Search Results for '"how to"'



How to read a phylogenetic tree

Nowadays even the media seem quite happy to occasionally put up a phylogenetic tree as part of their scientific coverage, and they are proliferating on the internet on websites, research papers and blogs, in addition to books and magazines. However, while it is hardly difficult to get the gist of a tree, there is a certain skill and amount of knowledge that needs to go into pulling out all of the information correctly from a tree. It is easy to make mistakes about what a tree actually tells you so hopefully I can clear up a few misconceptions about tree creation and how trees should be read.

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How to spot a palaeontologist

Stereotypes are a double-edged sword. On the one hand they can be useful shortcuts to extrapolate a whole bunch of correct information based on very little. On the other hand they can be deeply flawed shortcuts to extrapolate a whole bunch of incorrect information based on very little. The typical stereotype of a scientist or indded a palaeontologist as presented to the world at large by the media is not exaclty flattering and full of deep inaccuracies and, well, stereotypes. However, there is always a reason for the stereotype and here is one of them…

How do you spot a palaeontologist? Allow me to be your guide:

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How to complete a PhD

Like the previous post, this is a document I created to help my own students with their work. Again, I think it serves as a useful tool for potential students, I’d appreciate feedback from other professionals, and if nothing else, might be interesting to those on the outside of academia. I am well aware that PhD’s can vary enormously in style between individuals in the same department, let alone in different universities or countries so don’t treat this by any stretch as an absolute. I strongly suspect many of these points are not entirely relevant to people working outside the UK or Ireland or at least would have to be highly modified – the fundamental interaction between students and supervisors is (I believe) rather different between the two. One thing (I think) said by Dr Vector (sauropod supremo Matt Wedel) is that you are not ready to try and do a PhD until you have finished one, a sentiment I wholeheartedly agree with. It is first and foremost (for me) about the learning experience – learning how to do research (and all that that entails) not just *doing* the research. How relevant this is outside of palaeo and / or geology / biology is another matter as well. Anyway, enough babbling, here it is:

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How to write a paper (and get it published)

The following post is based on a document I made a couple of years ago to circulate to MSc and PhD students I was supervising to encourage them to turn thesis work into papers and to show the process that takes papers from submission to publication. It seemed to me a good idea to recycle this here for a few reasons 1) it might be of use to other students out there who are trying to write papers for the first time, 2) I still use this document, so any feedback from other professionals that I can add in and update would be welcome, and 3) it might serve as an interesting essay for students or others as to the mechanics of writing and publishing a manuscript. I have covered bits of this before in other posts but this is far more extensive and practical rather than a simple review.

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Dinosaur tails redux

Getting on for ten years ago, I published a paper looking at the lengths of the tails of dinosaurs. The short version of that is that total length of tails in dinosaurs varies massively both between clades and even within groups (or within species!) which mean that a lot of the ‘total length X’ estimates for various dinosaurs are probably way out. Still, it wasn’t the biggest dataset and there’s not a lot of nuance to looking at total length vs body length, plus being restricted to only complete tails really cuts down on the number of specimens you can use.

Still, not too long after the paper was published, I set about trying to get a better dataset together as more dinosaur tails were coming out of the woodwork. That led to this appeal on here which helped reel in a few more specimens. Still, I wanted to do something more detailed and that led me to roping in my friend and colleague Steve LeComber.

At the Cheltenham Science Festival (L-R, Me, Steve Le Comber, Chris Faulkes, Jane Hallam)

Steve will be all but unknown to readers on the Musings as he never worked on dinosaurs before, though as a great science communicator he helped me out at a number of my events, especially when we went to the Cheltenham Science Festival together a few years ago.  Sadly, this will also be one of his last papers as he passed away at the end of 2019. Steve was one of my closest friends and colleagues, and was one of the most popular and friendly people I have ever met. He had an entire career as a journalist and writer before switching to science and was a superb statistician as well as a great biologist and a wonderful educator.It’s a testament to his work that papers are still coming out of his lab and his work on geographic profiling will have an important and lasting legacy in biology. He will be forever missed. (A scientific obituary was published for Steve here in the Journal of Zoology, where he was an editor for many years).

I had turned to Steve because he was tremendously creative with analyses and I had no idea how to approach the next problem I wanted to tackle – what was happening with individual vertebrae in the tails of dinosaurs? Very little has ever been written about this, and what there is implies or even states that as you go down the tail, each vertebra is shorter than the last. But you only have to look at a couple of specimens to see that this really isn’t the case. It’s true for big chunks of the tail, but the part closest to the hips often has short vertebrae but after that they tend to get longer, and in very long tails like those of sauropods you can find multiple sets of vertebrae that are lengthening. But how to capture this information? If groups of vertebrae are letting longer or shorter, and if this changes slowly or dramatically, or is just an oddity, can we capture it? Happily, he had some ideas.

As I was by now established at Queen Mary, I really lacked the time and opportunities to revisit collections and measure individual vertebrae so we then roped in Scott Persons, who has his own interest in dinosaur tails and had measurements we could use, or was able to get into some of the Canadian collections to procure more data. Various issues delayed the paper on numerous occasions but it is now out so here’s some quick take-home results (the full paper is in PeerJ and open access so you can see all the figs and data there).

First off, with more and better data, we did revisit the issue of overall dinosaur tail length and it is still very variable and unpredictable. Total length estimates without most of the tail present could easily be very wrong, and even some tails that you might think are pretty complete could easily truncate suddenly or go on much longer than you might think. There’s still a place for these of course (especially for engaging the public) but the standard ‘my theropod is longer than yours’ battles really need to stop. Total length isn’t a great indicator of size (mass is) and tail lengths, and by extension total lengths, are very hard to estimate without a near complete tail.

