Sexual selection in dinosaurs, the story so far…

I have a major new paper coming tomorrow on sexual selection in dinosaurs. This is an area in which I have been extremely heavily involved in the last decade and have published numerous papers on this subject with various colleagues, writing about the underlying theory of sexual selection and how it might appear in the fossil record, providing evidence for it and actively testing hypotheses. This has also led into my working on related issues of ontogeny and social behaviour in dinosaurs which feed back into these areas to try and deal with certain aspects that came up as a result of these analyses.

Suffice to say I’m not going to go back over the whole history of my work in the field, or that of plenty of other researchers which is both relevant and important. But a little bit of context is important with respect to the coming paper because it’s something that I’ve had in my mind to do for about as long as I’ve been working on this subject but I didn’t think I’d be able to do because the dataset didn’t exist.

All of the work I have done really tried to get into answer the questions of which features of which dinosaurs may have been operating under sexual selection and can we tell. (More properly, I should say socio-sexual selection since teasing out social dominance signals from sexually selected signals is probably impossible though mostly the two are more or less synonymous in various ways so it’s not a major issue conceptually). The short answer is that really quite a lot of features probably are under some form of sexual selection. We can see this by the fact that we can rule out functional explanations for things like ceratopsian crests as being anchors for muscles attachments, radiators, or for defence because they are highly variable and / or fundamentally don’t work (Elgin et al., 2008; Hone et al., 2012). They are costly traits to grow and lug around (be they stegosaur plates or hadrosaur crests) and so clearly have a fitness cost, ruling out species recognition as a signal (Knell et al., 2012; Hone & Naish, 2013). Similarly, there is no clear pattern of differentiation among sympatric species as would be critical for a recognition trait (Knapp et al. 2018). They are highly variable both within and between species, another hallmark of sexually selected traits (Hone & Naish, 2013; O’Brien et al., 2018) and finally they grow rapidly as animals reach sexual maturity which is absolutely characteristic of sexual selection (Hone et al., 2016; O’Brien et al., 2018).

The one issue that has remained elusive in all of this is the vexed issue of dimorphism. This has proven very hard to detect for a variety of reasons, but most notably the generally small sample sizes we have for dinosaurs and the tendency for males and females to overlap in size and morphology over much of their lifespan (Hone & Mallon, 2017). To top it off, mutual sexual selection can reduce or even eliminate dimorphism making it harder still to detect and meaning even an apparent absence of it, does not mean sexual selection is not in operation (Hone et al., 2012).

It would be nice to be able to explore the issue of dimorphism in particular in more detail with an extant analogue. Plenty of comparisons have been made to various living taxa in terms of dimorphism (be it body size or major features like a crest or sail) but they run into various issues. Mammals are nice and big and often have things like horns that differ between males and females (either in shape or presence / absence), but they’re phylogenetically very distinct and have the problem of growing quickly to adult size and staying there. Lizards offer something interesting with some dimorphic species with various signal structures (like some chameleons) but then while they are reptiles, most are small and the biggest varanids have no sexually selected structures. Birds are obviously literally dinosaurs but have a mammalian-like growth and are not very big. While there’s plenty of size dimorphism in them, there are few that have obviously dimorphic traits that would show up in the skeleton (like horns).

That leaves the crocodylians, which are off to a good start. Some are very large and take a long time to grown to adult size, all are egg layers, they are sexually mature long before full size meaning they would likely express sexually selected traits while still quite small (like dinosaurs and unlike birds or mammals), and a number are also sexually dimorphic in body size. The only thing missing is some kind of sexually selected bony feature, or at least one with a clear osteological correlate.

And so to the gharials, the wonderfully weird crocodylians of the Indian subcontinent which tick every single one of these boxes right down to the growth on the snout of males, the ghara, that is absent in the females. This has long been obviously the one taxon that ticks pretty much every possible box and would provide an excellent living model to analyse and see how easy (or not) dimorphism is to detect when you have a known dataset to work from. The obvious limit to this plan is that these animals are extremely rare and most museums have few, if any, specimens. The one species that was pretty much perfect for my plans immediately fell out of contention because I couldn’t see how I could get a dataset together that would be sufficient for analysis, so the idea was shelved. Until recently…

Obviously, to be continued.

 

Papers on sexual selection, dimoprhism, socio-sexual signaling, social behaviours and related subjects in fossil reptiles:

O’Brien, D.M., Allen, C.E., Van Kleeck, M.J., Hone, D.W.E., Knell, R.J., Knapp, A., Christiansen, S., & Emlen, D.J. 2018. On the evolution of extreme structures: static scaling and the function of sexually selected signals. Animal Behaviour.

