• Category Archives Extinct Reptiles
  • Articles about extinct reptiles

  • Sprawling crocodylians walk straight even if there isn’t much O2 to go around.

    Photo of estuarine crocodile by: D. Parer and E. Parer-Cook
    Photo of estuarine crocodile by: D. Parer and E. Parer-Cook

    Two new papers have recently hit the journal circuit. Both of them involve using living crocodylians to gain a better understanding of paleo-life.

    The first one comes from Denver Museum of Natural History paleontologist, Dr. Kenneth Carpenter:

    Carpenter, K. 2009. Role of Lateral Body Bending in Crocodylian Track Making. Ichnos. Vol.16:202-207. doi:10.1080/10420940802686137.

    The study used an adult Caiman sclerops (first use of a large adult reptile for a locomotion study; at least as far as I know) placed in a small room with two 30cm walls placed on either side of it. This restricted any lateral movement, and “funneled” the animal out the singular opening. At this opening, a camera was placed. It would photograph the animal as it left the room. The room itself, had a smoothed mud covering. This muddy floor would record the tracks of the C.sclerops as it walked by.? Several runs were done, and photographs were taken for each run.

    This is the first study I have seen that gave a front view shot of an adult crocodylian as it walked along. As Carpenter mentioned in the paper:

    This front view is in contrast to most photographic studies which only capture pro?le and top views….

    Carpenter also mentioned the potential of there being an ontogenetic change in limb stance as animals move from hatchling to adult. This is something that I have hinted at previously Hatchling crocodylians seem to have weaker femoral adductors than adults. This is understandable given the greater weight that adult femora need to bear. This can result in a skewed view of crocodylian erect stance; with most authors tending to underestimate the degree of “parasagittality.”

    That said, I was surprised to read that Carpenter had found the adult Caiman sclerops to have a hip adduction angle of approximately 65? from the horizontal. Judging from figure1B, the hindlimb appears to be much closer to the midline than the forelimb. Fig1D seems even closer to, if not 90?. It is important to point out that much of the hindlimb is blocked by the body in this shot, as the animal is fully laterally extended. A concurrent shot from behind would have been very useful here; as would an x-ray series of shots throughout the walk phase (for instance: see this long video of a Crocodylus acutus walk cycle. Pay special attention to the position of the femur).

    Alas, that is not what the paper is about.

    The paper is about how lateral movements during locomotion, have substantial effect on trackways. Dr. Carpenter points out how, despite the semi-erect stance of the forelimbs, the track evidence would suggest an animal with a much narrower (parasagittal?) stance. This has bearing on how prehistoric reptiles, in particular: quadrupedal dinosaurs, may have stood.

    One might rightfully ask if we should expect dinosaurs to have had any lateral movement to their walking cycle at all. Carpenter points out that lateral body bending, though not quite as exaggerated as that of crocs, is present in most tetrapods. Birds seem to be the sole exception, with their extremely stiff thorax. However birds are also obligate bipeds, and the avian thorax is much shorter and stiffer than that of dinosaurs.

    So it would seem to be a likely bet that quadrupedal dinosaurs likely exhibited some degree of lateral body bending.

    Triceratops pic from britannica.com, but originally from: Mounted Skeleton of Triceratops elatus? by Henry Fairfield Osborn, American Museum Novitiates, Sept. 6, 1933
    Triceratops pic from britannica.com, but originally from: Mounted Skeleton of Triceratops elatus? by Henry Fairfield Osborn, American Museum Novitiates, Sept. 6, 1933

    Carpenter’s work rightfully asks us to caution reconstructions of stance based largely off of trackway evidence. A fine case study that the paper brings up, is ceratopians. This group, more than any other, has received considerable attention for how the forelimbs were oriented. Early work on ceratopians, favoured a hefty sprawl to the forelimbs (e.g.? Gilmore 1905, or Lull 1933). This was critically evaluated during the heyday of the dinosaur renaissance. Authors such as Bakker (1986), Paul and Christiansen (2000), instead favoured a fully erect stance. A large portion of the data supporting this assertion, was trackway based. The results of this study call into question that view. However this was not the first paper to have done so. Thompson and Holmes (2007) also questioned the “erect ceratopid” view, using a half scale model of a Chasmosaurus irvinensis forelimb. Their results come closer to the results from this paper. Though Thompson and Holmes felt that there was no real modern analogue to ceratopian forelimb mechanics.

    In the end, Dr. Carpenter reminds future researchers of the importance in incorporating the entire animal when analyzing trackways.

    The second paper comes from the Journal of Experimental Biology.

    Owerkowicz, T., elsey, R.M. and Hicks, J.W. 2009. Atmopsheric Oxygen Level Affects Growth Trajectory, Cardiopulmonary Allometery and Metabolic Rate in the American Alligator (Alligator mississippiensis). J.Exp.Biol. Vol.212:1237-1247. doi:10.1242jeb.023945.

    The authors embarked on a study of how previous paleo-atmospheric oxygen levels might have affected the lives of animals that would have been alive through these times. According to Owerkowicz et al, crocodylians were chosen because:

    Given their phylogenetic position and highly conserved morphology throughout their evolutionary history, crocodilians are often thought to retain many characteristics of basal archosaurs.

    I do take some issue with this, as prior reviews on crocodylomorph diversity (Naish 2001) coupled with many new discoveries ( Buckley et al 2000,? Clark et al 2004, Nobre & Carvalho 2006)? continually cast doubt on the old view that crocodylians have survived “unchanged” for some 200 million years. Nevertheless, the results of the study are both interesting, and relevant to reconstructions of how paleo-life would have adapted to these wildly different paleo-atmospheres.

    Owerkowicz et al raised groups of hatchling American alligators (Alligator mississippiensis) under three different atmospheric conditions. A hypoxic (12% O2) condition reminiscent of paleo-atmospheric models for the late Triassic/Early Jurassic periods. Current atmospheric conditions (21% O2), and a hyperoxic (30% O2) condition reminiscent of paleo-atmospheric models for the Carboniferous and Permian periods.

    The results were interesting, though not too surprising. As expected, hypoxic alligator hatchlings were smaller than their normal and hyperoxic counterparts. However, the degree of growth stunting is pretty surprising. Hypoxic hatchlings were about 12% shorter and 17% smaller than normal hatchlings.

    Baby alligators pic from REPTILES mag. December 94. Author unknown.
    Baby alligators pic from REPTILES mag. December 94. Author unknown.

    Surprisingly, hatching time did not change under any conditions. This suggests a degree of “hard wired” embryological development inside the egg. In the case of the hypoxic hatchlings, they came out “almost done.” While all three groups had remnants of a yolk sac upon hatching, the hypoxic hatchlings actually had the yolk sac still protruding (normal and hyperoxic hatchlings just showed distended bellies). In some cases, the yolk sac was larger around than the hind legs, thus making movement clumsy and cumbersome.

    Other interesting results from this study, included notable changes to the cardiopulmonary system. Hypoxic hatchling lungs were actually smaller than the lungs of normal hatchlings; which appears counterintuitive. The heart, meanwhile, showed distinct hypertrophy in hypoxic animals. The authors believe that lack of lung growth in hatchlings may have been due to the fact that lung function does not start until after hatchlings have hatched.? The heart, on the other hand, is hard at work circulating blood just as soon as it is formed; so it would have experienced the challenges of hypoxia at a very early stage.? Bolstering this hypothesis from the authors was the fact that three months after hatching, hypoxic alligators showed a distinct increase in lung growth rate (the lungs appeared to be “catching up” to the heart).? Hypoxic alligators showed shrunk livers as well. No real explanation for this was given, but it was mentioned that reduced liver mass seems to be a common trait in animals raised in hypoxic conditions. It appears to have some bearing on overall metabolic rate.

    Hyperoxic hatchlings exhibited “typical” organ growth rates.? Where hyperoxic animals excelled was in breathing and metabolic rate.

    Breathing rates were smaller in this group, while metabolism and growth rate were all larger. The explanation by the authors was that these hyperoxic animals were receiving such high amounts of oxygen in each breath, that they were actually hitting saturation at much shallower breaths; hence the shallow breathing. The higher metabolic rate is believed? due to a lack of right-left shunting in the crocodylian heart. This shunting is usually caused by low oxygen levels (like that experienced in diving), and tends to result in metabolic depression to conserve available oxygen stores.? Since these alligators lungs were constantly saturated with oxygen, right-left shunting never occurred, resulting in an elevated metabolism.

    Incidentally, Owerkowicz et el give mention of a cardiac shunt known in embryological birds (via the ductus arteriosis). Though only analogous, one can’t help but wonder what this might have meant for all those dinosaurs that lie between these two groups.

    Interestingly, hypoxic alligator hatchlings also showed a higher standard metabolic rate. Though these animals would voluntarily eat less than their normal and hyperoxic counterparts, their metabolism was more like hyperoxic hatchlings than they were normal hatchlings.? Owerkowicz et al believe the reason for the increased metabolism was due to the higher cost of breathing in these animals. Despite taking “normal” breaths, hypoxic hatchlings were taking in a larger tidal volume than their normal and hyperoxic siblings. The heart was also working harder to deliver enough oxygen to tissues.

    Finally the authors give mention of growth rates in hyperoxic animals. Basically, it is faster. The authors mention that this might be caused by the persistently elevated metabolic rate, or perhaps from channeling saved energy from breathing (which is one of the main energetic costs in reptiles) into biomass.? It could be a mix of both, but I’m more inclined to think that it comes more from channeling energy reserves into other parts of the body. A high metabolism means nothing, if there is not enough free energy to go around. Just look at the hypoxic gators from this study. Despite their high metabolism, they grew slower than their peers.

    The results of this study showed how modern animals can acclimate to different atmospheric conditions. They don’t show how animals would adapt and evolve in these conditions, but they do hint at the general directions, and help give us a clearer picture of what life was like millions of years ago.



