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The changing life appearance of dinosaurs

The views expressed are those of the author and are not necessarily those of Scientific American.


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Jurassic dinosaurs as illustrated by Peter Zallinger: these are svelte, lightweight animals typical of the late 1970s and 80s. Hat-tip to LITC for the scan.

Anyone who knows anything about Mesozoic dinosaurs will be – or certainly should be – familiar with the fact that our view of what these animals looked like in life has changed substantially within the last several decades. The ‘dinosaur renaissance’ of the late 1960s and 70s saw the flabby-bodied, tail-dragging behemoths of earlier decades be replaced by sprightly, athletic animals with big, bulging limb muscles, erect tails, and dashing patterns and colour schemes. This ‘new look’ for dinosaurs was initiated by (sometime Tet Zoo reader) Robert Bakker and then taken forwards by Greg Paul and Mark Hallett; several other artist-writers of the 1970s and 80s also helped perpetuate ‘new look’ dinosaurs, including John McLoughlin, Peter Zallinger and Doug Henderson (arguably the greatest palaeoartist of them all).

Robert Bakker's dinosaurs (and other extinct animals) really changed the game in terms of how these animals became depicted in life. I still want to know more about the inspirations behind his illustrative style. This montage comes from my All Yesterdays talk. Images (c) Robert Bakker.

The influence of Greg Paul in particular has been so significant that the majority of ‘modern’ dinosaur renditions – those of Jurassic Park and numerous artworks, museum installations and so on – are, effectively, ‘Greg Paul dinosaurs’. Many palaeontologists don’t like crediting Greg Paul’s influence, in part because they dislike or disagree with the arguments, proposals and contentions he has made in his many technical articles and books. I think that ‘Greg Paul the publishing scientist’ is a different entity from ‘Greg Paul the technical artist’, and that Greg’s influence on how we imagine and reconstruct fossil dinosaurs needs to be fairly credited (see comments in Naish 2008, Conway et al. 2012). So, ‘Revolution # 1’ as goes the portrayal of Mesozoic dinosaurs* was instigated by Bakker, Paul, Hallett and their contemporaries, with Greg Paul being of pre-eminent importance.

* Because birds are dinosaurs, it should be noted that articles like the one you’re reading now are specifically about those dinosaurs that lived during the Mesozoic Era. Early birds are included in this general subject area, meaning that ‘Mesozoic dinosaurs’ and ‘non-avialan dinosaurs’ (= non-bird dinosaurs) are not synonymous.

More than any other single person, Greg Paul has had a major influence on how Mesozoic dinosaurs are imagined by other palaeoartists, by scientists, and by the public. His images of dinosaurs have often been revised over the years. This scene, showing the east African sauropods Dicraeosaurus (at far left) and Giraffatitan, has appeared in many different versions over the years. Image (c) Greg S. Paul.

I should say, by the way, that all of what I’ve just said is very familiar stuff to those interested in the world of palaeoart. However, many things that are ‘common knowledge’ for certain sets of people are not necessarily familiar to interested parties at large.

Moving on… So, those of us interested in the life appearance of fossil animals grew up with svelte, muscular, sometimes fuzzy or feathery ‘Paulian’ dinosaurs. Blubbery, fat-limbed dinosaurs that somehow persisted into the artwork of the mid-1980s – produced by artists, and presumably given the ok by palaeontologists, who shall remain nameless (some of you will know who I have in mind) – looked weirdly anachronistic when published, and their existence during the 1980s and persistence beyond them has always been inexplicable. What? You mean you hadn’t seen the Paulian dinosaurs that everyone else was drawing by now? Huh. Anyway…

Revolution # 2

Shrink-wrapped dinosaurs at their very best (or worst): Ely Kish's Apatosaurus, from Dale Russell's 1989 An Odyssey In Time: The Dinosaurs of North America.

Fast forward to the early decades of the 21st century. As ridiculous as it would have seemed to the palaeontologists and palaeoartists of the 1980s and before, feathered non-bird dinosaurs are now “commonplace” (to quote one study), and integumentary fuzz has been discovered on ornithischians and numerous theropods (including big tyrannosaurs). Assorted studies have shed substantial light on dinosaur facial tissues, forelimb orientation, posture, locomotion, muscle size, and tail shape. We have learnt enough for ‘Revolution # 2’ to occur – the ‘soft dinosaur revolution’ (hat-tip to Jason Brougham for this term).

With Paulian dinosaurs as the framework or bedrock, we have entered the age whereby people are able to add a more realistic amount of musculature, skin and other integumentary structures… to make the animals less shrink-wrapped. The concept of shrink-wrapped dinosaur syndrome (SWDS) arose sometime round about 2010 and has since been widely used in discussions of dinosaur life appearance. I’m not sure who originated the term, since it was used approximately simultaneously by sauropod expert Matt Wedel and palaeoartist John Conway.

We really need to talk about palaeoart. A new, augmented edition of All Yesterdays will appear in time.

Whatever, the concept emerged among several interested parties. The ‘All Yesterdays Movement’ – which has rigorous skeletomuscular reconstructive work at its core – has emerged from a desire to portray dinosaurs (and other fossil animals) with the right amount of soft stuff (Conway et al. 2012). It’s really not, as some seem to have assumed, built on the idea that anything goes. Muscles may sometimes be more extensive and more voluminous than illustrated within the ‘Paulian’ paradigm (Hutchinson et al. 2011, Persons & Currie 2011), dinosaurs may sometimes or often have sported wattles, dewlaps, soft frills and other epidermal features, and fuzzy and feathery coatings of various species were frequently thick and extensive, not sparse.

In the rest of this article I want to say a few brief things about the life appearance of Mesozoic dinosaurs. The old, chunky, tail-dragging dinosaurs of the 1950s and before are dead, but the shrink-wrapped, sparse-feathered ones of the 1980s should be, too. Again, this idea is familiar to those who keep up to speed on dinosaur life appearance, but I get the impression that it’s not that appreciated overall.

A very brief guide to dinosaur life appearance

Habitually raised necks and tails are the norm for most dinosaur groups, as shown here in diplodocid sauropods. Image by Mark Witton.

Therizinosaurs almost certainly adopted a diagonal or sub-vertical pose when foraging and walking. And soft tissues mean that they might well have looked very different from conventional interpretations. Image by John Conway, from Conway et al. (2012).

Articulated skeletons, trackways, and the way bones fit together show that dinosaurs generally walked and ran with horizontal bodies and tails that were approximately parallel to the ground. Tail-tips might have drooped or dangled, but tails only really sloped downwards in horned dinosaurs, and to a degree in therizinosaurs and brachiosaur-like sauropods. This doesn’t mean that all dinosaurs were all horizontal all the time. Bipedal species of many sorts likely stood with diagonal or even near-vertical bodies when scanning the landscape, testing for odours, or showing off to other animals. And quadrupedal species like certain sauropods (most notably diplodocids) and stegosaurs were also almost certainly capable of semi-erect poses too. Therizinosaurs must have walked and stood with a perpetual diagonal body posture.

Theropods – the predatory dinosaurs and birds – did not walk around with ‘bunny hands’ as used to be shown (that is, with their palms facing the ground). Rather, the arms and hands were articulated such that the palms faced inwards and the hand could not be pronated – that is, it could not be rotated to face downwards (e.g., Gishlick 2001, Senter & Robins 2005). This raises all manner of issues as goes hand function and predatory behaviour, but that’s an issue I can’t cover here. ‘Palms-inward’ hands were also present in bipedal sauropodomorphs (the plateosaurs and their kin) (Bonnan & Senter 2007).

Greg Paul's 1988 PDW, one of the most influential books as goes the portrayal of dinosaurs in life.

The idea that bird-like non-avialan coelurosaurs were feathered has been popular in some circles since the late 1980s at least. That’s right, feathered (non-avialan) dinosaurs are not a new thing, but were ‘normal’ and oft-illustrated by a whole generation of people interested in the life appearance of dinosaurs. Bakker, Hallett and Paul were all illustrating feathered theropods throughout the late 1970s and 80s but it was Paul’s 1988 book Predatory Dinosaurs of the World (Paul 1988) that launched the idea into mainstream dinofandom (see also Paul 1987). Paul’s arguments were pretty sensible: they basically hinged on the fact that non-bird maniraptorans like Velociraptor are extremely similar in form and anatomical detail to indisputably feathered Archaeopteryx. While quite a few palaeontologists agreed that the notion of a feathery Velociraptor was at least plausible, what I remember from the 1980s and early 90s is those palaeontologists who declared this idea unlikely and overly speculative. Nope, it’s scales scales scales until proven otherwise, they said. Of course, it turns out that Paul and those other palaeoartists were actually right all along.

Celebrate the 'soft dinosaur revolution' by purchasing your own Palaeoplushie Velociraptor! Model by Rebecca Groom.

Well, actually: now that we have lots of feathered non-bird theropods, it turns out that Paul and his followers were too conservative. These animals didn’t have a thin or sparse veneer of feathers on just part of their bodies. Rather, they were thickly clothed in them just as birds are, with fuzz covering much of the face and snout, long feathers obscuring the arms and hands and much of the legs, and fan-like arrangement of large feathers sprouting from the tail. You can do your bit to help spread the news as goes properly feathered non-avialan theropods by backing Rebecca Groom’s Palaeoplushie Velociraptor project or by purchasing my new “Just say NO to unfeathered non-avialan maniraptoran theropod dinosaurs” t-shirt at the Tet Zoo Redbubble shop!

Just say no to inaccurate maniraptoran renditions, the t-shirt design.

Sauropods with softer faces

Composite image showing a few things to keep in mind when illustrating sauropods. Drawings by Darren Naish, other diagrams from Paul (1987) and Czerkas (1992).

Moving on to sauropods… Sauropods were mostly covered in non-overlapping scales but some had osteoderms and tubercles across the back. Diplodocids – and maybe others – had a row of triangular, laterally compressed spines running along the dorsal midline (Czerkas 1992). The hands of ‘advanced’ sauropods were columnar, semi-circular structures where the thumb claw was the only claw present (and even this was reduced and lost in the largest, most speciose sauropod clade: Titanosauria). Hindfeet were oval, backed by a giant fat-pad, and with three (sometimes two, sometimes four) laterally compressed claws on the innermost toes.

Sauropod heads: a whole lot of soft stuff needs accounting for. This diagram is by Mathew Wedel and originally appeared over at SV-POW!

Debate continues over the neck posture of sauropods. I’m one of several researchers who thinks – based in part on data from living animals – that sauropods (and other sauropodomorphs) routinely held their necks in high, raised poses, not horizontal or downward-sloping ones (Taylor et al. 2009). Sauropods have traditionally been illustrated with sunken, skeletal faces and nostrils perched high up in the bony nostril openings. However, work on sauropod facial tissues (Witmer 2001) means that we should imagine them with ‘softer’ faces where tissues obscured much of the underlying bony anatomy, and the fleshy nostrils were located down on the muzzle and not well up and back in the bony nostril opening [adjacent illustration take from this SV-POW! article on the life appearance of sauropods]. The notion that sauropods might have had tapir- or elephant-like trunks has been suggested a few times but is not consistent with any aspect of skull anatomy, nor with the tooth wear seen in the group. It’s also contradicted by data on nerve anatomy (animals need big facial nerves to operate a trunk) (Knoll et al. 2006). I’ve written about this idea before – see the links below.

Ornithischians, fuzzy and otherwise

Details of ornithischian anatomy relevant to life appearance. From top to bottom: a large 'cheek' scute in the ankylosaur Panoplosaurus (as illustrated by Lambe in 1919), the gigantic, complex bony nostril of the ceratopsian Triceratops, and integumentary bristles in the small ceratopsian Psittacosaurus.

Finally, what about ornithischians – the third great group of dinosaurs, the one that includes stegosaurs, ankylosaurs, ornithopods, ceratopsians and pachycephalosaurs? Beak tissue definitely sheathed the anterior parts of the jaws in these dinosaurs (this is actually preserved in some hadrosaurs) but several other aspects of their facial anatomy have been controversial. The idea that skin and other soft tissue spanned the side of the mouth cavity – this is typically termed ‘cheek’ tissue even though this is very likely technically incorrect – has been popular but occasionally contested. The distribution of nutrient foramina on the jaw bones of these dinosaurs supports the idea that an extensive amount of tissue did indeed cover the sides of their jaws (Morhardt et al. 2009), and the presence of ossifications that fit in the space between the upper and lower jaws of some ankylosaurs show that a tissue web of some sort really was present.

Preserved skin impressions show that many ornithischians possessed polygonal scales over most or all of their bodies; at least some hadrosaurs also had serrated or ribbon-like frills along the back and tail. The gigantic, complex bony nostrils of hadrosaurs and ceratopsians almost certainly housed erectile or inflatable structures of some sort. Soft crests, dewlaps and other structures are suspected or known to have been present in hadrosaurs and other ornithischians, and the horns of ceratopsians, and plates and spines of stegosaurs and ankylosaurs, were certainly enlarged in size (sometimes substantially) by keratinous coverings.

The big deal about ornithischian life appearance right now concerns the presence of filamentous integumentary structures in several taxa: in the heterodontosaurid Tianyulong, the ceratopsian Psittacosaurus, and in Kulindadromeus, a bipedal ornithischian that would once have been identified as an ornithopod but is actually outside the clade that includes ornithopods and marginocephalians. Kulindadromeus is remarkable in that it is partially covered in simple filaments but also in parallel fibres that emerge from broad, plate-like structures, and in bundles of parallel, ribbon-like filaments (Godefroit et al. 2014). None of these structures are longer than 2 or 3 cm. Scales cover the feet and imbricated, rectangular scales – arranged in several longitudinal rows – are present across the dorsal surface of the tail.

New for 2014: Kulindadromeus, bipedal ornithischian with filamentous fuzz, multi-branched structures, ribbon-like structures, imbricating rectangular scales, and tiny, rounded scales too. Image (c) Andrey Atuchin.

The question now is how widespread such filamentous structures were across Ornithischia, and across Dinosauria in general. Were they restricted to one or two lineages, were they normal across the small-bodied members of all lineages, or were they present across diverse small-bodied and large-bodied lineages? And are the structures in ornithischians homologous with the filaments of theropods and pterosaurs? We simply need more data from more fossils before we can go further with this.

Finding information is hard – so, what to do?

Dinosaurs Past and Present Vol II (specifically, Greg Paul's chapter within it): one of the most important books as goes Mesozoic dinosaur life appearance. The problem: 1987 is a long, long time ago...

Needless to say, there’s a ton more that could be said about dinosaur life appearance. What I’ve done here is merely overview, in very brief fashion, some of the more easily summarised subject areas. What do people do when they need up-to-date information on these sorts of issues? That’s not an easy question to answer. The only competent and comprehensive review of dinosaur life appearance is Paul’s 1987 book chapter (Paul 1987), and it’s now woefully out of date.

Your other recourse is to scour through the vast primary literature, or to team up with a friendly expert (and don’t go assuming that palaeontologists are necessarily useful on this sort of stuff. Those who work on phylogenetics, diversity across time, histology and so on are often not up to speed on soft tissue anatomy. Exhibit A: all those execrable and hopelessly inaccurate dinosaur images published in books that were supposedly authenticated by august working scientists). So, what’s needed? The answer: a grand new illustrated work that provides a comprehensive guide to the life appearance of fossil dinosaurs. The good news: plans to produce just such a project are underway right now. Watch this space…

For previous Tet Zoo articles on palaeoart and the life appearance of Mesozoic dinosaurs, see…

And – entirely coincidentally – today all sees the publication of my colleague Mark Witton’s article on palaeoart Patterns in Palaeontology: Palaeoart – fossil fantasies or recreating lost reality?

Refs – -

Bonnan, M. F. & Senter, P. 2007. Were the basal sauropodomorph dinosaurs Plateosaurus and Massospondylus habitual quadrupeds? Special Papers in Palaeontology 77, 139-155.

Conway, J., Kosemen, C. M., Naish, D. & Hartman, S. 2012. All Yesterdays: Unique and Speculative Views of Dinosaurs and Other Prehistoric Animals. Irregular Books.

Czerkas, S. A. 1992. Discovery of dermal spines reveals a new look for sauropod dinosaurs. Geology 20, 1068-1070.

Gishlick, A. D. 2001. The function of the manus and forelimb of Deinonychus antirrhopus and its importance for the origin of avian flight. In Gauthier, J. & Gall, L. F. (eds) New perspectives on the origin and early evolution of birds: proceedings of the international symposium in honor of John H. Ostrom. Peabody Museum of Natural History, Yale University (New Haven), pp. 301-318.