Knapp, A., Knell, R.J., Farke, A.A., Loewen, M.A., & Hone, D.W.E. 2018. Patterns of divergence in the morphology of ceratopsian dinosaurs: sympatry is not a driver of ornament evolution. Proceedings of the Royal Society, Series B.

Hone, D.W.E., & Mallon, J.C. 2017. Protracted growth impedes the detection of sexual dimorphism in non-avian dinosaurs. Palaeontology, 60: 535-545.

Hone, D.W.E., Wood, D., & Knell, R.J. 2016. Positive allometry for exaggerated structures in the ceratopsian dinosaur Protoceratops andrewsi supports socio-sexual signaling. Palaeontologia Electronica, 19.1.5A.

Hone, D.W.E. & Faulkes, C.J. 2014. A proposed framework for establishing and evaluating hypotheses about the behaviour of extinct organisms. Journal of Zoology, 292: 260-267.

Hone, D.W.E., & Naish, D. 2013. The ‘species recognition hypothesis’ does not explain the presence and evolution of exaggerated structures in non-avialan dinosaurs. Journal of Zoology, 290: 172-180.

Knell, R., Naish, D., Tompkins, J.L. & Hone, D.W.E. 2013. Is sexual selection defined by dimorphism alone? A reply to Padian & Horner. Trends in Ecology & Evolution, 28: 250-251.

Knell, R., Naish, D., Tompkins, J.L. & Hone, D.W.E. 2013. Sexual selection in prehistoric animals: detection and implications. Trends in Ecology and Evolution, 28: 38-47.

Hone, D.W.E., Naish, D. & Cuthill, I.C. 2012. Does mutual sexual selection explain the evolution of head crests in pterosaurs and dinosaurs? Lethaia, 45: 139-156.

Taylor, M.T., Hone, D.W.E., Wedel, M.J. & Naish, D. 2011. The long necks of sauropods did not evolve primarily through sexual selection. Journal of Zoology, 285: 150-161.

Elgin, R.A., Grau, C., Palmer, C., Hone, D.W.E., Greenwell, D. & Benton, M.J. 2008. Aerodynamic characters of the cranial crest in Pteranodon. Zitteliana B, 28: 169-176.

 

 

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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.

10. 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

11. 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.

Can we make pterosaur planes yet?

Short answer, no, longer answer, maybe one day but there is at least some cool potential here. That’s the basic gist of a new paper I have out today with Liz Martin-Silverstone and Mike Habib on flight in the fossil record and its implications for aircraft design.

Back in the earliest days of human-powered flight there was an inevitable draw to birds for inspiration as heavier than air fliers, and there’s more than enough videos of cranky machines flopping around on their wings failing to get off the ground if you are into that sort of thing. Aerospace technology has moved on though and bird-like flying machines (called ornithopters) do now exist. More and more technology takes inspiration from living organisms (biomemetics, bioinspired tech) and when it comes to flight, so often at the forefront of engineering, this has included all manner of bits of bird and feather-like features. Bats have played a lesser role too and insects are increasingly looked at since now aircraft do not have to have pilots and remote controlled craft, drones, autonomous vehicles (and plenty of other names and acronyms) are increasing in number and diversifying in form.

Amidst all of this, the fossil record goes almost unnoticed. Flying organisms have all manner of adaptations for weight reduction, streamlining, ways of manipulating lift, drag and control and of structural support with unusual forces and combining issues like take-off and landing on usual surfaces with having to actually fly. They provide known working models that can be directly copies and mimicked, or at least used as a starting point to investigate ideas. Given the plethora of flying animals in the fossil record (both gliders and powered fliers) that have no living analogues, these would seem an excellent place to seek out new technological innovations and ideas and the idea of this paper is to try and trigger some interest in this. True, people have looked at pterosaur flight, though mostly to see how pterosaurs might have flown. Only a very limited amount of work has been done looking at these as possible aircraft models and even then it’s been holistic with no real look at the details of wing construction or control. And this is just one clade and ignores things like Yi, with its combination of membranes and feathers, Microraptor with its multiple control surfaces, Sharovipteryx the delta-winged glider and others.

The paper is short though and writing such a piece that is trying to work for engineers with potentially little knowledge of biology, biomechanicists with little knowledge of palaeontology and palaeontologists with little knowledge of either. As a result, it’s rather superficial in terms of its treatment of many ideas and concepts despite a vast amount of cited literature (we had to get dispensation for the editor to include so many and the referees were still unhappy and wanted more) but it does hopefully provide some real information and ideas for these three groups of researchers to come together and make use of the palaeontological resources at their disposal.