    Bakker, R. 1986. The Dinosaur Heresies. William Morrow. New York. ISBN: 0821756087, 978-0821756089 pps: 209-212.Buckley, G.A., Brochus, C.A., Krause, D.W., Pol.D. 2000. A Pug-Nosed Crocodyliform from the late Cretaceous of Madagascar. Nature. vol.405:941-944.

    Clark.J.M., Xu, X., Forster, C.A., Wang, Y. 2004. A Middle Jurassic ‘Sphenosuchian’ from china and the Origin fo the Crocodylian Skull. Nature. Vol.430:1021-1024.

    Gilmore, C.W. 1905. The Mounted Skeleton of Triceratops porosus.? Proceedings United States National Museum. Vol.29:433-435.

    Lull, R.S. 1933. A Revision of the Ceratopsia, or Horned Dinosaurs. Memoirs of the Peabody Museum of Natural History. Vol.3:1-175.

    Naish, D. 2001. Fossils Explained 34: Crocodilians. Geology Today. Vol.17(2):71-77.

    Nobre, P.N. and Carvalho, I.S. 2006. Adamantinasuchus navae: A New Gondwanan Crocodylomorpha (Mesoeucrocodylia) from the Late cretaceous of Brazil. Gondwana Research. Vol.10:370-378.

    Paul, G.S., and Christiansen, P. 2000. Forelimb Posture in Neoceratopsian Dinosaurs: Implications for Gait and Locomotion. Paleobiology, 26(3):450-465.

  • A critical evalution of Tianyulong confiusci – part 3: Plucking at the idea of feathered dinosaurs

    This post took a little longer to get together than I expected. Much like the first installment of this series, I found myself writing more and more. This time, though, rather than bother with breaking the post up into a bunch of smaller sections, I’ve decided to just dump the whole thing online at once.

    Don’t worry, I’ve provided lots of pretty pictures to ease the eye strain. 🙂


    While an in-depth look at Tianyulong confiusci‘s filaments (or as in-depth as one can get with just photos), has left me with doubts regarding their validity, one question still lingers.

    If the filaments do prove to be genuine epidermal structures, then what does this mean for dinosaurs in general?

    When this little ornithischian was announced, many in the paleo community (in particular the paleo-art community) seem to have used this little guy as a license to draw feathers on pretty much any dinosaur. After all, if protofeathers are found in ornithischians and saurischians, then it seems likely that they were a basal trait for dinosaurs in general. Some have even argued that the filaments alleged for Tianyulong, along with the protofeathers of maniraptorans, and the “fur” in pterosaurs, are all homologous structures; thus making a “furry” covering a primitive (plesiomorphic) trait for all of Dinosauria.

    This is where we really need to start putting the brakes on. One only needs to do a cursory examination of any archosaur cladogram to see that there is a problem with this argument.

    Though it is all too often forgotten, we have found the skin impressions from practically every major dinosaur group known to science. You know what these impressions show?


    Scale impressions from the stegosaur Gigantspinosaurus sichuanensis, from Xing Lida's Dinosaur Channel


    In practically every case, “skin” impressions from dinosaurs show them to have been scaly. Impressions from hadrosaurs (Sternberg, 1909, Anderson et al 1999), ceratopians (Brown 1917, Sternberg 1925), stegosaurs (Xing et al 2008, and photo on the left), ankylosaurs (Parks, 1924), sauropods – including embryos (Coria and Chiappe 2007), and most theropods (Abelisaurs [Czerkas & Czerkas 1997], Allosaurs [Pinegar et al 2003] and Tyrannosaurs [Currie et al 2003]) have all shown the presence of hexagonal, or tuberculate scales. Dinosaurs were a decidedly scaly bunch. (Proto)feathers were the exception, not the rule.

    A common counter-argument to this has been that protofeathers could have been lost as animals got larger, or that protofeathers were an ontogenetic thing, with fuzzy babies going bald as they reached adulthood.

    The essential problem with this argument is that scales are not equivalent to naked skin.

    Scales, like hair and feathers, are a form of integument. Though they form as an infolding of the epidermis, they nonetheless lie on top of it. There are certain mutations in reptiles that will produce scaleless mutants (e.g. “silkback” dragons). These mutants retain their epidermis (which often looks very loose). The epidermis can also be clearly viewed between the scales of snakes while they are swallowing a large prey item. If dinosaurs really did lose protofeathers as they got larger, then one would expect to see patches of naked skin in between patchy feathers (much like what we see in extant pachyderms), but that’s not what we are seeing.

    "Silkback dragons." A new breed of bearded dragon that lacks scales. Photo from the Bearded Dragons and Other Creatures website. Click the photo for more information.
    “Silkback dragons.” A new breed of bearded dragon that lacks scales. Photo from the Bearded Dragons and Other Creatures website. Click the photo for more information.

    It is often pointed out that birds have both scales and feathers, thus making it possible for scales to occur in conjunction with feathers on dinosaurs.

    However, this generalizes the relationship between scales and feathers. The fact is scales in birds do not occur because of an absence of feathers, but rather from active suppression of feather formation (Sawyer and Knapp, 2003). If one has ever plucked a chicken one might notice a distinct lack of scales on the most of the body. Despite the fact that feathers form along tracts in the skin, the areas between these tracts remain bare. Ostriches (Struthio camelus) provide another prime example of this.

    Ostrich pic from: T-Rat's Dinosaur Pages. Click to visit.
    Ostrich pic from: T-Rat’s Dinosaur Pages. Click to visit.

    Ostriches are large birds that, like most large animals living in tropical climates, have undergone a fair amount of insulation loss in order to avoid overheating. One need only look at the bare flanks, or neck of an ostrich to see that scales are nowhere to be found on these section. Scales only occur on the tarsometatarsal (ankle and toe) portion of the body. In fact there is a rather sharp demarcation where this occurs. This demarcation agrees well with embryonic studies of diapsids which show how integument formation occurs (Alibardi & Thompson 2001).

    Feather ß-keratin proteins are likely homologous with scale ß-keratin. However they are also smaller than scale proteins (likely caused by a deletion to the scale ß- keratin gene [Gregg et al 1984]). Taken together all of this suggests an antagonistic relationship between scales and feathers. One that would determine integument placement based off of where one protein cascade ends, and another one begins.

    To put it another way, the chances of a scaly dinosaur with a feathery mohawk, are extremely unlikely.

    The ontogenetic argument seems even less likely, as it posits that dinosaurs lost one type of integument as hatchlings and then grew a completely different type as they reached adulthood. This would make dinosaurs unique among vertebrates in doing that.

    To summarize then, scaly dinosaurs were not “naked” like elephants and rhinos. If we are to believe that a dinosaur group lost protofeathers as it evolved to be larger, then we must also assume that group then re-evolved scales in its place.

    It is at this point where a cladogram comes in handy.

    The following are three cladograms showing the possible evolution of filamentous integument in archosaurs. Each terminal group is one that we know the integument for (though not the exact member who’s picture I used). I’ve simplified things a bit with the coelurosaurs due to the nebulous nature of both Sinosauropteryx prima and the putative tyrannosauroid Dilong paradoxus. This should have little effect on the results as all these guys would do is add even more steps to the following situations. The general outcome remains unchanged.

    The following are a few hypotheses that have been proposed over the last month for dinosaur integument evolution.

    Hypothesis 1: The filaments seen in Tianyulong, Psittacosaurus, maniraptors, and pterosaurs are all homologous structures, thus making protofeathers the plesiomorphic trait for all of Dinosauria.

    If these filaments are homologous. Blue dots indicate where filaments would have been lost, and scales would have re-evolved. Click picture to enlarge.
    If these filaments are homologous. Blue dots indicate where filaments would have been lost, and scales would have re-evolved. Click picture to enlarge.

    Take a look at our first cladogram. The blue dots indicate cases where a trait was lost, or reversed. In order for our first hypothesis to be true, then protofeathers would have to have been lost a total of 7 times! Also keep in mind what I mentioned previously. We are not just talking about protofeather loss, but also scale re-acquisition. That would also have to have occurred 7 times; making for a whopping 14 evolutionary steps!

    Hypothesis 2: The filaments seen in Tianyulong, Psittacosaurus, maniraptors, and pterosaurs are merely analogous to each other. They represent yet another case of convergent evolution.

    If filaments are convergent. Red dots indicate areas where filaments would have evolved independently. Click to enlarge.
    If filaments are convergent. Red dots indicate areas where filaments would have evolved independently. Click to enlarge.

    As the second cladogram shows; if this position is true, then protofeathers would have evolved a total of 4 different times. Once in the theropod line, once in pterosaurs, and twice in Ornithischians. That’s still a lot, but not nearly as many as in our first case.

    Hypothesis 3: Protofeathers were the plesiomorphic trait for ornithodirans (pterosaurs and dinosaurs), but were lost at the base of Dinosauria, and subsequently reacquired by various dinosaur groups over time.

    If filaments were ancestral, but were lost early on and then reacquired. Click image to enlarge.
    If filaments were ancestral, but were lost early on and then reacquired. Click image to enlarge.

    As one can see from cladogram 3 there, this situation results in a messy outcome. We see a single re-evolution in theropods, while Ornithischians show a helter-skelter pattern of filament reacquisition, and subsequent loss. The result is 1 case of evolution, 4 cases of filament loss as well as 4 cases of scale reversal, and 2 cases of filament re-evolution; making for a grand total of 11 steps.

    Technically one could make the 3rd cladogram a bit different by having filamentous integument evolve twice within Ornithischia. This reduces the steps needed to 6, and makes for a cladogram very similar to cladogram 2.

    A general rule of thumb for systematic paleontology, is to assume that evolution takes the least amount of steps possible (we assume Nature is generally lazy that way). As such, the evolutionary situation that produces the fewest “steps” is assumed to be the most likely situation. Nature doesn’t have to flow that way. There are cases out there where evolution might take a more complicated road, but in general this assumption that the simplest explanation is the most likely, tends to hold up.

    So what does that say about our current situation?