Obviously we do now have a much better Spinosaurus tail, but this old image by Scott Hartman demonstrates just how wildly different tail lengths (and so total lengths) of an animal could be for the same body size.

On to patterns within tails. First off we do find that individual vertebrae within tails simply don’t tend to get shorter as you go along them. There’s some interesting and cool patterns going on and I don’t want to cover all of them here (for example Coeplohysis is all over the place, and Juravenator seems really weird) but here’s a few of the more interesting ones. We use broken-stick regressions where we can have multiple different trajectories of sections of the tail lengthening, staying the same length or shortening. It’s a great tool to see what is happening and is visually nice and easy to follow, without getting mired down in the odd vertebra that’s rather out of place with the others.

First off, that means that it’s good for spotting changes in patterns of vertebrae lengths and also deal with (bits of) missing data quite well. This is also really useful for predicting the lengths of missing vertebrae and this is likely to be useful for things like working out total lengths of animals and the sizes of individual verts when reconstructing fossils. It’s also absolutely ideal for putting together skeletals and even mounted skeletons in the future.

Second, many dinosaurs have a pattern of a set of short vertebrae, then longer ones, and then the rest of the tail does indeed taper off. The second switch (were the long ones stop and it starts to taper) coincides with the ‘transition point’ in the tail, where the main leg muscles terminate, suggesting an important link between the two and from this we hypothesis that this short-longer- tapering pattern is a functional one linked to tail flexibility and muscle power. This clearly needs more work, but it’s a very interesting starting point.

Next, some exceptions. Plenty of dinosaurs don’t fit this pattern for various reasons (some it’s probably just missing data or it’s a subtlety like the tapering happens in two different phases), including some that do just generally taper. There’s some huge intraspecific variation in some but others are very consistent. All three specimens of Archaeopteryx we included show a weird humped distribution which is also very similar to Microraptor, and also different to other dromaeosaurs. That rather implies that this is flight related and that this is an important convergence, though again quite what and how is well beyond what we cover in the paper, it’s an area that hopefully others will pick up on. And aside from Microraptor, the dromaeosaurs appear to be highly variable which we attribute to their ‘sheath’ of elongated supporting rods for most of the tail length which would dominate any other functional issues and might leave the lengths of individual vertebrae to be fairly free of constraints.

I’ll leave it there since the paper is freely accessible and there’s lots that can be extracted from it, but I think this covers some of the more interesting points. The methods in particular should work well for any repeating units and while we have focused on dinosaur tails here, they should apply equally to any vertebral series or things like ribs, arthropod segments, and so on. I’d really hope that people will immediately see the use of this for describing things like sauropod or plesiosaur necks, pterosaur tails, or the lengths of neural spines or size teeth in a series. Of course I also need to say thanks to Scott and Steve and various referees and editors for helping get this published, and especially thanks to all those who contributed data to get this moving.

Hone, D.W.E., Persons, W.S.C. & LeComber, S.C. 2021. New data on tail lengths and variation along the caudal series in non-avialan dinosaurs. PeerJ. 9:e10721.

Terrible Lizards – a new dinosaur podcast

With a near global lockdown and people stuck at home there’s been a rash of new podcasts forming (or at least a rash of jokes about everyone starting new podcasts while they are stuck at home) and here is the latest (and by extension, greatest) – Terrible Lizards. In my defence, I’m no stranger to podcasts and actually this one had been in the works since January and the lockdown has merely hastened its arrival rather than being its origin.

I’m no stranger to podcasts having been interviewed for loads of them at various times, but I’ve certainly never run one so this is a big step up. It is something I’d been considering for quite some time but there were various barriers to getting it going (not least time and some real expertise) when a chance meeting with an old friend suddenly made everything viable.

At a mutual friend’s Christmas party, I couldn’t help but spot the distinctive figure of Iszi Lawrence who I’d not seen in nearly 15 years so went over to say ‘hello’. Iszi was starting out as both a stand-up comedian and an undergraduate student in Bristol back while I was doing my PhD and we lived in the same block of flats. We got on well and hung out a bit and then I jetted off to Germany and we lost touch (this was before Facebook and other things like that) and as so often happens that was the end of a small friendship.

However, as also so often happens, meeting again it was like no time had passed and we were soon chatting nineteen to the dozen and catching up. She’d continued on the comedy circuit and also now runs and hosts several podcasts and radio shows (as well as writing childrens’ books and doing other stuff – find it all here) and we talked about me doing a guest spot on one of the history ones to talk about the early days of palaeontology and cover people like Mary Anning and Gideon Mantell. This though quickly morphed into doing an actual, proper, new and dedicated dinosaur podcast and so here we are.

There are of course, plenty of natural history podcasts, those on palaeontology generally, dinosaurs specifically and all kinds of others. I don’t think there’s real competition between them since it’s not like people can’t listen to them all, but it does immediately beg the question of what’s different or special about this one. I think the answer there is that we are trying to reach a truly lay audience – this isn’t a podcast that’s aimed at dinosaur geeks and nerds or students and academics, or even children – but one for people who like science but may know little more than the names Tyrannosaurs, Triceratops and Diplodocus.

We try and delve into a different subject in each episode and this is aided, in the best possible way, by Iszi’s ignorance. She can steer me to what needs to be said and explained and given context and of course her wit is there to stop me rambling on about gastralia excessively.  Her experience and expertise also means she generally knows how to host and edit one of these things so against all odds I even end up sounding vaguely professional, it’s quite a marvel. If all of the wasn’t incentive enough, we’ve managed to secure a special guest for each episode so alongside comedian Jo Caufield, Richard Herring and Alice Fraser we have historian Tom Holland, podcaster Dan Schreiber, dino-nerd and cake-maker Ralph Attanasia and legendary biologist Chris Packham to ask me some obscure, odd and downright naughty (Richard Herring, inevitably) questions about dinosaurs.

