Why I Don’t Trust Jack Horner 1: The Holes in the Old Triceratops Idea

By Carlos Augusto Chamarelli

As my friends know very well, I’m a fervent opponent of Jack Horner’s ideas. So naturally I had to start a series for analyzing and counter attacking some of his wackiest theories about dinosaur which, I hope, aren’t brainwashing an entire generation of paleoartists. Let’s get to know the star of the first post of the series: the Triceratops.

People might remember some time ago, it was everywhere in the news: “Triceratops didn’t exist”. That’s BS, even Horner himself said so. What he actually meant is that the ceratopsian dinosaur Torosaurus is nothing but an aged Triceratops: over the years the frill of – presumably male only – Triceratops would grow to the astounding size of Torosaurus‘ frill, about 2.5 meters (8.5 feet) long.

So in reality what should have been in the news is “Torosaurus didn’t exist”. In zoological nomenclature, a basic principle is that when a species received two different names, the earliest correctly published name, called senior synonym, takes precedence and thus should be used to name the species, excluding the later name (junior synonym). And since Triceratops was named before Torosaurus, Triceratops is the senior synonym and has to be the official one. But naturally media figured most mainstream people don’t know what a Torosaurus is, so their solution was to mess everything up and make some sensationalism, because that’s very surprising.

Naming issues aside, there are a few points about this theory that just seem off to me:

A little less known aspect of Horner’s theory (or maybe not so much anymore since he already released a paper about it) is that before becoming Torosaurus, Triceratops became something else first, and that is Nedoceratops (formerly Diceratops).

Nedoceratops skull

Nedoceratops skull. Photos by Andrew A. Farke, from Wikipedia, 2011

Nedoceratops have a long history of debates about its validity as a separated species or as a synonym for Triceratops (the small windows in the frills simply being caused by pathologies, for example). For Horner, the holes in the frill indicate the beginning of the transformation into Torosaurus, but that’s about where things get weird.

Drawing of the two Torosaurus skulls by Marsh, 1893.

Really now, how exactly does a hole form outta nowhere? So okay, Horner demonstrates that Triceratops’ frill is not entirely solid, some areas are thinner, and these are about the same areas where the holes appear in Torosaurus, so it apparently makes sense Torosaurus to be an old Triceratops, but even if dinosaur’s bones were very plastic and enabled many transformations as they grew, the bone retroceding and becoming so thin to the point where it disappears and leaves a hole is something not even sheer open-mindness is able to accept.

Reason number one is ceratopsian growth in general. Let’s use Protoceratops as the example since there are plenty of skeletons from individuals of varying ages, from baby to adult:

Protoceratops growth series. Photo by Harry Nguyen, 2008.

As you can see, the holes in the frill are present even in the youngest individuals. And if people can use Psittacosaurus quilled tail as an excuse to put quills in all other ceratopsians tails, then darn it, I WILL use baby Protoceratops as an argument that baby ceratopsians maintain holes in their frills all the way to adulthood, which takes us to reason number two, which is the baby Triceratops skull itself:

Baby Triceratops skull casting. Photo by BrokenSphere, from Wikipedia, 2009.

It’s not known (for me, at least) how old this baby was when alive, but judging by his size and features, he might very well been a newborn. Anyway, let’s take a look at his frills:

Baby Triceratops frill detail. Photo by Brokensphere, from Wikipedia, 2009.

So there, he does have some kind of holes in his barely formed frill. But these quickly disappear, as shown by the rest of the growth series. Maybe the thinner areas of Triceratops’ frill is a heritage of his baby form, maybe that part is naturally thinner for whatever reason. The point is that if it was true that Torosaurus is an old Triceratops, then the holes should have been present in all the younger forms just like Protoceratops, no matter how small they are compared to other ceratopsians.

But I give credit where credit is due. Horner presented solid evidence: the bones of Triceratops are spongy, which is characteristic of young individuals, which means that, true, Triceratops may not represent fully grown individuals. Still, it’s a long shot to assume Torosaurus is the mature form.