Godefroit, P., Sinitsa, S. M.,  Dhouailly, D., Bolotsky, Y. L., Sizov, A. V., McNamara, M. E., Benton, M. J. & Spagna, P. 2014. A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science 345, 451-455

Hutchinson, J. R., Bates, K. T., Molnar, J., Allen, V. & Makovicky, P. J. 2011. A computational analysis of limb and body dimensions in Tyrannosaurus rex with implications for locomotion, ontogeny, and growth. PLoS ONE 6(10): e26037. doi:10.1371/journal.pone.0026037

Knoll, F., Galton, P. M. & López-Antoñanzas, R. 2006. Paleoneurological evidence against a proboscis in the sauropod dinosaur Diplodocus. Geobios 39, 215-221.

Morhardt, A. C., Bonnan M. F. & Keillor, T. 2009. Dinosaur smiles: correlating premaxilla, maxilla, and dentary foramina counts with extra-oral structures in amniotes and its implications for dinosaurs. Journal of Vertebrate Paleontology 29 (supplement to 3), 152A.

Naish, D. 2008. The Great Dinosaur Discoveries. University of California Press, Berkeley.

Naish, D. 2014. Rediscovering the dinosaurs. Science Uncovered 7 (June 2014), 68-72.

Paul, G. S. 1987. The science and art of restoring the life appearance of dinosaurs and their relatives – a rigorous how-to guide. In Czerkas, S. J. & Olson, E. C. (eds) Dinosaurs Past and Present Vol. II. Natural History Museum of Los Angeles County/University of Washington Press (Seattle and London), pp. 4-49.

- . 1988. Predatory Dinosaurs of the World. Simon & Schuster, New York.

Persons, W. S. & Currie, P. J. 2011. The tail of Tyrannosaurus: reassessing the size and locomotive importance of the M. caudofemoralis in non-avian theropods. The Anatomical Record 294, 119-131.

Senter, P. & Robins, J. H. 2005. Range of motion in the forelimb of the theropod dinosaur Acrocanthosaurus atokensis, and implications for predatory behaviour. Journal of Zoology 266, 307-318.

Taylor, M. P., Wedel, M. J. & Naish, D. 2009. Head and neck posture in sauropod dinosaurs inferred from extant animals. Acta Palaeontologica Polonica 54, 213-220.

Witmer, L. M. 2001. Nostril position in dinosaurs and other vertebrates and its significance for nasal function. Science 293, 850-853.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.



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  1. 1. Trisdino 9:34 am 09/1/2014

    What a happy coincidence that this article should be released almost immediately after I received a copy of 2012′s “Dinosaur art”, which of course features several of the illustrations that you showcased in this very article.

    And a new book concerning the appropriate methods by which one should reconstruct extinct dinosaurs? Now that certainly is interesting, I will of course keep an eye out for it.

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  2. 2. Jerzy v. 3.0. 9:38 am 09/1/2014

    What is current verdict on spines or knobs on the rump area of ceratopsians?

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  3. 3. Trisdino 9:43 am 09/1/2014

    Also, what are you folks thoughts on sauropod integument? Phylogenetic bracketing would, if not suggest, then at least hint at the possibility of fuzzy sauropods. I personally find it to be quite likely, as we all know that feathers and other integumentary structures can both exist on, and alongside, scales.

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  4. 4. BillSkaggs 9:46 am 09/1/2014

    Fascinating! As far as I can tell you don’t say very much about lizard-hipped theropods. The question that has long intrigued me is the significance of the massive and very striking pubic bone in bipedal theropods such as t-rex.

    Regarding illustrations, a thing that always irritates me is the prevalence of drawings of bipedal dinosaurs in impossible postures, with the center of mass well forward of the front leg — a position that would cause the animal to immediately fall on its nose.

    Anyway, I really enjoyed reading this.

    Best regards, Bill

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  5. 5. Felix2 9:49 am 09/1/2014

    I love the shirt. You should draw more often, Darren, your pictures are beautiful. On integument, with the discovery of Kulindadromeus, do you think that a feathered integument was present at the origin of Dinosauria (or even Ornithodira, and pterosaur pycnofibers are actually a form of protofeathers)? That might make Carnotaurus secondarily featherless…

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  6. 6. Trisdino 9:54 am 09/1/2014

    To Felix – Maybe carnotaurus was not even featherless, as seen by certain owl species, feathers are capable of growing on top of scales.

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  7. 7. AndreaCau 10:07 am 09/1/2014

    Even Dave Peters depicted feathered dromaeosaurids in the late ’80s: https://pterosaurheresies.files.wordpress.com/2013/08/deinonychus800.jpg

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  8. 8. Jerzy v. 3.0. 10:10 am 09/1/2014

    Only one more thing: coloration. So many anatomically accurate illustrations have impossible colors.

    Very few extinct animals preserve coloration directly, but there are principles of animal coloration which are obeyed by most living animals.

    One principle is that camouflage coloration is common, and the rule in ambush predators and herbivores living in densely forested environment.

    Another is that animal colors match visual systems of conspecifics and predators. Here mammals are unusual among vertebrates and not a good model for dinosaurs. Mammals have poor color vision, especially all placentals except primates cannot duistinguish red from green colors. This means that modern large herbivores are often uniform, and most mammals have red coloration (which is physiologically easier to produce) replacing green. This is because for any ungulate, rodent or ungulate, orange tiger is the same color as green grass.

    Dinosaurs are believed to have full color system, so coloration were perhaps more similar to large ground-living birds. Additionally, egg-laying in ground nests suggests extremely good camouflage of the sex which incubated.

    I imagine that forest herbivores and ambush carnivores like Tyrannosaurus had complex camouflage pattern, perhaps less like bongo antelope and more like female pheasants, bustards or even nightjars. Omnivores, carnivores which fed on small prey and fast-running herbivores living in open habitats would be more colorful, perhaps like many open-country birds. In forms where male incubated eggs in open nests, perhaps the male would be crypticaly colored and females more colorful.

    Living birds often have both camouflaged and display pattern on different parts of the body, depending on which parts are usually seen by predators and conspecifics. For example many birds have brown back to confuse flying predators and brightly colored face and breast. I think this may be the clue for ground-nesting dinosaurs. Predators like tyrannosaurids I expect to have disruptive or camouflage pattern on their fronts, which would be exposed to prey.

    And sexual and age changes of coloration are common. Should an illustration of a herd or family group of dinosaurs show animals with two or more different color patterns?

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  9. 9. Jerzy v. 3.0. 10:11 am 09/1/2014

    And great post, Darren, naturally. I can see why Jurassic Park film 4 is so long in production! ;)

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  10. 10. Trisdino 10:24 am 09/1/2014

    What do you people think will be the next big change in our perception of dinosaurs? It is always hard to to imagine what will be new, I mean, if we look at the past, nobody excepted dinosaurs to be fast, agile, and warm blooded creatures, and after that, very few thought that they would be feathered, so perhaps predicting future discoveries, or at least the more ground breaking ones, is an exercise in futility?

    Whatever the case, here are my predictions for large discoveries:

    - A feathered Tyrannosaurus rex specimen(Predictable but would certainly have a large effect on the public’s perception of dinosaur integument)

    - Sauropods with integument

    - Some new, intriguing lineage of dinosaurs, currently not represented in the fossil record

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  11. 11. Cahokia 10:38 am 09/1/2014

    @Jerzy v. 3.0.

    While dinosaurs presumably had good color vision, I wonder if they how vividly hued they would have been. Most large birds and non-avian reptiles are pretty dully colored.

    Maybe most maniraptorans were covered in browns and greys like contemporary ratites, and most sauropods were the dark greens and greys that we’re familiar with from children’s dinosaur books. On the other hand, we do have those studies on coloration in species like Anchiornis and Sinosauropteryx which seem to suggest they were colorful.

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  12. 12. Trisdino 10:44 am 09/1/2014

    I would not say that most avians are dull, but then again, what is “dull”?

    Sure, they are often not exactly vibrant, with blues, greens, yellows, and the likes being present in relatively few lineages, but beautiful combinations of red, brown, black, white, and grey, are very common. A swan is mostly just one colour, but that one colour is enough to make it really stand out.

    I think find few birds to be truly dull in colour, and since they are the last living representatives of the group, they should obviously be our best reference. The other closest relatives are the crocodilians, and they are mostly brown and green, yes, but then again, they are also adapted to a life in murky rivers, the reason they are all so dull in colour is that they are mostly ambush predators, relying almost solely on camouflage. Extinct dinosaurs, active as they were, probably were not that dull.

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  13. 13. naishd 10:49 am 09/1/2014

    So many great questions and comments, thanks indeed. Some quick responses…

    – Knobs or spines on ceratopsians (comment # 2): the only ‘hard’ data yet comes from Psittacosaurus. A Triceratops that has nipple-like structures on some of the scales from its tail might provide evidence for similar structures in other ceratopsian taxa, but nothing has been published yet. Lots of rumours but no good data, yet. We do know that scales covered much of the body in several ceratopsian taxa… but was this true of all of them? Also worth noting is that heterodontosaurids have been found to be close relatives of ceratopsians in some phylogenetic studies (fuzzy Tianyulong is a heterodontosaurid).

    – Fuzz and feathers on the dinosaur tree (comments # 3 and 5): we all talk about this a lot. The presence of filamentous integument in pterosaurs, ornithischians and theropods does suggest that it is primitive for Ornithodira, in which case we should expect fuzzy sauropodomorphs to turn up at some point. But the possibility also exists that these structures evolved independently, and that the earliest members of the respective lineages were scaly. Indeed, some workers have argued just this, pointing to the presence of scaly baby sauropods, scaly small ceratopsians etc. We can’t say anything with confidence until we have more fossils. If you think that an elevated metabolism of some sort was ancestral for Ornithodira (and it seems to be, based on histology and growth rates and so on), then we probably should expect integumentary fuzz to be primitive for the main dinosaur lineages.

    – BillSkaggs (comment # 4): it does often look as if many theropods are front-heavy and set to topple onto their faces. Some artists are aware of this and have corrected for it, others have not. However, mass balance in theropods is interesting. The head and thorax was lighter than it might look due to extensive pneumatisation while the hindlimbs and tail may have been far weightier than conventionally thought – you will note that tails are looking fattier and more muscular these days.

    – Dave Peters (comment # 7): it seems widely acknowledged that Dave is an excellent artist, and his feathery dromaeosaurs confirm that he’s always been on the ball (I guess he produced scaly-skinned ones for that Raptors: the Nastiest Dinosaurs book because the author – Don Lessem – wanted it that way). Shame he gave up on that and went down the path that led to his special digital tracing technique…

    – Colour (comment # 8): it’s true that many colour scheme for fossil animals are invented purely on the basis of what looks neat, not on what might be realistic. It is likely that bright and bold colours were widespread on the display structures of Mesozoic dinosaurs, and their good colour vision (probably extending into the UV) means that camouflage and complex patterns were probably normal. However, big lizards and birds are frequently muted, not gaudy, overall, and thus might serve as good models for some Mesozoic dinosaurs. Furthermore, the manufacture of colour is limited in several ways – carotenoids, for example, are not manufactured across all birds, or indeed across all tetrapods. This means that some animals are destined to be more ‘muted’ than we might otherwise have guessed. I’m sure we’ll talk more about this as the discussion evolves…

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  14. 14. Trisdino 11:00 am 09/1/2014

    - Darren: It is certainly true that we have found scale impressions on many dinosaur lineages, but as I stated in my previous posts, it is known that feathers can grow on top of scales, and, as proven by Kulindadromeus, feathers and scales, even if they are not growing on top of each other, can still coexist on separate parts of the body.

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  15. 15. naishd 11:02 am 09/1/2014

    I agree; scales and feathers are not somehow mutually incompatible. Having said that, some of the non-avialan dinosaurs preserved with an extensive scaly integument (some of the psittacosaurs, for example) are so well preserved that we can be confident that a fuzzy or filamentous covering was absent.

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  16. 16. Heteromeles 11:05 am 09/1/2014

    I’m just waiting until someone does the UV view of dinosaurs.

    However, I’m not so sure about the camo bit. One could equally argue that that the biggest ones (especially the sauropods) had more issues with thermal regulation than with camouflage. It’s possible, for example, the titanosaurs were highly reflective. After all, they had a really good heat generator in that huge stomach. Keeping from overheating might have driven their coloration more than avoiding ineffective predators that were a lot smaller than they were.

    I’m also waiting to see when someone does a lousy (or more explicitly, louse-y) dinosaur. After all, it’s not clear how many of them would have groomed themselves, and if they had dense fuzz, then they’d be crawling with bugs of various sorts. If we want to get really speculative, the world of dinosaur ectosymbiotes awaits.

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  17. 17. Andreas Johansson 11:05 am 09/1/2014

    this is typically termed ‘cheek’ tissue even though this is very likely technically incorrect

    So what does technically distinguish cheek tissue from other forms of tissue closing the sides of the mouth?

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  18. 18. naishd 11:09 am 09/1/2014

    Heteromeles (comment # 16): yes, good call.. colours associated with reflectance and absorption might have been selected for in those big dinosaurs that were perpetually out in the open. Funnily enough, exactly this was considered by Mark Witton in his reconstruction of a very pale sauropod. I’ve also mentioned this area before in my review of Long and Schouten’s book on feathered dinosaurs.

    As for dinosaurs and parasites, there is a messy-looking feathered dinosaur in All Your Yesterdays. And have you seen this Tet Zoo article?

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  19. 19. John Scanlon FCD 11:16 am 09/1/2014

    “A swan is mostly just one colour…” – i.e. mostly black, of course. Round here.
    Among birds, reptiles, mammals and any other reasonably diverse group some species have simple, bold patterns, some are drab and subtle, and some are flamboyantly fabulous. Some are sexually dimorphic, and some polymorphic independent of age or sex. Any of these can work in either display or crypsis. But of course we all know this, I thought.

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  20. 20. Trisdino 11:40 am 09/1/2014

    - John Scanlon: Around here, swans are exclusively white, so that is what I was talking about, should probably have been more specific in mentioning that.

    I do agree with you though, it varies greatly, based both on diet, lifestyle, location, and gender, but generally, as a rule of thumb, birds are relatively speaking a quite vibrant bunch, with a proportionally high percentage of species being in some way either in possession of vibrant colours, stark and drastic contrasts, elaborate patterns, or various combinations of the former. I think we can all agree that extrapolating this pattern to dinosaurs, especially maniraptorans and other bird-like theropods, is the most logical way to reconstruct their colouring.

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  21. 21. Felix2 12:40 pm 09/1/2014

    A feathered sauropod would be wonderful. What we need is and Cretaceous lagerstatten from Southern Australia. As for colors (using the American spelling), birds generally have more muted tones, in my opinion. The colors blend together more. What I find weird in palaeoart is when people draw dinosaurs in the same color schemes as modern birds.

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  22. 22. Trisdino 12:48 pm 09/1/2014

    - Felix: I do not see how drawing dinosaurs with modern bird colour-schemes is weird. Sure, it is a bit overdone, and yeah, they probably did not have exactly the same colours, but there are so many birds, with so many combinations, that it seems inevitable that many of them have been similar in colour through time.

    And I just really do not agree that birds have muted tones. Okay, many of them do not have incredibly vibrant colours, they typically stick to the browns, whites, blacks, and greys, but the combinations they make with those colours are often mindblowing, I mean, just look at this thing, it is mostly just brown and white, but damn is it beautiful.

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  23. 23. JoseD 2:42 pm 09/1/2014

    Finally, a new TetZoo dino post! I especially like that Peter Zallinger’s work is front & center, given its significance to my childhood. Here’s hoping I can get my questions answered.

    Naishd: “This ‘new look’ for dinosaurs was initiated by (sometime Tet Zoo reader) Robert Bakker and then taken forwards by Greg Paul and Mark Hallett”

    Now that you mention it, has Bakker mentioned TetZoo in any of his writings or commented on any TetZoo posts?

    Naishd: “Blubbery, fat-limbed dinosaurs that somehow persisted into the artwork of the mid-1980s – produced by artists, and presumably given the ok by palaeontologists, who shall remain nameless (some of you will know who I have in mind) – looked weirdly anachronistic when published, and their existence during the 1980s and persistence beyond them has always been inexplicable.”

    I’m glad you mentioned that b/c some of my up-coming Amazon Reviews are for recent books that fit that description, including what’s probably the most obnoxiously big (taller/wider than my torso) popular dino book ever. It’s as if they didn’t think the content was bad enough & wanted to add insult to injury (more like injury to insult, given that a kid would probably get crushed under the book’s weight).