Obviously readers on here won’t normally fit our key target audience but I’d still hope it would be enjoyable to listen to and you’d learn something from it. There’s so much to talk about and explore and recover that it should be appealing no matter your existing levels of knowledge. Do though please share this to anyone who might want a listen and might enjoy it, reaching out well beyond the dino aficionados is a key part of this and you can make a huge difference with a like and share and tweet and whatever. The first two episodes are up right now here on iTunes and on here website here and we’ll be adding one a week for the next few weeks. This is something of an experiment so if we don’t get a good number of followers and subscribers this may be a short series (so consider that either a warning or a blessed relief).

Do give it a try and do give it a share. First episode? Well it could hardly be anything else, could it?

 

Books to read to become a palaeontologist

Despite (or because of) writing a long piece on ‘how to become a palaeontologist’, I still get loads of questions from people who want help and advice about getting into this field. While I encouraged people to read a lot, I didn’t get too specific since everyone has different backgrounds and areas they want to get into, and books (especially on dinosaurs) come out in a huge flurry and tend to date quickly. However, a recent query and some pondering led me to realise that actually there’s a core group of books I would recommend which is likely to be a useful starting point years or even decades from now (and indeed, many of the books are already decades old).

What may surprise people is that basically there’s no dinosaurs on the list and not really any palaeontology. This is because people who want to learn about palaeontology, whether just because they are interested, or because they have an active plan to becomes one, tend to get really obsessed with facts. Learning lists of formations and dates and faunal lists and how many teeth a species have are useful, but this use is limited. This stuff constantly changes and gets out of date and if you don’t know it or forget it, you can always look up the answer. What is infinitely more useful, is understanding – a knowledge of the principles at play and the fundamental basis of how organisms and systems work, and how we obtain and apply that knowledge.

In other words, reading dinosaurs books is a poor way to learn about palaeontology (in some ways, I’m obviously not suggesting someone who wants to work on dinosaurs shouldn’t read books on dinosaurs or learn about them). So with that in mind, here’s my list of ten books to read to get into palaeontology. I should stress that this is very far from exhaustive and it’s skewed to books in areas that I am interested in, and as a result there’s not a lot of geology in there. Still, at least ¾ of this list will be useful for anyone wanting to embark on a palaeontological career or just getting a better understanding of the field, or for that matter almost any are of biology.

These are presented in a rough order in which to read them where I think they would most benefit and build on each other, though equally that is far from important and it wouldn’t really be an issue to read them in a random order.

 

  1. Charles Darwin – Origin of Species

If I’m honest, it’s pretty tedious and repetitive as a book to read (the Victorian style of popular science writing doesn’t necessarily hold up too well 150 years later) but it can hardly be avoided. It’s so fundamental to the basis of modern evolutionary theory as well as being so important historically that even if it’s a slog to get through, any wannabe biologist of any stripe should read it.

  1. Richard Dawkins – Selfish Gene

A modern classic and important to understand the role and important of genetics in evolution. As such it’s an important successor to The Origin and is also something of a period piece for the state of biology and evolution when it was written.

  1. Carl Zimmer – Evolution

A few years old now, but an excellent introduction to modern evolutionary theory and its foundations and a very good place to start for anyone wanting to learn anything in depth about biology.

  1. Bill Bryson – A Short History of Nearly Everything

For me the best ever popular science book. This is a brilliant grounding in both the basics of science (geology, physics, chemistry and biology) as told through the history of those fields with input from a huge number of respected authorities in their fields. I reread it every year or so.

  1. Steven Levitt and Stephen Dubner – Freakonomics

Something of a wildcard this, it’s not without issues, but it’s a very entertaining read and it shows well that with careful thought you can make the most of almost any dataset to say something meaningful about a subject. With data at a real premium in palaeontology, a book on creative analysis (which is also a lot of fun) from limited informationis something rather useful.

  1. Ben Goldacre – Bad Science

All the examples might be medical, but this really is an exemplary book on how experiments should be set up and how things should be analysed. It’s a wonderfully easy read and while it’s not about statistics per se, it does really get to the root of preparing and planning your work and understanding what you can and cannot grasp from data, as well as how people mishandle and misinterpret results.

  1. Armand Marie Leroi – Mutants

An absolute favourite of mine and the book that got me to be interested in, and understand, development. A wonderfully written book and deeply engrossing and linking together human biology, development, genetics and history.

  1. Paul Colinvaux – Why Big, Fierce Animals are Rare

This book is slowly aging but as an introduction to population ecology it’s still excellent and provides an excellent foundation for understanding so much of the pressures that influence organisms.

  1. Matt Ridley – The Red Queen

A brilliant and perennially popular book on sex and sexual selection and its importance in shaping evolution, diversity anatomy and behaviours. A must read if you want to understand a selective driver than can be even more powerful than natural selection.

  1. Neil Shubin – Your Inner Fish

The closes this list probably comes to palaeontology, this book explores the world of EvoDevo and the increasingly important role palaeontology plays in other branches of biology to understand evolution and deep time. It also covers some major palaeontological discoveries and advancements in the field so is rather a 2 for 1 in that sense.

 

And an extra bonus number 11 that is actually (a bit) on dinosaurs

  1. Deborah Cadbury – The Dinosaur Hunters

Wonderfully written book on the story of the origins of palaeontology as a science and featuring Owen, Mantell, Buckland, Anning and plenty of others. This is pretty much a historical book, but having an appreciation for the origins of the field and science of the time is important and useful to know and this is a very compelling read.

