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Sunday, 9 December 2012

Deconstructing All Yesterdays, or How palaeoart is flawed, but everything's cool

It's time to face facts. Try as we might, we will never reconstruct long extinct animals accurately. We may be able to cobble together fairly accurate images of Pleistocene mammals through analysis of their frozen remains and heavy reliance on closely related modern species, but the appearances of species extinct for millions of years are beyond are grasp. Our problems are far greater than the most common complaint, that we simply do not know what colours they were. So much data on soft tissue distribution, muscle bulk and integumentary structures are lost through the death, taphonomic processes, fossilisation and exhumation of extinct creatures that very little can be said for certain about their actual life appearance. The remains that weather the fossilisation process - skeletons and shells - only provide the bare minimum of information about the life appearance of their owners, and it seems that osteological correlates - features of skeletons that betray the presence or development of certain soft-tissue structures - are often ambiguous or unreliable. And we haven't even mentioned the problems with trying to deduce behaviour from bones alone. (Image above: the underlying sketch to this controversial painting of a carrion-eating, bristly Styracosaurus. From 2007.)

This is one of the messages I've taken from the presentations, internet articles and new book All Yesterdays. The brainchild of John Conway, C. M. Kosemen and Darren Naish, this minor internet phenomenon needs little introduction to most of the readers here (if you're unfamiliar with it, check out the provided links for background info). This opinion contrasts with the attitudes of some palaeontologists and artists, who consider our abilities to reconstruct extinct animals fairly decent and reliable. Pains me as it does to say it, but I have to agree with the All Yesterdays chaps. There's simply too much anatomical and behavioural detail lost to time, and we're never going to get that back.

The All Yesterdays project seems to be the result of looking into this deep abyss of lost palaeontological data. But rather than staying safe at the edge, Conway et al. have dived in, exploring the virtually infinite possibilities of ancient animal reconstructions, critiquing the rationale and methodologies of palaeoart and questioning its very purpose. The results are novel, highly creative, insightful and thought provoking, and should be given serious thought by anyone interested in the palaeobiology and depiction of extinct animals. In short, All Yesterdays argues that modern palaeoart fails one of the only tests we can apply to it, that many depictions of extinct animals compare poorly against the morphological and behavioural diversity of modern species. Specifically, modern palaeoart is too conservative, frequently depicting set behavioural patterns for some species (e.g. the Tenontosaurus vs. Deinonychus meme) and 'shrink wrapping' skin over the skeletomuscular system without any consideration of other soft-tissues. All Yesterdays argues that this can be rectified, in part, through bold transference of modern animal anatomy and behaviour to extinct species, which fills the gulfs of missing data and creates more plausible concepts of life in the past than by following the current, perhaps overly conservative palaeoart methods. The word 'concept' is important here, as this is all we can hope to realistically hope to achieve in palaeoart. For all our efforts, our reconstructions will probably never depict these animals exactly as they were in life, and we just have to live with that. Science will hone and refine our concepts to more closely resemble what was once reality, but most of the details we need to exactly reconstruct ancient worlds are unlikely to ever emerge. There will always be several plausible ideas for the life appearance of extinct creatures*, and we should focus on exploring these concepts to reproduce believable renditions of animals, not ignoring because of (probably) unobtainable data or because they stray from established ideas.

*Is there more than one way to reconstruct a fossil animal? According to some, no, but others would disagree. I think the answer lies somewhere inbetween. The skeletomuscular system of extinct animals may be reconstructed more-or-less correctly from fossils of some species but, as we'll see below, this is only half of the story.

But we must be careful with this liberation of creativity in a science-based discipline. All Yesterdays calls not for recklessness in palaeoart, but confidence, allowing extinct animals to be diverse and unusual, but still constrained by what is known for their evolutionary history and anatomy. The payoff for this confidence is that the All Yesterdays project often portrays extinct animals in a more convincing and realistic manner than much of the work we're familiar with. For example, John's tripodal Therizinosaurus is just as plausible, scientifically speaking, as a more traditional version, but is 100 times more believable. John's Camarasaurus rolling in mud is just as plausible as the hundreds of illustrations of this animal standing and eating, and Memo's super-stocky Lambeosaurus is entirely consistent with fossils of this species. The results are just as valid as hypotheses of appearance and behaviour - arguably moreso - than the ultra-conservative reconstructions currently dominating palaeoart. Erring on the side of caution is still an error, and some of the entrenched, 'conservative' reconstructions of ancient life are actually harder to substantiate than the seemingly bolder ones.