There is one little detail Horner overlooked in his theory: there IS a dinosaur that is bigger and is similar to Triceratops – even more than Torosaurus –, and whose remains were found in the Horseshoe Canyon formation in Alberta, which not only isn’t that far from Montana, but is also known to contain remains of dinosaurs also present in the Hell Creek formation, including Triceratops.

This dinosaur is called Eotriceratops xerinsularis, described in 2007 by Xiao-Chun Wu, Donald B. Brinkman, David A. Eberth and Dennis R. Braman.

Eotriceratops skull casting. Royal Tyrrel Museum, 2010.

I don’t think this picture does justice for it, so here’s what it may have looked like next to a standard Triceratops:

Eotriceratops size compared to Triceratops. Image by Conty, from Wikipedia.

There are some debates over the total lenght, but it’s quite larger than Triceratops. But then you can say “but PK, doesn’t ‘Eotriceratops’ mean “early Triceratops’? How can he be an adult Triceratops if he lived before Triceratops?”. Evidently the temporal range is estimative, and might not be entirely accurate; giving an error margin for this estimative, Eotriceratops would still be at the same time of Triceratops. If anything, Eotriceratops is the one that should have been theorized to be the aged Triceratops and be considered a synonym.

In his lecture Horner tries to argument there hasn’t been found any juvenile Torosaurus, but that’s false syllogism; I could, for example, argue that pterosaurs gave birth to live offspring since pterosaur eggs were never found. Except they were found, a few years ago, and they were soft-shelled eggs, for everyone’s surprise. What’s with this, you ask? Soft-shelled eggs are usually found in species that don’t take care of their offsprings, so this implicates that the scenario of mama pterosaur nurturing her babies in a nest, like birds do, is unlikely – but there might have been an exception here and there.

A female pterosaur preserved together with her egg. Lu Junchang, Institute of Geology, Beijing. Taken from CBC.

In other words, no juvenile Torosaurus was found because paleontologists have to rely on luck and patience, but some day they will be rewarded with such discovery. They found Tiktaalik, so why not?

The final hole in Horner’s theory is ceratopsian speciation. Amusingly enough, Horner himself kind of deliver that one: Early in his presentation, Horner show the growth series of the double-wattled cassowary, Casuarius casuarius, showing how different younger forms are compared to adult forms, and how the same thing could be applied to dinosaurs that could have been mistaken for separated species.

Double-wattled cassowary, Casuarius casuarius, growth series. Extracted from Horner's lecture "The Shape-Shifting Skulls of Dinosaurs".

That’s nice and all, but then you have to consider this guy here:

Dwarf cassowary, Casuarius benetti. Photo from Zoo Institutes.

This is the dwarf cassowary, Casuarius benneti, and if the name is any clue, he’s a smaller cassowary. He’s native to Papua-New Guinea and nearby islands, but his range also overlaps with the population of double-wattled cassowaries, and his skull looks like this:

Dwarf cassowary skull. Photo from Bird Skull Collection (skullsite.com).

So comparing it with the double-wattled cassowary growth series, things get kind of interesting, because the dwarf cassowary’s skull looks a lot more like a younger form of the adult double-wattled cassowary. You could easily put the dwarf cassowary skull in the diagram and pretend you didn’t know these were different species.

Now think of a place with lots of similar species, such as the African savannah and its wounderful antelope species variety. Some might have similar characteristics one to another, but they are all unique in their own right, even if their skeletons are virtually identical.

Naturally if you were some kind of alien paleontologist in the future and you dug up antelope fossils, you could too think that the tiny dik-dik is just a baby gazelle, which in turn is the younger form of the sable since all you have to work with are their bones.

Maybe the reason Torosaurus looks a lot like Triceratops is because they are very closely related, and might have lived in the same areas, but this doesn’t mean they are one and the same.