    Naishd: “Just say no to inaccurate maniraptoran renditions, the t-shirt design.”

    Now there are 2 t-shirts I have to get at some point. Arg, stop making me want to spend money on clothes!

    Naishd: “And are the structures in ornithischians homologous with the filaments of theropods and pterosaurs? We simply need more data from more fossils before we can go further with this.”

    What’d be cool is if Kulindadromeus & Tianyulong (& thus, heterodontosaurids) turned out to be primitive cerapods/ornithopods/marginocephalians: Correct me if I’m wrong, but I’m thinking that would mean that ornithiscian quills/fuzz are most probably 1) specific to cerapods in particular (as opposed to ornithodirans/dinos in general), & 2) modified scales (as opposed to proto-feather/true feather homologues).

    Naishd: “The only competent and comprehensive review of dinosaur life appearance is Paul’s 1987 book chapter (Paul 1987), and it’s now woefully out of date.”

    What about Chapter 2 (Specifically, GSPaul’s sub-chapters) of “The Scientific American Book of Dinosaurs”?

    Naishd: “The good news: plans to produce just such a project are underway right now. Watch this space…”

    Is that what you were referring to when you said “A new, augmented edition of All Yesterdays will appear in time”? Put another way, will your new paleoart book be its own thing or a new edition of AY? I’m hoping for the former b/c that’ll mean I can include both books in “My Serious Dino Books” collection ( http://www.amazon.com/My-Serious-Dino-Books/lm/R2H4F8H299AK8M/ref=cm_lm_byauthor_title_full ) without being redundant by including multiple editions of the same book.

    Naishd: “Shame he gave up on that and went down the path that led to his special digital tracing technique…”

    You mean the dark side of the paleo-force? ;)

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  24. 24. JoseD 2:45 pm 09/1/2014

    Trisdino: “It is certainly true that we have found scale impressions on many dinosaur lineages, but as I stated in my previous posts, it is known that feathers can grow on top of scales, and, as proven by Kulindadromeus, feathers and scales, even if they are not growing on top of each other, can still coexist on separate parts of the body.”

    1stly, it has NOT been proven that Kulindromeus had true feathers or feather homologues. If anything, there’s evidence against Kulindadromeus having them & for it having “bristle-like scales” ( http://reptilis.net/2014/07/31/new-siberian-ornithischian-and-the-over-feathering-of-dinosaurs-again/ ).

    2ndly, in reference to the relationship between scales & feathers, see “The feather-scale dichotomy” for what Evo-Devo currently tells us (& yes, it does cover the exception of feathered feet): http://reptilis.net/2012/07/23/feathers-on-the-big-feathers-on-the-small-but-feathers-for-dinosaurs-one-and-all/

    3rdly, no offense, but why do keep commenting the same thing over & over? It looks like you’re trying to convince yourself more than anyone else.

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  25. 25. Percival 4:54 pm 09/1/2014

    Well… when you talk about “our” changing views of dinosaur coloration (and their onboard ecosystems), I wonder who “we” is. Back in 1969 Analog SciFi magazine had a cover with a nearly psychedelically colored T. Rex, annoying some readers but delighting others. SciFi has also had dog-sized proto-fleas attacking time-traveling Really Big Game hunters who had just bagged their host dino (in 1958′s _Poor Little Warrior_), and we should all know that real scientists read SF.

    I’d say “outlandish” ideas like these have been circulating for some time now but are just recently impacting serious scientists’ consensus.

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  26. 26. Felix2 5:19 pm 09/1/2014

    Trisdino- the likelihood of similar color schemes is possible, but I’m talking about reconstructions that follow modern birds down to things like ornamentation. That seems to me to be going to far.
    JoseD- if Kulindadromeus is a cerapod, why would that mean that feathers didn’t originate with basal dinosauria or ornithodira? that would only be true if their quills also turned out to be distinct from protofeathers.

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  27. 27. naishd 5:54 pm 09/1/2014

    And now there’s too much stuff for me to respond to. Some brief comments.

    – JoseD (comment # 23). Bob Bakker has corresponded with me privately about material he’s read on Tet Zoo. The planned palaeoart volume is not the same thing as the also-mentioned ‘augmented’ version of All Yesterdays. I don’t own the Scientific American Book of Dinosaurs (ironically); am not sure what GSP says therein.

    – JoseD (comment # 24): I am thinking more and more that we should avoid the term ‘protofeather’ when discussing the integumentary structures of fossil ornithodirans – it’s a loaded term. And the idea that they might be termed ‘feathers’ is even worse. I’m hoping that I’ve been consistent in referring to them as ‘filaments’ or ‘integumentary structures’.

    – Percival (comment # 25): I’m not sure who you’re addressing in your comment, but – as I said in the article – remember that what might be ‘common knowledge’ for one group of people is often not ‘mainstream’ or ‘widespread’ knowledge for interested parties in general. Many of us who’ve gone to trouble to procure and read obscure literature are familiar – even bored, perhaps – with ‘obscure’ ideas… it doesn’t mean that these ideas are familiar overall. So, while gaudily patterned, feathered dinosaurs indulging in weird or exciting behaviour have been a constant presence to me, I routinely meet educated and well-read people who have never seen such things.

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  28. 28. JoseD 6:07 pm 09/1/2014

    Felix2: “if Kulindadromeus is a cerapod, why would that mean that feathers didn’t originate with basal dinosauria or ornithodira? that would only be true if their quills also turned out to be distinct from protofeathers.”

    B/c it would mean that non-theropod dino filaments are only known directly from (& thus, probably specific to) cerapods. Kinda thought that was obvious, but whatever. In any case, the phylogenetic evidence against said filaments being feather homologues is already pretty convincing ( http://www.nature.com/news/feathers-were-the-exception-rather-than-the-rule-for-dinosaurs-1.14379 ). Looking forward to the paper itself.

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  29. 29. JoseD 6:33 pm 09/1/2014

    Naishd: “And now there’s too much stuff for me to respond to.”

    My bad for overwhelming you with questions.

    Naishd: “The planned palaeoart volume is not the same thing as the also-mentioned ‘augmented’ version of All Yesterdays.”

    Sweet! Good thing I decided to wait on getting AY (I try to get the last/most recent edition of a given book).

    Naishd: “I don’t own the Scientific American Book of Dinosaurs (ironically); am not sure what GSP says therein.”

    It’s been a while since I’ve read it, but from what I remember, GSPaul’s 1st Chapter 2 sub-chapter (“Restoring the life appearance of dinosaurs”) is basically an updated version of his “1987 book chapter” (albeit for casual readers). Last I checked, you can read said sub-chapter in its entirety here (If not, you can get said book here)

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  30. 30. naishd 7:18 pm 09/1/2014

    Oh – don’t hold your breath on that ‘augmented’ AY edition… it won’t be done for years yet! I have to get at least four other books out of the way first.

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  31. 31. JAHeadden 7:29 pm 09/1/2014

    Hiyo Darren. Yay! Soft-tissue reconstruction, my favorite. It’s a good thing I’ve spent the last [five] years writing on this subject, and especially on facial anatomy. I think you’re misinterpreting what Morhardt’s thesis and the consequent abstract/presentation at SVP said about the topic of ornithischian “cheeks.” You write:

    “The distribution of nutrient foramina on the jaw bones of these dinosaurs supports the idea that an extensive amount of tissue did indeed cover the sides of their jaws (Morhardt et al. 2009), and the presence of ossifications that fit in the space between the upper and lower jaws of some ankylosaurs show that a tissue web of some sort really was present.”

    However, what Morhardt et al. (2009) wrote was:

    “Taxa with fewer nutrient foramina (mammals, snakes, lizards) have more pliable extra-oral tissues covering their teeth [...] When compared to the extant sample, both saurischian and ornithischian dinosaurs fall with amniotes that have covered teeth.” (emphasis added)

    Unless they are implying theropods had cheeks, it simply leaves the question open, into which you inserted the long-standing argument of nodosaur “cheek scutes,” an issue that may suggest that those dinosaurs had these structures … but no further. The arguments for ornithischian cheeks remain contentious and based on either misinformation about how jaw mechanics work or an understanding of the tissues involved. (See here for my dicsussion on the topic, and check the “Cheek” tag on the post for how I covered the issue with sauropods (implied in Wedel’s reconstruction slightly), and then returned to figuring out how ankylosaurs specifically don’t influence whether ornithischians generally had cheeks.)

    I mean not to be harsh about this, but this should be corrected above.

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  32. 32. naishd 7:44 pm 09/1/2014

    Hi Jaime — I wondered if the mention of ‘cheeks’ might draw you in. My recollection from Morhardt’s talk at the SVP meeting concerned is that the data from foramina size and distribution did support the idea that ‘cheeks’ were present, though I’m not saying that she stated this specifically and I will in fact go and ask her. You didn’t note the last few lines of the abstract, which are…

    “Our results support the hypothesis that foramina density and the presence/absence of extra-oral structures are correlated. We suggest that at least the teeth of many dinosaurs were covered in life by a pliable and somewhat mobile extra-oral tissue” (Morhardt et al. 2009).

    By the way, it’s never been clear to me just what you do actually think about ornithischian facial tissues. Nature is complicated and all about infinite shades of grey, but I do think that the evidence for extensive soft facial structures – ‘cheeks’ in ornithischians and ‘lips’ in saurischians – is looking good.

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  33. 33. GrantHarding 7:50 pm 09/1/2014

    Great summary!

    Matt Martyniuk wrote an excellent post on the subject of dinosaur colours, and the constraints placed on them by chemistry: it’s here.

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  34. 34. JoseD 7:53 pm 09/1/2014

    “Oh – don’t hold your breath on that ‘augmented’ AY edition… it won’t be done for years yet! I have to get at least four other books out of the way first.”

    Darn.

    BTW, I think you accidentally deleted to the link for GSPaul’s “Restoring the life appearance of dinosaurs”. Just to be safe, here it it is again. [From Darren: yes, sorry; I thought it was the wrong link.]

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  35. 35. naishd 7:56 pm 09/1/2014

    By the way – please try to embed url codes properly, don’t just paste them into the comments box! I always have to go edit them as they screw up the formatting of the article. Thanks.

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  36. 36. Tayo Bethel 9:45 pm 09/1/2014

    BTW, Matt Martyniuk’s A Field Guide to Mesozoic Birds and Other Winged Dinosaurs is an excellent read.

    On dinosaur colouration: Has anyone remarkedonthe fact that among birds, the brightly coloured species tend to be insectivorous or omnivorous or frugivorous, while those that specialize in eatingother tetrapodstendto be more muted? Is this a function of diet or ecology, or both? Might the fact that predatory birds tend to have muted colouration indicate that predatory dinosaurs,too, were muted?

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  37. 37. JoseD 10:43 pm 09/1/2014

    “By the way – please try to embed url codes properly, don’t just paste them into the comments box!”

    How do you do that?

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  38. 38. Alex Kleine 11:49 pm 09/1/2014

    “With Paulian dinosaurs as the framework or bedrock, we have entered the age whereby people are able to add a more realistic amount of musculature, skin and other integumentary structures… to make the animals less shrink-wrapped.”

    Are Luis V. Rey and Julius Csotonyi one of those non-Paulian paleoartists?

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  39. 39. Allen Hazen 12:25 am 09/2/2014

    Just on the history…
    My guess is that the 1987 book “Dinosaurs Past and Present” (cover of second volume shown near bottom of post) was very influential: papers in it ranged from straight palaeontology to straight art history (history, that is, of dinosaur reconstruction and portrayal), and anyone interested in dinosaur portrayal at the time would have looked for it. It’s the first place I ever saw a picture of feathered Velociraptors!

    The change in view of dinosaurs in the 1980s… I think if one palaeontologist ought to be singled out as stimulating the change, it would be Ostrom: not an artist, but closely associated at least with Bakker on your list. The iconically dynamic Deinonychus picture (reproduced just to the right of the picture of Bakker near the top of the post) was apparently done by Bakker as a frontispiece for Ostrom’s monograph on D.

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  40. 40. Andreas Johansson 1:49 am 09/2/2014

    Since the cheek issue resurfaced, I’ll take the opportunity to repeat my question from #17:

    So what does technically distinguish cheek tissue from other forms of tissue closing the sides of the mouth?

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  41. 41. Heteromeles 1:58 am 09/2/2014

    @Trisdino: I’m another one who thinks that ripping off modern bird color schemes wholesale is intellectually lazy, if not worse. There’s little point in, say, putting a Chinese pheasant’s pellage on a large theropod, just because it looks cool. I’d much. rather see something that makes sense in the Mesozoic, rather than a cheap rip off.

    However, I can understand that artists are constrained by more than just the science. The image still has to sell.

    For example, if sauropods are large and pale, and if males use a color display that involves inflatable, possibly moving structures on the neck and head, and if this display needs to have a high contrast to both the sky and the surrounding vegetation, then the most appropriate color is pink, provided simply by dilating capillaries in the skin. I’m sure we can all imagine what a large, throbbing, pink sauropod neck and head would look like. Unfortunately, even though one can make a sober case for such a structure existing, it’s dubious that it will ever be so portrayed in dino-art, especially in books designed to get bought by parents in more conservative parts of the US.

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  42. 42. CS Shelton 2:17 am 09/2/2014

    ^I’d like to see an answer to Andreas on cheeks as well, if anyone is up for it. Regarding drab v. colorful birds, I like what Trisdino said about the beauty possible in brown and white.

    “Cryptic” coloration can be very specific and elaborate – more than just camouflage when observed up close. I feel like I read somewhere that some cats may differentiate each other in part based on the shapes of facial stripes. They break up the shape for hiding in grass, but could serve a different function when stealth isn’t needed.

    Jerzy’s rundown at 8 is pretty convincing. I’ve often thought of deinonychosaurs as “wolf pheasants,” and would call them that in a fantasy genre story. Pennaceous feathers are great for concealing display structures – you can be cryptic one moment and showy the next. I’d guess non-avialan dinos used arms and tails for stashing the cool feathers.

    Although I wonder sometimes how drab an animal really has to be to survive. Pheasants can get mad showy without being very strong fliers. Being small probably helps.

    Re: the links from Jose at 24, that sucks the situation with Kulindadromeus is all jacked up. What is this, the 1800s?

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  43. 43. CS Shelton 2:22 am 09/2/2014

    ^I also like Heteromeles at 16 – I imagined sauropods changing color through life until the big ones were iridescent. Freaky. :-) As for the pink throbby heteromeles comment at 41, I’ll leave my imagination behind for that one.

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  44. 44. Trisdino 3:08 am 09/2/2014

    - heteromeles: I agree that it often is lazy, but there are cases in which it works well. For example Mark Witton did a pigeon therizinosaurus, specifically for an article that talked about how similar extinct and modern birds are.

    That said, if I never see another turkey dromeosaur or cassowary pterosaur, I will be happy.

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  45. 45. Tayo Bethel 3:49 am 09/2/2014

    @comment 43:

    Who came up with the turkey dromaeosaur idea? Dromaeosaurids and turkeys,as far as we know,had completely different ecologies and certainly radically different diets and behavior. Large, active predators tend to be cryptic, even when they are highly social. and the cassowary pterosaur falls apart without any argument,since the only things pterosaurs seem to have shared with birds are flight and its associated adaptations,and those only went so far.

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  46. 46. naishd 5:52 am 09/2/2014

    Again, more stuff than I can begin to keep up with — thanks to all for comments.

    Luis Rey and Julius Csotonyi are definitely among the wave of palaeoartists who illustrate ‘Paulian’ dinosaurs (I’m sure they won’t mind me saying that). Luis, in fact, was quite the innovator from the start of his involvement, deliberately illustrating non-bird maniraptorans with flamboyant, extravagant soft tissue structures and extra feathering. As a result, some of his dromaeosaurs and so on have been mocked as ‘turkeys from hell’ or whatever: in fact, his dinosaurs are not that inconsistent with the way we think they probably looked. Luis and I corresponded extensively before email became a regular thing. I will confess that I’ve lost interest in his work as he’s made the shift to digital montages… they just don’t work for me at all.

    I also have a problem with the colour schemes and patterns of extant animals being co-opted for fossil ones. In most cases, it’s too obvious and shows that the artist simply copied a colour scheme they saw in nature, and in many cases it’s not tremendously likely (you can imagine it as a hypothesis about the animal’s appearance that should be consistent with its lifestyle and ecology). I recently worked as consultant for a book where the oviraptorosaurs were modelled after cassowaries: wholly black, with naked head and neck skin, and red and blue wattles. But cassowaries are predominantly forest birds, whereas the oviraptorosaur concerned was a desert-dweller. Some desert animals are very dark (some corvids, for example), but big, flightless animals are generally light, not dark. Alas, there was neither the time nor enough slack in the budget to change it. This happens a lot.