Pairi Daiza Zoo

Sleeping Tasmanian devil

My most recent zoo outing was the Pairi Daiza collection in Belgium. I’d not actually heard of this place until finding a flyer for it in a hotel in France but was drawn to its claim of having won two ‘best zoo in Europe’ awards (from who I don’t know) clearly being very large and the fact that it has somehow passed me by. I managed to have a chance to go recently however so made the trek out to it and found what must rank as one of the strangest collections I’ve ever been so, so strap in for a pretty long and detailed review.

First off the basics, the animals were numerous, generally well cared for (though a couple of terrariums in the reptile house were poor and one alligator was rather badly overweight) and in good set-ups. There was lots of space and with well managed environments and the animals appeared to be doing well.

Young gharials

As usual, it’s worth touching on some of the more interesting and rare animals since these days going to a zoo and seeing a lion on Celebes macaque doesn’t really do much for me (or I suspect, many of the readers). So, I got to see blesbok, rufus hornbill, Tasmanian devils, and potoroos (all wonderful), a displaying Bulwer’s pheasant (amazing), Spix’s macaws (well, sort of, they were in nest boxes but I could see a bit of one) and best of all, gharials! Only a pair of very young juveniles, but still an utter delight to see and something I’ve been after for many, many years.

There were lots of other cool things too (especially on the bird front), giant pandas, lots of pheasants, parrots and touracos, shoebill, bird of paradise, spotted hyena, cock of the rock, hummingbirds, couscous, and a really wide selection of classic big things (giraffe, rhino, hippo, apes) as well as less-often seen ones like moose, bushbuck and various vultures. There was a lake with lots of wild waterfowl and then sections were partitioned off for the seals and penguins which was nice, and then a good reptile house and aquarium, and several walk-through sections, but here is where things start to get odd.

Potoroo

The zoo is fundamentally constructed in a very odd manner. It is absolutely huge and built mostly up the side of a huge hill, and it is signposted badly when meant for a very long day (more than a few shades of LA Zoo). There’s lots of bizarrely wasted space such as a walk through tropical house with a massive waterfall and lake and a rope-bridge over it, but no fish or other animals in the water or on the little islands in the middle. It looks nice, but there’s no animals to see in that part, they’re all at the other end. There’s big laws which clearly are in part there for corporate events (there were a couple on, even at the weekend) but it only adds to the spacing out between exhibits. Much more than that though, huge chunks are given over some kind of tribute to the homelands of various animals. There is, for example, an absolutely huge and basically full-sized Thailand temple on top of the hill. It’s utterly huge and very detailed, but, and this is quite crucial, it’s not part of the exhibits. It’s not a huge façade to the elephant house, or is the small mammal house, it’s literally just a huge replica of a temple. There’s a Chinese one next to the pandas as well, and a fake warehouse with a real seaplane in it and canoes next to the bears and moose. It’s basically a huge amount of land taken up with a very expensive (and really quite faithful) replica of major buildings.

Similarly, the aquarium is themed around captain Nemo’s Nautilus with steam-punk type copper piping everywhere and gas lanterns etc. and even a control room with a very poor mannequin propped up again a steering wheel. The reptile house is built inside a mock Victorian steam ship that’s sinking (the whole thing is built on a slant) with the theme of the animals escaping from their containers. There’s even a fake lighthouse over the seal pond (which at least houses an icecream stand but otherwise seems to be functionless).

Blesbok

It’s all just set dressing, and while it mostly looks nice, I really can’t see the point. It must have added a colossal amount to the cost of the zoo and takes up a monstrous amount of space and it really adds not that much. These reviews as a whole are coming from a place where I’m both a huge animal enthusiast and someone who has been to a lot of zoos. I absolutely recognise that things that appeal to me as a visitor may not appeal at all to the average zoo goer but I’d hope I have enough empathy to know why they love seeing elephants and ring tailed lemurs even when I’m more interested in elephant shrews and ring tailed cats. But here’s the thing, the visitors (and there were many) didn’t seem that bothered by it either. They were mostly looking at the animals and the small sections of pseudo-museum exhibits there were plugged into a couple of these were completely empty. I really can’t fathom why they would do this, and it only adds to long walks to get from section to section and confusing detours when trying to get past them.

Bulwer’s pheasant displaying

The zoo was also rather expensive to get into (more than London Zoo by a margin which obviously suffers in part from being in London) and then the carpark was a lot on top of that. Given that it’s absolutely in the middle of nowhere in the country where land is cheap, and there’s no other real mechanism of getting there (I didn’t see any bus stops or any public transport coming or going) this seems an utterly unnecessary and mercenary addition.

So, how to sum up? It’s an amazing collection with lots of great exhibits and a mix of the ‘traditional’ animals and lots of real rarities and things that would appeal to even rather jaded zoo goers. But it’s a huge amount of ground to cover and the huge and badly signposted gaps between exhibits is frustrating and coupled with the price and inaccessibility means it’s not a trip for the casual visitor (unless you already live in rural Belgium).

 

Dinosaur dimorphism, cryptic absence

Yes it’s new paper time and this is one I want to talk about in some detail, so here’s a longer than normal post on this. It’s an issue that has been in my brain for years but has taken time to mature with the right set of circumstances and quirks that make up the profile of a research paper possible. This one is returning again to the much investigated area of sexual selection in the extinct Dinosauria. I think it’s fair to say I’ve been a leading researcher in this field with a string of papers on various issues surrounding sexual selection and dimorphism in dinosaurs (and others), how we might detect sexually selected traits and what they may mean for behaviour, ecology and evolution.