In the end, Horner’s idea is just slightly interesting, but is inherently flawed. Some say what he’s doing is constructive trolling, making outrageous theories to incite other paleontologists to show their work. That would be acceptable (if a little annoying indeed), but my credibility on him was buried for good in the very first episode of Terra Nova, where he’s the paleontological consulter, and allows one character to point out that the brachiosaur “supplement their diets with small reptiles”. Damn.

Anyway, I hope you enjoyed this article, and as usual, any questions all you have to do is comment and I’ll answer it.

Thanks for reading!

For more about dinosaurs, you might want to see:

– – –


Scannella, J., & Horner, J. 2011. ‘Nedoceratops’: An Example of a Transitional Morphology PLoS ONE, 6 (12) DOI: 10.1371/journal.pone.0028705

TEDxVancouver – Jack Horner – The Shape-Shifting Skulls of Dinosaurs . 2009. Available on-line in: <http://www.youtube.com/watch?v=xYbMXzBwpIo&gt;. Acess on December 5, 2011

Wikipedia. Triceratops. Available on-line in: <en.wikipedia.org/wiki/Triceratops>. Acess on December 5, 2011.

Wikipedia. Eotriceratops. Available on-line in: <en.wikipedia.org/wiki/Eotriceratops>. Acess on December 5, 2011.



Filed under Paleontology, Systematics

27 responses to “Why I Don’t Trust Jack Horner 1: The Holes in the Old Triceratops Idea

  1. Jordan

    You didn’t so much falsify Horner’s (or rather, John Scannella’s) claims as offer alternative — sometimes ad hoc — explanations of the same evidence.

    • Pangeia King

      I’m not quite sure what you meant by that, but if you could elaborate which points exactly you think are faulty I would be happy to explain my thoughts on them.
      Thanks for the critic 🙂

    • Steven White

      Some people just don’t like having to hear that two of every three dinosaurs – just in the 12 major ones of North America – were incorrectly classified. They don’t want to hear it because that would mean thousands more in the minor species are in all likelihood also misclassified, along with those of other continents.

      All someone has to do to prove him wrong – is cut open bones of young and old animals of the present and see just how well his hypothesis fits the facts. but I think we all already know the answer to that.

      So instead of accepting good science, people will object so they don’t have to reclassify all the other claimed species as well. Not to mention what this will do to already huge gaps in the record.

      I think it is simply fear of what the results bring about. A major overhaul of the entire classification system. But mainly fear that creationists will use this against evolutionists. In my opinion, neither of which is scientific and I have yet to see any real arguments against his position accept ad-hoc fluff.

      The antelopes are merely variations of the same species – just as a bulldog and greyhound, or lion and tiger are different breeds of the same species. Just as Finches with different beaks are each and every one a Finch – just different breeds amongst the same species. How often we overlook what is right before our eyes while we dream of what other things were. Things we have never once observed in life and so really have no clue about. Conjecture all we like, but his science is sound.

  2. I’d like to say that while you offer an alternative explanation, to falsify the arguments John Scannella and Jack Horner offered requires having data that shows their argument is wrong. However, that isn’t really necessary because their argument doesn’t necessarily prove their own case. The issue here is that you merely need to argue that Scannella and Horner haven’t demonstrated proof of their own argument, merely analogy to it. As you note (and so do they, in fact!), closely related animals will have similar developmental trajectories and involve many of the same morphologies changing the same way over time. Problematically, they haven’t shown a way to discriminate closely related adults with similar or identical juveniles, and the argument they pose is that while they have looked they cannot find any dissimilar near-adults that do not match a trajectory that includes Nedoceratops hatcheri and Torosaurus latus within it. Almost certainly, demonstrating they cannot discern closely related taxa at less than adult stage is enough to push their identification of juveniles to particular sides of this debate into doubt. But that requires more substantial work, and the full argument of species separation and evolutionary development, including stratigraphy, hasn’t been published yet, so this argument would also have to wait until much more of the data in favor of Scannella and Horner’s side is available.