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  47. 47. Trisdino 8:23 am 09/2/2014

    - Darren: I have no doubt that the turkey raptors are fully accurate, it is just that they are no more so than all the far more “dignified” looks, so the fact that they are constantly(and I do mean that, it has almost become a meme at this point)portrayed seems almost like a joke at this point – “look at how ugly they are!”. And yeah, environments obviously should be taken into account when colouring an extinct animal, making desert cassowarys is straight up unrealistic, but even in a forest setting, I would still argue that one should avoid directly copying their colour scheme, as for example the guanlongs in Dinosaur revolution did. That said, I do think that partly basing a colour scheme off an extant animal, as long as it is plausible, is okay, as, with the amount of colour variations currently present in animals, it is almost impossible to make a plausible colour scheme without it at least vaguely resembling some modern creature.

    - Tayo Bethel: I highly doubt that they actually made the cassowary colour schemes because they thought it was realistic, rather, I find it far more likely that they just did it because they thought it looked nice, as tends to be the case.

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  48. 48. Lars Dietz 9:16 am 09/2/2014

    I agree that directly copying an extant animal’s color scheme for illustrating a fossil one is just lazy, especially if done without thinking about the environment where that animal lived. However, it should be remembered that even some unrelated extant animals have strikingly similar color schemes, and it isn’t always caused by mimicry. For example, here’s a Great Tit (Parus major) and here’s a male Golden Whistler (Pachycephala pectoralis). They are not closely related (the former is a passeridan, the latter a corvidan) and they don’t occur together, so it’s not any kind of mimicry. But still, except for the black streak on the great tit’s belly, their plumages are very similar. So I wouldn’t exclude that some extinct animals had a color scheme that would remind us immediately of some modern animal.

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  49. 49. AndrewD 9:32 am 09/2/2014

    The discussion on plumage and skin colouration brings to mind a question, When did colour vision evolve and what sort of colour vision did Dinosaurs have? If Dinosaurs only saw in black and white( the limit situation) the pattern, not colouration, is important (think Dazzle camouflage). If Dinosaurs could only distinguish say red and blue (say) then Green and Yellow would be unimportant and evolutionary neutral(Not selected for or against) I look forward to comments from the experts as I am only a Chemist.

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  50. 50. CMHolliday 9:55 am 09/2/2014

    “The concept of shrink-wrapped dinosaur syndrome (SWDS) arose sometime round about 2010 and has since been widely used in discussions of dinosaur life appearance.”

    This is a concept older than the snappy acronym. I knew it as the ‘hungry dinosaur look’ in the 1990s. I’m sure it benefited from your all’s blogs, but its by no means a new idea. And sadly it still hasn’t gained acceptable traction.

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  51. 51. John Scanlon FCD 9:57 am 09/2/2014

    Jaime quoted “Taxa with fewer nutrient foramina (mammals, snakes, lizards) have more pliable extra-oral tissues covering their teeth…” which I find odd. Snakes and mammals have independently evolved tissues capable of making a watertight seal external to the teeth, with few and large nutrient foramina, but lizard lips are mostly very thin (e.g. problematic to separate from the bone, post mortem) and the foramina small and numerous. The ability of snakes to drink by sucking may have depended initially on increased mandibular kinesis before much modification of labial tissue, and/or varanoids may be intermediate to some extent, but an argument treating snakes and ‘lizards’ as sharing one character state seems suspect. Anyone seen Morhardt’s actual dissertation?

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  52. 52. naishd 10:14 am 09/2/2014

    CMHolliday (comment # 50): nice to see you in the comments here :) Yes, ‘hungry dinosaur syndrome’. I guess the problem is that, when things aren’t ‘documented’ somewhere, other people don’t get to hear about them. I also recall seeing dinosaurs being referred to as ‘anorexic’ or ‘hollow-bellied’ long before shrink-wrapping was mentioned.

    As for lizards and snakes and their extra-oral tissues (comment # 51), the generalisations used in the abstract apply to exemplar taxa (though I’m not sure which ones).

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  53. 53. Jerzy v. 3.0. 11:20 am 09/2/2014

    Some more about colors.

    I loved the blog post about different structural colors of birds, and how to use microstructures to discover real pattern of fossil species. However, in general, selection pressure is so great that any animal group (or dinosaur) is likely to come with any color pattern which is selected by evolutionary forces. Good example of parrots evolving new green pigment because their feathers are too delicate to produce green camouflage by method used in other birds.

    Being ‘drab’, whatever it means, is not some default state of animal coloration nor it is difficult to evolve into bright colors. It is common in modern ecosystems because placental mammals poorly see colors. So a rhea needs no complex pattern to hide from a jaguar, nor a Nile crocodile needs a complex camouflage to ambush an antelope.

    In Mesozoic, animals were likely more camouflaged to escape attention of sharp-eyed predatory theropods. This applied to dinosaurs, other Mesozoic reptiles, avialan birds and Mesozoic mammals which themselves poorly saw colors. Think of nightjars, snipes, bustards or green iguanas.

    Yes, modern birds of prey are not well camouflaged, but they fly and attack prey from bigger distance than a predatory theropod could. So terestrial predatory dinosaurs had likely also complex camouflage, think modern big and medium-sized cats.

    So you can imagine eg. that Tyrannosaurus rex (large terrestrial ambush predator of tropical rainforest) most likely had complex camouflage pattern of green and brown spots and stripes all over the body, especially front. I only remember one T-rex illustration which got it this way. It was in old issue of National Geographic, with three camouflaged Edmontosaurs and one camouflage tyrannosaur in polar Alaskan forest.

    In contrast, when dinosaurs displayed, their colors were likely as bright as modern birds.

    I share with Darren a dislike of obvious lifting exact colors from a modern bird or mammal. Now, with internet, the public will easily recognize ‘it is cassowary’ or ‘it is male ostrich’ and comment on intellectual laziness. If you are illustrator who is stuck with lack of inspiration (as I sometimes am), just take likely colors and draw randomly without looking. After some trials you will likely have something both new and plausible.

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  54. 54. SciaticPain 11:30 am 09/2/2014

    #36 Tayo Bethel – Yes there is much truth to your observations. Especially among birds it is well known that much of the color pigmentation they use is based on carotenoids which they obtain from their diet. Carotenoids can be picked up from plants but also crustaceans (think pink flamingoes), insects, fungi and probably loads of other things can be a source of carotenoids. I’ve also noted, but I don’t know if there has been any rigorous studies on this, a preponderance of highly colored animals in the tropics compared to the temperate latitudes. Going a little further I wonder if the gymnosperm flora of the Mesozoic, lacking the bright fruits and flowers of angiosperms, would have fostered a more muted colored bestiary. But as many have noted even muted tones can be used to create awesome displays of contrasts and tones and brighter colors limited to specific display areas – likely around the head, eyes.

    Other stuff here I want to comment on but I have to go to work.

    Duane Nash

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  55. 55. RndrpsOnRoses 12:31 pm 09/2/2014

    Hi Darren! Thanks for bringing my attention to the article. The work I did in 2009 on dinosaur “lips” and “cheeks” related to my Master’s thesis, which I completed but haven’t published. My dissertation, which I’ve been working on since, is about dinosaur brain morphology and evolution. In any case, my M.S. work considered whether foramina density might yield insight into the presence and/or thickness of extra-oral tissues. My results, which were largely preliminary and inconclusive, suggested that high foramina density was correlated either with a croc-like condition, where thin skin sits closely to the bone, and/or the presence of highly sensate touch receptors like vibrassae and integumentary sense organs (ISO’s). Conversely, low foramina counts were associated with a more mammalian-like condition, with larger foramen size and thick extra-oral tissue. This led to the development of my “carpet tack” hypothesis, wherein thin skin was innervated by many small nerve branches that emerged from the bone via foramina and would “tack” the integument close to the underlying bone. Whereas, in vertebrates with thick, extra-oral tissue and few-but-large foramina, the sensory branches of the trigeminal emerge from the bone and ramify within the thick overlying soft tissue into small cutaneous branches. This “untacked” condition could potentially permit freer movement of the overlying fleshy tissues. The “carpet tack” idea is an interesting hypothesis I think, but a lot of work still needs to be done to really test it, including broader surveys of anatomy and histology in extant vertebrates, as well as phylogenetically-informed analyses of ancestral character state reconstruction and evaluation of evolutionary rates (and thus, probabilities) for each possible tissue type. Right now, the EPB, with its parsimonious assumption of “no cheeks, no lips” really does stand. I don’t really ascribe to the Galton hypothesis of cheek shelves (the shelf is not a shelf…a doughnut-or-the-hole problem), and I really don’t like the whole “but how did it keep the food in its mouth when chewing?” argument either. Rather than approaching the question from a behavioral standpoint (really, putting the cart before the horse), I feel it’s better to evaluate the fossils for direct anatomical evidence of soft tissues, using hard-core precision and broad surveys to get a better sense of what our search image should be for correlates of soft tissues (and I really feel histology is where it’s at for that). In the meantime, the cheek debate sputters on. One last thought–and it’s more of a pet peeve that I’ve voiced on the interwebs before. We really should stop using the terms “lips” and “cheeks” with regard to dinosaurs. What paleontologists, and the public, understand them to be are fleshy outgrowths derived from the platysma muscle, which is innervated by the facial nerve and not the trigeminal nerve. Lips and cheeks are features that are exclusive to mammals and evolved for suckling. So, when talking about dinosaurs, we should say rictal plate when we mean rictal plate (or whatever) and not replace it with the more familiar term “cheek.” At the very least, we should put the mammalian terms in quotes to signify our understanding that dino “cheeks” are not mammal cheeks (same goes for “lips”). This way, we keep our terminology and corresponding concepts straight. On that note, thanks for using quotes in your article, Darren. Have a good day! –Ashley Morhardt

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  56. 56. Andreas Johansson 1:04 pm 09/2/2014

    Ashley Morhardt wrote:
    One last thought–and it’s more of a pet peeve that I’ve voiced on the interwebs before. We really should stop using the terms “lips” and “cheeks” with regard to dinosaurs. What paleontologists, and the public, understand them to be are fleshy outgrowths derived from the platysma muscle, which is innervated by the facial nerve and not the trigeminal nerve.

    Thanks for answering my question. I trust you’ll forgive me for doubting that the general public understands anything so anatomically specific.

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  57. 57. Heteromeles 1:22 pm 09/2/2014

    Of course, the amusing thing about all this talk of camouflaging bulldozer-sized dinosaurs (even ones that are smaller–say the size of a horse), is the size of the nasal cavity on those beasts. No use of olfaction in hunting and predator detection? I’m shocked, shocked. I’m also shocked that no one’s talking about them using hearing for predator or prey detection. After all, some birds do that too. If we’re going to ignore one of the bigger sense organs on the dinosaur, why focus on the eyes?

    And yes, I’m being sarcastic. It’s just that camouflaging a Triceratops from a Tyrannosaur seems a wee bit ridiculous. I’ve got no qualms about talking about camouflage with smaller animals, but there comes a point when anything other than simple countershading won’t materially aid anything huge that has to move regularly to stay alive.

    As for the dazzle camouflage, remember that it was designed to screw up WWI rangefinders, especially those on submarines, and that only because torpedoes were designed to explode at a given distance, so screwing up distance to target was useful. AFAIK, in zebras, one of the few putative examples of dazzle camouflage in animals, the latest hypothesis is that zebra stripes are there to mess with horsefly vision, rather than lion vision. If you want dazzle, I’d suggest that horizontal racing stripes (as on racer snakes) might be more useful than dazzle, simply because the stripes on a snake make it harder to target for a grab. Otherwise, dazzle patterns would be more useful for individual recognition than for defense, IMHO.

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  58. 58. Trisdino 1:27 pm 09/2/2014

    - Heteromeles: I can easily see a camouflaged tyrannosaur. Just imagine them being green and brown, with military-esque patterns, and hiding in the treelines, even an animal that large would fit in pretty well, and it would help them in getting close enough to dash for the kill.

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  59. 59. Heteromeles 1:28 pm 09/2/2014

    Actually, thinking about it, if we make the questionable assumption that zebra stripes and similar patterns mess with parasite vision, perhaps dinosaurs were all dazzley, but to protect themselves from biting insects, rather than from carnivorous dinosaurs.

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  60. 60. Trisdino 1:33 pm 09/2/2014

    I am pretty sure zebra patterns are to confuse predators depth perception, since, as has been noted several times, many placental mammals lack good colour vision, so a bunch of stripes in a sea of grass, all more or less the same colour, gets very confusing to, say, a lion.

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  61. 61. Felix2 2:27 pm 09/2/2014

    A colorful tyrannosaur would probably have had some problems hunting. Tyrannosaurs likely ambushed their prey, waiting around water sources, so I think that camouflage would have been valuable. It should be noted that Matt Martyniuk’s aforementioned book talks a lot about coloration in oviraptorids and paravians. It says that, except for neognaths, most feathers could only have been shades of brown, grey, black, etc., although iridescent feathers would have been possible. If I had the book with me now I could tell you why he thinks so.

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  62. 62. Cahokia 2:39 pm 09/2/2014

    I’m starting to wonder whether JoseD is right and the bristly integument on ornithischians like Kulindadromeus is not homologous with theropod proto-feathers.

    Ornithischian bristles look like more like modified scales than the dino-fuzz we see, for example, on Sinosauropteryx. The fact that they’re so unevenly distributed among ornithischians is odd – by contrast, we can assume that all maniraptorans bore full plumages.

    It may simply be the case that endothermy evolved two or more times among non-avian dinosaurs as well as among pterosaurs but is not the ancestral Ornithodiran condition and that the integumentary structures we’re seeing are evidence of that. Perhaps most dinosaurs were mesotherms but were at the same time prone to evolving to true endotherms, and whenever they did, they developed fuzzy or bristly integument.

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  63. 63. Trisdino 2:56 pm 09/2/2014

    - Cahokia: The evidence is rather vague, but I am going to say that it is SLIGHTLY leaning towards it all being related. It just seems like it is a lot more plausible that they all share a common origin, than that these integuments rapidly evolved and de-evolved across multiple lineages in short spans of time – Not impossible mind you, but it just seems like a weird conclusion to jump to when we have what appears to be a relatively solid explanation, with some evidence backing it up.

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  64. 64. vdinets 4:23 pm 09/2/2014

    Tayo (#36): are carnivorous birds really dull-colored compared to others? Owls are cryptically colored, but so are nightjars; it’s probably because they hide during the day. As for diurnal raptors, some are not dull at all: look at white hawk, Steller’s sea eagle, or crested caracara.

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  65. 65. vdinets 4:58 pm 09/2/2014

    Heteromeles (#57): giraffes are pretty big and stick out a lot, but they are camouflaged. I don’t think there’s a size limit. Camo is cheap to produce, so it is worth using even if it rarely works.

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  66. 66. Heteromeles 5:26 pm 09/2/2014

    @65: and elephants are even larger, theoretically not camouflaged, and still as hard to spot as a giraffe in similar habitat. Your point?

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  67. 67. Heteromeles 5:32 pm 09/2/2014

    By the way, what’s the largest terrestrial animal that uses green in its camouflage? A kakapo? An emerald tree boa? In most habitats, there’s a lot more brown than green, and it only really works as a camouflage color if there’s a lot of green in the background. I’d suggest, all else equal, that large terrestrial dinosaurs could more easily be earth and tree-trunk colored, rather than foliage colored if they’re camouflaged at all.

    I’d also point out that military camouflage is not a great model. One of the central tenets of military camouflage is asymmetry of pattern to break up the fundamental shape of the soldier or vehicle, because human eyes use symmetry to find things. Most animals use some form of stripe or fractal pattern as camouflage, because it’s much easier to produce developmentally (if I remember the math), than is a set of random, overlapping blotches, which make great camouflage, but are more easily painted on than grown.

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  68. 68. Allen Hazen 5:49 pm 09/2/2014

    Re: Heteromeles (#66)–
    “By the way, what’s the largest terrestrial animal that uses green in its camouflage?”

    Sloths have algae in their fur that gives them a greenish look: I would guess that this is for camouflage. And probably in body mass they outdo even a large kakapo.

    As for symmetry… Nice point! But apparently it IS possible for even a mammalian developmental program to produce wildly asymmetrical colour schemes: the Fin Whale (Balaenoptera physalus) is a spectacular case.