    Assuming that filamentous integument occurred a few times in ornithodiran evolution, results in a cladogram with substantially fewer steps (4). As such, it appears the most likely, or most parsimonious case.

    Protofeathery integument could still be basal to Dinosaurs, and all those necessary reversals could still have occurred, but the road getting there seems unnecessarily complicated, and thus rather unlikely.

    As it stands right now, it appears that if the filaments on Psittacosaurus and Tianyulong did belong to their respective owners, then they are a case of convergent evolution. Though generally frowned upon in systematics (mostly because it is a pain in the ass for phylogenetics), convergence is a rather common feature of evolution. For instance, in squamates alone the evolution of live birth has occurred a conservative 100 times (Shine 2005)!

    So yeah, convergence happens; even for seemingly complicated things. That the filaments in these ornithischians, bear almost zero similarity to those of Sinosauropteryx and kin, further supports the hypothesis that they are an independent case of evolution.

    There is another alternative that seems to rarely get mentioned. It is possibile that these filaments are actually scale derivatives. This would not be that surprising. Scales produce a wide variety of different ornamental structures in extant reptiles (from strange nose protuberances in certain iguanians, to flashy frills in agamids, and soft velvety skin in some geckos). In fact, the presence of the Psittacosaurus “quills” alongside scales, suggest that they are more likely to be a scaly derivative, than a feathery one.

    Test caption



    Gonocephalus grandis, Rhacodactylus ciliatus, and Atheris hispida. Just some examples of scale diversity in extant reptiles.

    What of the other major implication for basal “fuzz” in dinosaurs. Does this clinch the “dinosaurs were warm-blooded” argument?

    Despite the wishes of some of the more vocal dino enthusiasts on the internet, this does not signal the death knell for bradymetabolic dinosaurs.

    Both mammals and birds have an insulatory coat. From what we can gather, the role (or one of the roles) of this coat is to keep body temperature fairly constant. Therefore it is tempting to look at both feathery birds and fuzzy mammals and assume that a high metabolic rate (or automatic endothermy) must be associated with insulation.

    However mammals and birds only represent two instances of insulation. As any statistician will tell you, two points make a line, not a pattern. What would help would be if there was at least one other group of critters that had insulation.

    Well, it turns out that there are: Arthropods.

    From the “woolly crustaceans” of the deep ocean, to bees and tarantulas, “hair” is fairly common among arthropods. This hair (deemed: setae) has a different embryological origin from mammalian hair, so it cannot be considered homologous.

    So there is a third outgroup that shows filamentous coverings. Is it also associated with a constant body temperature and automatic endothermy?

    Well no.

    In many species, the setae appear to function primarily as touch sensors; whether it be for the legs of a fly, or the body of a orb weaving spider. Still there are a few (moths, bees, certain beetles), that do use their hair for insulation. These animals are “functional endotherms.” That is to say that they use muscular power to generate heat internally. The difference between them and the classic “warm-blooded” mammals and birds, is that heat is generated solely by “skeletal” muscle, and can be turned off.

    That insulation should not automatically equal “warm-bloodedness” has been recognized before. Previous authors (Schmidt-Nielson 1975, Withers 1992) have pointed out that while insulation does seem to lead to homeothermy, it does not associate so well with a high metabolism.

    So then could we say that Tianyulong and the “feathered” theropods were using their insulation to maintain a stable body temperature.

    Maybe not.

    If one is to use filaments for insulation, then they need to be spaced close enough that they will trap a layer of air between them and the skin. In mammals and birds this results in a notably fuzzy coat. Yet, sometimes this look can be deceiving. Consider polar bears. Despite their hairy look, polar bear fur offers very little insulatory benefits (Lavers 2000). The main use for the fur, seems to be to hide the black, sun absorbing skin underneath. Polar bears stay warm by maintaining a large layer of fat between their skin and the body core. The wide spacing of the hairs also allows them to quickly drain water from the body when the bears emerge from their icy swims (where insulation benefits of fur equal exactly zero). So if one is going to keep warm by being fuzzy, then that fuzz better be pretty thick.

    For the protofeathered/feathered maniraptorans, the fuzz count appears high enough to allow for functional (possibly passive) homeothermy. This is not the case with Tianyulong. The filaments in T.confiusci are spaced too far apart to allow for much in the way of heat retention. These filaments must have been used for something else. Possibly as a means of defense by keeping attention focused on the tail, or (if backed by erector muscles) by making the animal look substantially bigger and more intimidating to a potential predator. They may have been used in a more passive sense by conferring camouflage to their owner. All are possible alternative uses for these filaments (ignoring, for now, the likelihood of these filaments being used for multiple purposes).

    Besides all that, the Mesozoic is well known for being a time of high global temperatures. This doesn’t lend well to the assumption that filaments were evolved to keep their owners warm.

    Now if they evolved to help keep heat out…

    ~ Jura


    Anderson, B.G., Barrick, R.E., Droser, M.L., Stadtman, K.L. 1999. Hadrosaur Skin Impressions fom the Upper Cretaceous Neslen Formation, Book Cliffs, Utah: Morphology and Paleoenvironmental Context. Vertebrate Paleontology in Utah. David Gillette (ed). Utah Geo Survery. ISBN: 1557916349, 9781557916341 pps: 295-302.
    Alibardi, L. and Thompson, M. 2001. Fine Structure of the Developing Epidermis in the Embryo of the American Alligator (Alligator mississippiensis, Crocodilia, Reptilia). J. Anat. Vol.198:265-282.
    Brown, B. 1917. A Complete Skeleton of the Horned Dinosaur Monoclonius and Description of a Second Skeleton Showing Skin Impressions. Bul AMNH. Vol.37(10):281-306.
    Coria, R.A. and Chiappe, L.M. 2007. Embryonic skin from Late Cretaceous Sauropods (Dinosauria) of Auca Mahuevo, Patagonia, Argentina. J. Paleo. Vol.81(6):1528-1532.
    Currie, P.J., Badamgarav, D., Koppelhu, E.B. 2003. The First Late Cretaceous Footprints from the Nemegt Locality in the Gobi of Mongolia. Ichnos. Vol.10:1-12.
    Czerkas, S. A., and S. J. Czerkas. 1997. The integument and life restoration of Carnotaurus. In D. L. Wolberg and G. D. Rosenberg (eds.), Dinofest International, Proceedings of the Symposium at Arizona State University, pp. 155?158. Philadelphia Academy of Natural Sciences, Philadelphia.
    Gregg, K., Wilton, S.D., Parry, D.A., and Rogers, G.E. 1984. A Comparison of Genomic Coding Sequences for Feather and Scale Keratins: Structural and Evolutionary Implications. Embo J. Vol.3(1): 175-178.
    Lavers, C. 2000. Why Elephants Have Big Ears: Understanding Pattersn of Life on Earth. St. Martins Press. NY. ISBN: 0312269022. pg 104.
    Parks, WA. (1924). Dyoplosaurus acutosquameus, a new genus and species of armoured dinosaur; and notes on a skeleton of Prosaurolophus maximus. University of Toronto Studies, Geological Series 18, pp. 1-35
    Pinegar, R.T., Loewen, M.A., Cloward, K.C., Hunter, R.J., Weege, C.J. 2003. A Juvenile Allosaur with Preserved Integument from the Basal Morrison Formation of Central Wyoming. JVP. vol.23(3):87A-88A.
    Sawyer, R.H. and Knapp, L.W. 2003. Avian skin Development and the Evolutionary Origins of Feathers. J. Exp. Zool. (Mol Dev Evol). Vol.298B:57-72.
    Schmidt-Nielson, K. 1975. Animal Physiology Adaptation and Environment. Cambridge University Press. Cambridge. ISBN: 0521570980, 978-0521570985. pg 669.
    Shine, R., 2005. Life-History Evolution in Reptiles. Annu. Rev. Ecol. Evol. Syst. Vol.36:23-46.
    Sternberg, C.H., 1909, A new Trachodon from the Laramie beds of Converse County, Wyoming. Science, v. 29, p. 753-754.
    Sternberg, CM., 1925, Integument of Chasmosaurus belli: Canadian Field Naturalist, v.39, p. 108-110.
    Withers, P.C. 1992. Comparative Animal Physiology. Brooks Cole. ISBN: 0030128471, 978-0030128479. pg 949.

  • A critical evaluation of Tianyulong confiusci – part 2

    Continuing from yesterday, the following is what I garnered from the Tianyulong confiusci specimen announced last week.

    When looking at the fossil, a couple preliminary questions came to mind.

    1. Is the fossil real?

    2. Is the integument real feathers/protofeathers?

    Is the fossil real?

    Main slab for _Tianyulong_ with highlights showing the breakage in the slab
    Main slab for Tianyulong with highlights showing the breakage in the slab. Click the image to enlarge.

    The initial paper gives no mention of how the fossil was collected (i.e. if it was collected by local farmers – as most of these fossils are – or if it was found in the field), so it is hard to tell how many hands this fossil has passed through before it was described. The specimen is broken into at least 3 different slabs (as shown in the first pic. Highlights [mine] show where breaks occur). The first, and most obvious, is across the top of the body, separating the dorsal vertebrae from the rest of the fossil. The second break, is a little less obvious. It appears to neatly separate the anterior part of the body, from the posterior part (pretty much right before the hip). It’s hard to tell from the photos, but this section might have been glued together. Whether this was before it reached the scientists, or after is left unclear. So there is room for suspicion there. The characters used to determine heterodontosaurid affinities come exclusively from the skull. The preservation of the hip makes it very hard to tell what one is looking at. The ischium appears quite a bit thicker than in Heterodontosaurus tucki. This could be chalked up to generic difference, or even an ontogenetic one. The authors mention the presence of extensive ossified tendons on both dorsal and ventral sides of the caudal vertebrae. This is actually unusual for an ornithopod. Ossified tendons tend to be arranged in a lattice-like geometry throughout the dorsal portions of the caudal verts, but not the ventral side. Tianyulong not only has ossified tendons on both dorsal and ventral sides of the caudals, but they are arranged in a parallel fashion rather than the more typical lattice work. This sounds much more like what one would expect to see in a dromaeosaur, not a heterodontosaurid. Especially since the eponymous Heterodontosaurus lacked ossified tendons. This would make this tendon arrangement both unique for heterodontosaurs, and unique for ornithopods.