So while we might not see any pterosaur-based drones around anytime soon (or indeed ever) we hopefully will see considerably more interest in flying animals in the fossil record on all sides and this certainly has the potential to feed back into new designs. I’d obviously love to see an azhdarchid drone that can walk, run, launch and fly but even seeing something like an anctinofibril-based system of wing warping or pteroid-supported propatagium would be super cool. Stanger bits of the biological world have been looked at for engineering and hopefully various fossils will become a part of this in the near future.

 

Martin-Silverstone, E., Habib, M.B., & Hone, D.W.E. 2020. Volant fossil vertebrates: potential for bioinspired flight technology. Trends in Ecology and Evolution.

Note: this has gone live a week earlier than we were told to expect and the version out there is currently the uncorrected proof, and while we didn’t make any substantive changes, a better version of this should follow.

Big wings in the Solnhofen

The Solnhofen limestones of Bavaria are famous for their well-preserved fossils and for a pterosaurs researcher, the plethora of specimens and taxa that are represented. Finds continue to this day and we now have more species known from more specimens than ever before, including from a variety of a branches of the pterosaurian tree. The Late Jurassic was an interesting time with the pterodactyloids diversifying, the non-pterodactyloids soon to fade (though doing pretty well) and a few intermediates (wukongopterids, or if you prefer, darwinopterids) are still about. One thing that is true of all of them though is that they are not very big.

While later pterosaurs are famous for producing numerous lineages with wingspans well in excess of 4 and 5 meters and all the way up to 10, before the Cretaceous, there’s basically nothing that even gets up to 2 m in wingspan, and even those tend to be relative giants and quite rare. This is especially true of the Jurassic pterodactyloids which really don’t seem to have got going yet in the size stakes. However, there are some tanatalising hints of bigger individuals or even big species with various bits of limb elements (and slightly bizarrely, some isolated but articulated feet). Not much has been done with these in part because they tend to be very incomplete.

However, quite a few years ago now, Dino Frey at the Karlshue museum in Germany acquired a complete and articulated wing of a large Solnhofen pterodactyloid. It was much bigger than any other known complete wing and it eventually feel to Ross Elgin (then a PhD student under Dino and myself) to work on. We started on this and worked up a manuscript and then sometime later I happened to be in Berlin and spotted on the wall of the collections, another, equally large (though rather less complete and less well preserved) Solnhofen wing. This has apparently sat all but ignored for many years and as far as we can tell, it’s never featured in any paper or been referred to before. So now we had two wings to describe, each of which would have been from an animal with a wingspan of just over 2 m and they turned out to be pretty similar to each other, but what were they?

Working out what they were took some work. After all, it’s perfectly possible that these represent known taxa, but are merely unusually large individuals. And with only the wings to go from, a lot of the anatomical data you would normally want from the skull or some gross proportions of the neck, legs and so on are missing. To make it more awkward, we don’t have a great understanding of the growth patterns of many pterosaurs so it’s not obviously what the trajectories might be of the rarer species where we have only a few specimens.

Looking in detail at our two wings and various other larger Solnhofen pterodactyloids and other isolated large wings showed that these two new ones are different to each other and there are likely two different ‘big wing’ morphs present. A number of major pterodactyloid clades are either around or at least suspected to be present in the Jurassic, and so there was a wide range of possible candidates. However, the anatomy present ruled out most of them (ornithocheiroids, istiodactyloids, azhdarchoids) though it did leave the identity uncertain and they could be ctenochasmatids or very early dsungaripterids.

So while we don’t know exactly what we have here (and we suspect there’s a new taxon in this material based on some unusual features of the Karlsruhe specimen) it is still interesting stuff. We now have a good record of all the largest Jurassic pterodactyloids and clear evidence of animals of over 2 m wingspan. We also have much more detailed information on their anatomy and while the exact identities are uncertain, it looks like there is more diversity here than previously realised and that there are more taxa to be discovered. New specimens are still being uncovered in the Solnhofen so hopefully it is only a matter of time until we have complete, large, pterodactyloids before the Cretaceous.

The paper is open access and fully available here.

Elgin, R.A. & Hone, D.W.E. 2020. A review of two large Jurassic pterodactyloid specimens from the Solnhofen of southern Germany. Palaeontologica Electronica.

Toronto Zoo

Snow leopard

Take a long drive (or in my case, an interminable bus ride at the end of a subway line) north of Toronto and you eventually come to the zoo. Thus despite the name this is not a city zoo but one very much out in, and even beyond, the suburbs (wild turkeys were present alongside the bison for example). As such it’s a very large zoo, which is always nice when it means that the larger animals have a lot of space but be prepared for a good workout with some decent hills thrown in too.

