National Geographic, extracted from animals.nationalgeographic.com

Amazingly, dinosaurs too had their moments of relaxation, playfulness, even (preposterous!) boredom. Modern paleoartists (and as consequence, their audience) should divorce dinosaurs of their image as monstrous beasts in a hellish struggle and begin to see them like real animals, because as much it’s hard to imagine, that’s what they were. A restrained scene can be just as inspirational, but because of the overexposure of the more artistically-oriented depictions (dynamic/spiked) the average person tends to mistake the latter as a realistic approach.

It’s not about obliterating dynamic scenes, but not shying away of picturing their softer side just as much. Avimimus feeding babies, picture by John Conway, not sure where extracted from.

Hey, since we’re at it, let’s talk about…

– Photorealism vs. Lifeness (And why you should shoot for the latter)

This is probably one of the hardest tips I ever gave, simply because since we don’t know for sure how dinosaurs looked like, so I’ll try to summarise it saying that  trying to make them “photorealistic” is an ungrateful task of herculean proportions that probably will never stop looking out of place, so if you can’t make it LOOK real, the solution is to make it SEEM real. And that’s hard.

I’ll give an fair example (i.e. not comparing different artists), using John Sibbick’s Styracosaurus.  Same author, same technique, only years apart. The one on the left is the iconic Styracosaurus that is actually part of a larger scene depicting short-frilled ceratopsians like Centrosaurus and Triceratops (when he was still considered to be a short-frilled ceratopsian), dating from about 1985. The one on the right is a more recent one, I have no idea from what year it is exactly (90’s? Early 2000’s?), but it’s once again Styracosaurus hanging out with other short frilled ceratopsians (and Triceratops, again).

The odd thing is, the recent one has the wrong posture of the front legs. Pictures by John Sibbick, extracted from Dinosaurs! – Discover the giants of the prehistoric world #19 (Left) and The Concise Dinosaur Encyclopedia (Right)

Now, I don’t know about you, but if someone asked me to choose which one depicts a real Styracosaurus, I definitely would say it’s the former. I find that to be one of the most intringuing things about Sibbick’s older art: they are actually more realistic than his most recent ones despite of being grossly outdated.

So I kept thinking of why was that, and I’m positive that, for one, it’s not because I grew up with the older ones because I’m not that old and I in fact grew up seeing his newer art (well, relatively new). After some time I concluded that, although he didn’t make it accurately, he made a very convincingly depiction.

That’s the key word for this tip: convincingly. It’s entirely possible to create a paleoart picture making the creatures the most accurate as possible, but still end up with something that looks rather artificial, simply not conveying life to the creature (at the same time it’s possible to make a VERY good one at the expense of accuracy, but that’s not desirable if you’re trying to take it seriously). I mean, there’s a reason as to why to this day the great masters of paleoart like Charles Knight, Rudolph Zallinger and Zdenek Burian (my personal favorite out of the thee) are considered such great artists: their dinosaurs are anything but accurate, but they managed to apply all of their knowledge on what a living thing looks and acts like and  all of the elements the composes  a natural scene in such an effective manner that it’s almost like they travelled in time and painted the animals in their enviroments.

Yo have NO idea how cranky I got with the news about cloning dinosaurs being impossible. Come’on science, try hard! Picture by Zdenek Burian, extracted from zburian.blogspot.com

Sibbick can also be considered a great master os paleoart of the same rank, but as I said, his older art does a much better job of depicting dinosaurs as living beings: It’s almost possible to touch and feel the leathery texture of their hides and the dirt encrusted in their scales, the rustling of the foliage as it moves, and the heat of its breath. Yet the recent depiction severly lacks the same essence despite using the same gouache media and visual details like the clouds of dust. It would be delightful if Sibbick went to mimick his old style while making it up to date.

Also have nothing to do with the media used; While I do think that paint has a certain feeling of being touchable and bitable* that’s virtually unrivalled by digital media, it is possible to create paleoart in a convincingly manner with it.