    Incidentally, there is yet another crack that separates this section of the tail from that of the proximal (and apparently tendonless) portion of the tail. It doesn’t look like the crack goes all the way through the slab, but this can’t be verified from the photos. Nonetheless, this is yet another cause for skepticism.

    Another bit of strangeness is the presence of an apparent stain along most of the skeleton. It appears as a lighter, white colour, and is found within the body cavity, and along the back and tail. This might have been caused by the dissolving of the soft tissue. Whatever it is, this stain cuts off all the apparent filaments from the rest of the skeleton (save one small section that will be described later). In fact, there is one part where the stain appears to cut ? rather sharply ? right through the tail filaments. This cut is at an angle to the tail, thus not following the body contour at all. In fact, it almost looks like a deep gouge like that caused by a shovel, or (in this case) a trowel. Perhaps this was a casualty of the preparation/excavation.

    After looking the fossil pictures over, I have to say that Tianyulong more than any other “feathered dinosaur” before it, has the potential to be a chimera.

    Is the integument protofeathers/feathers?

    Well, the answer is an emphatic no to the latter. These are definitely not feathers.

    So then are they protofeathers?

    In the paper, Zheng et al mentioned that the filaments bear a similarity to both the “quills” on Psittacosaurus , and the protofeathers of Sinosauropteryx. Curious; I decided to compare the three.

    Comparison of the _Psittacosaurus_ "quills" (top), _Sinosauropteryx_ protofeathers (left) and _Tianyulong_ "filaments" (right)
    Comparison of the Psittacosaurus “quills” (top), Sinosauropteryx protofeathers (left) and Tianyulong “filaments” (right). Click the image to enlarge.

    Right off the bat, I’d say one can dismiss any real relationship to the protofeathers of Sinosauropteryx. The filaments on Tianyulong are similar only in the sense that they don’t branch at all. Short of that, the size, and density of Tianyulong‘s filaments are quite different from those of S.prima (being wider, longer and more loosely packed).

    When compared to the “quilled” Psittacosaurus, a much greater similarity can be seen as both filaments are rather long. The Psittacosaurus “quills” however, are quite a bit thicker, and seem to show up within the skin, while Tianyulong‘s filaments don’t touch the skeleton at all, save for the same spot where the strange (possible) groove is found.

    Some folks have stated that the large filaments are focused on the caudal portion of the body, just like in the “quilled” Psittacosaurus specimen. I would caution against this. Most of Tianyulong‘s body is not preserved. Unlike the Psittacosaurus specimen, where one could tell that these “quills” appeared only on the tail, there is very little evidence for the same arrangement in Tianyulong. I would extend this caution to statements about Tianyulong being completely fuzzy too. There are some filaments found by the dorsal vertebrae and under the cervicals. However, these filaments are much removed from the body. The dorsal patch does not follow the arch of the vertebrae; instead lying more anterior to the bones. As for the ventral patch, unless one wants to posit a double chin on Tianyulong, they also don’t actually associate with the bones, nor do they follow the body contour.

    The caudal filaments are strange in their own right. Like all the rest of these filaments they don’t follow the body contour (compare, for instance how the protofeathers of Sinosauropteryx follow the body rather tightly). In fact many of these filaments seem to be tangled amongst each other.

    Note there is yet another apparent break in the slab, between the filaments.

    If everything is arranged correctly, then these filaments seem to be tangling up with filaments that would have emerged much further up the back. Also unlike the singular “quills” on the Psittacosaurus, these thinner filaments all appear to protrude from the same narrow area. Instead of being more evenly spaced along the caudal vertebrae, they all bunch up by the proximal caudals. If these filaments did belong to the living animal, then it would appear that Tianyulong was brandishing a “smokestack haircut” long before Kid from Kid and Play ever did.

    Final verdict:

    Readers will no doubt have noted my extensive use of quotes around certain instances of protofeathers, as well as the mention of quills in the infamous Psittacosaurus specimen. I do so because of the questionable assignment of these filaments to those particular structures. In doing so, I am following in the steps of David Hone, who also suggested that one be cautious with one’s interpretation of some of these Yixian fossils (though my view is a little more extreme). Many of them have been described briefly, with little follow up work. The Psittacosaurus with the “quills” is a particularly nasty case. It received a quick right up in Nature, before it was discovered that the specimen was illegally collected. Now there is a veritable “shit storm” surrounding the fossil. This has resulted in it becoming a pariah that no journal dare touch. A result that has essentially put a halt to any further research for now. It’s unfortunate, as the identity of the Psittacosaurus filaments remains in limbo (not everyone is “happy” with the diagnoses of quills).

    As for Tianyulong, there appears to be a fair amount of evidence to suggest the animal might have died on a plant, or was possibly being devoured by nematode like parasites prior to death. As for being protofeathers, they appear as unlikely in Tianyulong, as they do in Psittacosaurus. The relationship to the protofeathers of Sinosauropteryx prima, appear to be at the most basal geometric level (i.e. they are both straight and unbranching).

    Still, what if everything is genuine? What kind of implications would that hold for dinosaurs?

    For my answer to that, stay tuned.


  • A critical evaluation of Tianyulong confiusci – part 1



    Apologies to all for the delay between blog posts. It seems I really should avoid putting deadlines on these things, as every time I do so, something in real life pops up to divert my attention.

    I have since had the chance to examine the Tianyulong confiusci paper thoroughly. My initial trepidations about the fossil remain. Tianyulong is a very important find…if what it preserves is real?

    As I sat to write this post up, I watched as the pages piled up. Because of the unexpected length of the post, I decided to break this evaluation into two, or three parts (likely three, but I’m covering my bases just in case). This first part has little to do with T.confiusci, and is mostly a primer for what’s to come. Tune in tomorrow for the meat of this post.

    The story thus far

    In the interim between blog posts, Time.com has published an article on the Tianyu museum in Pingyi China (home to T. confiusci). This natural history museum has quite possibly the largest collection of fossils in the world. Their dinosaur hall alone features some 480 fossils randomly on display. The issue is just how authentic they all are.

    From the article:

    Tianyu has purchased most of its fossil collection from individuals an illegal practice permitted by authorities only because it is technically a state-owned institution. More problematic, however, is that there is no way of knowing how many of those fossils are real. Chinese scientists say fake fossils are so pervasive in Chinese museums that using authenticity as the basis for judging a collection’s worth is unrealistic.

    This has been a rampant problem in China for some time now (~10 years at least). While here in the states, paleontologists have to worry about the locality in which a fossil bought at a shop, or auction, was collected (both for legal purposes, as well as scientific documentation); fossils in China also bear the burden of possibly being faked. Fossil poachers in China know what types of fossils are preferred (“feathered” dinosaurs in particular), and have gotten very good and making fakes. So good in fact, that a thorough vetting of any major find in China should really be done. Some authors have already started inventing techniques for doing just that (Rowe et al 2001, Mateus et al 2008).

    Sadly a thorough vetting process remains the exception, not the rule for Chinese fossils. Only two major dinosaur finds have been authenticity tested. The first was the seminal “feathered dinosaur”: Sinosauropteryx prima (Chen et al 1998). The second was NGMC-91; otherwise referred to as “Dave” (Ji et al 2001). This specimen is believed to be a member of another “feathered dinosaur:” Sinornithosaurus milleni.

    Technically there was one more specimen that has received authenticity testing, but I’ll get to that in a bit.

    Photo from National Geographic's 1999 mag.

    It really seemed that once Sinosauropteryx was found to be authentic, many of the other “feathered” finds were given a free ride. Within a year’s time four separate “feathered” dinosaurs were published in Nature. There was the therizinosaur Beipiaosaurus inexpectus (Xu et al 1999a), along with Caudipteryx zoui, Protarchaeopteryx robusta (Ji et al 1998) and the dromaeosaur Sinornithosaurus milleni(Xu et al 1999b). All were preserved with variations of what seemed like “feathers” (generally referred to as protofeathers now). None appeared to have been given an authenticity test, and were (for the most part) presumed to be the real thing. Protofeathers became something to be expected from Liaoning province. If someone posted a news article about a dinosaur fossil from the Yixian formation, it was practically a given that the animal would have protofeathers of some sort.

    Then, in November of 1999, National Geographic reported on the discovery of yet another “feathered dinosaur” coined: Archaeoraptor liaoningensis (Sloan 1999) The animal was found with the true feathered wings of a bird, along with a feathered dromaeosaurid legs and tail. Though informally published by National Geographic (who had jumped the gun on the story), it was nonetheless accepted by the paleo community.

    As the weeks passed, the validity of Archaeoraptor started to get called into question. The specimen itself consisted of numerous slabs that were glued together. This was suspicious, but not surprising given that the shale of the Yixian is weak. There were some mentions of it being a chimera (one leg was apparently longer than another), but regardless, it was generally believed to be the real deal (I even had a chance to ask one of the paleontologists working with it, Phil Currie, about it’s validity, and he felt it was genuine).

    Finally, after thorough examination, it was found that “Archaeoraptor liaoningensis” was indeed a fake. The animal was a chimera composed of a bird (front half), the feathered dromaeosaurid Microraptor gui, and a third, unnamed animal. Alas, despite the apologetic retraction from National Geographic, the damage was done. The Archaeoraptor hoax was well publicized around the internet. In particular, on the websites of creationists who toted it as the newest Piltdown man (the fact that both Piltdown and Archaeoraptor were found to be hoaxes through the use of science [Rowe et al 2001], seems to be a fact that is lost by creationists).