The new paper is written with Jordan Mallon, and in it we tackle the issue of the apparent lack of dimorphism in dinosaurs and why there is still no good case for a dimorphic dinosaur. Despite numerous studies suggesting a split between male and female morphs (or similar robust and gracile ones) revisions have generally found the cases to be lacking and Jordan’s own recent paper in this area is relevant for several reasons. The story though starts quite a few years ago.

My own works on sexual selection mostly kicked off with a paper discussing mutual sexual selection and the idea that both sexes in many populations of dinosaurs may have borne ornaments for social and / or sexual dominance. In short, males had big ornaments (claws, horns, frills, crests etc.) to advertise their general good health and status to females for mating and other males in terms of competition, but females likewise advertised their general quality with the same signal. That meant that in something like a typical ceratopsian both males and females had a big frill and horns and hence an inability for us to identify and separate out the two populations.

This general concept had been completely overlooked in the literature in sexual selection and dimorphism in dinosaurs and it’s worth repeating that this can totally confound some ideas and tests for sexual selection and it needs to be borne in mind when discussing these kinds of traits. While later papers have built on this issue and surrounding ones for the function of crests and the like, in my mind it has always been an unsatisfying explanation for things. Sure, it’s a big issue and to ignore it is incorrect, but while we are finding more and more examples of mutually sexually selected species, it seems unlikely that so many dinosaurs (huge numbers of hadrosaurs and ceratopsians, various theropods and other lineages) all had equal ornaments. Sexual dimorphism, be it in body size or crest size and shape (or of course, presence / absence) surely was present in a few of these lineages?

One issue is of course that for a lot of species we have very few specimens (often only one) and certainly don’t have lots of adults in good condition from a single site for many. As I noted in a paper on social behaviour in dinosaurs, lots of large terrestrial mammals at least show different fundamental patterns in group behaviours between the sexes so even if we do have 50 animals from a mass mortality site, there’s no guarantee it is not a group of 50 males or 50 females. Identifying different sexes is also problematic of course but it would help if in a few cases we *knew* we had both present in a sample size.

Even so, where was the dimorphism? Was it really absent or merely for some reason, hard to detect? After quite some thought I realised that what might be a major factor is the growth patterns of dinosaurs. Where large mammals and birds rather race to adult size and then stick there, dinosaurs (at least the larger ones) took a longer and more reptilian growth pattern with an extended growth phase (even if they were sexually mature during much of this). That means that much of the reproducing population isn’t full size and that even if say males were much bigger than females, you’d struggle to tell apart and old female from a young male which might be comparably sized. Right, now I had a hypothesis and a mechanism to test it by getting a dataset on dimorphic animals with differential growth and see how they looked depending on how things were sampled.

And then I got stuck. Datasets like this, (especially with reptiles and birds) simply didn’t seem to exist in the literature. Over perhaps 5 years I sent out dozens of e-mails and spoke to various people about data, including biologists, palaeontologists, conservation and zoo workers – anyone I thought might have or know of a dataset of mass for lots of individuals of known sex and age. I got nowhere. Even trying to compile sets from lots of individual measurements didn’t get me anywhere and I was resigned to having a good idea I couldn’t test, until Jordan got in touch.

He sent me a draft of his now published paper re-examining analyses that had looked for dimorphism and found them wanting. Reading it through I was annoyed to see that he seemed to be leaning the same way and that the elongate growth might be a decisive factor, but while the paper discussed some issues around detection it didn’t go there. I was relieved that my idea seemed to still be mine to work on, but as Jordan had asked for any comments to help improve things, it also seemed a bit mean to withhold an idea that might provide a nice extra aspect of the paper.

Happily, as these things often do, a quick chat via Skype helped revolve things. Jordan liked the idea but agreed we could try and combine forces, as he thought he had a good lead on some data we could finally use and importantly also knew how to run the analyses. So with new impetus, the idea was resurrected and the final output of this collaboration is now out.

So, what did we find? Well it looks like my thoughts were generally correct but far more so that either of us suspected. We used alligators as the reptile model since they form a part of the dinosaur phylogenetic bracket and have large dimorphism (at full size, males are 30% and up longer than females), with rheas on the other side (also show major dimorphism and are large birds). Doing various subsamples of each it is clear that it’s much easier to detect dimorphism in the birds because you are tending to sample animals that are at full size. You can use a much smaller sample size to detect dimorphism in birds than reptiles. You typically need around 30 animals of *each* sex to get a statistically significant difference in alligators, even though that have one of the highest levels of dimorphism recorded.

Given how few dinosaurs even have a dataset of 60 animals (and then the issues of making sure you can measure them all accurately, and of course the fact that you’ll be lucky if even a few are sexed, and you may have all of one sex, and there is often variations between populations) and then it becomes little surprise we have picked up no good signals for dimorphism in dinosaurs to date. This does become a little better when we sample from larger individuals (as there are several biases against juveniles in the fossil record) but still well below what we can do for almost any dinosaur.

One other aspect that we look at is the range of dimorphism appearing in extant reptiles. There’s a surprising (to me) level of variation in populations with major variations in terms of just how dimorphic one population is versus another and these can also change over time. Some populations of single species even show males being larger with others having larger females. That’s also potentially an issue given our tendency to have to lump together specimens from multiple different sites to get to a decent number of animals to measure and while it might not be common, it’s clearly a potentially confounding signal.

This is of course not the final word on any of this. There are other aspects to both growth and dimorphism and how we measure it in both living and extinct animals. Certainly I think it’s possible to make a good case for dimorphism with only a limited sample (as has been looked at for example with oviraptorosaur tails, or indeed for some pterosaurs) but the apparent lack of dimorphism for dinosaurs in the fossil record is not as alarming as it might seem. Yes we might expect numerous species to have been dimorphic but it appears that our sample sizes are simply too small. Through in the unknown age and sex of most specimens, and the potentially confounding effects of mutual sexual selection and it becomes perfectly possible that many species (even those represented by large numbers of good specimens) were strongly dimorphic but we are simply unable to identify it.