Of course, it’s also possible to make catastrophically terrible too. With the ascencion of computer photomanipulation it became easier to texture creatures using various real animal photograph references as bases, so wouldn’t make them look more realistic? No. I say this technique has mixed results at best that most of the time, in my opnion, are awkward-looking and still doesn’t quite look like something alive. That would be such a case where, despite using “real” things to compose a scene, it ends up looking artificial when sewed together.

One artist that uses mainly digital media while still making dinosaurs look convincg is John Conway, and you can (and definitely should) check his gallery here . Yes, that would be the same who featured in Dinosaur Art – The World’s Greatest Paleoart (which I reviewed here), and who I consider one, if not the, best modern paleoartist. Ironic since, as stated in the book, he doesn’t aim for super-realism, and ends up being one of the few who depict dinosaurs realistically.

But Ctrl+C, Ctrl+V does get in the eyes. Picture by Conway, extracted from http://johnconway.co

Despite having the characteristics of a picture made with Photoshop (which some might consider ugly), the results are astonisihng to say the less, by the simple fact that “less is more”. Without resorting to superdetailed features, he’s able to show dinosaurs in such a way that they too convey the sensation of touch, albeit in a more stylized manner than Sibbick’s.

So these are the tips I one again have to offer. I think this time around it was less of a rant… Eh. Once again I hope these were helpful enough for all of you who want to get into paleoart as business or just as a hobby.

Thanks for reading!

* Excuse me, that’s a personal term I use.


Filed under Paleoart

Why I Don’t Trust Jack Horner 2: Why the King deserves his crown

by Carlos Augusto Chamarelli

Hey there again. After the previous article about Jack Horner’s plan to transform chickens into dinosaurs, what’s better than go back to showing contempt for his other theories? So let’s talk about his opinions regarding that one elusive theropod nobody ever heard about: the Tyrannosaurus rex.

Most specifically, about the most heinous and debated of his claims: that T.rex was so ill-suited to be a hunter that he had to live entirely of kills from other predators and was no more than a giant vulture. Understandably not many people were happy with this, and many studies since were made to verify if Horner’s claim were true. With mixed results, but not that stopped some to agree with him.

In reality he wasn’t the first to try and discredit T.rex of his predator status; back in 1917, paleontologist Lawrence Lambe concluded Tyrannosaurus couldn’t be a predator because Albertosaurus (yeah, I don’t know either) teeth did not show any sign of wear, which soon enough was pointed out as BS because theropods constantly changed their teeth throughout their lives. So T.rex continued to enjoy his status as the supreme predator he’s cracked to be and the scavenger theory was mostly left aside.

I’m not sure when Horner first proposed T.rex was a scavenger, but his opinions were already present during the early 90’s; during the production of Jurassic Park, in which he was one of the paleontological consulters, he stated that T.rex should be depicted as such. Fortunately, everybody knew better and made him a hunter like Bakker suggested, and we could see the creature in all his glory in the first two movies of the series.

You people, I don’t care if it’s outdated and full of inaccuracies; this is the only place where dinosaurs genuinely feel like they’re real things. Screencap of Jurassic Park. Extracted from jurassicpark.wikia.com

Until the early 2000’s that is, when Horner’s theory came in full power to the public. His TV-special “Valley of the T.rex” was entirely devoted to show the creature as a stinky scavenger, and during the production of Jurassic Park 3, Bakker knew better than participate of this train wreck, leaving the movie at the mercy of Horner as its sole consulter…

And from there, everything went downhill. Screen cap of Jurassic Park 3. Extracted from gonemovie.com.

As Wikipedia so nicely resumes for us, the main aspects that Horner uses to rationalize the idea of T.rex as a scavenger are as follow:

– Tyrannosaur arms are short when compared to other known predators. Horner argues that the arms were too short to make the necessary gripping force to hold on to prey.