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  69. 69. Felix2 6:49 pm 09/2/2014

    Trisdino- I agree that it seems likely that filaments of some sort developed at the origin of ornithodira, or even archosauria. Many crocodylomorphs (better than mammals and dinosaurs put together!)seem to have many features of endothermy, so I wonder if some (sebecians and sphenosuchians leap to mind) might have actually had filaments of some sort. That could mean that feathers* and/or endothermy (are we sure if they go hand in hand?)are found at the origin of the archosaurs.
    This is quite specualtive, I admit. But here’s an abstract on it.
    http://www.ncbi.nlm.nih.gov/pubmed/15674775

    *I should note that when I use the word feathers, I’m including protofeathers and other “primitive” forms of integument in its definition.

    On coloration; would things like a jaguar’s spots be considered “blotches?” And isn’t it true that striped patterns are more efficient camouflage in grassy environments, of which there was a dearth of for just about all of dinosaur history.

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  70. 70. John Scanlon FCD 8:49 pm 09/2/2014

    Hi Ashley (comment 50), what was your exemplar lizard? It’ll make sense to me if it’s Varanus.

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  71. 71. SciaticPain 9:03 pm 09/2/2014

    As for the size constraint issue for cryptic coloration I have read and watched many accounts of large African elephants disappearing into the bush, especially when being hunted. They also can walk quite softly, there large padded feet muffling breaking branches etc etc. I am sure big dinos could have done the same.

    Alert, attentive, and color vision capable humans miss seeing car-sized and truck-sized objects every day on our roadways. Large animals have an uncanny skill at hiding in plain sight, where by virtue of their large bulk simply by staying still they can often melt into their environment.

    Duane Nash

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  72. 72. John Scanlon FCD 9:11 pm 09/2/2014

    (Pardon me, I meant 55)

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  73. 73. Tayo Bethel 11:04 pm 09/2/2014

    @Heteromeles:
    Point taken, even if you were being sarcastic. Something just occurred to me. Cryptic prey animals tend to be solitary,or at least not as social. A herd of large animals would find it very difficult to hide, and large groups of animals rarely attempt it, instead relying on speed or group defense for protection. Also, many large theropods have already been shown to have enlarged olfactory bulbs indicative of a superb sense of smell. So sauropodsand other large group-living dinosaurs may have been cryptic only as hatchlings and small juveniles.

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  74. 74. Heteromeles 1:08 am 09/3/2014

    Thanks Tayo.

    Here are two other dermal schemes that might be worth considering.

    As Duane pointed out last year, the huge piles of dung produced by sauropods would have supported a whole decomposer ecosystem of their own, probably including some smaller entomophagous or coprophagous dinosaurs. What did they look like? If one accepts the notion that zebra-striping might be useful for warding off biting flies, it’s possible that some dazzle-coated critters were foraging through the dung heaps, and using their bright coats to minimize the amount of biting they experienced. What would all those coprophages look like, anyway? Al dingy and dung colored, or something more exotic?

    A second idea comes from an obscure weevil Gymnophilus (Symbiophlus) lichenifer, which is famous for having a cuticle that’s covered by liverworts and lichens. It occurs to me that a number of dinosaurs, including anklyosaurs and sauropods, may well have hosted lichens and liverworts on parts of their anatomy that were impossible for them to groom off. I remember seeing a small pterosaur proposed as a parasite forager on large sauropods, but there’s no reason they couldn’t be considerably more covered with epiphytes. Couple that with a bright pink neck as a mating display, and you’d have a truly odd animal.

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  75. 75. Mark Robinson 1:33 am 09/3/2014

    #54. SciaticPain – this doesn’t invalidate the point you were making but I’m pretty sure that at least some flamingos get their caratenoids directly from cyanobacteria and tend to be darker (more strongly pink) than those who get theirs from animals which feed on cyanobacteria.

    Also #70. (not trolling you, I swear!) – elephants can indeed be surprisingly quiet when they wish but are quadrupedal and therefore able to keep three feet on the ground at all times upon which to distribute their weight.

    With bipedal animals, I wonder whether the weight transfer from one foot to the other would be quite as smooth? It prob wouldn’t be much of an issue if the modus operandi of, say, a large tyrannosaurid was to squat in a copse and wait for lunch to be delivered.

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  76. 76. Tayo Bethel 6:56 am 09/3/2014

    Is there any reason to think that large tyrannosaurids were ambush predators? According to Tom Holts JR. they were built more like pursuit predators. Assuming that formfollows function,large tyrannosaurids probably employed a range of hunting strategies but were first and foremost opportunistic pursuit predators.
    @Heteromeles:
    Parasitic tetrapods seem to be quite,quite rare in modern times. On the other hand, no living tetrapod is a potential moving, breathing self-contained ecosystem. So, lichen grows on some inaccessible part of a gigantic sauropod.Some insects feed on the lichen. Others feed on the blood of the sauropod. All are annoying. Small pterosaurs, maniraptorans and squamates take advantage of this bonanza, perform incidental cleaning servicesand,maybe, even live around the sauropods as valued symbiotes. Sauropod dung must have been a haven for all manner of coprophagous insects, which again would draw in the insectivores. Not sure if any dinosaurs would have made their living in sauropod dung piles, though.

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  77. 77. Jerzy v. 3.0. 7:21 am 09/3/2014

    @Heteromeles
    Ever heard of animals called lion, tiger or polar bear? They use camouflage alhtough weigh as much or more as a horse.

    About green, you missed my post that mammals other than primates have green-red color blindness, and why this cannot be expected from dinosaurs.

    And you obviously never been to a tropical forest or bush. Otherwise you would know that elephant-sized or buffalo-sized animals can easily hide in dense vegetation. And all mammals other than humans, even elephants, can walk absolutely noiselesly.

    As Mesozoic paleo-environments were often forested (generally, open habitats were less common than today) camouflage was even more common than today.

    Re: zebra stripes assumed to evolve to confuse vision of biting tsetse flies. This is one exception proving the rule: zebra striking colors are only effective because zebras are relatively rare, and flies evolve to pick up antelope and buffalo. Zebra also live in open savanna and rely on speed to escape from carnivore enemies.

    Of course, my rants depend on the assumption that dinosaurs had full color vision. This is supported by phylogenetic bracketing, by full color vision in the surviving sub-group of theropods (birds) and shining colors on few Mesozoic non-bird feathers which would be useless for animals without good color vision. For now it seems best supported. If somebody comes with primary data that dinosaurs partially or fully lost color vision, the argument does not truly hold of course.

    About dinosaur smell and hearing:
    It is well known that many dinosaurs had very good developed sense of smell and hearing. However, back to polar bears, reliance on smell doesn’t mean lack of camouflage. There were attempts to model sounds produced by hardosaurs. You are welcome to ask questions how dinosaurs smelled.

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  78. 78. DavidCerny 7:40 am 09/3/2014

    @ Cahokia #62:

    Ornithischian bristles look like more like modified scales than the dino-fuzz we see, for example, on Sinosauropteryx.

    How so? The bristles of Psittacosaurus and Tianyulong are hollow and tubular, unlike the bristle-like or spine-like elongated scales present in some extant squamates (e.g., iguanas). Rauhut et al. (2012) even take the fact that the bristles of Psittacosaurus extend beneath the skin layer as indirect support for the presence of feather follicles. Kulindadromeus also complicates the situation, as Godefroit et al. (2014) note that its monofilaments are more similar to the protofeathers of Sinosauropteryx than to the bristles of other ornithischians.

    Refs:

    Godefroit P, Sinica SM, Dhouailly D, Bolotskij JL, Sizov AV, McNamara ME, Benton MJ, Spagna P 2014 A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science 345(6195): 451–5

    Rauhut OWM, Foth C, Tischlinger H, Norell MA 2012 Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany. Proc Natl Acad Sci USA 109(29): 11746–51

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  79. 79. Dartian 8:23 am 09/3/2014

    Echoing what Trisdino said:
    many [birds] do not have incredibly vibrant colours, they typically stick to the browns, whites, blacks, and greys, but the combinations they make with those colours are often mindblowing

    The American kestrel, for example, sticks to the “browns, whites, blacks, and greys” (apart from its yellow skin parts), but I certainly wouldn’t call it ‘dull’. Ditto for the marbled teal, which has a plumage that’s basically just brown and white.

    However, this I disagree with:
    I am pretty sure zebra patterns are to confuse predators depth perception, since, as has been noted several times, many placental mammals lack good colour vision, so a bunch of stripes in a sea of grass, all more or less the same colour, gets very confusing to, say, a lion.

    Zebras typically spend very little time in vegetation tall anough to even partially cover their bodies (if anything, they seem to avoid very tall grass). Most of the time zebras are out on the open plains where the camouflage value of their stripes is very low.

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  80. 80. Trisdino 9:07 am 09/3/2014

    Well, I will be the first to admit that I do not know a damn thing about mammals, because honestly, they do not interest me particularly much. That is why I said “pretty sure”, as really, it was just something I had heard being echoed multiple times, by people who I assumed knew more than me.

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  81. 81. Heteromeles 10:24 am 09/3/2014

    @Jerzy (77): Thanks for the lecture. I’m glad you read post 66, where I linked to a picture of an elephant camouflaged in the bush.

    Getting back to this fixation on green dinosaurs, if an animal has to deal with predators that are fully color sighted, obviously being green against a background that is primarily brown (tree trunks, rocks, soil) is the best way to go, right?

    Not at all. If you actually look at the world, you’ll notice that there’s not a lot of green in most places (look at the elephant and giraffe pictures in 66, for example). There are green leaves in canopies during the growing season, and absent those green leaves, green stands out, rather than blending in. Given this, it would be counterproductive to be a giant, bright green dinosaur.

    Given your fixation with imperfect mammalian color vision, I’d expect you to be talking about the paradox that more large mammals should be bright green (because it apparently doesn’t matter), rather than that the dinosaurs with their putatively perfect (or ultra-perfect, since they may have seen UV light as well), color vision would pick such a marginally useful color. Why don’t we see green tigers, for example, if their prey can’t see the difference between red and green?

    I’d also point out a little paradox that goes back to 1940 or so (google on “color blindness camouflage detection”). People with red-green color blindness were found to be better at spotting camouflaged positions than those with normal color vision. The US Army put this to work in WWII, testing for color-blindness and putting those soldiers on photo reconnaissance. Scientists have even tested this in color-blind capuchin monkeys (http://discovermagazine.com/2007/apr/the-upside-of-color-blindness), and found that they were better at capturing insects than their normally-sighted conspecifics.

    One could argue, therefore, that mammals are better camouflaged than any dinosaur, because they’ve had to evolve to beat a better optical detection system than the dinosaurs had. The paradox is that perfect color vision may overwhelm the bearer with too much information, making it paradoxically easier to fool them with camouflage. Anyone who’s followed the NSA debacle (wherein they’ve trampled on everyone’s civil rights to gather all sorts of personal data from all over the world, but have proved unable to find any terrorists, thus repeating a mistake made by over a century of spy agencies) hopefully realizes that information is only as useful as the ability to process it. Investing in a good processor (such as a mammalian brain) can beat investing in incredible eyes that are linked to an inferior processor (as with mantis shrimps, whose eyes see way more than any vertebrate eye ever will, but who apparently lack the brain to do much with all that data).

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  82. 82. Heteromeles 10:40 am 09/3/2014

    @76: Tayo, sorry about the confusion. I remember a pterosaur being used as the mesozoic equivalent of an ox-pecker, pulling ticks off of sauropods, rather than eating the sauropod itself. I didn’t make that clear.

    As for dinosaurs having specialized dermal ecosystems of things like lichens, liverworts, and perhaps algae, that ecosystem would have to be pretty well established for arthropods to live on this material, let alone for tetrapods to eat those arthropods. Lichens don’t grow that fast, except in the tropics. The usual scaling rules of a trophic pyramid (90% loss of energy between trophic levels) mostly apply, except that there would also be arthropod parasites directly on the dinosaur, and any tetrapod predator in such a system would undoubtedly eat the pests along with the lichen grazers. Still, it’s something to think about, if we’re talking about an old dinosaur. After all, if a weevil can host an ecosystem of liverworts, mites, and nematodes, why not a dinosaur?

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  83. 83. Andreas Johansson 10:40 am 09/3/2014

    I read somewhere that most of the Mesozoic was not only significantly warmer but also wetter than our age (which makes intuitive sense: higher temp -> greater evaporation). Does that mean it was also greener, at least the bits not under water?

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  84. 84. RndrpsOnRoses 11:01 am 09/3/2014

    @John Scanlon (70, 72): My dataset included 24 lizards (6 of which were varanids), 13 snakes, 7 turtles, 11 crocs/gators, 26 birds, and 23 mammals. After assessing preliminary patterns from the dataset, I then looked at 86 dinosaurs.

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  85. 85. Trisdino 12:16 pm 09/3/2014

    Honestly, I do not really care about mammalian vision, I am just echoing what I have heard before.

    What I do care about is archosaurian vision, and how it may affect the looks of extinct dinosaurs.

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  86. 86. Felix2 3:49 pm 09/3/2014

    The talk of coprophagous animals reminds me of the rectal probe and other strange creatures from Spec. The size of many dinosaurs mean that there were doubtless countless micro-ecosystems associated with them.
    Heteromeles- If color blind vision makes it easier to detect camouflage, then wouldn’t that mean that dinosaurs likely were camouflaged, because it would be easier to hide from predators or prey?

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  87. 87. Halbred 4:37 pm 09/3/2014

    Oh GAWD anytime an Ely Kish painting turns up, I wince. How could anyone–including Kish–look at those living skeletons and consider them reasonable?

    Like Darren, I used to be a Luis Rey fan, but I’ve become more conservative in my old age, and his “Technicolor Mesozoic” (as I call it) looks garish and overly stylized now. Is the man capable of producing a Tyrannosaurus rex picture where the animal does not have its gaping maw open directly at the viewer? And yes, his move to composite images has been extremely rough:

    http://luisvrey.wordpress.com/2014/06/03/the-deinocheirus-saga-continues/

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  88. 88. Heteromeles 5:19 pm 09/3/2014

    @Halbred: Ooooh, thunderchickens! That’s what we should call them. That’s actually a fairly good example of camouflage, in that it takes honest work to pick out the number and orientation of critters in that picture. Somehow, I’m pretty sure that’s *not* what he was aiming for, though.

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  89. 89. Heteromeles 5:33 pm 09/3/2014

    The talk of coprophagous animals reminds me of the rectal probe and other strange creatures from Spec. The size of many dinosaurs mean that there were doubtless countless micro-ecosystems associated with them.
    Heteromeles- If color blind vision makes it easier to detect camouflage, then wouldn’t that mean that dinosaurs likely were camouflaged, because it would be easier to hide from predators or prey?

    My point is that the phylogenetic evidence suggests, but does not prove, that dinosaurs had full color vision at least as good as ours. The does not prove part is important, because it’s easy to lose color vision through a non-functional gene, and I’m quite sure it happened at least once in the dinosaurs, though I have precisely no idea in which lineage or to what effect.

    The other point is that dinosaurs tend to have smaller brains than do modern mammals. This also suggests, but does not prove, that they were less efficient at visually detecting camouflaged objects. The outcome is that one could suggest either that dinosaurs were more camouflaged (because it would work better against enemy visual systems) or conversely one could suggest that they were less camouflaged than mammals, because there was less selective pressure to become better camouflaged. Either outcome is possible.

    The trouble with talk of camouflage is that we’ve got a three-part system: the hide of the camofleur, the eye of the enemy, and the enemy’s visual processor. In dinosaurs, we don’t know much about any of these, so forceful statements about what dinosaurs must have looked like are worth messing with, rather than deferring to.

    While I’m a botanist, I do like playing with camouflage a lot. Partly this was because I was brought up to spot rattlesnakes so that I wouldn’t step on them. Since I’m a total weirdo, my favorite WWII Unit is the US Army 23rd Headquarters Special Troops, aka the Ghost Army (look it up. The film is also excellent). I’d finally suggest Peter Forbes’ Dazzled and Deceived is worth reading, if you want to learn more about the topic and see some good pictures of what dazzle paint jobs actually looked like and learn why they were made that way.

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  90. 90. Jerzy v. 3.0. 5:45 pm 09/3/2014

    Funny break: genet rides buffaloes
    http://wildlifeact.com/blog/camera-traps-catch-strangest-behaviour/

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  91. 91. Felix2 8:50 pm 09/3/2014

    The genet on the buffalo…interesting, shows a bit of the “Protoceratops syndrome” (I just made the term up; based off the All Yesterdays illustration that shows the aforementioned dinosaur climbing ’cause they could). Why on earth do any people think we’ve even begun to scratch the surface of animal behavior?
    The genet and buffalo also makes wondered about symbiotic relationships in the Mesozoic. We have some evidence of parasites, but I’ve never heard of any sort of commensalism or mutualism recorded in the fossil record (how could it be?).