One nice hallmark of the zoo was the extensive collection of ‘local’ species – groups of both prairie bison and the wood bison subspecies (your definitions may vary), moose, bobcat, wolves, polar bear, snowy owls and Arctic fox (a new species for me) and others were all present and correct. Indeed, the polar bears were about as well kept as I’ve ever seen and one in particular was taking great delight in sliding down the snowy banks of the hill in its enclosure and rolling around in the snow. Much as LA Zoo makes great use of the local weather to keep lots of tropical species outside, Toronto does well in the same vein with cold weather species with things like snow leopards and ibex in addition to the Canadian animals.

Giant African soft-shell

They do though also have lots of more ‘traditional’ species and it’s rather neat to see white lions, rhinos and hyenas in the snow. Of particular interest though were the several walk-through tropical and temperate houses that had some especially neat animals. One house was linked to various species that had access inside and out including relative locals like beaver (sadly not visible) and grey shrike. It was especially cool to see the extremely rare black footed ferret though this spot was tempered somewhat by the fact that it was only visible as a sleeping ball of fluff.

I also got to tag some other species that have loomed a long time on my list of animals I wanted to see. First off was a pair of wombats which were everything I’d wanted and even were good enough to move around a bit and nearby in the Australian section were some galah cockatoos which was neat to see too. Sadly, the allegedly existing but not actually visible short-beaked echidna repeated the trick of it’s conspecific in the Berlin Tierpark and was underground and invisible.

Tentacled snake

On the upside though I did get two more stellar reptiles and both in the larger walk-through house that included pygmy hippos, crocodiles and numerous birds. First off a tentacled snake which was kind enough to sit near the glass allowing me to get a decent photo of this essentially aquatic animal. The second was another aquatic specialist, an African soft shelled terrapin. It was a huge one and much larger than I’d expected and was sat out on the bank but did extend and retract its neck which was fascinating to watch.

All in all, it’s a very good zoo, but be prepared for a long day and a decent hike. Even skipping some of the more distant parts of the zoo will still involve a healthy bit of exercise but it’s a great collection and, rarely, one that is very rewarding to visit in the deep of winter.

Wombat!

 

 

 

A little more Luchibang

Life reconstruction of Luchibang by Matt Van Rooijen

After the previous mammoth post on the long and painful history of the publication of the new paper, I still wanted to write a little more about the specimen and what we have learned. As noted in the first post this specimen is preserved alongside a couple of fish and apparently has some soft tissues associated with it.

The istiodactylids are one of those groups where their ecology has been very uncertain with a variety of activities suggested. Based on their affinities with the highly piscivorous ornithocheiroids it’s been suggested they were fish eaters, though their teeth don’t look well suited to catching fish at all, and that little cluster of interdigitating and cutting teeth has been used to put them forwards as scavengers. That doesn’t sit too well either since they appear to generally be quite aquatic in their habits and while we have a great many birds that are specialist scavengers today, none of them are marine soarers.

Luchibang doesn’t actually help resolve this much. While it’s limb proportions and especially long legs point to greater terrestrial competence and might point to an animal that is therefore scavenging more, it’s also preserved with two fish specimens. One of these is down and under the ribs and apparently in the ribcage. In the paper we are cautious over this specimen as small fish are commonly associated with these kinds of Liaoning specimens (indeed, there’s one already here by the head which clearly wasn’t’ eaten) but it is certainly possible that it represented preserved stomach contents.

So we can provide some tentative evidence to support both scavenging and piscivory in this animal (and of course these are not mutually exclusive positions) and so while what we have here is interesting it doesn’t resolve much. This uncertainty is reflected in the very nice life reconstruction that Matt Van Rooijen kindly did for the paper (quite a few years ago now, he’s been sat on it a while!). In the foreground Luchibang is wading in the shallow waters and grabbing a fish while nearby is the carcass of an iguanodontian which is available as an alternate source of sustenance.

One last thing to comment on is the preservation of soft material on the specimen that we interpret as soft tissues. It is really rather poorly preserved and is little more than some stains on the rock but with some regular patterning and shape that appears to be organic. There are several spots and they all look similar and are associated with the skull, the neck and the ulnae. They don’t appear to be parts of the wings suggesting these are skin traces. There’s no indications of any pycnofibers but then, assuming these are soft tissues, they are rather decayed.

That’s quite enough on Luchibang for now, the paper is fully open access so you can read the full description and discussion there. This only leaves me to thank Matt for his artwork, my coauthors and the referees and editors on this paper.

 

 

Ten years in the making of Luchibang

Some research papers can take a long time to finish and delays for all kinds of reasons can put projects on hold indefinitely or even kill them eventually. Luchibang has a particularly long lead up time but the history of this description and naming take in a whole bunch of issues over publication which are informative and important.