– Tyrannosaurs had large olfactory bulbs and olfactory nerves (relative to their brain size). These suggest a highly developed sense of smell which could sniff out carcasses over great distances, as modern vultures do.

– Tyrannosaur teeth could crush bone, and therefore could extract as much food (bone marrow) as possible from carcass remnants, usually the least nutritious parts.

– Since at least some of Tyrannosaurus’s potential prey could move quickly, evidence that it walked instead of ran could indicate that it was a scavenger.

That said; let’s take a closer look at each of these points, shall we?

– Arms

Ah yes, T.rex arms. Those sorry excuses for limbs are the trademark of the king and his kin. Completely out of proportion and with only two fingers, it’s easily one of its most puzzling characteristics as many theories and no agreement exist about their real utility; ranging from a prosaic, moderately believable but ultimately flawed use like lifting his body when the animal was lying down, to the most reason defying such as picking his teeth or holding struggling prey.

At least it makes him easy to impersonate. Extracted from blogs.smithsonianmag.com

But I do believe the answer is in fact quite simple, but lots of people will be outraged exactly because of that.


T.rex most likely didn’t use them for anything because, well, it didn’t need. They were in a process of atrophy*. It’s really sad that the only mention of such occurrence is usually attributed to the outdated theory of Lamarckism, with the law of use and disuse, because, in a way, that’s kind of what happens.
To understand it better: you know that evolution work by mutations, right? They occur at random in the process of reproduction, but as the model always goes, if said mutation proves to be an advantage for that individual, he has higher chances to pass on his genes for the next generations. But sometimes, things go in a different direction.

Let’s make this one model with two different species, a caveman and a T.rex.

Why yes, MS Paint & MS Word work just fine for me. Picture by yours truly.

The caveman is like your average caveman: he has two legs, two arms, a head and a big, spiked club. The T.rex, on the other hand, is actually an ancestor form which have long arms, fictionalized for the sake of the explanation**, he’s like “cool, I can grab things with these, but my mouth already does everything I guess”.

Now say that they both at some point had offspring with mutations that affect their forelimbs, making their arms dwindle and become useless. For the cavemen, this could be fatal since he relies on his hands to grab things, make tools, maybe even socializing, so the natural conclusion is that this bad gene results in a dead caveman who never stood a chance to have children. For the T.rex, his tiny arms doesn’t affect him as much, because his jaws do all the work of killing prey and fighting rivals, which means he can survive normally and pass on his “bad” genes and create an entire dynasty of short-armed dinosaurs.

Putting a magnolia flower on her head is the way to tell she’s a female. Also, poor caveman. Picture by yours truly.

In other words, if a mutation doesn’t have a big impact in the creature’s lifestyle, it probably will carry on to next generations until the whole species has it. Among some examples where this happened we can cite snakes and other legless reptiles (which became, you guessed it, legless), primitive tetrapods (which lost fish characteristics such as fins) and even us humans (which lost our tails).

Degenerated arms are not even an exclusivity of tyrannosaurids; other dinosaurs had similar occurrences, from the small, one-fingered alvarezsaurids such as Linhenykus (whose arms were more like pointed stubs) to giant Abelisaurids, the “T.rexes of the south hemisphere”, so to speak. The latter, in fact, had much more pathetic-looking limbs than T.rex.

I mean, really, what the heck, nature? Carnotaurus skeleton mount from the Chlupáč museum in Prague. Extracted from http://commons.wikimedia.org

There were also the famous terror birds, which appeared in the Cenozoic; these too were large-sized predators with beaks as deadly as their wings where shamefully small. The logical conclusion with all of this is that arms for bipedal predator dinosaurs are overrated, and the fact T.rex had tiny arms as he did is completely irrelevant as evidence for scavenging habits.

Unless you think they were ALL scavengers, but… Why would you think that? Picture by Zdenek Burian.