    Incidentally, the small, baby Triceratops (UCMP 154452) doesn’t really seem to preserve parietal fenestrae; what is present as a large open fracture on one side is apparently closed on the other. See this mock up for clarification.

  3. The horseshoe Canyon formation is solidly earlier (much earlier) than the Hell Creek formation. I’m not sure where you’re getting the idea that the chronology of Eotriceratops may be wrong, but unless its locality was mis-reported, I don’t think there’s any way this can be the case.

    However, this is a major issue in Horner’s hypothesis that still needs to be addressed. Somebody needs to publish a detailed stratigraphic (and chronological) diagram showing the relative positions of all known skull specimens before anybody should say this issue is near being resolved, or before we can determine how many distinct species/populations we have and how they morphed into each other over time. The situation is far more complex than simply Torosaurus/Triceratops. We’re likely dealing with numerous chronospecies here.

  4. That would be acceptable (if a little annoying indeed), but my credibility on him was buried for good in the very first episode of Terra Nova, where he’s the paleontological consulter, and allows one character to point out that the brachiosaur “supplement their diets with small reptiles”.

    That’s almost certainly true and has been mentioned on SV-POW and elsewhere, IIRC. Large sauropods would certainly have taken small vertebrates as they vacuumed up massive quantities of leaves in their daily lives. Even cows accidentally ingest small animals, and sometimes actually prey on them purposefully for calcium and protein.

    Not that much on Terra nova should be taken as fact, but don’t blame the science consultants. They’re usually hired to lend fake credibility and then totally ignored by producers who just want stuff to be as cool and sensational as possible 😉

    • Erin

      Consultant means he advises, but he’s not the final word. This happens to science advisers in Hollywood all the time.

  5. “You could easily put the dwarf cassowary skull in the diagram and pretend you didn’t know these were different species.”

    Sorry to tipple post but i just noticed this :/

    You could do that and, lacking any evidence to the contrary, you’d be justified in thinking a dwarf cassowary was a juvenile of a contemporary species. You’d be wrong, but you’d be using parsimony and assuming the simplest explanation (juvenile of a known species) is better than a more complex one (new, dwarf species). If you hear hoof-beats, think horses, not zebras.

    Now, if you performed actual science to test your idea (bone histology, etc.) you might discover evidence that is contrary to the idea that the dwarf skull is a juvenile (adult bone patterns, for example). This would lend credibility to the alternative, complex hypothesis (new dwarf species). Or you might not have enough evidence to test it either way, in which case some would say you should stick with the simple explanation (juvenile) and some would say you should stick with the complex (dwarf). If neither has any data backing it up, it’s a toss up and we must admit we may never know for sure, pending more evidence. At that point it becomes a matter of philosophy, like lumping vs. splitting. But let’s not pretend we can’t support these hypotheses either way using the scientific method.Usually there is some way to test these hypotheses but nobody gets around to ever doing it.

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  8. Pangeia King

    Sorry everyone for the late, late reply; I was away and had no internet connection and when I came back I didn’t had much time. Anyway:

    @Jaime A. Headden:
    In retrospect, this post may be in fact a bit hasty, but I judged it necessary to be pointed out nonetheless. I belive my real problem with this theory in general is the overacceptance; surely people with deeper understanding of dinosaurs can dismiss Horner’s theory (ok, it’s Scanella’s, but he’s like Horner deputy, so basically it’s talking about the same person in this) as nothing more than a wacky theory, but other people simply accept it as fact with little to no critic.

    And thanks for that picture! It still tells me this section of the triceratops frill is just thinner than usual and prone to be damaged like that. Curiously, Nedoceratops also have a hole in just one side in the upper part of the frill.

    @Matt Martyniuk
    That’s one long reply there, but no problem triple posting if you have something to say.