    I like Luis Rey’s work, but those Deinocheirus remind me of hay bales :) !
    Heteromeles- I agree that color vision could argue both for or against camouflage in dinosaurs. I just looked up the ghost army- I had never heard of it (and I thought I knew a reasonable amount about WWII). Dazzled and Deceived looks excellent- I will try to order it soon.

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  92. 92. Mark Robinson 8:52 pm 09/3/2014

    #90. Jerzy v. 3.0. – a member of the genet public is photographed riding a busalo? Perfectly ordinary.

    Ok, it’s awesome.

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  93. 93. Tayo Bethel 9:38 pm 09/3/2014

    @Heteromeles:
    If there was any cause for confusion, it would be on my part–I never even imagined that pterosaurs would be preying on sauropods.
    All this talk of howor if dinosaurs were camouflaged has really stirred up the imaginations, I see. The bright green dinosaurs were probably originally inspired by iguanas, which are large,highly arboreal lizards. The dinosaurs commonly depicted as bright green behemoths are very large,highly terrestrial archosaurs. Also,the smaller you are, the more likely you are to be eaten, and the more need for crypsis of some sort. Since many of the dinosaurs discovered thus far seem to have been either terrestrial or scansorial, we can probably rule out bright green as a common colour in most of them except, possibly,on display structures. Of course, the question would then arise–how did they acquire the green colour to begin with? And on it goes …

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  94. 94. Cahokia 11:46 pm 09/3/2014

    I’ll be the odd man out here, but I rather prefer Luis Rey’s photomontages to his paintings. The latter always struck me as more garish and more cartoonish than the former.

    For example, his latest reconstruction of Spinosaurus looks quite lifelike and believable.

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  95. 95. JoseD 12:47 am 09/4/2014

    Tayo Bethel: “Is there any reason to think that large tyrannosaurids were ambush predators? According to Tom Holts JR. they were built more like pursuit predators. Assuming that formfollows function,large tyrannosaurids probably employed a range of hunting strategies but were first and foremost opportunistic pursuit predators.”

    Young T.rex, yes, but adult T.rex “had clearly sacrificed speed to size. If it did not catch its quarry in the first rush there was no question of setting off in a lengthy pursuit” (See Gardom/Milner’s “The Natural History Museum Book of Dinosaurs”).

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  96. 96. Andreas Johansson 12:59 am 09/4/2014

    Why on earth do any people think we’ve even begun to scratch the surface of animal behavior?

    Because they have no idea how many sorts of animals are out there behaving.

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  97. 97. vdinets 1:25 am 09/4/2014

    Heteromeles (#66): my point is that even the largest dinosaurs could use complex camo patterns.

    Everybody: It’s simply not true that all large predators have cryptic coloration. Think killer whales, black leopards/jaguars, and African wild dogs. Asian wild dogs aren’t camouflaged, either.

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  98. 98. Dartian 4:36 am 09/4/2014

    Trisdino (comment #85):
    Honestly, I do not really care about mammalian vision

    1) You already said the very same thing in comment #80 – why so defensive?
    2) Perhaps you should be more interested in mammalian vision. That’s something that we at least can study directly; the vision of Mesozoic dinosaurs is, and likely always will be, a far more speculative and thus untestable subject.

    Vlad:
    black leopards/jaguars

    I disagree. A black leopard or jaguar in dense rain forest, and especially at dusk or during the night (when these cats frequently hunt), seems extremely well camouflaged to me.

    As for killer whales and canids; neither would seem to rely on camouflage much or even at all when hunting – no disagreement there. But then again, they don’t seem to much rely on ambush either when hunting; they run (or swim) down their prey. To me, hunting method seems to be a crucial factor in presence/absence of cryptic colouration in predators.

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  99. 99. Jerzy v. 3.0. 4:55 am 09/4/2014

    Point is that Mesozoic was on average wetter and warmer than modern time. Green was likely a dominant color there and used for camouflage by dinosaurs. Think green squirrels and pygmy marmosets, which themselves cannot identify green-red, are green to confuse rainforest predators. Paleonvironment of Deinonychus AFAIK was swampy forest.

    Animals living in Mesozoic plains and semi-deserts (eg. Velociraptor and Protoceratops) were more likely brown or greyish. BTW, was there anything like dry and wet seasons in Mesozoic Mongolia?

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  100. 100. Chabier G. 5:32 am 09/4/2014

    I wonder if there is any special reason to depict those scaly faces in feathered theropods. Even when the artists put feathers in the dinosaur’s face, they use to depict scales around the mouth, in a sort of weird teethy beak. Looking at the faces of extant birds of prey, they only lack feathers around nostrils and, obviously, in the part covered by the ramphoteca. Big eagles and kin shows a decreasing complexity in feathers from the top of the head to the beak edges, so I can imagine theropods mouth surrounded by arrays of filoplumes, rather than covered with scales, unless there were some evidence for the latter, of course.

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  101. 101. naishd 6:20 am 09/4/2014

    Chabier G (comment # 100: congrats)… the ‘scaly face’ meme is an old one that predominantly originated because archaic birds and bird-like non-birds surely had to be shown as ‘semi-reptilian’ in some way (you first see it in depictions of Archaeopteryx, like those by Heilmann from the early 1900s). During the 1980s, it was partly replaced by Greg Paul’s idea that the snouts and lower jaws of feathered dinosaurs should be shown as sheathed in both rhamphotheca and scaly skin.

    Data from feathered fossils has more recently shown that early birds and dromaeosaurs and so on actually have short fuzz/feathering across the side of the snout and lower jaw. In fact, it’s probably only the jaw tips/snout tip and jaw edges that have beak tissue, and scaly skin is absent from the face so far as we can tell. Even more recently, work on the evolution of the beak – it’s a compound structure, the different parts of which were assembled in piecemeal fashion – has shown that an extensive beak covering much of the snout and lower jaw is a ‘recent’ invention and not present in non-bird dinosaurs nor early birds.

    Matt Martyniuk has written about this in his book A Field Guide to Mesozoic Birds and Other Wings Dinosaurs.

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  102. 102. Dartian 6:49 am 09/4/2014

    Incidentally, here is a green polar bear. And yes, it’s real. (Although admitteldy, that kind of thing apparently only happens to polar bears in zoos.)

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  103. 103. Dartian 6:59 am 09/4/2014

    …and, while I’m at it, here are two more examples of green-ish non-primate mammals: a green ringtail possum Pseudochirops archeri (in an atypical terrestrial setting) from Australia, and a Pallas’s tube-nosed bat Nyctimene cephalotes from Sulawesi. (The bat looks almost too good to be true, but apparently its wing colours are genuine.)

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  104. 104. Tayo Bethel 7:08 am 09/4/2014

    Green squirrels? Green marmosets?

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  105. 105. Dartian 7:10 am 09/4/2014

    …and here is a green acouchi Myoprocta pratti.

    So yes, there are a handful of ‘green’ mammals, but the point is that there aren’t many, and they aren’t particularly brightly green either. Becoming green is not an evolutionary path that mammals have been very successful at taking.

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  106. 106. Dartian 7:15 am 09/4/2014

    Tayo: Jerzy probably meant the green bush squirrel Paraxerus poensis from Africa. Here is a (not particularly good) picture of it.

    As for the pygmy marmoset Cebuella pygmaea, it is somewhat greenish too.

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  107. 107. Kenshin 11:50 am 09/4/2014

    Threat hijack. I hate the name dreadnoughtus with the fury of 10000 exploding suns. Someone tell me it’s a joke.

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  108. 108. Cahokia 12:30 pm 09/4/2014

    “I hate the name dreadnoughtus with the fury of 10000 exploding suns. Someone tell me it’s a joke.”

    Couldn’t agree more. Terrible, terrible name. But then scientists have taken to using humorous nomenclature in recent decades. I’m still not over the naming of the sonic hedgehog (SHH) protein and gene.

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  109. 109. Halbred 1:52 pm 09/4/2014

    How do you feel about Crash bandicoot? ;-)

    Hell, I like the name Dreadnaughtus. It’s stupid, sure, but it’s preferable to giving it a place-name. I can easily envision the authors calling it Fortalezatitan or something, but THANK GOD THEY DIDN’T.

    My biggest naming pet-peeve recently is Utahceratops, a name that is about as creatively bankrupt as you can get given that the other ceratopsid described in the same paper has a wonderful name (Kosmoceratops).

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  110. 110. Gigantala 2:33 pm 09/4/2014

    http://dinogoss.blogspot.pt/2013/09/youre-doing-it-wrong-dino-foot-scales.html

    People who whine about Kulindadromeus having “branched scales” so don’t bother to realise that archosaur scales as a whole may be stunted feathers.

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  111. 111. Kenshin 2:57 pm 09/4/2014

    It is the -us that really bothers me in dreadnoughtus. Adding -us doesn’t make it Latin.

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  112. 112. DavidMarjanovic 2:59 pm 09/4/2014

    That book where the Zallinger illustration is from! ^_^ I read it a lot when I was little. Almost every animal in it is yellow with green stripes!

    I’m surprised nobody answered the question on how to embed links. You have to spell out the HTML: <a href=”http://www.asdf.com/”>this</a> automatically becomes this.

    When did colour vision evolve and what sort of colour vision did Dinosaurs have?

    It is the default setting for vertebrates to have four pigments in the cones in the retina: one with an absorption maximum in the red part of the spectrum, one yellow or green or something, one blue, one ultraviolet. Placental mammals have lost the middle two, retaining the red and the ultraviolet one; often (in us, for example), the one for ultraviolet has shifted its absorption maximum towards the blue part of the spectrum. Within primates, the gene for the red one duplicated, and a few mutations later one copy had its absorption maximum in the yellow area; that’s us.

    Marsupials have three kinds of cone pigment, IIRC. A few complete losses of color vision have happened, like in at least some bats and, IIRC, in crocodiles (which are nocturnal a lot). On the other hand (maybe), lissamphibians have an extra kind of light-sensitive cell in the retina, “green rods” with a green pigment that doesn’t occur elsewhere; it seems to be completely unknown what that’s good for.

    I am pretty sure zebra patterns are to confuse predators depth perception, since, as has been noted several times, many placental mammals lack good colour vision, so a bunch of stripes in a sea of grass, all more or less the same colour, gets very confusing to, say, a lion.

    They’re red/green-blind, not completely colourblind; zebras are black & white, not yellowish like a… lion.

    A colorful tyrannosaur would probably have had some problems hunting. Tyrannosaurs likely ambushed their prey, waiting around water sources, so I think that camouflage would have been valuable.

    Why do you think that tyrannosaurs were ambushers? Anatomically, as has long been known (mentioned above), they look like pursuit-and-bite predators, not like grapple-and-bite or grapple-and-slash predators – more like wolves and hyenas than like cats or crocodiles.

    What would all those coprophages look like, anyway? Al dingy and dung colored, or something more exotic?

    Extant dung flies are often iridescent…

    A second idea comes from an obscure weevil Gymnophilus (Symbiophlus) lichenifer, which is famous for having a cuticle that’s covered by liverworts and lichens. It occurs to me that a number of dinosaurs, including anklyosaurs and sauropods, may well have hosted lichens and liverworts on parts of their anatomy that were impossible for them to groom off.

    Keratin doesn’t stay put, though. It grows at one end and erodes at the other.

    Given your fixation with imperfect mammalian color vision, I’d expect you to be talking about the paradox that more large mammals should be bright green (because it apparently doesn’t matter), rather than that the dinosaurs with their putatively perfect (or ultra-perfect, since they may have seen UV light as well), color vision would pick such a marginally useful color. Why don’t we see green tigers, for example, if their prey can’t see the difference between red and green?

    I guess it’s true that, as mentioned above, green pigments are harder to make. Phaeomelanin was already there – there’s no need to evolve an additional green pigment to hide from red/green-blind predators or prey.

    I read somewhere that most of the Mesozoic was not only significantly warmer but also wetter than our age (which makes intuitive sense: higher temp -> greater evaporation). Does that mean it was also greener, at least the bits not under water?

    Yes. Parts of the Mesozoic (and Cenozoic!) were warm enough that there were no deserts.

    Honestly, I do not really care about mammalian vision, I am just echoing what I have heard before.

    :-) No need to get defensive! We’re not trying to trounce you or anything; you said something that happens to be (most likely) wrong, so we explained why.

    Oh GAWD anytime an Ely Kish painting turns up, I wince. How could anyone–including Kish–look at those living skeletons and consider them reasonable?

    I have no idea. The Apatosaurus in the OP has a drooping tail and neck because it has no muscles along the entire vertebral column, just ligaments. It boggles the mind.

    Young T.rex, yes, but adult T.rex “had clearly sacrificed speed to size. If it did not catch its quarry in the first rush there was no question of setting off in a lengthy pursuit” (See Gardom/Milner’s “The Natural History Museum Book of Dinosaurs”).

    What reasons did Gardom & Milner state, or what papers did they cite?

    I’m still not over the naming of the sonic hedgehog (SHH) protein and gene.

    Oh dear. Most genes & proteins in development biology have names like that. You know SUPERMAN and KRYPTONITE?

    Hell, I like the name Dreadn[o]ughtus. It’s stupid, sure, but it’s preferable to giving it a place-name. I can easily envision the authors calling it Fortalezatitan or something, but THANK GOD THEY DIDN’T.

    I agree wholeheartedly!

    The open-access paper is here, BTW; too bad the authors misused the term “Old English” so blatantly (they’re off by a thousand years).

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  113. 113. DavidMarjanovic 3:02 pm 09/4/2014

    Another gene: MOTHERS AGAINST DECAPENTAPLEGIC

    It is the -us that really bothers me in dreadnoughtus. Adding -us doesn’t make it Latin.

    What do you think of Varanus and Vombatus, then?

    And keep in mind that the Code doesn’t require Latin or any pretense thereto. It only requires Latin letters.

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  114. 114. Kenshin 3:51 pm 09/4/2014

    Varanus doesn’t offend my delicate sensibilities, perhaps because I didn’t realize that -us was added to an Arabic word to make it. Dreadnought is just so British (stiff upper lip and all that) that adding a Latin suffix to it sounds silly to me.

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  115. 115. Felix2 4:08 pm 09/4/2014

    To all, on tyrannosaurs as pursuit predators. Most predators, excepting coursing ones in open environments, will wait for prey near water sources. In forested areas, even cursorial animals find it easier to hang around water than to go charging about after food. Tyrannosaurus, living in what was, to my knowledge, a forested environment, would have certainly taken advantage of the fact that prey animals must drink. I’m not claiming that was its only attack strategy, but it was likely used enough to influence breeding, favoring more heavily camouflaged individuals.
    On scientific names, I agree with what Darren and John said on Crash bandicoot in the podcast; a few of the bizarre scientific names are funny and/or interesting, but when there are too many, it gets dull.

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  116. 116. WarrenJB 8:21 pm 09/4/2014

    On the general topic of tiresome memes and themes: I hadn’t heard of Dreadnoughtus. I googled it. The first result was a headline comparing it to ‘T-Rex’.

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  117. 117. Felix2 8:52 pm 09/4/2014

    Yes, Dreadnoughtus is “larger than T. rex.” The same way a toaster is larger than a phone…

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  118. 118. SciaticPain 9:02 pm 09/4/2014

    On the subject of large theropods hanging out at watercourses: One thing immediately apparent when watching large, multi-ton mammals in hot environments is that they seem to absolutely relish the chance to get wet. I often wonder if, it wasn’t for the pesky chore of eating, if they would leave the mud and splashing at all if they had the choice. I imagine large theropods, with a lot more free time and a mobile buffet coming to waterholes all the time, would have spent long hours just lounging in the water and mud. Large dominant individuals monopolizing the best water spots and lesser individuals pushed into more patchy water holes and wallows.

    Also several people above have commented above that the Mesozoic was wetter than the Cenozoic. I don’t know if this was true. Painting with broad strokes there was no wet tropical forest equatorial belt – instead an extremely arid equatorial belt often occurred. Things got wetter going towards the pole. I have read it suggested that peak dinosaur diversity and abundance coincided with more midlatitude realms, although it can also be argued that these latitudes also coincide with much of Europe and North America so maybe some bias in collecting. Monsoonal climate regimes dominated – so torrential storms and then a bit of a dry spell. Of course one must keep in mind it was a looooong time and there were several oscillations of colder/warmer or wetter/drier in the Mesozoic. But I am no expert on climate or paleoclimate but I gather that this is close to where current thinking lies but would love to hear if anyone has any contrasting info. At least this is what I read in the latest edition of The Complete Dinosaur.