– Senses

Remember that one scene in Jurassic Park where the T.rex escapes and Grant has to save Hammond’s grandchildren and they stand perfectly still because then the T.rex couldn’t see them? Of course you do, you read about it everywhere how it’s bonkers because he could have smelled them: T.rex had an exceptional sense of smell, just one more of his claims to fame.

Pictured: Bonkers. Screencap of Jurassic Park. Extracted from lost-world.com

T.rex’s sense of smell is thought to be surpassed only by the modern day turkey vulture (Cathartes aura), which is all too convenient to Horner’s theory, right? Except having a good sense of smell is just as useful for hunting animals, as proved by modern canids and felines. “But, PK, those are mammals, we’re talking about dinosaurs! They’re closer to birds!” you might say, but that’s alright, because contrary to what many might believe thanks to the super-sniffing vultures, some non-scavenger birds do have a good sense of smell.

The majority of them use it to detect predators, but there are some species that use it to hunt prey, like the kiwi birds, whose nostrils are so long they actually go all the way to the tip of the beak, excellent for sniffing worms underground.

It is fair compare it with T.rex, right? Right? Extracted from rmagibess.wordpress.com

But even more bonkerous is the fact that, never mind his extraordinary olfaction, he COULD see them!

It’s not always apparent, because most of the time you see pictures of T.rex’s skull in profile, but if you have the chance to look at one from the front, you’ll see that the hind part of the skull is actually visibly wider than the snout, causing the eyes to face forward rather than the sides as it’s more commonly seen in dinosaurs; it’s also at a higher level than the snout, giving it a clearer view and the distinctive shape.

It’s also kinda hard to find such picture, specially one that haven’t been seen around a thousand times. Sue’s skeleton mount at the Chicago Field Museum of Natural History. Extracted from wikipedia.org… Do I even need to say that?

Eyes facing forward are a characteristic of animals with good eyesight, such as primates and birds of prey, with the owls being the ultimate example of this; the binocular vision provided is essential for calculating distances better and maintain focused on targets. So that’s a tricky question: if T.rex was a purely a scavenger, then why did it had eyesight akin to predatory birds who are such efficient hunters?

– Teeth and jaws

Tyrannosaurids are an interesting lot when it comes to teeth. Usually, carnivore dinosaurs have slicing teeth shaped like steak knives, efficiently tearing the flesh out of the victim’s bone. T.rex, on the other had, had teeth at one point described as “deadly bananas”: they where thick and with very deep roots, which made them incredibly strong.

Those are medium sized, by the way. Extracted from discovery.com

In addition, their jaws were also different: the classic model has the jaws roughly the same width; while in T.rex the upper jaw was wider, giving him the characteristic overbite appearance, which allowed him to stress bones in such a way that they could easily crack them.

On top of that, T.rex is thought to have had the most powerful bite in the dinosaur world. How powerful it was? The most recent study, released this year, indicates around 30,000 and 60,000 Newtons. To puts things in perspective, the previous study pointed up to 13,000 Newtons,  enough to crush a car. That being said, I’m not surprised if someone told me that if a T.rex and a tank were in a fight, the dinosaur would’ve won.

Once again the internet proves it has everything. Extracted from nebomusic.net

But once again, this isn’t an indicative that T.rex was purely a scavenger, since powerful bites aren’t unique to such behavior. Think of the jaguar (Panthera onca), which isn’t one of the largest big cats out there, but even for its size it has an unusually strong bite that can crack even a man’s skull, and is the apex predator of its habitat.

Hypothetically speaking, if jaguars were to evolve into much larger species, then forms with even stronger bite power could appear. For a creature as big as T.rex, this could be one such scenario; their ancestors could be like the jaguar in size and potency, but things went out of hand and produced a big animal with an insanely strong bite, and being able to feed on bone marrow was just an appreciated bonus.