For years I’d been puzzled by the apparent lack of dimorphism, and Jordan’s paper confirmed that we really have yet to show it clearly in any dinosaur. Mutual sexual selection is a major issue but it probably doesn’t explain all the cases we know about, but I think this paper adds a pretty substantial concept to our understanding of dinosaur dimorphism. Or rather, that we don’t understand it that well but that the apparent absence could well be a classic absence of evidence problem. As with a number of issues in behaviour and ecology, I rather suspect we don’t know as much as we think we do, but understanding what we do and don’t know with confidence is a major step forwards to getting to grips with the problem, so this hopefully is progress even if we can’t find much right now.

 

Hone, D.W.E., & Mallon, J. [joint first authors]. In press. Protracted growth impedes the detection of sexual dimorphism in non-avian dinosaurs. Palaeontology.

 

Sauropods and pterosaurs

Csotonyi_Rhamphorhynchus_1000

Following on from the recent interview with Julius Csotonyi and Steve White about the new palaeoart book, I wanted to take a closer look at one image in particular. This is both because it is covered fairly extensively in the book by Julius who writes about its genesis and production and because it is, in part, a result of discussions between him and myself.

Julius was kind enough to ask for my advice and suggestions and I was naturally happy to give him some feedback and thoughts for artworks that appear in the book. Here though we are going to chat about one in particular as it’s so unusual: a fish-eye view of a group of sauropods making their way through the Morrison. One adult is using its bulk to push down and ultimately snap a tree, while Stegosaurus and Ceratosaurus appear in the background and some small pterosaurs take flight. While obviously presented one way up in the book, the image can be rotated in either direction and to any degree and should still work fine. I’m not aware of any other image quite like it, and its certainly dramatic.

Ultimately this started in Canada. Although we’d been in contact before, when I was visiting the Tyrrell as part of the “Project Daspletosaurus” work (by the way that is still ongoing, there’s a draft manuscript now and I’m working on the figures) and Julius was also down. Both of us attended the fossil preparation symposium and this gave us some good opportunities to chat in the breaks and talk palaeoart. Two things that were covered in particular are areas I have an interest in: behaviour and aspect ratios.

The former is perhaps no big surprise given my work on signaling, feeding, and similar areas. Some themes are rather understandable in palaeoart, when you’re working to commission or trying to make money, you will tend to produce things that are popular and that means lots of fighting animals, and carnivory and dramatic scenes (crossing rivers, laying eggs), but too little of things like sleeping, generally wandering around, and other behaviours that might make up most of the time of many dinosaurs and so they do tend to be rather bypassed when they would at least make a change from the endless rounds of violence that we normally see

The other one might well sound a bit odd, but it’s actually linked to the point of some things being overly familiar. Both digital art and physical art often produce works that are pretty close to A4 in proportions, and while there’s nothing wrong with that per se, personally I find things that are in odd ratios (either very long or very tall) draw the eye in a very different way and can make you see and appreciate things rather differently. Perhaps it’s just a question of personal taste, but I do really like them and think it’s worth exploring more.

I’m not sure if Julius felt the same way already, or was convinced by my magnificent and elegant arguments, but he was looking for some ideas for the book and so we went through a few possibilities and that was the last I’d head of it. We did discuss the pterosaur and squid picture a fair bit shown above, which resulted from a Solnhofen specimen at the Tyrrell I’m working on (and while we’re at it, there is a wee error in the book on this, it’s not skimming, and nor is it supposed to be) and I was occasionally asked about details on various pterosaurs and dinosaurs. Then one day, my inbox unexpectedly contained the first version of the fisheye image with a note to say it was inspired by our conversations in Alberta. It was a most pleasant surprise and at this point I’ll hand over to Julius to explain how and why he went for this particular composition.

Csotonyi_Apatosaurus_Stage-3_1000

JC: A couple of things came together to generate the unusual composition of this piece. Ultimately, I’d have to blame Dave Hone for it. When I approached him about what he’d like to see in new paleoart, since I was working on a series of new pieces for the book at the time, we had a lively discussion about both dinosaur behaviour and artistic technique. It undoubtedly helped to be surrounded by dozens of archosaur skeletons in the Royal Tyrrell Museum’s Dinosaur Hall as we did so; it makes it that much easier to imagine a heavily gesticulated reenactment of dinosaur behaviour when the bones of the subjects are staring you down from ten or twenty feet above eye level.

Dave voiced some great ideas about species interactions that had been relatively less explored by paleoartists in the past, including hypothetical tree-tippling feeding strategies of giant sauropods such as Apatosaurus. I have only seen a few reconstructions of this sort of behaviour, including an especially impactful one by paleoartist John Sibbick. However, in addition to biological subjects, Dave and I also discussed in a general context the appeal of applying unusual aspect ratios for artwork. Most of my collaboration with paleontologists involves an exchange of paleontological knowledge. The choice of the most effective artistic composition is usually left to me, though it is typically constrained by the requirements of the medium in which a piece is to be published. For example, it’s useful to keep in mind the aspect ratio of journal covers to encourage selection of a figure as cover image.

For the current paleoart book, however, there was some more room for flexibility, and I am happy to consider people’s creative ideas for composition, and Dave was eager to express his interest in a departure from the norm of presentation format. For example, we talked about some unusually long and narrow canvases as interesting ways of depicting some sweeping scenes.