    1- As far as I know the Horseshoe Canyon is dated from late Campanian to early Maastrichtian, while Hell Creek is exclusively late Maastrichtian; still, they are just a few million years apart and wouldn’t be that much earlier in geological terms. In adition there are a few dinosaurs common to both places, such as Edmontosaurus and Pachycephalosaurus, but maybe my sources are wrong?

    2- Very true. It would be nice to see this for other dinosaurs such as Tyrannosaurus and Pachycephalosaurus who are others victims of the theory of growing dinosaurs.

    3- I’m aware of such theory about herbivore dinosaurs ocasionally eating meat (actually just the ceratopsian-related one), but about sauropods… I don’t know, I just can’t get convinced they would actually prey on smaller animals, even on small frequency; to have any real impact in its diet those “small lizards” should be what? The size of alligators?

    4- Haha, yes, but in that particular scene I couldn’t help but think it was solely Horner’s fault. Also, Jurassic Park 3.

    5- That’s why this matter for me will only be solved for good when A) a juvenile Torosaurus turns up, B) a Triceratops with mature bones turns up (if you don’t consider Eotriceratops in this), or C) many more years pass and neither are found. Luck and patience…
    Also, as stated in the above reply for Jaime, my real issue with the theory is the overacceptange: Horner simply came up, said “Torosaurus is an old Triceratops, deal with it”, and that’s it.

  9. “In adition there are a few dinosaurs common to both places, such as Edmontosaurus and Pachycephalosaurus,”
    Those aren’t dinosaurs, they’re groups of dinosaurs (genera are groups of species, like families are groups of genera). First of all I don’t know of any Pachycephalosaurus species from Horseshoe canyon, except maybe mis-attributed pachycepholosaurid remains. Edmontosaurus regalis is known from horseshoe but not from Hell Creek. The Hell Creek edmontosaurs are an entirely different species, E. annectens.

    “That’s why this matter for me will only be solved for good when A) a juvenile Torosaurus turns up, B) a Triceratops with mature bones turns up”
    But that’s not a very scientific mindset. IF (big if) Horner is right, A and b don’t exist and will never turn up, and so you will continue to doubt their hypothesis forever. In other words, there is no way to prove your hypothesis wrong if Horner is right. At least Horner’s hypothesis can be falsified.

    “Horner simply came up, said “Torosaurus is an old Triceratops, deal with it”, and that’s it.”
    No, he published his hypothesis in scientific papers and has attempted to test it. other people have published papers attempting to refute it. That’s science in process. Anybody who is accepting it based on his authority with no critical thinking is in the wrong, but please don’t imply everyone who leans toward Horner being correct is an unthinking sheep.

  10. Jade

    I compleatly agree. But if you could elaborate on which points that are faulty in more detail I would be gratefull. I am doing a speech about this topic and have found this a great source.

    • Pangeia King

      Oh my, so sorry I couldn’t get back to you sooner, hope it’s not too late.

      Well, first of all I’d like to point out that ever since this article was posted, a new study was released afterwards that added to discussions, in which skulls from many Triceratops and Torosaurus indviduals were analyzed and arranged in a way that would fit Horner’s theory. You can find the paper here: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032623
      In a very condensed way of the results, as it turns out, further analysis of the skull features such as the cracks that aren’t fully formed in younger individuals, could be identified on Torosaurus, at the same time that features of mature individuals were observable on Triceratops, so it’s difficult to attest that Torosaurus is a young Triceratops when there evidence that exist both young Torosaurus and old Triceratops, thought I think this issue only will be debunked for good if a baby Torosaurus is found.

      For now, I think my best evidence to base on that these are two different dinosaurs lie on the Protoceratops example: if Torosaurus was indeed to be Triceratops, the fenestrae on the frill should have been visible in Triceratops younger form, which, as you can see up there, isn’t what the evidence shows. Protoceratops have the most complete line of growth visible on ceratopsian finds, individuals anywhere from unborn to adults were found, which give us a very good notion on how the creature matured; most other ceratopsians are incomplete, but if we were to assemble the possible juveline stages basing what we know from Protoceratops, we too would observe that the frill fenestrae should present in very young individuals.There’s just no way the bone structure would retrocede so smoothly to form the structure seen in Torosaurus.