So anyways, remember that scene in Jurassic Park 3? Yes, THAT scene…

So many bad words were uttered directed at this. Screencap of Jurassic Park 3. Extracted from djgomasar.blogspot.com.b


The first bite to the neck would’ve been enough to kill the Spinosaurus. See, that’s one reason that makes T.rex lives up to its title: it doesn’t matter if Spinosaurus or Giganotosaurus or any other theropod was larger than him, his absurdly powerful bite would be more than able to overpower them.

But no, Horner had to have things his way and cheated by okaying them into making a Spinosaurus on steroids not care about fish and fight a sub-adult T.rex and survive a bone-crushing bite to the neck. Sorry about that little rant, but it’s all just too unnerving to see such gratuitous mockery of paleontology in one place.

SO MANY. Screepcap of Jurassic Park 3. Extracted from villains.wikia.com

– Legs and body build

Paleontologists have divergent opinions about the overall build of Tyrannosaurus; two body models commonly followed are the bulky type and the athletic type. The bulky body implies a slow-moving creature with a more limited ability to run, some might say one that would be unable to chase its prey, while the athletic body implies an active running creature.

Paleontologists who support the athletic type suggest that, despite it’s size, the overall proportion of the legs of the T.rex are more characteristic of a running animal, in other words, T.rex was very much able to catch up with its prey in a chase. So naturally this is what makes the most sense if you want to show T.rex as a hunter.

“Look, a Velociraptor!”. Sue’s skeleton again. Extracted from cmnh.org

My opinion? He was a bulky type.

“Say what?”

In reality, nobody is quite sure of how fast Tyrannosaurus was, but from analysis and calculations an estimative can be made, but even those don’t really support the image of T.rex running at overly high speeds as usually shown.

In a optimistic scenario, the top speed for T.rex is somewhere around 30 km/h (18 mph) at best, which isn’t terribly fast. I’ve read about some estimatives being over twice this value, but that seems more like an exaggeration to argue with Horner’s theory in the wrong direction.

Because the larger the creature becomes, the more heavily built it has to be in order to support its own weight, there’s a limit on how light the creature can be until it become too big and heavy to support itself, so a large bipedal creature like T.rex probably needed to have a solid build in order to stand in their feet. Not to mention that, in order to be able to run at the suggested exaggerated speeds, much of its body mass would have to be in their legs muscles.

Whoever, being slow doesn’t rule out the possibility of Tyrannosaurus being a hunter; he maybe just had a different approach. Instead of focusing in speed, Tyrannosaurus could be a robust creature built primarily for strength. Why would did he need to be so? Well, what manner of prey did he had available in his domain?

Spikes, spikes everywhere. Pictures by John Sibbick. Extracted from http://fineartamerica.com

Why, just the most dangerous herbivores ever to appear in the Mesozoic era.

Nobody can attribute speed as a quality of ankylosaurids; they had a solid build, covered in heavy armor and short legs for better standing their ground.

Ceratopsians, despite what most reconstructions tend to show, were probably very poor runners: their forelimbs weren’t even appropriate to run, (I intend to talk about this in a future post) so they probably relied more in numbers and their own weaponry for survival than making a dash for it. So if being fast wasn’t needed to catch its prey, the best option would build up endurance, and the apparent running legs of T.rex would be more like a way to trade speed for strength without being completely handicapped.

Meaning the T.rex wasn’t a creature made to pursue its prey. No sir. He was juggernaut made to stay there and fight them, and win. Somehow pure raw strength could prove to be a better strategy than speed to overcome a well armed opponent.

Suddenly this setup makes a lot of sense. Picture by Charles Knight.

While the T.rex could be injured or even killed by his prey, he could also finish it just as easily: biting the head or the backs would have shattered their bones and leave the prey paralyzed in the best of hypothesis, while just ripping a chunk could leave a fatal wound. In this scenario, T.rex’s eyes would then be an invaluable asset to focus on their prey during the fight, rather than be used during a chase. And if he ever needed to run, it would be more like walking real fast.