    Archaeoraptor stood as a cautionary example of why a thorough vetting process should be undertaken for important Chinese discoveries. Especially if they come from the remarkable shales of the Yixian formation.

    Now, 10 years later, the Yixian continues to pump out new and amazing finds. Unfortunately, it also continues to pump out numerous forgeries; many of which are very well done. Despite what happened with Archaeoraptor, there is still a distinctive lack of authenticity testing going on for these fossils. So there remains a good chance that some of these “feathery” finds are not what they appear to be.

    Which brings us to our “feathered” heterodontosaurid: Tianyulong confiusci.

    Tune in tomorrow for the analysis.


    Chen, P., Dong, Z.,Zhen, S. 1998. An Exceptionally Well-Preserved Theropod Dinosaur from the Yixian Formation of China. Nature. Vol. 391: 147-152.
    Ji, W., Currie, P.J., Ji, S., Norell, M.A. 1998. Two Feathered Dinosaurs from Northeastern China. Nature. Vol. 393: 753-761.Ji, Q., Norell, M.A., Gao, K. Ji, S., Ren, D. 2001. The Distribution of Integumentary Structures in a Feathered Dinosaur. Nature. Vol. 410:? 1084-1088.
    Mateus, O., Overbeeke, M. and Rita, F. 2008. Dinosaur Frauds, Hoaxes and “Frankensteins”: How to distinguish fake and genuine vertebrate fossils. Journal of Paleontological Techniques. Vol.2:1-5
    Rowe, T., Ketcham, R.A., Denison, C., Colbert, M., Xu, X., Currie, P.J. 2001, Forensic palaeontology: The Archaeoraptor Forgery. Nature. Vol. 410: 539-540. doi: 10.1038/35069145Sloan, C.P. 1999. Feathers for T.rex?. National Geographic. Vol. 196(5): 98-107.
    Xiao-Ting, Z., You, H., Xu, X., Dong, Z. 2009. An Early Cretaceous Heterodontosaurid Dinosaur with Filamentous Integumentary Structures. Nature. Vo.. 458: 333-336.
    Xu, X., Tang, Z. Wang, X. 1999a. A Therizinosauroid Dinosaur with Integumentary Structures from China. Nature. Vol. 399: 350-354.
    Xu, X., Wang, X., Wu, X. 1999b. A Dromaeosaurid Dinosaur with a Filamentous Integument from the Yixian Formation of China. Nature. Vol. 401: 262-266.

  • Feathers in ornithischians? Probably not.

    Easily the biggest news of the day is the finding of alleged “proto feathers” or “dino fuzz” in an ornithischian dinosaur. For the most part this quick post is just going to add to the echo chamber of Tianyulong confuciusi posts and link redirects that are currently popping up around the web.

    The news comes following a paper by Xiao-Ting et al, in the journal Nature.

    The paper’s title is:

    Xiao-Ting, Z. , Hai-Lu, Y.,? Xing, X. and Zhi-Ming, D. 2009.? An Early Cretaceous Heterodontosaurid Dinosaur with Filamentous Integumentary Structures. Nature. Vol. 458 : 333-336.

    I won’t be able to read over the article until tomorrow (at which time I will return to this).? Judging from its brief 3 page spread, I expect this discovery to be as briefly documented as the alleged feathers on Psittacosaurus find from a few years back.

    Nonetheless, as with the Psittacosaurus find, the news outlets and dino fan sites (including the Dinosaur Mailing List) are all a buzz with “feathered” dinosaur news and how it relates to the origin of feathers themselves.

    Unfortunately what I don’t see (and didn’t see in many of the previous “dino fuzz” finds) is any real vetting behind the find.? According to the news outlets, the authors seem pretty set on these structures being related to feathers in some way. No mention has been made of them being possible contaminants from where the animals died (i.e. plant material, or stains from parasites), or even a possible forgery (as it does come from Liaoning Province; which is well known for their forged fossils). Furthermore, the description of the find sounds much more like the “quill” like structures that are presumed to be on psittacosaurs, than it does the “dino fuzz” present on Sinosauropteryx.

    Thankfully there have been a few voices of reason/skepticism out there.

    Dr. Larry Witmer of Ohio University offerred some alternative possibilities:

    …it is unclear at this point if Tianyulong‘s feather-like structures are part of the same evolutionary lineage as the feathers on today’s birds and the same lineage that yielded the proto-feathers on early theropods. Also, it’s possible that the Tianyulong feather-like structures really occurred under the skin, not outside it. That would change all these arguments, suggesting that the structures are collagen features in the skin, not feathery.

    Live Science

    Additional caution came from Luis Chiappe of the Natural History Museum of Los Angeles:

    But Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles County, who has written about the origin of feathers, said he doubts that feathers evolved outside of theropods and birds. Interpreting Tianyulong‘s filaments as early feathers is questionable because of their appearance, he said.

    Moreover, Chiappe said, given the apparent lack of feathers in many dinosaur species, “I don’t see any reason why you’re going to conclude that feathers must have originated before the origin of dinosaurs or (at) about the same time.”

    AP News Feed

    At this point I will withold my conclusions on this until I’ve read through the paper, and compared it with some of the other “feathered” dinosaurs.

  • Two new paleo-herps illustrate the problems of a persistent reptile myth.


    Titanoboa picture by the paper’s co-author: Jason Bourque

    I was trying to wait until I could nab the papers for these guys, but since Geology does not feel like updating their site, I’m going to have to move without them.

    Reported on 1st February, John Tarduno of the University of Rochester, and his team have discovered an alleged freshwater turtle fossil in the Canadian Arctic. The animal – given the gorgeous name of Aurorachelys (“Dawn turtle” or “Arctic turtle” as the case may be) – was found in strata dating back to the late Cretaceous. According to the press release (which is all I have to go on at the moment), the presence of the turtle has lead Tarduno and his colleagues to suggest the presence of an immense halocline in the paleo-arctic ocean.? According to Tarduno:

    …the Arctic Ocean was more separated from the rest of the world’s oceans at that time, reducing circulation. Numerous rivers from the adjacent continents would have poured fresh water into the sea. Since fresh water is lighter than saltwater, Tarduno thinks it may have rested on top, allowing a freshwater animal such as the aurora turtle to migrate with relative ease.

    The other major discovery came out today in Nature.? Researcher John Jason Head, and colleagues have discovered the world’s largest snake. The new snake has been dubbed: Titanoboa cerrejonensis, and it has been estimated to grow to a whopping 13 meters in length (43ft) and could have weighed as much as 1,135kg (2,500lbs).? The fact that this immense animal even existed, is amazing enough, but the researchers took their find a little further.

    Since snakes are poikilotherms that, unlike humans, need heat from their environment to power their metabolism, the researchers suggest that at the time the region would have had to be 30 to 34 degrees Celsius for the snake to have survived. Most large snakes alive today live in the South American and southeast Asian tropics, where the high temperatures allow them to grow to impressive sizes.

    This is where I have my problems. First for Aurorachelys; how are the researchers determining that this animal was a freshwater turtle? As I mentioned prior, I have not had a chance to read either of these papers yet, but just off the top of my head, I can’t think of any specific osteological trait that can be used to determine whether an animal is capable of salt-excretion (i.e. marine). Edit: See Nick’s comment for a list of papers on osteological correlates to salt excretion. This is what I get for posting something right before bed. 🙂? Are the researchers, instead, using the extant phylogenetic bracketing method (EPB), and figuring that Aurorachelys was a freshwater inhabitant, based of critters it was most closely related to?

    If it’s the latter, then I have reason to pause. Uniformitarianism, or the assumption that present day processes are likely the same now as they were in the past, is a very useful tool.? It’s especially useful in the realm of geology, where rock cycles are unlikely to have changed.? In biology, too, uniformitarianism can be helpful for studying processes like evolution and ecological partitioning. However a uniformitarian view of life is much less sturdy when dealing with more labile things like behaviour, or the evolution of a specific trait. If the researchers are assuming that Aurorachelys was a freshwater animal based off of EPB, then I would have to assume that salt excreting glands must be a hard thing to evolve. But are they? I’m not sure we have an answer there.

    Another issue this raises is, if Aurorachelys was a freshwater turtle that was cast adrift, then what are the chances that it would have been fossilized in the first place. Fossilization is a one in a million process as it is. In general, parsimony tells us that unique individuals / behaviours, are unlikely to be preserved. When we find a giant representative of a species, it probably was not unique, but rather a high end average animal. So too, it would seem, with Aurorachelys.? It is highly unlikely that this turtle was caught out of its element.? This may mean that this large halocline was present and that freshwater turtles were undertaking this migration rather often, or it means that the ability to remove excess salt from the body, was present in this species. Interestingly, a similar situation exists for the giant alligatoroid Deinosuchus. Salt excreting glands appear to be a unique adaptation of crocodyloids,? and not their alligatorish kin. Yet Deinosuchus founds some way to cross the saltwater filled Western Interior Seaway. Again, how hard is it to evolve salt removing glands?

    The case of Titanoboa cerrejonensis is much the same. In this case, it appears to be a clear case of the erroneous belief that reptiles make good ecological thermometers; despite the presence of leatherbacks (Dermochelys coriacea) in the freezing Northern Atlantic, or the small Chinese alligator (Alligator sinensis) living in a part of China that readily freeze, or even the relatively tiny Andean lizards ((Liolaemus multiformis), who live in parts of the Andes mountain range that experience an average daytime temperature of 10°C (50°F) , all while maintaining body temperatures of 35°C (95°F). Both the Aurorachelys and Titanoboa cerrejonensis papers appear to make assumptions that seem questionable given the evidence.? However I will reserve final judgement until I’ve had a chance to read the respective papers. Hopefully there is some hard evidence to back up the assertions that have been proposed.

    Photo by Ray Carson

    Photo by Ray Carson

    Until then, check out the comparison on the vertebrae of a large Eunectes murinus (green anaconda) and Titanoboa cerrejonensis. This beast was huge.