    Duane Nash

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  119. 119. Mark Robinson 9:21 pm 09/4/2014

    #112. DavidMarjanovic – with regard to colour vision, I thought that the cone cells for most placental mammals were maximally sensitive to wavelengths roughly corresponding to blue and green light and therefore had vision similar to humans with red-green colour blindness. I wasn’t aware that they could detect light in the ultraviolet range.

    I also thought that the so-called red cones in humans are a misnomer since they are maximally sensitive to light that we would call yellow-green or green-yellow. It’s probably why people who work in that area seem to refer to them as ‘S’, ‘M’, and ‘L’ instead of using colours.

    Interestingly, because the photosensitive pigments of the cones are encoded on the X chromosomes in humans, some women who have a mutation in the relevant gene on one of their X chromosomes may technically be tetrachromats.

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  120. 120. JoseD 11:08 pm 09/4/2014

    DavidMarjanovic: “What reasons did Gardom & Milner state, or what papers did they cite?”

    IIRC, it’s based on recent biomechanical analysis (“Attaining a weight of 1,000 kilograms (2,200 pounds) was an important milestone in the life of a young tyrannosaur. Below that weight, the animal could move fairly fast; above it, life shifted into the slow lane”: http://www.amnh.org/exhibitions/past-exhibitions/dinosaurs-ancient-fossils-new-discoveries/theropod-biomechanics/the-young-and-the-fast ). I included the Gardom/Milner quote in its entirety below.

    Quoting Gardom/Milner (See Gardom/Milner’s “The Natural History Museum Book of Dinosaurs”): “The dinosaur era produced many fine hunters, but in Deinonychus we see the near perfect balance of an attackers skills. Intelligence to stalk, ambush or mount a co-ordinated attack, the speed to run a quarry down and the weapons to kill and dismember it.
    Many of the other meat-eating dinosaurs developed one of these qualities at the expense of the others. Tyrannosaurus, for example, depended on bulk and enormous strength to overpower its prey. Its head was heavily reinforced with bone and shock absorbing muscle to withstand the impact of crashing into a victim with mouth open and then delivering a crushing bite and neck twist. But with a body weight of 7 tonnes Tyrannosaurus had clearly sacrificed speed to size. If it did not catch its quarry in the first rush there was no question of setting off in a lengthy pursuit.
    At the other end of the scale, Troodon developed speed and brain power at the expense of size and weaponry. A small, fleet-footed predator, Troodon had a large brain and front facing, stereoscopic eyes, probably allowing it to stalk rat-sized mammals that came out at dusk, when other dinosaurs could not see to hunt.”

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  121. 121. Tayo Bethel 12:35 am 09/5/2014

    @comment 120:

    That quote should be suspect for various reasons. for instance, it states that Tyrannosaurids were crashing into prey with open mouths. Does any living terrestrial predator attack in this way? the likely result would have been a dislocated jaw–no matter how heavily reinforced–and prey that lives to fight a little while longer. Does the fossil record show any evidence of jaw trauma indicative of such a mode of attack? It’s like the allosaur hatchet model all over again. As pursuit and bite predators taking large prey, a large reinforced head would seem to be a necessity for retaining a grip on struggling prey from the rear or side once the predator had caught up with its fleeing prey. Incidentally, tyrannosauridsseem to have become specialized pursuit predators rather early in their history and the smaller ones at least would have been both fast and agile. Another aside: Denonychus, like most large dromaeosaurids, was no wolf or hyena capable of speedy chases–more like a lion or, considering itss ize, a leopard or jaguar–capable perhaps of incredible bursts of speed but not capable of sustained chases. Even cursorial predators which have been reported to engage in such sustained chases do so relatively rarely.

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  122. 122. Heteromeles 12:50 am 09/5/2014

    Ummm, wet and warm is not necessarily equivalent to green.

    For example, this fern forest from New Zealand: http://www.panoramio.com/photo/1950568

    Note how much of this is not green? Especially on the bottom? This is even more true in monsoonal areas, such as the ones noted above that were camouflaging the gray elephant and the earth-toned giraffe. Monsoonal means there’s a wet season and a dry season, and if it’s dry enough, the plants may be dry-season deciduous, which makes for a very brown world.

    Long story short, tropical=green only where there are leaves, and there’s a lot of the tropics (much of the tree trunks, for example) that are brown.

    That’s why green camouflage works best on small animals, especially those that are canopy dwellers. I’ve got no complaint with someone proposing a green arboreal theropod, provided it’s small. I’ve got a bigger beef with an iguana-green Tyrannosaur, because it would not be camouflaged very well against the trunks, branches, and rocks it would have to hide against.

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  123. 123. Jenny Islander 1:18 am 09/5/2014

    I remember references to the air sacs in dinosaur bodies as actual air-cooling systems and/or a more efficient breathing apparatus than is found in most mammals. Is this generally believed to have been the case? If so, wouldn’t that mean that great big carnivorous dinosaurs were particularly good at human-style follow-till-they-drop hunting? Might the predatory pyramid have shaken out like this:

    Wolves, African wild dogs, dholes: big tyrannosaurids and similar animals (bite ‘em, then trot ‘em to death, or trot ‘em down and then bite ‘em to death, possibly in packs(!!))

    Tigers, scimitar-toothed cats, sabertooths: big sickle-claws or medium-sized animals with big teeth (ambush large prey, grapple, deal one devastating blow, eat, probably solitary hunters)

    Lions, cheetahs, servals, etc.: medium-to-large animals with neither big heads nor big claws (use speed at least as much as stealth, try to outsprint it and then jump on it, may hunt cooperatively)

    Coyotes, small wildcats, leopards, jaguars, etc.: small-to-medium sickle-claws and other small but not tiny predators (if it’s big and I can take it, possibly with a buddy along, great; if it’s small, fine; if it’s dead and nobody’s on it, whoopee; but watch out for everybody else)

    Obviously this is incomplete even if accurate, and I don’t know whether that’s how air sacs worked anyway.

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  124. 124. Cahokia 1:22 am 09/5/2014

    “Ummm, wet and warm is not necessarily equivalent to green.

    For example, this fern forest from New Zealand: http://www.panoramio.com/photo/1950568

    Note how much of this is not green? Especially on the bottom?”

    Compared to most habitats, this New Zealand forest looks very green indeed.

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  125. 125. assumingdinosaur 4:17 am 09/5/2014

    Regarding Kulindadromeus filament morphology, simple parsimony would probably find that dinosaurs ancestrally had scales. However, consider that discoveries expanding the known phylogenetic range of filaments have been frequent in the last two decades while the rate of clades being confirmed to be scaly has slowed to a crawl. Given that, it seems more likely that there are more new feathered taxa to be found than scaly ones. Furthermore, the developmental explanation of multiple reversals to scales (i.e. dinosaur scales are stunted feathers) strikes me as more satisfying than the explanation for multiple origins of filaments (i.e. ornithodires had an ancestral genetic propensity for filaments which activated at least three times over tens of millions of years).

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  126. 126. Jerzy v. 3.0. 6:57 am 09/5/2014

    @122
    It would be interesting to know how precisely was climate and vegetation in ‘arid’ regions of Mesozoic Earth. Were there distinct dry and wet seasons, and vegetation seasonally dropped leaves and withered, changing the landscape between green and brown? Or Mesozoic rains were more spread or unpredictable, and enviroment looked more uniform?

    Now I will not talk about any general rule, but just a thought, which may be not true at all. :) If I imagined large carnosaurs, they would have a dappled pattern on their breast, similar to this crowned eagle: http://photos.zoochat.com/large/img_09784-206188.jpg
    and those jaguar, golden cat and black-footed cat:
    http://www.coolanimalpictures.com/jaguar_pictures/images/jaguar2.jpg
    http://www.buzzle.com/img/articleImages/354612-3049-8.jpg
    http://pixdaus.com/files/items/pics/3/75/198375_a65b430835dbb783ab3b0a36950e832b_large.jpg

    This is because they were relatively taller than herbivores, and their prey would see them partially from below, against the sky partially obscured by vegetation.

    They might have had also a bright patch on rump or tail, similar to white rump of many birds or white underside of tail-tip of cats.

    Reverse might be true for small and medium herbivores – their backs and tails would be cryptic, their faces and breasts would be colorful.

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  127. 127. Tayo Bethel 8:10 am 09/5/2014

    Comment 126:

    Well many dinosaurs, both theropods and ornisthischians, possessed head ornaments that were likely brightly coloured As fordappled breast patterning–maybe but not likely, especially not for the reason that you give. If we look at terrestrial carnivorous mammals, they all keep a low profile when approaching prey. At least, this applies to mammals. What would a stalking theropod have looked like? What might have been the biomechanics of stalking theropods? Anyway to my original point–while a dappled dorsal pattern might have been possible, there wouldnt seem to be a need for a dappled breast pattern in connection with predatory behavior. Of course, predatory behavior is hardly the only reason to evolve disruptive colouration–the killdeer plover of North America has long been used as an example of disruptive colouration for the purposes of staying hidden while sitting on eggs on the ground.

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  128. 128. Yodelling Cyclist 9:47 am 09/5/2014

    For those engaging in a discussion of the predominant colour of the Mesozoic environment (and yes, I’m being a bit sarcastic), this colour chart may be of help:

    http://www.ralcolor.com/

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  129. 129. Heteromeles 11:26 am 09/5/2014

    @YC: why spoil the fun? Everyone *knows* that the only color common to all mesozoic environments was black, on moonless nights, deep in the sea, under the soil, and inside theropods. Therefore, we should all know that all mesozoic animals would be colored black in the absence of light, at least as seen by other animals.

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  130. 130. JoseD 3:32 pm 09/5/2014

    Tayo Bethel: “It’s like the allosaur hatchet model all over again.”

    Last I checked, they’re the best-supported hypotheses for how T.rex & Allosaurus killed their prey, respectively ( http://blog.everythingdinosaur.co.uk/blog/_archives/2013/05/22 ).

    Tayo Bethel: “Incidentally, tyrannosauridsseem to have become specialized pursuit predators rather early in their history and the smaller ones at least would have been both fast and agile.”

    We’re not talking about “the smaller ones”, just adult T.rex (which, as indicated by recent biomechanical analyses, weren’t fast runners).

    Tayo Bethel: “Another aside: Denonychus, like most large dromaeosaurids, was no wolf or hyena capable of speedy chases–more like a lion or, considering itss ize, a leopard or jaguar–capable perhaps of incredible bursts of speed but not capable of sustained chases.”

    Having “the speed to run a quarry down” =/= being “capable of sustained chases”.

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  131. 131. Halbred 4:00 pm 09/5/2014

    I think a lot of people forget that T.rex didn’t necessarily have to run FAST–just faster than its prey. The same size/weight factors that would impact an adult Tyrannosaurus would also impact an adult Edmontosaurus or Triceratops, both of which may have been heavier than their pursuer. This assumes that adult tyrannosaurs were usually going after adult prey, but as Dave Hone has emphasized, this may not be the case.

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  132. 132. Yodelling Cyclist 7:22 pm 09/5/2014

    Heteromeles wins!

    :-)

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  133. 133. Tayo Bethel 8:38 pm 09/5/2014

    JoseD :
    Please do remember that when it comes to the behavior, most of it will probably remain a mystery unless someone invents a time machine. Sounds familiar? Good. Now that we’ve established that much of what we can say about dinosaur behavior is purely speculative, wouldn’t you agree that in the name of good science that we speculate sensibly? I stand by, and will continue to stand by, my assertion that no theropod dinosaur crashed into a large, potentially dangerous herbivore with wide-open jaws, instead using them either hold and possibly cripple the prey, in the case of tyrannosaurids, or to assist the grappling action of the forelimbs in the case of Allosaurids. A paper by Mauricio Anton,published in 2009, goes into some detail on this as concerns the probable prey acquisition behavior of Allosaurus A sustained chase, in what is probably my opinion,is one where both the predator and prey travel a considerable distance. This is the kind of chase which large canids and hyaenids are adapted for. Lions,leopards and other large cats with proportions somewhat similar to dromaeosaurids attempt to get as close as possible–within a few feet–before sprinting toward prey. A lion chasing a wildebeest over any distance is more than likely to lose its prey and will most likely give up the fruitless chase. Eudromaeosaurids, like pantherine and especially machairodontine cats,were built for power,not speed over any distance. As for the tyrannosaurids are not fast runners argument–I think a commenter has already covered that–they didnt have to be particularly fast–that is, not greyhound or cheetah fast. A large tyrannosaurid runing at close to or at the speed of a running human would be doing quite well for itself.
    Dr. Naish: I hope I didnt become too defensive with this long rant. Going to read up on muskrat evolution now. Keep up the good work.

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  134. 134. Felix2 11:21 am 09/6/2014

    Tyrannosaurs were more cursorial than I gave them credit for. I was wrong. As for dromaeosaurs, yes, they were definitely ambush predators, although Dromaeosaurus and Atrociraptor seem to have more elongate proportions. Speaking of which, am I the only one that thinks dromaeosaur taxonomy needs to be rewritten? There are a lot of long ghost lineages…

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  135. 135. amdurso 4:39 pm 09/6/2014

    Super cool post Darren. What do you know about/make of the “bristles” on the Triceratops skin impression in the Houston museum?

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  136. 136. JoseD 11:43 am 09/7/2014

    Tayo Bethel: “Please do remember that when it comes to the behavior, most of it will probably remain a mystery unless someone invents a time machine. Sounds familiar? Good.”

    Condescending much? Seriously, that’s pretty much a given to everyone here, so bringing it up was completely unnecessary (especially the way you did). In any case, it looks like you’re just ignoring WitmerLab’s anatomical evidence for a paper by a non-dino expert.

    Tayo Bethel: “Eudromaeosaurids, like pantherine and especially machairodontine cats,were built for power,not speed over any distance.”

    1stly, they’re eudromaeosaurs (as in eudromaeosauria), not eudromaeosaurids.

    2ndly, again, having “the speed to run a quarry down” =/= being “capable of sustained chases”. Why you’re not getting that IDK. No one who knows better argues that big cats can’t run fast just b/c they can’t do so over long distances (E.g. Quoting Turner: “Most of the cats are capable of achieving high speeds at least for short distances”). The same probably went for eudromaeosaurs which, based on recent biomechanical analyses, seem to have been capable of top speeds of ~25mph ( http://rspb.royalsocietypublishing.org/content/274/1626/2711.full.pdf ) ( http://dml.cmnh.org/2008Aug/msg00031.html ).

    Tayo Bethel: “As for the tyrannosaurids are not fast runners argument–I think a commenter has already covered that–they didnt have to be particularly fast”

    Never said adult T.rex did, just that they weren’t & how they probably hunted, given the anatomical & biomechanical evidence which you seemingly chose to ignore.

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  137. 137. Halbred 12:46 pm 09/8/2014

    @amdurso: I just learned that particular Triceratops skin impression, while still unpublished, is actually on display in the Houston Museum of Natural Science (the particular Triceratops is nicknamed “Lane”).

    This may be the impression that everybody’s excited about, but I’m not sure: http://www.pinterest.com/pin/516436282242840587/

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  138. 138. vdinets 3:04 pm 09/8/2014

    Wow, that looks heavy!

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  139. 139. Felix2 4:35 pm 09/8/2014

    @ Halbred- Those look like pretty convincing bases for something, to me at least.

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  140. 140. Halbred 5:02 pm 09/8/2014

    Well, notice that only two or three of the scales (or scutes?) have projections, and I’d very much hesitate to call them “nipple-like.” They look more like spikes–we need better photos. I’d also like confirmation about where on the body this impression came from.

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  141. 141. Halbred 5:04 pm 09/8/2014

    Ah, here’s another (but not necessarily “better”) photograph, along with a news story.

    http://rapidcityjournal.com/news/replica-of-rare-triceratops-skin-goes-on-display-in-hill/article_2b66c924-bcce-5c0d-bcbb-806cec3d1209.html

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  142. 142. Jerzy v. 3.0. 10:07 am 09/9/2014

    Bug thanks for the links!

    For now I will remain non-believer in spines on Triceratops. These skin impressions appear to show the real surface of the skin (almost) as in life, without much extra material. And knob-like structures seem not to be good attachment points of anything much longer, as they lack holes for supplying the external thing with blood, and are broad-topped (for spines I would expect a tapering point, on which the further sheath would grow). Anyway, I don’t remember any tetrapod with spines, horns or similar structures supported by a similar base. Perhaps the eventual microstructure of the knob surface would tell something conclusively.