Elements of what I'll call 'the All Yesterdays philosophy' have been creeping into palaeoart for years, but I think Conway et al. have burst the dam here, highlighting the need for a fresh approach in how we approach the reconstruction of extinct life. So far as I see it, there are four points to consider in the All Yesterdays philosophy that both palaeontologists and palaeoartists need to embrace: when to apply it, the composition of our images, what it means for animal appearance, and its application for extinct animal behaviour.

All Yesterdays is entirely about reconstructing long extinct animals with no ecologically similar modern relatives. We don't need to extrapolate data wildly for relatively recently extinct species with lots of closely related modern relatives, and doing so will probably make our work less accurate. All Yesterdays is a philosophy that need only be applied to species for which soft-tissue data and behavioural aspects are inadequately known or entirely unknown. This includes some of the stranger Cainozoic mammals, reptiles and birds, and essentially everything that lived in the Mesozoic or before.

Composition, or aspect and attitude
What do extinct animals look like when not viewed in direct lateral view? Because the fossil skeletons of many species are laterally compressed, and because lateral views arguably show off more anatomy than other aspects, palaeoartists rarely show animals in anything other than side-on attitudes. 3D skeletal remains allow us to reconstruct animals in multiple aspects however, often with surprising and unfamiliar results. This has not percolated into palaeoart yet however, and if animals are shown in non-lateral aspects, their proportions are often 'generic'.  In my view, one of Greg Paul's crowing achievements was revealing the variation in dinosaur width, highlighting the extremely wide ribs of ankylosaurs and pachycepahlosaurs, and the narrowness of many theropods. All Yesterdays encourages us to remember that animals are three-dimensional beings, and can be accurately treated as such in art. (Below: the rarely seen anterior aspect of a famous pterosaur. But which one? Detail of a painting from my book.)

Appearance: the anti-shrink wrapping movement
Arguably the most important aspect of All Yesterdays is our reconsideration of extinct animal appearance. As a response to the inaccurate and often shapeless animals common to palaeoart in the early 20th century, most artists in the Age of Greg Paul employ the celebrated 'Rigorous Anatomical Approach' (RAA) to reconstructing fossil animals, and depict their animals with much of their detailed musculature and skeletal anatomy obvious under the skin (classic example of strict RAA in dinosaur art, Greg Paul's running Daspletosaurus, shown below. Image © Gregory S. Paul, from his website). These ultra-lean, toned animals are often devoid of any obvious extraneous tissues, including fats, loose skin or elaborate integuments. Strict RAA remains the most scientifically sound route to reconstructing an extinct animal, as it rigorously employs available data to render an extinct animal, and minimises speculation. It is also an effective way to demonstrate anatomical distinctions between extinct species and produces dynamic looking creatures, which are undeniably appealing to viewers. The rise in popularity of this technique at the time of the Dinosaur Renaissance is probably not a coincidence.

© Gregory S. Paul
However, most modern animals do not look like those produced under strict RAA. Fat, excessive skin, and integumentary structures hide much of their muscle profile and skeletal details, so they are not 'shrink wrapped' in the way that strict RAA suggests. The All Yesterdays philosophy embraces this fully, using RAA to provide the blueprint for an animal, but appreciating that not every anatomical feature will be discernible. Openings in the skull are not clearly seen on animal heads, large teeth are sheathed behind lips, limbs can be hidden beneath fur and feathers, details of muscles are obscured by wrinkly or thickened skin and so forth. Palaeoart produced with this in mind is more consistent with the appearance of modern animals, and make their subjects seem more plausible as living species. We must also not be too concerned about depicting extinct animals as looking ridiculous on occasion: there are numerous modern species which are frankly preposterous to behold, which surely must be true for some ancient species too. If our intended soft-tissue depictions can be functionally rationalised, and are consistent with fossil data and evolutionary hypotheses, then they are plausible inclusions for palaeoart. 