The intent was to convey the huge size of the tree-tipping sauropods, so a view from a low angle looking up at looming animals seemed like a logical move. Normally, sauropods are terribly suited to depiction on low-aspect-ratio media (such as the nearly square shape of the planned book’s pages), so two solutions presented themselves: (1) foreshortening from a frontal view and (2) distortion, as from a wide-angle lens. The second option better suited the goal of depicting things in an unusual way, so I flew with it.

Csotonyi_Apatosaurus_Stage-1_1000

It then occurred to me that the most extreme wide-angle perspective distortion, showing all 360 degrees of the landscape arranged around the entire sky, would not only provide the best fit to a square page, but would also make for a very intriguing composition, with the long bodied sauropod wrapped around the image, following the curving horizon. Think of a reflective silver ball. If you were to set it down on the ground and stare into it from above, the reflection that you’d see on its surface represents the kind of image I’m describing. This was actually something that I had explored earlier in a 2005 pencil sketch of Seismosaurus (Diplodocus) and Allosaurus, and I’d been hoping to do something more substantial with it since. Well, here was the opportunity.

I chose to place one of the feet of an Apatosaurus very near to the viewer in the image, because the resulting high degree of perspective would best convey the imposing size of the sauropod. This masochistic decision naturally required calculation of the greatest amount of perspective distortion of the animal’s body, and it took quite a few drafts to figure out how to properly wrap a receding sauropod around a circularized horizon. However, I found that an even greater challenge was the assignment of the angle of incident light on surfaces throughout a painting that is governed by Non-Euclidean geometry. The path of sunbeams on the Riemannian geometry of the surface of a sphere do not appear linear when mapped onto flat representations, but as curves whose degree of curvature depends on the distance that they approach zenith (the center of the image). I overlaid on the image a kind of field diagram of light rays from the sun to various target surfaces, which helped to render not only the correct phase of objects (analogous to the phases of the moon in various positions in its orbit) but also the shapes and directions of shadows cast by these objects onto the ground.

Once the shape and lighting of the central sauropod was established, the rest of the scene was relatively easier to set up, because the remaining animals and plants were farther away, and therefore closer to the horizon, which in turn meant that they exhibited much less distortion and a narrower range of degree of light path curvature. Lacking an extensive academic artistic background, I’ve had to rely on principles of optics that I studied in physics courses during my undergraduate science program, and this project certainly required me to put some of this training to use.

Csotonyi_Apatosaurus_Stage-2_1000

DH: Obviously the result here is stunning, I’m unaware of any other piece of palaeoart that uses a perspective like this and it does show off the sauropods from a most unusual angle as well as getting in some stunning detail and including a nice piece of possible behaviour. There are some details in there two, there’s a pair of stegosaurs, a Ceratosaurus skulking in the background, and a small pterosaur overhead with a some more escaping in the background. In the book, there’s also a companion piece to this in a much more orthodox view that shows an apatosaur group also mowing down a few trees, as well as a longer and more detailed description of all the work in perspective, lighting, and techniques that have gone into this piece.

Importantly though, I think it brings something new to the table. We can grow goatees and put on berets and stroke our chins to debate the meaning of ‘art’ almost indefinitely, but this is something that goes beyond what we would normally consider palaeoart. Jon Conway has advocated the term ‘palaeontography’  for much of what we would currently term ‘palaeoart’, suggesting that (if I understand him correctly) that most works are often illustrative rather than artistic to draw a nice comparison, as with say wildlife illustration) . That’s not to criticise or dismiss any other form of palaeoart in any way, (if so, I’d be throwing out most of the Julius’s book, and the vast majority of what I’ve covered here on the Musings before) – I value the work, the skill and the aesthetics of much palaeoart (it hangs on my wall because I like looking at it), and the importance of these things for science communication or generally interesting people in the subject. Nor do I think we should stop producing mainstream works and move into things like this as a primary output.

However, there are those who I think would dismiss palaeoart as ‘merely’ illustration (I’ve seen wildlife compositions and landscapes similarly dismissed), and this piece I think provides a resounding answer to that accusation. Yes there is talent, skill and artistic merit to huge amounts of palaeoart, but if works like this can help bridge that gap and help more people take this field more seriously, well that I think is most welcome for everyone involved in palaeontology. This piece is good because the image is well composed, has a fundamental aesthetic to it, the anatomy and scientific details are accurate, and there’s a clear skill in the technique and execution to it, but it is undoubtedly also highly creative and original and worthy of some extra note.

 

 

 

 

 

 

Interview with Andrey Atuchin

Xenoceratops

Today’s palaeoart interview is with Andrey Atuchin. He has rather stormed onto the scene recently with a string of beautiful artworks, especially with some of the recent new discoveries coming out of Utah. As forever, the works here are his and used with permission so please to do not reuse them or take them without his express permission.

Lythronax

How long have you been an artist?

Frankly, I think that I have never been an artist at all. 
I drew from early childhood as far back I can remember. Maybe I had some artistic ability and my classmates often asked me to draw something, they thought that I was cool in drawing. Later I became interested in scientific illustration. The style of scientific illustration attracted me, with attention to details and scientific accuracy. I’m really fond of these books with illustrations, the encyclopedia, the catalogues of animals. I started drawing my own illustrations, just for fun. Being a teenager, I started collecting insects. Also, after reading an antique book of Professor Neumayr «Erdgeschichte» (translated Russian edition of 1903), I was interested in finding and collecting fossils. I painted beetles, which I collected and I loved to paint them as in an encyclopedia. One day I brought my drawings to the art-school and showed to teachers. I wanted them to teach me how to draw well. The teachers took me to art-school without an exam, so now I can boast a pair of years of study at an art school. I also took personal lessons in drawing.
 