    Head, J.J.,Bloch, J.I., Hastings, A.K., Bourque, J.R., Cadena, E.A., Herrera, F.A., Polly, D.P., Jaramillo, C.A. 2009.
         Giant Boid Snake from the Palaeocene Neotropics Reveals Hotter Past Equatorial Temperatures. Nature. Vol 457 :715-717
    Vandermark, D., Tarduno, J.A., Brinkman, D.B., Cottrell, R.D., Mason, S. 2009. New Late Cretaceous Macrobaenid Turtle with Asian
        ?Affinities from the High Canadian Arctic: Dispersal via Ice-Free Polar Routes.Stephanie Mason. Geology, Vol 37.

  • Arctic dinosaurs special on NOVA

    Photo from Smithsonianmag.com
    Photo from Smithsonianmag.com

    Given all the recent stink over a certain other documentary, I’m not exactly itching to jump back into dino docs.

    Oh well.

    The Public Broadcasting Service’s long running series NOVA, has a new episode out, entitled Arctic Dinosaurs. The episode is about a particularly exciting find in Alaska, and its implications for our view on dinosaurs. The researchers; namely museum Victoria’s Tom Rich and MNS Dallas’ Anthony Fiorillo, came across a fossil bed along Alaska’s north slope, that revealed the existence of hadrosaurs, ceratopians and coelurosaur theropods, all living in far North Alaska.

    As I had mentioned previously, NOVA tends to get lauded for its well put together documentaries. I would argue that this doc was no different; though there were some missteps that I feel may be a sign of NOVA’s producers trying to fall more in line with the fare seen on Discovery Channel and the A&E networks.

    First, and foremost, I would like to applaud PBS for making this NOVA special available online.

    Secondly, I would like to lambast PBS for what is probably their most egregious error with this, and other NOVA specials. Namely the lack of Firefox love. The only way I am able to watch these NOVA specials is by firing up Internet Explorer. If I use Firefox all that happens is I get a dead loading screen.

    The premise of the series is fine, and as in previous iterations, NOVA has done a good job of letting the scientists talk how scientists really talk (i.e. with lots of caution and caveats).

    I was far less impressed with the writing for the narrator. There were more than a few instances where the narrator resorted to straight up hyperbole. Especially in the beginning when it is revealed that all these dinosaur fossils had been found in this polar state.

    The narrator said:

    The startling discovery that these ancient reptiles, “thunder lizards,” lived and thrived in the arctic has taken scientists by surprise.

    Then a little later:

    According to conventional wisdom, it shouldn’t be here, because this is how dinosaurs are typically pictured: cold-blooded reptiles living in tropical climes, not in cold, arctic environments like this one. And the Hadrosaur is not alone.

    Um, no. We have had discoveries of dinosaurs, and other reptiles from polar and paleo-polar latitudes, for decades now. The real neat thing about this find, was the sheer number of animals discovered. This doc served more as a review of what we have learned so far, rather than a breaking news story.

    There was another writing snafu that occurred a little further in too that I feel needs clarifying:

    Scientists long believed that dinosaur biology resembled that of cold-blooded reptiles like crocodiles, animals that require warmth to survive and cannot withstand prolonged exposure to temperatures below freezing. But not one crocodile fossil has been found along the Colville, which suggests that polar dinosaurs found a way to adapt to an environment that their cold-blooded cousins couldn’t tolerate. But how?

    This statement is misleading. We do have evidence of non-dinosaurian polar reptiles. These include Cretaceous crocodylian and turtle fossils found in Victoria, Australia (which would have been closer to the South Pole) and Axel Heiberg Island in Canada, as well as plesiosaur fossils from Antarctica, and at least the assumption that Meiolaniid turtles (large, ankylosaur like armoured turtles that lived from the late Cretaceous through to the Pleistocene) had once lived in Antarctica.

    Oh, and also Leaellynasaura amicagraphica was a herbivore; not a carnivore as was stated in the show.

    So there were those few writing missteps. The only other thing I can fault the show for was its very lackluster CG work. As NOVA is a mostly public funded series, I can forgive the lower quality CG work, though I still think they could have afforded to make their models at least a tad more realistic (especially since they teased feathers on Dromaeosaurus albertensis before returning to scaly maniraptors (i.e. the Troodon formosus). Plus their Gorgosaurus libratus was just atrocious.

    Regardless, most of these complaints are small. The writing flubs were probably the worst offenders. Short of that, the show was well put together. Though the show still fell a little more in the pro-warm-blooded camp for dino metabolism, it was the first and only time I have ever heard a documentary point out that warm-blooded and cold-blooded are opposite ends of a continuum. In fact one of the better writing moments occurred towards the end when the narrator stated:

    Dinosaurs likely had their own unique solution to the body temperature problem, which allowed them to survive for millions of years in the toughest seasonal conditions their world had to offer.

    It was nice to see a documentary that actually took a more objective stance on the whole thermophysiological debate.

    Finally another big plus for this show was the sheer number of paleontologists that rarely seem to make it in front of the camera, including Hans-Dieter Sues and Anusuya Chinsamy-Turan (the latter of whom while being a great scientist, has one of the harder to pronounce names in paleontology).

    Overall, this was another fine piece of work from the folks over at NOVA. Though there was a tendency to stray into the realm of hyperbole with the narration, and the CG work is somewhat painful to watch, the show proved informative and interesting.

    In the end, that’s really all a documentary should strive for.


  • JFC lockjaw

    I can’t help but laugh at the process by which things become popular in society. One can write various well thought out posts, or web pages that are heavily referenced, and rarely receive a response.

    Shoot from the hip and/or spout out a controversial opinion, though, and all of a sudden the traffic starts to spike.

    Hence why sites like badastronomy.com took years to get a devoted following, while LOL cats skyrocket to the top of the charts within days.

    Case in point with History Channel’s recent crockumentary: Jurassic Fight Club.

    I wrote a piece describing my thoughts on this terrible show. In it I explained exactly what was wrong with the series, and precisely what my gripe was with its main contributor: “Dinosaur George” Blasing.

    That’s all fine and good. Time passes and we all move on. Then, I discover that History Channel actually has allowed folks to watch this show online, and one day out of boredom, I decide to see if the show might have gotten any better. Seeing that the quality has continued to slide downhill, I officially give the show up for dead, but not before ripping into it one more time. This time, I get to the heart of the matter, and don’t bother being even handed.

    The result? A spike in traffic and the appearance of some George Blasing apologists.

    Ah, how funny the internet can be.

    Adding to said hilarity, I was recently informed of the fact that old “Dinosaur George” himself had been to my site, and had commented on it in his blog. Apparently I had touched a nerve, so now his fans feel the need to protect their favourite figurehead.

    That’s all fine and good. I don’t much care. As I had stated before, as far as I’m concerned JFC is just more “documentary” sewage being pushed out by Discovery Channel A&E and its subsidiaries.

    Still, I can’t help but notice a theme with some of these apologists. A theme that I can blame on old “Dinosaur George” himself. Apparently everyone thinks that I have issues with Mr. Blasing, because he is not an accredited academic.

    Or as George Blasing put it: “There is a very, VERY small group of people within the paleontology community who feel that their science should be treated like a private club, where no one outside of their tiny group of likeminded buddies can participate.”

    I’m afraid Mr. Blasing, and his fans have missed the point of my contention completely. My issue with “Dinosaur George” has little to do with his lack of formal training. True, I think that his lack of any real training in this field, poses a detriment to him, but as I wrote earlier, there is nothing wrong with being an amateur, or just a big dinosaur fan. Most new dinosaur finds come from amateurs, and not professionals. Furthermore, a doctorate, while important, does not necessarily make one qualified for a particular task. Look at “creation scientist” Dr. Duane Gish, or radio personality Dr. Laura Schlessinger. One can be an official academic and still be a Fruit Loop shy of a full bowl.

    No, qualifications are not what bug me about Mr. Blasing. It’s the fact that he presents himself as being equivalent to the scientists he interviews. “Dinosaur George” is masquerading around as an authority figure on these matters. He bills himself on the show as a “Paleontology Expert.” So for those people who don’t bother looking into exactly what that means, “Dinosaur George” comes off as an authority on par with Dr. Thomas Holtz, or Dr. Larry Witmer.

    So when Mr. Blasing spouts off something patently wrong like “dromaeosaurs could breathe through their bones,” or “megalodon was the size of a jumbo jet,” the audience at home will come away accepting that as a fact. Mind you, this is not me complaining about “Dinosaur George” taking a matter of fact stand on one particular theory. Mr. Blasing has repeatedly made glaring mistakes on specific facts about animals. Saying that “megalodon” was the size of a 747 is just plain wrong. Jumbo jets are substantially longer than 50ft (more like 240ft), and a heck of a lot heavier.

    Another one I heard about recently was from that same “megalodon” episode. Apparently it was stated that “megalodon” could “taste” the water around it, because of taste buds in its skin called denticles. Once again, this is flat out wrong. It doesn’t take much effort to learn that denticles are sharp outgrowths of the dermis in shark skin. The result feels like teeth, or sandpaper. It makes the shark’s skin rough. It does not allow them to taste the water with their bodies. However, because “Dinosaur George” said it, his followers will take it as fact (as evidenced by some of the commenters in the previous post).

    To reiterate; my problem with Mr. Blasing is that he is impersonating a professional in the field, and in the process, he is misleading the public when he talks so matter of factly about some of his subjects.

    It is unfortunate. I explained all of this previously in my first post on JFC. Judging from the date of “Dinosaur George’s” blog post, it was apparent that this was the one he had read. Rather than deal with the impersonation and rampant speculation part of the show, Mr. Blasing instead wound up focusing on my pointing out his lack of credentials.