To begin at the beginning, way back sometime around 2010 (or possibly even 2009) while I was doing my postdoc at the IVPP, Xu Xing came to my office and asked me to look at a pterosaur specimen. A colleague of his was looking to acquire it for a museum and had been assured it was a new taxon but wanted confirmation. It was, of course, what has become the holotype of Luchibang, and it was immediately obvious that this was unusual and new with the large legs and somewhat odd tooth arrangement and so after a few minutes of checking various details and cross referencing with a few papers, the curator left happy.

A few months later the specimen was back as I’d been invited to describe it. I really hadn’t expected the opportunity and was delighted to do so and so set about the task of doing a full description. I didn’t include a phylogenetic analysis for a number of reasons, but notably as the specimen was so clearly an istiodactylid and their own relationships were rather unresolved, adding what was obviously a juvenile into the mix would have been a fair bit of work to not actually add any real information.

Looking through my files this was submitted sometime in late 2010 or early 2011. The paper came back from review after a time when I had left China and was now in Ireland, with one referee liking it a lot, but with the other review came a bombshell. They through the specimen might be a composite.

This was obviously a huge problem because first, I was worried it genuinely was and I’d somehow missed this and second because now I was back in Europe the specimen was hardly easy to access, and proving it was genuine was going to be tough. The referee pointed to the unusual hindlimbs and what they thought were unusually long cervical vertebrae and suggested this was an azhdarchid body on an istiodactylid head. My lack of phylogeny had also come back to haunt me as they suggested an analysis where the head and body were coded separately should reveal what respective animals they might come from. It then took me about three years to be able to begin to resolve this issue. Eventually I did get back to see the specimen and was able to do the most important thing to show it was genuine – to reprepare bits of it myself by hand.

The matrix and even the bone vary quite a lot in the specimen and that’s quite common in various specimens from Liaoning so this itself was no concern. It was suggested UV photographs might reveal any shenanigans, but work Helmut Tischlinger and I had done on several specimens at the IVPP showed that even those collected and prepared by the museum could show dramatically variable reflectance on single slabs and this would be unreliable in this situation (not that Helmut was around at the time either!). So instead I set to the specimen with some picks and carefully chipped away at the matrix at various points on the specimen where the head met the body. There was no glue, no cracks, no joins, no restoration, only natural and original sediments. Checking the margins of the slab also showed no cracks or joins where a piece could have been incised into the rest of the specimen and again, no traces of glue or other tampering at the margins. The very tip of the snout also is broken off at the margin of the specimen which helps trace the bones to the very edges. Critically, if you look closely it’s also clear that every part of the main skeleton is in direct contact to another part. The bones of the skull actually touch those of the neck, which contact those of the wings and chest, which contact the legs. If the head had been added to the specimen, it has been done to make the bones touch each other and even merge with each other (this happens on flattened specimens) and with no joins between them under preparation. In short, this must be genuine.

I have seen plenty of faked, and otherwise ‘improved’ specimens at various times and they are never even close to looking convincing once you study them in detail (and most are not convincing at all) and there’s some other circumstantial evidence to support his being genuine. Despite the odd loss of the back of the head, we’d expect in such a juvenile animal that the skull bones would not be fused together and so the ontogenetic status of the head does match the body and the proportions are about right too. It seems unlikely that not only were people able to insert a skull perfectly onto a postcranium but did so with an animal of the right size and growth stage (and why would they not put in a complete skull at that?). Minor points compared to the lack of evidence for any tampering, but all suggesting a genuine specimen.

Despite the lack of a phylogeny, I now wrote to the editor of the journal and pointed out that I was now able to confirm that the specimen was genuine. I’d been able to show that some of the alleged azhdarchid traits were actually shared with some ornithocherids too reducing that side of the equation, and I had even had a PhD student who was in China at the time do some prep themselves and confirm my observations and was able to have them send a supporting letter to support this. To my dismay, despite having previously agreed this would be sufficient, the editor now said they didn’t think it was enough to support publication of the specimen and they wanted to see some systematics.

I no longer had access to my systematics programs and while a couple of times I approached potential coauthors to help me run some phylogenetics, no one with the expertise I needed had the time. With my career now changing and my having less and less time for such work and the frustration of the delays the whole project fell to one side. I couldn’t convince the editor and didn’t have the time to do the new analyses and couldn’t get help with it. I didn’t abandon it, but nor did I think it was ever going to get done. I also had doubts about being about to convince any other referees or journals about the specimen so didn’t want to invest time and just have the paper bounce from journal to journal.