Nasutoceratops
How long have you been producing paleoart?
I was interested in dinosaurs as far I can remember from my early childhood, as well as in nature, animals, space, astronomy and science in general. Once, when I was 5 or 6 years old, my older sister brought me from Moscow a set of plastic toy dinosaurs and other ancient animals (made in Poland). I remember that moment, and these animals fascinated me. 
 Lythronax2
What first got you interested in dinosaurs and art?
 In the same years, I drew my first paleoart (if I can call it that). I drew a scene where paleontologists dig a dinosaur skeleton and then lifted by helicopter. I guess I saw it on the news on TV. After that, rare books and articles in popular science magazines fueled my interest in this theme. Articles about Soviet paleontological expeditions to Mongolia, novels: “Plutonia” by Obruchev and “Lost World” by Conan Doyle. 
As for the paleoart with fleshed-out dinosaurs that I remember, the first drawings I made in 1994-95 under the influence of the film “Jurassic Park”, I think it was the Tyrannosaurus that attacks the ornithomimids. 
Translated foreign books about dinosaurs began to pass in our country, probably on a wave of popularity of dinosaurs after the movie. As I said, I loved the encyclopedias but Russian books about dinosaurs were a rarity, especially in provincial regions and in my town, I did not even know that there is such a wonderful book with pictures of Zdenek Burian somewhere. One day in the book-store I saw an amazing and terrific book – an illustrated encyclopedia of dinosaurs by Dougal Dixon. I had never seen such book: many different dinosaurs with their Latin names, colorful images, description, and most importantly – the figures of a skeletons and skulls. This book has been read so much by me that it is falling apart. So you could understand my feelings when someday I have received the offer to illustrate Dougal Dixon’s new illustrated encyclopedia of dinosaurs in 2004 . I didn’t believe it … such amazing coincidence.
The lack of books with good illustrations also prompted me to start drawing illustrations by myself. I just wanted to read a good book about dinosaurs and started drawing dinosaurs how I wanted to see them in a book. I really liked the style and technique of illustrations by Denys Ovenden and I put this style as the basis of my own artworks.
 Leninia
What is your favorite piece of paleoart that you have produced?
 I do not really like my own artworks. My trouble is that I’m a perfectionist, I am always not happy with the result. I am very self-critical yet and I would never put on the wall most of my artworks. But occasionally I like something, for example Nasutoceratops or Lythronax
 
Who is your favorite paleoartist or piece of paleoart?
 I truly love many artists. Also, now there are many new young artists and sculptors who are very talented. I was also fortunate to have the pleasure of working with some of them on joint projects, such as with Julius Csotonyi, Alain Beneteau or talented 3d artist Vlad Konstantinov. Nevertheless, my most favorite paleoartist is Douglas Henderson. The Real Genius of Paleoart in my opinion. His great works are full with the spirit of ancient landscapes, very atmospheric and always breathtaking. Animals in his paintings are an integral part of the landscape, and the scenery is majestic. This is the windows in the extinct ancient worlds.
 Europelta
What is your favorite dinosaur / archosaur?
 In fact, I do not have a favorite dinosaur or another animal. Rather, I love the groups of dinosaurs. I love hadrosaurs, ceratopsians, and abelisaurs and some others. I often and gladly draw dinosaurs from these groups for publishing.
Also, I think that my favorite dinosaur or archosaur is the one that I’m working on at the time, or one that has not been published yet and it needs to work with professional paleontologists to create the reconstruction together. This is what actually favorite for me. I make my favourite as all that I’m working on (or at least I try to). 
 
Is there any animal you would like to paint but have not?
 All of them, I think, or at least a huge amount. I now have tons of ideas in my head, but I have to admit that I’m just not able to implement them due to time constraints.
Liopleurodon_rossicus
 
What do you think is the most important part of good paleoart?
First of all it needs to study the subject, and many sciences. I know some perfect wildlife artists or scientific natural history illustrators who are professional ornithologists, entomologists or just amateur naturalists. That is the best way to do professional artwork. My biological education helps me in my work as I know the animals, their anatomy, behavior, evolution, ecology, and more. Study science books and original publications about dinosaurs. Consult with paleontologists often, and collaborate and work together with them. Sometimes I study the real bones, take part in expeditions and excavations, and prepare fossils. In fact I was a scientific researcher at first, and I have learned as an artist in the second turn to qualitatively depict animals. 
Insofar as it is an art then also a good technique is important, knowledge of composition and other artistic skills. 
Paleoart shows pictures of the distant past that is available to us only in the form of scarce fossils, so one of the main problems for any paleoartist is to produce a naturalistic depiction of the animals so that they look lively and believable to the audience. Many extinct animals look unlike modern animals, very strange and unusual, but it is above all living organisms and is necessary to represent them appropriately. 
In general the paleoart is unity, interconnection of science, paleontology and art, projected through the paleoartist’s personality.
IMG_6632

Ankylosaur!

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This place is going to be Theropod Central for a bit (until the huge volume of ceratopsians kick in), so here’s an ankylosaur to keep things ticking over. As usual, enthralled though I was with the exhibitions, I didn’t pay that much attention to the various signs or details of some of what I was looking at. As a result I don’t know all the identifications exactly and when it comes to things like these guys, well it’s hardly my best subject either.

Happily however, Victoria Arbour has just published a monster paper with Phil Currie on the taxonomy and identity of North American ankylosaurs and is also furiously blogging about it. So hop on over to her blog and start reading up on them. Handily there’s guides to the various parts of the skulls and rings of armour on the neck too which will really help out here. So while I’m obviously being too lazy to look it up myself, I’ll claim I’m inspiring readers to learn how to do it themselves.

Late edit: Victoria has joined in the comments to point out this is a nodosaur, and thus not in her review. D’oh. Still, go read her series anyway, it’s ace, and look at the pretty nodosaur skull (also ace). It is Edmontonia.

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