    Still, things aren’t all bad with “Dinosaur George.” While reading his behind the scenes blog, I was happy to see one good thing about the show:

    I was very careful not to put any of our experts into situations where they were made to look like they supported a theory that I knew they were opposed to. I made sure that I took on the role of speculating how the fights could have occurred, because they were based solely on modern animal behaviors and not any real fossil evidence. Since most of our experts owe their careers to the scientific community, they have the deal with their peers and those that they answer to. So to insulate them from being attacked by those within their industry, I made sure to keep them out of the fight scenes and instead used them to support the factually based stuff earlier on in the show.

    At least “Dinosaur George” was willing to do this. So JFC is at least one step better than Animal Face-Off was.

    Still, when all is said and done, I stand by my initial claim. “Dinosaur George” still comes off as a fanboy. That JFC turned out to be his pet project, does little to alleviate this thought. Rather than use his funds to talk about how these animals may have lived, or how we know what we know about prehistoric life, he used his funds to make a series of films devoted to prehistoric cage matches. As if the only time animals are interesting is when they are fighting each other. Each show boiled down to which animals is better.

    To me that sounds an awful lot like being a fanboy.

    ~ Jura

  • Jurassic (Bites) Club

    Tyrannosaurus rex vs. Nanotyrannus lancensis

    A few weeks ago the History Channel aired their first in a twelve part series on prehistoric creatures.

    Now, being the History Channel – a subsidiary of Discovery Channel A&E Networks – one would expect this series to detail some aspect of prehistoric life. Well that it does…sort of.

    The series is called: Jurassic Fight Club. Many of you have probably already watched the first three, or four episodes, but for the uninitiated the premise is as follows:

    Imagine all 4.6 billion years of prehistory as being one planet wide cage match somewhat akin to Primal Rage. Each week two animals (usually dinosaurs, but there are the occasional mammals) are pitted against one another.

    Each hour long show is supposedly based off of a real fossil site. For instance the first episode was about a Majungasaurus skeleton that was found with bite marks of another Majungasaurus (erroneously referred to as “Majungatholus” despite paleo-consultant disapproval). One of the recent ones involved the infamous Tenontosaurus tilletti / Deinonychus antirrhopus fossils (a find with one large, dead T.tilletti and a few dead D.antirrhopus nearby. One of the first bits of evidence in favour of pack hunting behaviour in some theropods).

    The show sets the “battle premise” and then seeks to justify its reasoning by cutting to various paleontologists for their take. The paleo crew is fairly diverse and include: Dr. Thomas Holtz Jr. Dr. Larry Witmer and Dr. Phillip J. Currie.

    Okay, so maybe all that doesn’t sound so bad to some of you, but what may seem okay in theory has turned into an utter failure in execution.

    Let me state up front that I immediately left this series for suck back when I first heard the title. It sounded like just another useless “documentary” that is little more than an excuse to watch two CG animals fight each other in order to satisfy some sophomoric need to watch things fight.

    Still, there were proponents of the series (namely the paleo folks that worked on it) that urged the most skeptical of us to give the show a shot. As such, I refrained from commenting on it until now.

    Four episodes in and now even the scientists who helped on it are starting to back away.

    Honestly who could blame them. The show uses minimal information from the actual scientists. The shot of Dr. Witmer comparing theropod maxillae is continuously reused, and I could swear the show spends more time on the non-professional guys than they do the actual scientists.

    This is a problem because it is the non-professional crowd (one fellow in particular) who really bring the show down.

    The show features the likeness of one Dinosaur George Blasing. A quick perusal of his qualifications finds him to be little more than a particularly successful dinosaur fanboy. He apparently makes his living by talking about how cool dinosaurs are, to elementary school children. In effect, he is little different from Dinosaur Don Lessem, who writes books about dinosaurs for children.

    Now don’t get me wrong. There’s nothing wrong with being an amateur, or a big, but non-professional, dinosaur fan. The problem I have is with History Channel essentially letting the fanboys run the show. This is supposed to be an educational program. History Channel is supposed to be the repository for all things historical. As such, it should be held to a higher standard than, say ABC, or Fox. Yet, here we get to witness the production of another terrible program that only seeks to snatch eyeballs. It offers practically no educational value.

    Frankly that just ticks me off. Jurassic Fight Club is about as terrible as Animal Face Off was (another Discovery Channel property that not only embarrassed the subject matter, but also the scientists involved with it, by forcing them to give trash talk to one another).

    The question that shows like JFC leave me asking is: what audience is it meant for? By seeking out professional paleontologists for their input, one would assume that the makers were looking for scientific accuracy. This, in turn, suggests that the goal is to pass knowledge on to their viewers. Yet, if one can slog through the first episode they will find themselves assaulted with absolutes left and right, tonnes of MTV style quick takes and replays, and a metric tonne of speculation. Each episode ends with Dinosaur George giving “his take” on how the whole story unfolded (complete with the CG animation). Now this sounds like nothing more than Godzilla style popcorn entertainment.

    So which is it? Is JFC trying to be a documentary, or a popcorn flick?

    By trying to do double duty, it comes off as more of mockumentary. A documentary that seeks to mock the subject material in which it presents. When done right, mockumentaries can be great (e.g. This is Spinal Tap), but in cases like this, where the parody does not appear intentional, the result is more of a slap in the face to those of us who do work in the field. To ask for professional advice and then completely ignore it, is a huge insult to both professions. The History Channel people should know better.

    One question that is left from all this is: must we sacrifice scientific accuracy for entertainment, in order to get the knowledge across to the viewers?

    As one person had mentioned on another forum: if scientists were to get the documentary that they wanted, no one would watch it.

    Pardon me if I decide to call bullshit on this one. If one wants to see a documentary that is designed in a way respectful of the subject matter, one need only look at PBS’s NOVA series. Rarely does NOVA falter in their presentation style. Because of this consistent high quality the series tends to be lauded by many in the fields of science.

    Okay, so maybe NOVA is a fluke. Besides, it’s on PBS and we all know how small and concentrated the PBS demographic tends to be. Are there any other examples?


    David Attenborough – King of great documentaries

    If one really wants to see how to make a series of successful and scientifically sound documentaries, one need only to look over to the UK, and the BBC. In the realm of documentaries, the David Attenborough docs reside in the upper echelon of quality. Not only are Attenborough’s documentaries well done, and accurate, but they are also popular. Planet Earth, one of the latest Attenborough docs, was the most watched cable show of all time. Discovery Channel pulled in 100 million viewers when it first aired in the United States. That is huge for a majour network, much less a cable network (Discovery’s average prime time ratings are around 5 million viewers).

    So not only does a scientifically sound documentary bring in the audience, but it can bring them in droves. When BBC released “Life in Cold Blood,” it was an event in England, bringing in more viewers that the average drama.

    If we head back to the states, we can look at an old staple of children growing up in the 1990s; Bill Nye the Science Guy was a show that garnered a large and devoted fan following. Bill Nye was not only a great presenter and funny comedian, but he was/is also a real scientist. Though the show did its best to avoid using large words (for its young demographic), the show repeatedly and successfully showed off how awesome science was and how amazing the real world is.

    Bill Nye – Champion of science education

    You know why I think these shows did as well as they did? Because they didn’t dumb stuff down. There was no push to show the flashy stuff in order to maintain audience attention (equivalent to showing something shiny to distract a cat). The BBC documentaries, Bill Nye and NOVA all respected the intelligence of their audience, and the audience reciprocated by showing up in droves. People from all walks of life enjoy a good challenge. Today’s current documentarians would benefit from remembering this.

    So for all those scientists who are asked to participate in the next big Sci Fi/Discovery Channel/ABC show/ whatever documentary; I say don’t fear speaking your mind on the importance of keeping the science up to snuff. If the filmmakers start bitching about having to “keep things simple” or removing the science for the sake of “the story,” just tell them:

    That’s not how David Attenborough would do it.

    ~ Jura – who will probably never get a consulting job on one of these shows.

  • The old grey sauropod just ain’t what she used to be.

    Actually, I’ve never thought that sauropods were grey. Mammals in general tend to be rather bland in their colour schemes. Reptiles don’t have that problem. With xanthaphores (yellow pigmented cells), erythrophores (red pigmented cells) iridophores (iridescent cells) and melanophores (dark pigmented cells), the range of colour available to reptiles, and by extension – dinosaurs, is quite vast.

    That said, I always pictured sauropods as either a brownish green colour, or maybe a very pale blue (blue is generally rare in tetrapods, hence the thought of it being a weak blue).

    But I digress.

    I grew up during an interesting time for dinosaur research. Unlike the majority of paleontologists working right now I didn’t grow up learning about dinosaurs being slow and sluggish mistakes of nature. I also didn’t grow up with the “hummingbirds on crack” version of dinosaurs that is currently pervading popular culture. Rather, I grew up during that strange transitory phase of the Dinosaur Renaissance where dinosaurs were sometimes viewed as sluggish beasts and other times as racecars of the Mesozoic.

    The result, I think, has been a slightly detached and objective look at how perceptions of dinosaurs have changed over time.

    Image borrowed from the Old Dinosaur Books site

    A “Brontosaurus” getting attacked by Allosaurus during a sojourn on land to lay her eggs. Ah, the classics.

    One book I remember fondly was the Golden Book of Dinosaurs (shown above). It featured these beautiful drawings of dinosaurs living life as best we thought at the time. One picture that really stuck in my head, was a shot of two Brachiosaurus; one on land and the other so deep in a lake that one could only make out the crest on the head. I found that page to be so immersive and atmospheric. My knowledge of physics was not so good at the time, so it never dawned on me that this poor sauropod was basically breathing through a straw with its lungs separated by at least 2 atmospheres from the air entering (as best it could) the nostrils.

    Then around the early nineties when Jurassic Park the book came out I started to note a distinct change in how dinosaurs were being portrayed. No longer were sauropods swamp bound behemoths. Now they were fully terrestrial titans that could not only support their weight on all four legs, but could even do so on 2 (well 3 if one counts the tail). It was around this time that Robert Bakker’s infamous “Dinosaur Heresies” started making the rounds.