      As for the speciation aspect, I base on the fact that a lot of dinosaurs do share the same body, for example, the basic layout for large ceratopsians (and many other dinosaurs such as hadrosaurs) is the same, with only the skull presenting pronounced differences, much like what happens to animals today, so it’s possible that dinosaurs who were very closely related would look like each other without necessarily being of the same species (or the same gender, for that matter). It’s also possible that Torosaurus could be in fact be Triceratops, but NOT T. horridus, which is the one we’re used to read about. T. prorsus, another Triceratops species, possess a frill a little more smilar to that of Torosaurus, having a slightly elongated and smoothed frill on the borders, but still lacking fenestrae, though it’s possible to see that the bone structure is visibly thinner on the exact place where Torosaurus have these. So in this respect, I believe there’s a possibility that Torosaurus share a common ancestor. I could be wrong, but finding evidence is what makes the final saying.

      Hope that was useful, I don’t know of any other way I can elaborate this further, so I’m sorry if I’m just repeating myself there.

  11. Hikaru Amano

    @ Pangeia King:

    In a video of the debate Horner and Longrich had in Yale, Horner said that bone texture and skull fusion are not always good indicators of maturity, insisting that bone tissue structure remodeling is the only guaranteed way to determine the maturity of an animal? However, they have not actually tested how truly reliable bone tissue structure remodeling is (which is one of the critical flaws in their methodology). In the video, Dr. Longrich showed the histological sections of a leg bone with a rapidly-growing immature tissue structure (which Dr. Horner claims as indicative of juvenile and subadult individuals) alongside the histological section of a bone with heavily remodeled tissue structure (which is thought to be characteristic of old adult individuals). He then asked the audience whihc of the to pictures came from an old individual and which is from a youngster. Moments later, Dr. Longrich demonstrated that the two sections came from different regions of the very same bone from the same individual! He said that unless one makes many histological sections from different regions of the same bones at different orientations, the tissue structure may mislead one into believing that it came from a differently-aged individual. But far more than that, he and Mr. Field pointed out in the article you have cited above that although a bone with a more heavily remodeled structure came from an older individual, this hold true only if the rates and or/extent of bone remodeling is consistent between and amongst different bones within and between different individuals of a species. However, the results of several experimental studies have demonstrated that the rates and/or extent of bone tissue remodeling could significantly vary between and amongst different bones of the same individual. In fact, some of those studies even demonstrate that even within the very same skeletal element, the rates and/or extent of remodeled bone tissues could be variable! And they also pointed that in those studies(actually, I have to read upon other journal articles concerning the variability of bone remodeling aside from references 60-62 of Longrich and Field’s 2012 article-and those articles also support Longrich and Field’s contention that bone tissue structure remodeling may not always be a good indicator of maturity), factors and/or processes other than ontogeny (such as differences and/or changes in the mechanical strain regimes various regions of different bones from different parts of an individual, metabolism, nutritional status, developmental origin of different bones, health) could radically alter the rates and/or degree of bone remodeling. And those factors and/or processes (including ontogeny) interact in more complex ways -which are not yet discovered-with some or all of the other above-mentioned factors and/or processes to significantly affect the rates and/or extent of bone remodeling within, between, and amongst different bones at different regions within the same individual and amongst other members of its species. That means a bone from a subadult individual could have ILLUSORY HEAVILY REMODELED tissue structure- that are found in old adults- due to one or several of those phenomena acting in that individual’s bone. They also did not place a standard for the type of bone remodeling they are using to determine the age of an individual. Hence, Scanella and Horner needs to rigorously test first how to discriminate remodeled bone tissues caused simply by old age from those caused by other factors and processes, how significant the contributions (rates and/or extent) of those other factors are to the observed bone tissue structure remodeling, at what phase of the animal do those factors become significant contributors to bone tissue remodeling, and so forth before scientists in general could reliably use bone tissue remodeling for estimating the maturity of animals….Another critical flaw is that the number of sampled individuals is very small to make a conclusive case. At any rate, I would continue to insist that the issue of the TAST (Torosaurus-As-Senescent-Triceratops) be settled via bimolecular examinations (i.e. consensus amino acid sequence profiling, identical gene DNA sequence profiling)…..