Then came the most recent Flugsaurier conference in LA and this coincided with my having a bit of free time. I decided this would be a great opportunity for a test case – I could present the specimen to a whole raft of researchers and lay out everything as I’ve done here and see what people said. After all, various experts on istiodactylids, ornithocheirds and azhdarchids would be there and the collective knowledge in the room would be greater than mine and a couple of coauthors and referees. In creating the talk, I was also able to delve back into the pterosaurian literature and with many years of new papers and in particular phylogenies meaning there were lots of new traits described and defined that could be used to support various taxonomic affinities. This really helped as I could now also find more traits in both the vertebrae and even the long legs that were clearly ornothocheiroid in nature and not azhdarchoid.

To my delight the audience was very receptive to the idea and only one person flagged a single trait that they thought might compromise my diagnosis as it should be present but didn’t appear to be. Talking to them more about it afterward and going through some photos we were able to establish that this was there as well and the apparent last of the questions over the possibility of any fakery were removed. Still though, a phylogeny would be nice and at this meeting I met Adam Fitch who was playing with pterosaur phylogenetics and had the time to get involved. We ran analyses to show that both the head and postcranium independently clustered with other ornithocheirids and I wrote a section to provide the evidence that the specimen was genuine. So the paper was dragged out into the light, got updated and revised and had a new phylogeny added that Adam and I produced. And so, submission and plain sailing to publication.

If only.

The first journal we sent it to rejected it with a long review pointing out that we really shouldn’t have included a lot of information showing the specimen was genuine. If there was any question about it, it shouldn’t be published at all, so we should take that information out. So the paper was revised, the material relegated to the supplementary information and onto the next journal.

This time it got rejected with the referee noting that the specimen either was actually a weird toothed azhdarchid or might not be genuine and we should include a clear explanation as to why we thought it was. They clearly hadn’t read the supplementary info with several pages of material on this exact subject or considered that maybe the long list of traits that we showed were homologies of ornithocheirids and istiodactylids. To make it worse, that same person then phoned me a couple of months later to say they’d seen a very similar specimen in another lab in China. So not only is there allegedly another one out there (making this seem more likely to be genuine) but now after all this time we might get eaten to the punch by another lab while we were being rejected for publication based on the review of a person now telling me they thought it was genuine.

So, we submitted to Palaeontological Electronica. It meant we could include lots of colour images and come out with an OA publication and importantly they require a four week turn around for reviews. Of course the paper then sat with the journal for nearly four months and several e-mails went ignored by an editor which only added to the frustration. During this time a new istiodactylid was published from China and then a near-complete specimen of the very closely related Mimodactylus meaning the paper managed to get out of date more in 3 months in review than it had in a 10-year hiatus. Eventually the reviews came back and the only substantive comments from the referees were that we should include the taxa which had just come out while our paper was in review. That meant redoing the phylogenetic analysis which wasn’t trivial (and it yielded effectively identical results), but we were able to return the paper fairly swiftly and now it’s finally out.

Hopefully this goes a very long way to explaining the various dips and delays in taking this specimen from first penning a description a decade ago to coming out now. Self-imposed breaks, unavoidable delays in accessing the specimen while on the wrong side of the world, other commitments, and recalcitrant referees and editors have all played a part. Establishing that the specimen is genuine was obviously important once the spectre had been raised, and it clearly improved the paper by forcing me to refine my arguments and make more detailed comparisons with various other taxa and by delving deeper into their anatomies. That said, it was a huge issue I could have done without and the timing could not have been worse as I’d just left China. This is though, the end of the tale now that the specimen is published, but there’s still more blog to come on the wonderful (and rather late) Luchibang.

A long overdue welcome to Luchibang

 

Luchibang has arrived

Today sees the publication of a new pterosaur that has been a very long time in coming. There’s a hell of a lot to unpack here with both the animal itself and the history of the research so this is going to take quite some time to get through. So, here’s the start of a lot of information on this really rather unusual animal.

First off, this is an istiodactylid. These are a branch of the pretty familiar ornithocheiroids which include things like Anhanguera and Ornithocheirus and (according to most researchers) aare close to Pteranodon too. In short, a group of medium to large sized, ocean-going fish eaters, many of which have lots of large grabby teeth to go with big wings and small legs. The istiodactylids are really rather unusual in that they have only a few small teeth at the front of the jaws and they also have giant fenestrae in the skulls which makes them very recognisable. Apart from the eponymous British Istiodactylus, they are all known from China which has really quite a diversity of them though in varying degrees of completeness. This is another specimen attributed to the Yixian Formation and its diverse pterosaur biota.