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  143. 143. Jerzy v. 3.0. 10:07 am 09/9/2014

    big thanks (a bug) :)

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  144. 144. John Scanlon FCD 11:33 am 09/9/2014

    Although the spines are broken off short on the convex specimen, and the one in the box is a negative where the pits are too dark and low-res to get a shape, I now imagine Triceratops looking a lot like Moloch – the spines a bit sparser and relatively smaller, but ‘thornlike’, and more like that than anything else extant. Not feathery or porcupiney at all, on the bits visible. (I hope someone can map the impressions to the body surface convincingly, will wait and see)

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  145. 145. Trisdino 11:54 am 09/9/2014

    Considering that I believe almost all ornithischians, and maybe even sauropods, had a form of integument, this looks like compelling evidence.

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  146. 146. naishd 11:57 am 09/9/2014

    I should hope that they all had a form of integument :)

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  147. 147. Felix2 3:59 pm 09/9/2014

    It seems t me that the basal ornithodiran had some sort of integument.

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  148. 148. naishd 4:40 pm 09/9/2014

    Guys guys guys… ‘integument’ does not mean what you think it means :) ‘Integument’ merely refers to the organism’s external covering; it is not synonymous with ‘filaments that grow out of the epidermis’.

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  149. 149. Mark Robinson 11:54 pm 09/9/2014

    So T. horridus‘s skin possibly looked like M. horridus‘s? Wonder if Gryponyx africanus and Atherurus africanus are also similar?

    Probabably not.

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  150. 150. Tayo Bethel 3:05 am 09/10/2014

    JoseD:
    I admit I lost my temper–the way you phrased your comment was equally condescending imo. Thanksfor the refs, btw, will check them in a bit. Since terms like cursorial, sustained chase and so forth seem to be a matter of opinion as well, I wont bring it up again. As for the biomechanical evidence … I’m not ignoring it, I just think that the proposed behaviors seem unlikely. and I will remain skeptical of such theories as the allosaurus using its upper jaw as a hatchet until there is strong compelling evidence for me to change my opinion. It just seems far too risky for any predator to so endanger its life by exposing its one means of procuring food. True,the paper I cite is by a non0dino expert,but the reason I agree with this same non-dino expert is becausenot so very long ago, machairodontine cats were believed to kill in much the same way, on the basis of seemingly more compelling evidence than the types of teeth found in the upper jaws of Allosaurus. And the teeth of Tyrannosaurus seem designed to grip and hold, not stab. Anyway …this is the last i will say on the subject–we will just have to agree to disagree.

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  151. 151. Dartian 3:12 am 09/10/2014

    Darren:
    I should hope that they all had a form of integument

    LOL! Yes indeed. :)

    ‘Integument’ merely refers to the organism’s external covering

    Not only that, but ‘integument’ is sometimes also used when referring to the tissue layers that cover individual organs of the body.

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  152. 152. Tayo Bethel 3:49 am 09/10/2014

    JoseD:
    I admit I lost my temper–the way you phrased your comment was equally condescending imo. Thanks for the refs, btw, will check them in a bit. Since terms like cursorial, sustained chase and so forth seem to be a matter of opinion as well, I wont bring it up again. As for the biomechanical evidence … I’m not ignoring it, I just think that the proposed behaviors seem unlikely. and I will remain skeptical of such theories as the allosaurus using its upper jaw as a hatchet until there is strong compelling evidence for me to change my opinion. It just seems far too risky for any predator to so endanger its life by exposing its one means of procuring food to such unnecessary hazards. True,the paper I cite is by a non0dino expert,but the reason I agree with this same non-dino expert is because not so very long ago, machairodontine cats were believed to kill in much the same way, on the basis of seemingly more compelling evidence than the types of teeth found in the upper jaws of Allosaurus. And the teeth of Tyrannosaurus seem designed to grip and hold, not stab. Anyway …this is the last i will say on the subject–we will just have to agree to disagree.

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  153. 153. Tayo Bethel 3:52 am 09/10/2014

    Oh sorry–double posting. Sorry. Stupid Firefox.

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  154. 154. Felix2 3:34 pm 09/10/2014

    Thanks Darren-so, not integument…filaments, then; protofeathers; “dinofuzz.” So many terms!

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  155. 155. Heteromeles 5:53 pm 09/10/2014

    So if we’ve got dino-fuzz, is everyone going to freak out when someone suggests that bout Triceratops had a bunch of, erm, dinonipples on its backside?

    I’m also surprised that no one’s invoked sexual selection for the appearance of those structures, whatever they are. Maybe the horns were strictly functional (ha!), but those bump/spike/things were what got the chicks, um, horny….?

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  156. 156. naishd 5:56 pm 09/10/2014

    “I’m also surprised that no one’s invoked sexual selection for the appearance of those structures”

    Are you sure they haven’t?

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  157. 157. Halbred 6:30 pm 09/10/2014

    I believe a spiky Triceratops appears in “All Yesterdays,” possibly based on this skin impression, if memory serves.

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  158. 158. Heteromeles 8:52 pm 09/10/2014

    “I’m also surprised that no one’s invoked sexual selection for the appearance of those structures”

    Are you sure they haven’t?

    Well, if they have, that gives me hope for the future of the paleontological profession. Nothing more reassuring than applying a hoary trope to a mysterious feature.

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  159. 159. vdinets 10:11 pm 09/10/2014

    Dartian (#98): a black jaguar might be difficult for us to see in shady rainforest. But I don’t think we can just assume that nocturnal mammals can’t see it without any experimental data to support this idea. Melanism in other carnivores (wolves, foxes, mongooses) doesn’t appear to be camouflage-related.

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  160. 160. Jenny Islander 1:24 am 09/11/2014

    Judging by the downright wacky assortment of features that birds and crocodilians sexually select for, I wouldn’t be surprised to find out that quill-rumped protoceratopsians shook their booties in tandem to reaffirm their mating bonds every year and tyrannosaurs had bright blue feet and danced like boobies.

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  161. 161. DavidMarjanovic 6:36 am 09/11/2014

    and I will remain skeptical of such theories as the allosaurus using its upper jaw as a hatchet until there is strong compelling evidence for me to change my opinion. It just seems far too risky for any predator to so endanger its life by exposing its one means of procuring food.

    But why else was its skull so extremely strong, way beyond any stresses the jaw muscles could generate? Sabertooth cats and tyrannosaurs aren’t like that – and cats can’t replace their teeth (once they’ve grown up).

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  162. 162. DavidMarjanovic 6:37 am 09/11/2014

    Oh, forgot:

    Melanism in other carnivores (wolves, foxes, mongooses) doesn’t appear to be camouflage-related.

    Is it as common as in jaguars and leopards?

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  163. 163. Dartian 7:44 am 09/11/2014

    Vlad:
    I don’t think we can just assume that nocturnal mammals can’t see it without any experimental data to support this idea

    You need experimental data before you’re willing to believe that it tends to be harder to see in darkness than in daylight?

    Anyway, it is well-established that most such vertebrates that are of relevance when discussing potential prey items of rainforest leopards and jaguars (notably, ungulates and anthropoid primates) see better during the day than during the night. Those that are nocturnally and/or cathemerally active may have decent or even good visual sensitivity in darkness, but this comes at the cost of losing visual sensitivity (there is only so much space physically available in the eye’s retina, and the rods and the cones will be ‘competing’ for that space). In other words: nocturnal prey animals’ eyes can pick up what little light there is available, but they aren’t able to see much detail.

    Incidentally, melanism in leopards (and jaguars) may also be ‘cryptic’ in a less traditional sense. There are experimental data suggesting that macaques react more strongly to typical spotted leopards than to black ones (Coss & Ramakrishnan, 2000; Coss et al., 2005). In environments where black leopards are rarer than spotted ones*, the former could thus conceivably have a slight advantage over the latter in being able to approach prey more closely before being recognised.

    * Note that there are places, such as the Malay Peninsula, where the opposite is true (Kawanishi et al., 2010)!

    Melanism in other carnivores (wolves, foxes, mongooses) doesn’t appear to be camouflage-related.

    Why do you mention those taxa? I did specifically say that ambush hunters (such as most felids) are quite different from non-ambush hunters in this regard.

    But since you brought up wolves, for the record it may be noted that North American wolves apparently got their black colour from hybridisation with the earliest Native Americans’ domestic dogs thousands of years ago (Anderson et al., 2009). Thus, black colouration in North American wolves may not be adaptive at all. (In Eurasia, black wolves are very rare.)

    References:

    Anderson, T.M., vonHoldt, B.M., Candille, S.I., Musiani, M., Greco, C., Stahler, D.R., Smith, D.W., Padhukasahasram, B., Randi, E., Leonard, J.A., Bustamante, C.D., Ostrander, E.A., Tang, H., Wayne, R.K. & Barsh, G.S. 2009. Molecular and evolutionary history of melanism in North American gray wolves. Science 323, 1339-1343.

    Coss, R.G. & Ramakrishnan, U. 2000. Perceptual aspects of leopard recognition by wild bonnet macaques (Macaca radiata). Behaviour 137, 315-335.

    Coss, R.G., Ramakrishnan, U. & Schank, J. 2005. Recognition of partially concealed leopards by wild bonnet macaques (Macaca radiata): the role of the spotted coat. Behavioural Processes 68, 145-163.

    Kawanishi, K., Sunquist, M.E., Eizirik, E., Lynam, A.J., Ngoprasert, D., Wan Shahruddin, W.N., Rayan, D.M., Sharma, D.S.K. & Steinmetz, R. 2010. Near fixation of melanism in leopards of the Malay Peninsula. Journal of Zoology 282, 201-206.

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  164. 164. Dartian 7:48 am 09/11/2014

    Oh crap, I messed up a central point:
    Those that are nocturnally and/or cathemerally active may have decent or even good visual sensitivity in darkness, but this comes at the cost of losing visual sensitivity”

    That sentence should read:
    Those that are nocturnally and/or cathemerally active may have decent or even good visual sensitivity in darkness, but this comes at the cost of losing visual acuity”

    Incidentally, I’ve not heard of melanism in mongoose before. In which species does it occur, and, more importantly, how common is it?

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  165. 165. Yodelling Cyclist 10:48 pm 09/11/2014

    On the subject of dinosaur life appearance, I would urge all reading this who do not already know to go a googling spinosaurus. There is big news afoot.

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  166. 166. Jenny Islander 1:13 am 09/12/2014

    Yes, that’s what I came here to ask about! Apparently reexamination of the fossils suggests an at-most-facultatively-bipedal, probably-mostly-aquatic, possibly-most-massive-walking-predator-that-ever-lived?

    In that case, the fin on the back would have been for, what, reheating after a plunge in the water? Would this thing have dived very deep, or plunged in and motored around the surface grabbing stuff?

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  167. 167. Jerzy v. 3.0. 4:49 am 09/12/2014

    Yes, Darren, Spinosaurus Special, please, please!

    Spinosaurus reminds me now of giant giant otter.
    Anybody knows why Spinosaurus was reconstructed as bipedal in the first place?
    And what is the role of its forelimbs, which came as comparatively strong and clawed? Could they be used for walking or digging?
    And incidentally, Jurassic Park 4 movie just became extinct again. Another of its showcase dinosaurs turned to be reconstructed with major error. ;)

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  168. 168. naishd 5:15 am 09/12/2014

    Spinosaurus: be sceptical, the ‘quadrupedal’ proportions of the new reconstruction don’t seem right (pelvis too small according to their own measurements), nor is there any reason to think that the animal was using its forelimbs in locomotion. I’ll get round to covering this when time allows.

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  169. 169. Jenny Islander 11:38 am 09/12/2014

    Darn, I was starting to groove on the idea of a gargantuan bear-dragon treating sharks like salmon.

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  170. 170. Halbred 2:12 pm 09/12/2014

    Interesting and informative post from Scott Hartmann about the pelvis and hindlimbs:

    http://www.skeletaldrawing.com/home/theres-something-fishy-about-spinosaurus9112014

    Good comments, too, for the most part.

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  171. 171. Felix2 3:44 pm 09/12/2014

    I came here to talk about spiny, and found all you had beaten me to it. Here is my question about spinosaurs; those like Spinosaurus and Irritator had nostril high on their nose, which sounds more efficient for wading than diving, unlike baroynychines, which have nostrils at their snout tips, which is better for snorkeling. Am I wrong in my thinking that nostrils high on the snout are bad for diving, or what?

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  172. 172. MRueger 5:51 pm 09/12/2014

    With regards to the spinosaurid nostrils, if I recall correctly they interpreted the nostril placement for Spinosaurus as analogous (in function, not necessarily placement) to the adaptions that modern crocodilians have, nostrils that would enable steady, regular breathing while keeping most of the body submerged. But like you said, Felix2, this also seems like a handy adaption if the animal were wading in the water and foraging around for fish with its snout partially submerged. @Jerry V. 3.0, it was originally depicted as a biped because that is, more or less, the default build for theropods. Incidentally some of the older reconstructions of Spinosaurus depicted it with an allosaur-like head!

    Sorry to jump back a bit, but I was really enjoying some of the comments about tyrannosaur predatory strategies (finally, a T. rex dietary debate that isn’t titled “Predator or Scavenger?” Why can’t it just be both, like most carnivores?). I think it’s reasonable that tyrannosaurs shifted their diets based on age-related morphological changes (I think someone touched on this already). Young T. rexes were lean, long-legged, and more adapted for chasing prey. As they got older and more mature, their bodies grew heavier, their heads larger and stronger, leading to a much stockier animal. Perhaps they could still run, but only half as fast as their younger selves. An adult T. rex instead seems more suited for tackling slow moving, armored prey, like ceratopsians or ankylosaurs, and/or scavenging on bone marrow. Komodo dragons go through an equally drastic change as they mature. Young dragons are partially arboreal, staying out of the reach of their larger, cannibalistic kin, while eating basically anything smaller than they are that they can chase down. As they grow, they get too heavy to climb readily, and adapt to life on the ground. Their prey selection broadens as well, shifting towards large ungulates.

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  173. 173. MRueger 5:59 pm 09/12/2014

    ^ Sorry, that should read *land ungulates. Pretty sure Komodo dragons don’t prey on cetaceans…

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  174. 174. Tayo Bethel 2:11 am 09/13/2014

    Comment 172:
    That seems like a very sound interpretation of the available evidence for the predatory behavior of T. rex.

    Just thought I’d post this here for anyone who’s interested
    http://www.huffingtonpost.com/2013/05/22/allosaurus-feeding-falcons-computer-simulation_n_3318567.html
    This would seem to go at least some way toward explaining why Allosaurus has such a specialized skull. Perhaps T. rex used a bite and shake technique in prey acquisition as well as in feeding, and attacking large, struggling prey using this technique would have a strongly reinforced skull capable of withstanding the stresses placed on it by large, struggling prey and the predator’s own head-shaking movements. Feel free to bore holes into that argument …I live to learn :)

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  175. 175. Felix2 11:38 am 09/13/2014

    What I’m saying about spinosaurs is that nostrils on the tip of the snout (like crocodilians) would permit easier breathing in water. No crocodilian has nostrils halfway down its snout. Then again, cetaceans do, and perhaps they’re more relevant to this.
    @MRueger- that is a very nice and logical explanation of Tyrannosaurus biology and hunting habits.
    @Tayo Bethel- that model looks logical enough to me (but I don’t know much about biomechanics)

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  176. 176. Heteromeles 11:13 am 09/14/2014

    I’m still bugged about the sail on the Spinosaurus. Assuming it’s not just some sort of sexual selection feature gone haywire, what’s it for? Reheating after being in the water? Near the equator? Yeah. Right. It’d do better to give half the animal shade so it could run on a thermal gradient. Could it be a fat store like a camel’s hump? Perhaps, but that would suggest it lived in an extreme, feast-or-famine environment that might even show up in the fossil record. That hump’s also a weird place to store a lot of fat, because it would pull the beast’s center of gravity up and make it more unstable, especially in the water. Generally, if center of gravity is important (as in a swimmer), you’d want to add weight symmetrically around the center of gravity so that it doesn’t change.

    And walking on those front claws. In the mud? Well, I guess the aquatic ground sloths figured out something similar, so it’s not impossible.

    Oh, and maybe it had feathers like a duck? The latest reconstruction is still shrink-wrapped and croc-scaled. Guess they didn’t get the memo yet.

    Weird beastie.

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