Anyone familiar with the history of palaeoart will recognise recurrent memes associated with specific animals. Ornitholestes always chases a bird. Archaeopteryx (which is always blue and green) perches on a branch with its wings outspread, its back always to the viewer. Tyrannosaurus is always roaring. Most prevalent of all is the depiction of prehistoric animals incessantly trying to murder each other. Memes often perpetuate because they reflect a certain trait specific to a certain animal (e.g. sleeping Mei, the use of the 'terrible claw' in Deinonychus), but they quickly became clichéd tropes when over used. All Yesterdays makes a case for showing animals undertaking other essential activities such as preening and bathing, socialising (without engaging in life-or-death intraspecific combat), playing, resting, sleeping, nesting and, well, all the other things that real animals do. Phylogenetic tracing of animal behaviour shows that there is no reason not to depict ancient animals undertaking these activities, but we rarely show them doing anything but fighting and eating. Moreover, All Yesterdays emphasises the behavioural plasticity of modern animals, noting that apparently strict carnivores or herbivores will supplement their diets with meat or plant matter on occasion, that animals can locomote in unexpected ways and are proficient at activities that we would not predict from their skeletons alone (this image being the chief All Yesterdays case study). As with the morphological aspects of reconstruction, this is not a call out for all unabashed craziness in palaeoart, but simply to say that we should be more broad minded about the way we depict the behaviour of extinct species, and that some initially outlandish ideas (like my carrion-eating Styracosaurus) are not as ridiculous as they first appear.

A new age in palaeoart?
Taken together, these points can be summarised in one two three sentences. Palaeoart must be both scientifically credible and realistic, but may be generally too conservative and clichéd to achieve these goals successfully. We are likely to be misjudging aspects of our reconstructions anyway, but we may be better off erring through the bold use of informed speculation about animal appearance and behaviour rather than through strict conservatism. Each produces results that cannot be refuted by current scientific data, but only the former produces art fully consistent with our understanding of real animals. 

It will be interesting to see how much of a shift All Yesterdays generates in attitudes to palaeoart. It's probably very clear by now that I'm a convert, but will others pick up on this, too? The rosy reviews of the All Yesterdays book suggest so, but what actual effect will this project have? I do not think the results will be as obvious as the popularisation of RAA in the 1970s and 80s, but I am optimistic that All Yesterdays marks a 'formalisation' of the anti-shrink wrapping movement, and need for depicting more complex compositions and behaviours. I look forward to seeing its results. Darren suggested at the All Yesterday's book launch that modern palaeoartists are currently working in the 'Age of Gregory S. Paul', with most of us following Paul's methods of strict RAA reconstruction to greater or lesser extent. Looking at the celebratory response to the All Yesterdays project across the internet, I wonder if the Age of Gregory S. Paul is about to end, and palaeoart will enter the 'Dynasty of All Yesterdays'?


  1. Why oh why do people swallow RAA without resistance? The way Paul does it results in pure BS, because the assumptions on skeletal anatomy and musculature Paul uses are unscientific and - usually - plain wrong.

    RAA is only useful if you use proper base data from which to reconstruct the skeleton and the 'known' soft tissues - i.e., those the bones tell you were there. That's something only a handful of people have been doing, and a lot of that is quit recent.

    1. Wow. that sounds like a lot of hate for somebody who did so much for paleoart and changing the popular notion of dinosaurs as lumbering overgrown iguanas. Besides, a work like All yesterdays wouldn't even exist is wasn't for people like Paul and Bakker that paved the way for it.

    2. Oh and I forgot, he even refuses to make reconstructions of species known just for fragments for the sake of accuracy, so that don't seems to me like unscientific. Maybe the guy can be a little outdated by now for not adding totally especulative skins and details, but calling him full of BS is way too much.

      Vlad fischert

    3. I don't think anyone is denouncing Paul's contribution to the Dinosaur Renaissance. What Heinrich is referring to is that many aspects of his reconstructions and inferences about dinosaur lifestyle are based on hunches and gut feeling, and not rigorous scientific work. The best discussion of this concerns Heinrich's work on Plateosaurus. References to this and some discussion can be found here. Alternatively, Heinrich's most relevant paper on this topic is Open Access.

    4. Ok. Isn't much of the reconstructions and inferences about dinosaur lifestyle based on imagination too in All yesterdays? Paul himself noted that his reconstructions aren't as precise as people might think. In other part he complained about people just copying his style and encouraged them to make new studies and reconstructions.
      After all, could paleontology be able to be accurate in reconstructing the appearance and specially the unusual lifestyle of a polar bear if it was a fossil species?
      I think his (Heinrich) main concern is about the biomechanics involved, but even in extant species there's much to learn.
      Hey Mark, I'm a fan of yours and pterosaurs, I've been following your work for some years now. I'm still waiting for my cousin to bring me my copy of your book from the US (I'm from Mexico, and I can't rely on the post office, they basically steal and lose packages on a regular basis), I'm eager to read it. Regards, Vlad Fischert.