Luchibang immediately becomes important as it’s by far the most complete known istiodactylid. It is, unfortunately, crushed nearly flat, but apart from the back of the skull, the tail and few tiny bits, everything is there. There’s even rare elements like the gastralia and sternum in good condition and there’s not too much overlap of bones meaning everything is visible (though often at odd angles). The loss of the back of the head is especially annoying but otherwise this is an exceptional specimen. This alone would make it important but it also has some patches of what may be soft tissues in places and it’s also apparently got a fish preserved in the chest cavity (more on this later). One top of that, it’s also really big, or at least would have got bigger. The specimen is about 2 m or so in wingspan but it is also a very young animal. One of the major fusions of various elements that we see even in some relatively young pterosaurs, let along subadults or adults, are present and so this animal would have been considerably larger at adult, perhaps being one of the largest istiodactylids.

The skull and upper body of Luchibang xinghe

If you take more than a quick glance, it quickly becomes clear that while Luchibang has the incredibly typical head and tooth arrangement of istiodactylids, it’s also got a few very odd features. Most obviously, the hindlegs are really long and the feet are very big. Although rather incomplete, there is no evidence for anything like these proportions in other istiodactylids or the ornithocheiroids as a whole and marks it out as being quite unusual. In fact, when we plot out the proportions of the fore and hindlimbs, Luchibang plots over with the azhdarchoids rather than other ornithocheirids and otherwise the two groups are quite distinct in their anatomical arrangements.

This rather strongly suggests that Luchibang is doing something rather unusual and was much more terrestrially capable than its relatives and also then led to its name. Luchibang translates from Chinese as the ‘heron wing’ to convey the apparent heron-like attributed of long legs and catching fish, with the species name xingzhe meaning ‘walker’ also relating to this. Although this name was first created many years ago, while this manuscript was making its way through development hell, the pterosaur community lost palaeontologist Lü Junchang. JC, as he was generally known, was a friend and collaborator on various pterosaur projects and so this new taxon then became a great opportunity to honour his work and his memory and so the etymology formally recognises him too.

So, welcome JC’s walking heron wing, and in the next post I’ll talk some more about the long and tortured history of this publication which dates back a full decade.

 

Hone, D.W.E., Fitch, A.J., Ma, F., & Xu, X. 2020. An unusual new genus of istiodactylid pterosaur from China based on a near complete specimen. Palaeontologica Electronica.*

 

*Yes, there’s an error in the abstract with their weird hanging ‘postcranial’ in the last line. We asked the journal to remove it at the proofs stage but they refused because it had already gone for translation, so we can’t fix it. Feel free to mentally delete it yourself. And the ‘original’ planned species name of ‘wuke’ has managed to sneak through the proofing process and appears in Fig 8. Annoying and stupid but doesn’t affect the taxonomy, though it means I’ve effectievbly accidentally created a nomen nudum.

Sauropod digestion suggestion

I do not normally go in for speculative pieces on the blog and when I have ideas about Mesozoic biology I tend to try and get an excuse to write a paper about them or consult with some colleagues and see what merit the ideas may have. But something popped into my head the other day and it’s been rattling around and I thought it would be fun to put it out there into internet land.

First off, I’ll preface what follows with the important point I’m no real expert on the details of sauropod physiology and digestive biology. So it’s quite possible that I’ve missed some major discussions on this in the literature (or online) be it that the idea is already out there and this isn’t new, or it’s already been discussed and dismissed. I’d also add that while I’ll discuss sauropods here, the central issue may also apply to sauropodomorphs, various other ornithischians and potentially even the bigger herbivorous theropods. I’ll try and boil down the argument as simply as possible, though of course I’m deliberately skipping a lot of nuance.

In short:

Big sauropods would need to eat a lot but allowing for thermal inertia, long digestion times with higher efficiency, and reduced metabolism at large size they have the potential to function without eating 24 hours a day.

For juveniles though, they lack some of these benefits and especially would not have the benefits of long digestion times to break down tough plants. They’d have (proportionally) higher metabolisms and would be getting less return from what they ate.

One solution to this would be coprophagy. And yes, that is what you think it is.

Elephants are a good example here (well without the XXXXeating bit) since they eat a lot of rough material like dried grasses and tree bark. They are bulk feeders cramming everything in, stripping out the nutrition they can and moving on. I was warned years ago when working at a zoo that if offered an apple when visiting the elephant house not to take it. Apparently these occasionally passed through untouched and then would be handed out to unknowing guests. The point is, elephant dung contains a lot of undigested material. If you are a young sauropod, something like that which has already passed through your system and is starting to be broken down could, second time round me a lot more nutritious. And you don’t have to go anywhere to find it, it’s a ready source of calories right there.

That really is the limit of my suggestion. As I say, I suspect I’ve missed something important but I can see an obvious few benefits from this and there’s a good few animals that go in for this practice so it has plenty of precedent. I recognise that reptile and bird waste is often very different from mammals, but then we don’t have many 5 ton lizards that eat ferns around for a comparison and the waste of large tortoises certain can contain plenty of grass shards.