    Now, admittedly, Heresies came out in 1986 and the changing view of dinosaurs actually started in the seventies. However, it wasn’t until the early nineties that the full effects of Bakker’s work could truly be appreciated. If anything this gives one an idea of the kind of inertia one must deal when it comes to getting scientific ideas out into the public.

    Again I digress.

    It was around the early nineties when I first read The Dinosaur Heresies. The first few chapters were amazing. I had never seen dinosaurs portrayed this way. They walked better and were more active. In many ways they better fit the concept I had in my head all along.

    Then I came up to the end of chapter 3. The thesis of this chapter was to explain why reptiles should not be viewed as inferior to mammals. In order to do so Bakker explained all the various ways in which extant reptiles outshine extant mammals. The end of the chapter features a beautifully drawn shot of the “panzer croc” Pristichampsus snatching a Hyracotherium (formerly Eohippus). The caption read:

    Pristichampsus hunted during the Eocene Epoch, about 49 million years ago, but it was very rare, much rarer than big mammalian predators, proof that cold-bloodedness was a great disadvantage.

    Predatory Dinosaurs of the World. Available on Amazon

    That’s when the real thesis of the book hit me. The argument wasn’t: “Dinosaurs weren’t slow and stupid, because of the following.”

    Rather the argument was: “Dinosaurs weren’t cold-blooded because the facts show the following.”

    In order to pull dinosaurs out of the mire, Bakker had to change their fundamental thermophysiology. The general concept, that cold-bloodedness is inferior to warm-bloodedness, remained the same. This despite Bakker’s initial attempt to explain how “cold-blooded” reptiles outshine “warm-blooded” mammals.

    Bakker’s book was just the start. From there, we had Adrian Desmond’s “The Hot Blooded Dinosaurs” (okay, technically Desmond was first by 7 years, but he largely stole Bakker’s work to make the book so it evens out) and Gregory S. Paul’s infamous: “Predatory Dinosaurs of the World.” Each new book taking the “dinosaurs can’t be cold-blooded” argument a little further. By the time we hit Predatory Dinosaurs of the World, Tyrannosaurus rex was running along at 40mph, dromaeosaurs were practically flapping around and every species of dinosaur was reaching adult size by between 4-10 years of age.

    Sadly it was at this point that Jurassic Park was written. As hardcore fans know it was Greg Paul’s erroneous sinking of Deinonychus antirrhopus into Velociraptor that gave us the JP “raptors.” It was also at this point that the pendulum of dinosaur physiology officially swung the other way.

    The thing that had always bugged me about this view of dinosaurs was the sheer lack of supporting data for it. The assumption was always that dinosaurs were so vastly different from “typical reptiles” that they had to have been doing something different. Yet when one looked at the actual data dinosaurs came out looking slightly odd at best. For the most part dinosaurs fit the reptile mold quite well. It was these elusive “classic reptiles” that didn’t appear to exist.

    Most reptiles don’t fit the “typical reptile” mold at all. Yet despite numerous papers over the past 30 years depicting reptiles doing things normally thought un-reptile like (e.g. caring for their young, competing with large mammals, etc), most of this was dutifully ignored in favour of an older, more outdated view.

    It was a problem that Nicholas Hotton III (1980) aptly called: The “endothermocentric fallacy.” Basically, the assumption that being an endotherm is inherently superior to being an ectotherm. Part of that superiority included the ability of endotherms to do everything faster and “better” than similar sized ectotherms. This problems with this way of thinking warrants an entire blog post to itself. So rather than get bogged down with this particular I’ll touch more on the endothermocentric fallacy at a later date. For now all that one needs to keep in mind is that the thinking of the time was that if dinosaurs were going to be active at all then they had to be endotherms.

    By the late nineties we had the first evidence of feathers in a small branch of the theropods (Maniraptora). Birds were officially adopted into the dinosaur family tree and the fully endothermic concept of Dinosauria was completely entrenched.

    The funny thing, of course, is that this dogmatic view of dinosaur metabolism was just as bad as the early 20th century’s “cold-blooded” swamp bound view. Sure dinosaurs were more active now, but the data supporting it was just as nebulous as the stuff that was used to keep dinos in the swamp.

    Enter the 21st century, and the late…um, 0’s (does anyone have a name for this decade yet?). Biomechanic work on dinosaurs has started to reveal amazing insights into the physical limits of what dinosaurs could do, and the results have started to pull the pendulum back again.

    Work by John Hutchinson and Mariano Garcia (2002) on T. rex showed that not only could T. rex not hit 40mph, but it technically couldn’t run either. A biomechanical assessment of theropod forelimbs by Ken Carpenter (2002) has shown that the “bird-like” dromaeosaurs could not fold their arms up like birds after all.

    Work by Rothschild and Molnar (2005) on sauropod stress fractures showed no signs of rearing activity in sauropods, while work by Kent Stevens and J. Michael Parrish (2005) pulled the swan-like curve out of sauropod necks, placing things far more horizontally.

    Work by Gregory Erickson and others (2001) on micro-slices of dinosaur bone has indicated that very few dinosaurs hit adult size in less than 15 years.

    Now we have a new study by Lehman and Woodward (2008) which follows up on Erickson et al’s work and actually shows that even this toned down version of dinosaur growth is probably too fast as well. Lehman and Woodward focused on sauropods and studies on their bone microstructure. What they did was compare bone growth data to a well used equation for growth in animals.

    Bertalanffy growth equation

    Deemed the Bertalanffy equation; it states that the mass at any given age is an exponential function limited by the asymptote of adult body mass. This equation has been used extensively in studies on bird and elephant growth among others. An example of the equation is given to the right for fish.

    When the authors did this they discovered something quite interesting. Instead of taking 15 years to reach adult mass, sauropods like Apatosaurus excelsus took closer to 70 years!!

    Other sauropods measured took between 40 and 80 years! This is a substantial decrease in growth rate estimated before. Mind you this is data taken, in some cases, from the same piece of bone that Erickson et al had used. So one can’t suggest anomalous bones being used as the reason behind the surprising results. The authors also went to great lengths to take into account differences in mass estimations as well as allometric growth of body parts. In each case the changes had little affect on the overall outcome (in many cases, it made growth go even slower).

    Now keep in mind we are talking about the time it took sauropods to reach full adult size. This is not the time taken to reach sexual maturity. Earlier studies by Erickson et al (2007) had already discovered that dinosaurs didn’t wait to grow up before engaging in sex, so there is no issue here of 80 year old sauropods finally “doing the nasty.”

    What this does show is that growth in dinosaurs might not be as determinate as initially thought. An 80 year old sauropod might just have been close to the edge of its lifespan at this point (though the possibility of bicentennial sauropods does still exist). It also shows that dinosaurs had growth rates far closer to the realm of reality (before it was hard to imagine how an Apatosaurus excelsus was able to pound down enough food daily to add 13.6 kg of new mass a day. Especially given their small mouths).

    Thermophysiologically what does this all mean? Were dinosaurs “cold-blooded” after all?

    That’s one of those questions that will never be fully answered (short of a time machine). What this does do is pull dinosaurs ever further away from the “definitely warm-blooded” category and push them right back into the middle again. When/if the dust settles on this metabolism debate I suspect that dinosaurs will probably remain in the middle somewhere.

    Of course while all of this is going on with dinosaurs we have other studies, like those from Tumarkin-Deratzian (2007) showing the existence of fibrolamellar bone growth in wild alligators, that are finally moving the rusty pendulum of reptile metabolism out of the “classic reptile” category and much closer to the middle.

    So in the end dinosaurs will still probably wind up being “good reptiles.” Thankfully the exact definition of what that entails will have probably changed by then.

    ~ Jura


    Bakker, R. 1986. The Dinosaur Heresies: New Theories Unlocking the Mystery of the Dinosaurs and their Extinction. William Morrow. New York.
    Carpenter, K. 2002. Forelimb Biomechanics of Nonavian Theropod Dinosaurs in Predation. Concepts of Functional Engineering and Constructional Morphology. Vol. 82(1): 59-76.
    Desmond, A. 1976. The Hot Blooded Dinosaurs: A Revolution in Paleontology. Dial Press.
    Erickson, G.M., Curry Rogers, K., Varricchio, D.J., Norell, M.A., Xu, X. 2007. Growth Patterns in Brooding Dinosaurs Reveals the Timing of Sexual Maturity in Non-Avian Dinosaurs and Genesis of the Avian Condition. Biology Letters Published Online. doi: 10.1098/rsbl.2007.0254
    Erickson, G.M., K. C. Rogers, and S.A. Yerby. 2001. Dinosaurian Growth Patterns and Rapid Avian Growth Rates. Nature 412: 429?433.
    Hotton, N., III. 1980. An Alternative to Dinosaur Endothermy: The Happy Wanderers. In A Cold Look at the Warm-Blooded Dinosaurs (R.D.K. Thomas and E.C. Olson Eds.), pp. 311-350, AAAS, Washington, DC
    Hutchinson, J.R., Garcia, M. 2002. Tyrannosaurus was not a fast runner. Nature 415: 1018-1021.
    Lehman, T.M., and Woodward, H.N. 2008. Modeling Growth Rates for Sauropod Dinosaurs. Paleobiology. Vol. 34(2): 264-281.
    Rothschild, B.M., and Molnar, R.E. 2005. Sauropod Stress Fractures as Clues to Activity. In Thunder Lizards: The Sauropodomorph Dinosaurs. (Virginia Tidwell and Kenneth Carpenter eds). Indiana University Press. pp 381-394.
    Stevens, K.A., and Parrish, J.M. 2005. neck Posture, Dentition, and Feeding Strategies in Jurassic Sauropod Dinosaurs. In In Thunder Lizards: The Sauropodomorph Dinosaurs. (Virginia Tidwell and Kenneth Carpenter eds). Indiana University Press. pp 212-232.
    Tumarkin-Deratzian, A.R. 2007. Fibrolamellar bone in adult Alligator mississippiensis. Journal of Herpetology. Vol. 41. No.2:341-345.