  2. I suspect that Paul's success is/was probably down to his relative clarity of method and the contrast of his results against the lumposaurs prevalent in palaeoart in the late 1970s/early 1980s. Of course, his work also chimed perfectly, both in time and content, with the Dinosaur Renaissance. Paul's work (including his essays and publications on palaeoart, which remain some of the few examples of written work on palaeoart methodologies) demonstrated that palaeoart could have a strong scientific component using strict RAA, and that those involved in palaeoart should be paying closer attention to the available data. As you say, further exploration of RAA has revealed its limitations and the importance of fully analysing the fossils to achieve satisfactory reconstructions. Still, RAA definitely has its place and can be used extremely effectively in some instances - think of Mauricio Anton's work with fossil mammals, but I agree that we must be realistic about its application and execution. I expect that the All Yesterdays project was a direct result of this sort of work. All Yesterdays is punk to Paul's prog rock, if you like. 'Post-Paul', anyone?

    On a related note, I looked at Paul's work a fair bit in writing this post, and must confess to seeing it as rather dated now, and especially in light of All Yesterdays and recent illustrations of feathered dinosaurs. It's all very 1980s/1990s. Even the stuff in his 2010 book is looking quite old fashioned. Although still well produced, his reconstructions look far too slender compared to real animals. His feathered species in particular, which probably had puffed up body profiles like those of modern birds, are merely fuzzy outlines of skeletons. It's ironic that one of the first individuals to depict and argue for feathers on dinosaurs uses them so sparingly, despite evidence for very extensive feathery integuments in so many species now.

    1. I should have been more exact: it is not that RAA is not an excellent approach. The problem is that if you want to "do" more than a handful of animals you simply can't keep abreast of the literature, and especially not of the literature on extant animals you need to read to do RAA properly. That's one of the reason Paul's dinosaurs are anorexic: he messed up the bones and muscles, and if you have an animal that's got muscles as if it was from the Sahel zone you'd need to put a lot of skin and fat on it to even get to "normal" - and the Paul pics tell!

      All Yesterdays isn't about this stage at all, but addresses the next step, once RAA is done - and here we hit the issue of "proof of existence" vs. "proof of inexistence": in mammals, if you can't prove it wasn#t there you simply C&P from extant animals. In dinosaurs, if you can't prove it was there you must not draw it. Stupid, as it uses two different yardsticks for one task. Which is why I can't wait for my copy to arrive :)

    2. David Marjanović10 December 2012 at 14:11

      It's ironic that one of the first individuals to depict and argue for feathers on dinosaurs uses them so sparingly, despite evidence for very extensive feathery integuments in so many species now.

      I guess that, because he was one of the first to put any feathers at all on nonavian dinosaurs, he used them sparingly to avoid of being accused of going too far beyond the evidence. Same perhaps for Bakker and his famous "Syntarsus".

    3. I think Paul does explain in the Field Guide that the plumage on his feathered dinosaurs in that particular book is deliberately kept sparse to show the body outline as much as possible.

    4. Heinrich: One issue I have with RAA is the lack of literature on a lot of osteological correlates and inferred functionality. There are a number of skeletal structures that are meant to reflect a behaviour or soft-tissue, but there is often less meat to these hypotheses than we might like. The lack of good form-function analyses in modern animals is a real issue in palaeontology and palaeoart.

      On "proof of existence" vs. "proof of inexistence": Yes, that old chestnut. I guess the only way for palaeoartists to work within this sea of unknowns is to think more about what is possible and plausible, and not what is necessarily the single "right" interpretation.

      Marc: I must have missed that bit, thanks for the clarification. I'm not quite sure what the point of that approach is, though. If Paul was worried about the plumage obscuring the visible muscle contours on the naked skin, he may have been better just sticking to myological reconstructions, or doing them as well as the fully feathered ones. Perhaps they're viewed better as schematic feather maps for non-avian theropods, then, and not as reconstructions.

    5. Yes, Paul also explained in the book that he deliberately draws his dinosaurs in a lean state for the same reason, and I don't see what the problem with that really is, his ceratopsians for example doesn't look more "anorexic" than modern african species of rhinos.
      By the way, I really dig All yesterdays.

      Vlad Fischert

    6. I must admit to looking for these statements of drawing lean animals with only bare minimal feathering, but I couldn't find it in the text. Does anyone have a page number for this?

    7. Predatory dinosaurs of the World
      On lean dinosaurs 105, 235
      On integument and feathers 122-127, insulation 161
      I think there's more but that's what I found.