Thoughts below, and if I’ve stumbled across a good idea here I’d be happy to try and expand on it.

Late 2019 roundup

I do try to do a roundup of each year and even with the Musings being more and more infrequently updated, I wanted to keep this up. The year has been very slow so not too much has happened in terms of publications or other news and the major even (the naming of Cryodrakon) I did manage to give some good coverage. My only other publication was a response paper written with Tom Holtz that argued (again) that some of the evidence suggested for highly aquatic lifestyles of various spinosaurs are overstated or at least much more complex than sometimes stated. Once again (see also adult dinosaurs, social behaviour etc.) this is at least in part an issue of definitions and the turn of phrase ‘semi aquatic’ which covers a vast range of behaviours and selective pressures and degrees of adaptation being used without anything like enough specificity.

I do now have a whole bunch of papers in review and a couple that are (provisionally at least) accepted and should be out this year, and so while the Musings is likely to carry on being generally quiet there will be some research to talk about with any luck. Most of that will be pterosaurian in nature but there’s some dinosaur stuff in the works as well.

Also coming at some indeterminate point are some new books. I’ve all but finished a first draft for my next popular science book that should be out sometime this year (probably late autumn) and I’m also involved in a couple of others so stay tuned.

In the meantime I am still posting photographs and micro-updates on projects on my Facebook page and this is the best place to keep up day to day, but I’ve no intention of shutting down the blog even if the posts will be sporadic.

Happy New Year.

 

 

Hone, D.W., Habib, M.B. and Therrien, F., 2019. Cryodrakon boreas, gen. et sp. nov., a Late Cretaceous Canadian Azhdarchid Pterosaur. Journal of Vertebrate Paleontology, 39(3), p.e1649681.

Hone, D.W.E. and Holtz T.R., 2019. Comment on: Aquatic adaptation in the skull of carnivorous dinosaurs (Theropoda: Spinosauridae) and the evolution of aquatic habits in spinosaurids. 93: 275-284. Cretaceous Research.

Many more Cryodrakon images

Scavening on a dead Cryodrakon by Mark Witton

Chatting to Mark Witton the other day it transpired that artwork of Cryodrakon has already existed for some year. Large azhdarchids would have been a decent meal for small scavengers and we know of at least two incidences of dromaeosaurs eating them, one of which being the holotype of Cryodrakon (the other was Velociraptor I described with a pterosaur bone in it). The above piece was done in reference to this but Mark told me his point was to specifically reference the Canadian specimen which only now has a name.

I’m sure there’s other artworks out there that similarly were based on this northern ‘Quetzalcoatlus’ and would now refer to Cryodrakon, but almost inevitably once the paper came out there was a rush on to produce new images that rapidly appeared online alongside the ‘official’ artwork of David Maas. Here are a few of those.

Cryodrakon attacks a dromaeosaur by Gabriel Uguerto

First off is that by Gabriel Uguerto and this one is a bit of a cheat perhaps because he drew it for me as a commission but I’m delighted to have the original and it’s nice to see an azhdarchid giving something back to the theropods and not just being eaten by them or only following what is now a meme and eating baby sauropods.

Cryodrakon skeletal (full sized) by Dean Schnabel

There are already skeletal outlines appearing for Cryodrakon too. Dean Schnabel (who goes under the pseudonym of Sassy Palaeo Nerd on Deviant Art and Twitter) has produced two. One of all the known material scaled to the incomplete giant cervical (above) and a second that is just the holotype material at the correct size for that specimen (below).

Cryodrakon skeletal (holotype only) by Dean Schnabel

Finally, Joschua Knüppe put out this black one on an especially snowy background. While on the subject of snow, it’s popping up a lot I artworks already. The name Cryodrakon was intended to invoke Alberta as it is now rather than when the animal was alive when it was semi-tropical. That doesn’t though mean that snow is wrong (indeed David Maas sneaked a bit into one of his images) as even the warmest places will get snowfall on occasion and azhdarchids generally could fly long distance and the newly forming Rocky Mountains were not far away. I’m sure on occasion Cryodrakon ended up striding through snow and flying over white landscapes even if it wasn’t the norm.

Cryodrakon in the snow by Joschua Knüppe

These are not the only ones out there, a quick google will reveal a wealth of alternate takes on Instagram, Deviant Art and elsewhere (alongside a load of older rebadged art that various media organisations stumbled to produce and plenty of versions of David’s work, often inappropriately rebadged with someone else’s watermark). More I’m sure are coming but it’s nice to see your own scientific work reach out into people’s imaginations and artistic efforts.

 

Coda: I spoke to all the artists about linking to their work before putting them up here.

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).