    • Pangeia King

      I appreaciate your time writing this wall of text and making my arguments look bad. But in all seriousness, those are very good points, I’ll be sure to talk about them in my future post where I revisit this topic. Thanks!

      • Hikaru Amano

        I don’t actually intend to make you post look bad. I just pointed out the flaws in Scanella and Horner’s methodology…BTW, I could send you the PDFs of the jounal articles regarding those experimental studies if you me to…I certainly want to see how they are going to address the issues regarding the limitations, misapplications, and flaws of relying too much on bone tissue remodeling as proxy for maturity. Thanks

      • Pangeia King

        It’s fine, I was just joking because your comment already made better arguments than my whole article.

  12. Hikaru Amano

    Here are those journal articles (one of which is actually a book) that I have read and which have not been used by Dr. Longrich and Mr. Field:

    Kini,U. and Nandeesh,B.N. (2012). Physiology of Bone Formation,
    Remodeling, and Metabolism. Radionuclide and Hybrid Bone Imaging, pp 29-57.

    McFarlin,S.C., Terranova,C.J., Zihlman,A.L., Enlow,D.H., and Bromage,T.G. (2008). Regional variability in secondary remodeling within long bone cortices of catarrhine primates: the influence of bone growth history. J. Anat., 2008 (213): pp308–324. doi: 10.1111/j.1469-7580.2008.00947.x.

    Oers,R.F.M.v., Ruimerman,R., Tanck,E., Hielbers,P.A.J., and Huiskes,R. (2007). A unified theory for osteonal and hemi-osteonal remodeling. Bone, 42 (2008): pp. 250–259.

    Pazzaglia,U.E., Andrini,L., and Nucci,A.D. (1997). The effects of mechanical forces on bones and joints:experimental study on the rat tail. J Bone Joint Surg [Br] 1997;79-B:1024-30.

    Ruimerman,R. (2005). Modeling and Remodeling in Bone Tissue. Netherlands: Technische Universiteit Eindhoven.

    Terrier,A., Miyagaki,J., Fujie,H., Hayashi,K., and Rakotomanana,L. (2005). Delay of intracortical bone remodelling following a stress change:
    A theoretical and experimental study. Clinical Biomechanics, 20 (2005): pp. 998–1006.

    (P.S.: I hope that the contents of these articles will be useful for your next blog. Arigato Gozai Mashitta)

    • Pangeia King

      Thank you very much! I’m still a little far from writing about this on the moment, but I’ll use it when I do.

      • Hikaru Amano

        However, I am a very vocal advocate of rather very destructive method of breaking dinosaur bones to search for good-quality preserved soft tissues to be used for biomolecular examination methods. It’s much more effective than ontogeny in demonstrating synonymy or distinction between taxa that are closely related that ontogeny.

    • Hikaru Amano

      Oh more more thing: I don’t intend to disrespect or make Scanella, Horner, and/or Fowler look bad. I’m just giving a critique on the limitations and/or misapplications of using bone tissue remodeling ofr telling the maturity of an animal. But I would agree with one of their points that the age of an animal should be considered when assigning them to a pre-existing species or considering them as reference material of a new species. I also agree that a combination of proxies must be used in order to accurately estimate the age of the creature being analyzed (extent of skull bones’ fusion, bone surface texture, extent of bone tissue remodeling, etc.).