In a way, one can think that ceratopsians and ankylosaurus where in a mutual armed race with tyrannosaurids, each developing even more powerful weapons against each other: they seemed to be found primary where those types of herbivores thrived (i.e. North America and Asia), and their evolution is somewhat consistent with the appearance and ascension of those herbivores. Now consider this: despite the duckbilled dinosaur’s fame as widespread, they were actually outnumbered by ceratopsians, which means something must have been preying on them to keep their numbers, right?

Oc course, that’s my personal opinion, I might be wrong: there’s no evidence of ankylosaurids with signs of predation yet, but I’m not convinced absolutely nothing would attack them if given the chance, specially something with a bite like T.rex.

And to think for the longest time museums didn’t like those kind of findings because they were “no good for exhibition”. Triceratops sacrum with T.rex bite marks. Extracted from palaeocritti.com

While there’s evidence that T.rex preyed on both hadrosaurids and ceratopsians (i.e. some show teeth perforations while others healed bite marks in bones that could only be possible if the dinosaur was alive), it’s safe to assume that the horned dinosaurs were his chief prey, at least to the fully mature individuals.

While there’s no official estimative on how fast hadrosaurids could run, it’s certain that they were faster than an adult T.rex, but if it’s true that they could also hunt in packs to a degree, then it could be an explanation for this finding. Alternatively, younger individuals could have preyed on hadrosaurids if they were light built. But even more impressive seem to be the fact that something actually could survive an T-rex attack.

-Anything else?

Actually yes, there’s one more point beyond the ones listed: Energy efficiency.

Modern scavengers like vultures and jackals are allowed the luxury having this lifestyle because they’re small and can cover a large area without wasting too much energy (i.e. vultures are soaring birds, meaning they are able to maintain flight without flapping their wings).

A large creature like T.rex would be doomed to extinction if it was an obliged scavenger because he would probably run out of energy trying to locate the next meal, and even then he has to hope there’s enough left to eat and no other T.rex claimed it already, not to mention this unviable lifestyle would make their population be massively reduced in order to be able to support just a handful of these dinosaurs

So there you have it. Tyrannosaurus might not have been the largest carnivore to ever exist, but he certainly was the most powerful. Despite all those evidences, there’s a consensus among those who support the hunting behavior of T.rex that he was an opportunistic hunter. That is, while he could very well kill his own prey, he wasn’t above stealing or eating carcasses. It’s a free meal after all.

In the end, this is what the whole problem is about: Horner didn’t take in account that the evidence he used to support his theory also had explanations that indicated the opposite. Just to make things clear with the “Why I Don’t Trust Jack Horner” series: while I don’t think he’s a bad paleontologist, I do believe he’s a little misguided about his recent theories. And quite frankly, I’m pretty sure that if Horner went back in time and was face-to-face with the creature he’s sure was a scavenger, he would NOT just stand there calmly.

Thanks for reading!

* Because once the first degeneration took place, nothing would stop it from being further degenerated by a subsequent mutation.

** Early tyrannosaurids did have longer arms, but in the model the dinosaur is already in its later form to illustrate that even a sudden mutation, as opposed to a gradual one, still wouldn’t affect it.
– – –
References & Further Reading:
Erickson, Gregory M. 2005. ‘Um Sopro de Vida no Tyrannosaurus rex’. Scientific American Brasil – Edição Especial: Dinossauros e Outros Monstros.

Wikipedia. Tyrannosaurus. Available on-line in: <en.wikipedia.org/wiki/Tyrannosaurus>. Acess on May 15th, 2012

BBC – T. rex bite was world’s strongest. Avaiable online at: <http://www.bbc.co.uk/nature/17159086&gt;

Science Daily- Birds Can Detect Predators Using Smell. Avaiable online in: <http://www.sciencedaily.com/releases/2008/04/080427233813.htm&gt;


Filed under Evolution, Paleontology