      Vlad Fischert

  3. I am (pleasantly) suprised not to have seen a single negative review of All Yesterdays yet. As I made pretty clear on SV-POW!, I think it's not only brilliant but also important, both artistically and scientifically. But I was expecting to see some kickback from traditionalists. That I haven't suggests that John's done a good job evangelising his vision -- probably those two SVPCA talks have helped.

    Looking at the celebratory response to the All Yesterdays project across the internet, I wonder if the Age of Gregory S. Paul is about to end, and palaeoart will enter the 'Dynasty of All Yesterdays'?"


    I wonder if Greg will modify his own work in response, or kick back against it, or just stay silent.

    1. Me too. I reckon there could be a lot learnt from discussions on the All Yesterdays approach, and probably lots of ideas for research projects, too.

  4. In other news ... why the heck have you started a new blog on Blogger instead of WordPress? It's a nightmare, constantly losing comments and so throwing up a barrier to actual discussion.

    I think this blog is new enough that you could pretty painlessly move to WordPress. I highly recommend it. (Much better spam-handling, too.)

    1. I third this. I find working with Wordpress (for the Dino Toy Blog) much easier than working with Blogger (for Chasmosaurs).

      Fantastic review by the way...I might add one to the pile, but I think David (Orr)'s got one in the works.

    2. David Marjanović10 December 2012 at 14:13


      Blogger doesn't even allow <blockquote>!

    3. Thanks for the thoughts on this, chaps. I have always found Blogger easy to work with (Pterosaur.Net is Blogger), and I figured it made sense to use the same dashboard for both the blogs I contribute too. So far as I'm aware, the comment problem Mike mentioned has never happened at P.Net (no-one has complained about it, anyway). Nevertheless, I'll look into migrating to Wordpress before I'm too much older and, if it's relatively quick and painless, will take the plunge.

    4. one really good thing about WP is that you can set first-timer comments to always require your approval, but all further comments from the same log-in are auto-cleared. Saves all the hassle with the captcha!

  5. As far as I am concerned, the biggest problem in the term RAA is the suggestion (sometimes even overtly expressed) that 'rigor' equates to 'objectivity'. But even the 'skeletals'of Paul and his followers are heavily loaded with suggestion regarding soft tissue anatomy and (perhaps even more problematically) behavior. Personally, I think that a more *overtly* subjective type of reconstruction does far more justice to inherent uncertainties.

    Finally, allow me to say that we all owe a lot to Doug Henderson.

  6. Yes. A great example of the lack of objectivity in skeletal reconstructions is skull anatomy. Despite being based on the same specimens, the skulls of two skeletals are rarely exactly alike.

    On Doug: I wish his work was more visible nowadays, as I think there's a lot to be learnt from it. His depictions of the Mesozoic are some of the most evocative and believable, but it' seems hard to find the majority of it nowadays unless you're willing to fork out for lots of out-of-print books.

  7. **On a related note, I looked at Paul's work a fair bit in writing this post, and must confess to seeing it as rather dated now, and especially in light of All Yesterdays and recent illustrations of feathered dinosaurs. It's all very 1980s/1990s.**

    This is something that I noticed as well. After digging through an old copy of Paul's Predatory Dinosaurs, I couldn't get over the swan-like curvature he'd allocated to his theropod's necks. How could I have missed it before? It was startling to suddenly realize how much progress has unfolded in paleoart.

    I can understand why the guy would want to show off his skeletal work. The time and effort he put into his reconstructions really did pave the way for years to come, and I can still remember a time when Paul-ian feathered dinosaurs were the future.

    Perhaps it's similar to artists who reconstruct ancient homminids: Kennis and Kennis have produced some amazing busts. One of their Neanderthals is presented with hair shaved from forehead to chin. It's a striking piece which also illustrates the apparent need to highlight disparate traits in extinct animals.

    It highlights a tendency; a factor that played into the success of RAA?

  8. As a great admirer of Paul's work I too agree it's dated in today's days, and hopefully artists and paleontologists will embrace it in the near future.

    And I couldn't help myself in thinking while looking side by side those Therizinosaurus reconstructions posted above that a 'The Future is Wild' like documentary about dinosaurs would help this new view to be embraced by the public.

    On the Blogger vs. Wordpress as a commentator I never had problems with Blogger but I can't say the same about Wordpress - they're constantly changing the users' interface and about one or two times I had problems commenting. But I'm a dupe regarding computing stuff.

  9. just to make sure all are up to speed on some of the Paul-issues:

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