      Also, I have asked Dr. Farke about what is his opinion regarding my position that calls for biomolecular examination methods to determine whether Torosaurus is the old adult form of Triceratops. Here was his email in response to that, dated (June 1, 2012):

      Dr. Farke:

      “It’s possible given enough samples (assuming biomolecule recovery works for enough fossils), but I think we will need many, many more specimens than what we have right now. Plus, there needs to be a lot of background work on fossils from other formations. Triceratops and Torosaurus, even if separate taxa, are very closely related, and so the first step would be to generate a reliable standard. How much variation is there across ceratopsians as a whole? How much variation between species would we expect in things like collagen or keratin (the most likely candidates)? A necessary first step would be to demonstrate the method in extant animals (perhaps using samples in the current molecular databases). So, I think the use of biomolecules to answer the question is intriguing, but a long, long way off.”

  13. Pingback: Triceratops, ¿no existió nunca? | SinapSit

  14. AWM1984

    I know this article is old, but it is refreshing to see as I am doing a project on ceratopsian frills and range of vision while a student at MSU and it is exhausting just how many of my fellow paleontology students blindly have accepted Horner’s new theory and try to apply it to everything without questioning him at all. Another problem with the whole Torosaurus/Triceratops bit is that if you look at the two dinosaurs you see Triceratops is a very active animal with anatomy geared for active movement while Torosaurus looks like kind of a beach ball in comparison being too round to easily be bitten into. If they were the same species then that is a dynamic shift in defense methodology from predators and a ceratopsian who is loosing speed but isn’t yet big around to prevent a bit from a Tyrannosaurus Rex is likely going to be picked off easily. I too am not a fan of a lot of Horner’s ideas for while he does make great strides in paleontology….this is the same guy who said T-Rex had to be a scavenger for decades till it was proven the king of all dinosaurs was a pack hunter. Anyway loved this post and thank you so much for sharing.

  15. Pingback: Triceratops, ¿no existió nunca? - Tendenzias.com

  16. Forgive me for being entirely ignorant to the realm of paleontology, and indeed if I missed an important text to describe my question.

    How much data can be inferred from fossils on the age of individuals? and indeed is there any comparisons to be drawn with birds, including this and various possible pathologies. Has Horner tried to establish that X dinosaurs he is claiming to be a different aged group of the same species — as opposed to unique species — by evidencing them to all belong to said specific age?

    Perhaps again it is my ignorance, but it does seem Jack Horner is prone to minor crusades in his field. T Rex being an exclusive scavenger seems utterly ridiculous; and he doesn’t appear to be willing to accept what seems to be a rather more sensible look at the animal as a hunter that is by no means above scavenging (as many hunters do). In fact I could imagine T Rex choosing to scavenge, as it may well require rather less expenditure of energy.
    The fact that he is so open about his dislike for this particular animal doesn’t really help, it just doesn’t seem like he’s being completely objective.

    • Pangeia King

      Sorry for the late, late response. Just as a reminder, I too not a professional paleontologist, so the chances I might spill out nonsense is a possibility, especially on very technical subjects. But let’s get to your questions: indeed it is possible to infer extinct animal’s age to a extent by bone material analysis; younger individuals seem to possess a “lighter” built bone structure, I believe the word Horner used was “spongy”, actually; while older individuals have a thicker, more solid structure. His reasoning is that the individuals he analyzed seemed to portray a clear growth series of triceratops from babies all the way to adulthood, with Torosaurus as the last stage since apparently all individuals found possessed the solid structure of an adult, while Triceratops supposedly had still-forming bones expected to found in young individuals.
      To be fair, this study (and by extent, this article) IS pretty old by now, and there have been many other studies since looking into this matter and the conclusion is that while many of the fossis Horner attributed to early stages of the Triceratops do seem to be of this species, Torosaurus is a completely separated species (i.e. Triceratops individuals with solid structures and Torosaurus with lighter ones).
      I do believe Horner is somewhat biased in certain subjects. I actually don’t have anything against him (and since he retired I don’t feel like still picking on him) and respect his work, but certain points about his ideas do seem to be controversial for the sake of it.

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