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The pterosaur uropatagium

Published 16/09/2025 Uncategorized 9 Comments

Pterosaurs have three parts to their wings. There’s the big ‘main’ wing (the brachiopatagium) that goes from the tip of the fourth finger down to the ankle, there’s the little propatagium that sits in the crux of the elbow and is supported by the pteroid bone, and then there’s the uropatagium (or sometimes cruropatagium) which sits between the legs.

The brachiopatagium gets all the attention and for good reason, it makes up most of the wing, and it’s the most commonly preserved, and we know a lot about it already including some remarkable details of the stiffening fibers, muscle fascia layers and the potential for airsacs to be embedded in them. The propatagium is perhaps the rarest to preserve, but given that it’s shape is largely controlled by the size and shape and orientation of the pteroid, and we have a good handle on that, it’s not a very contentious issue. The uropatagium on the other hand has been an issue for a very long time with all manner of arguments about its size, shape, structure and how it varied between lineages. And so my new paper out today with Edina Prondvai, is a long overdue review of the information we have on this unusual bit of the flight apparatus.

Lots has been written about this before, but the information is scattered across numerous papers and reinterpretations of interpretations which means that things are, at best, rather unclear and at worst actively contradictory – even for single specimens. This doesn’t mean that our work is the definitive or correct version, but hopefully it at least brings everything together and makes it all as clear as possible. I would say the main conclusions we came to on just about everything would really fit with the general current consensus anyway, there’s nothing heterodox here, but as ever, clarity is important!

So, the really short version (of what is really quite a long and detailed paper) is that there are two basic plans for the uropatagium. First is the classic non-pterodactyloid version that is large and sits between the legs, being attached on both sides down to the ankle and supported by the long fifth toe, and is also attached to the tail in the midline. The derived pterodactyloid condition has a split uropatagium, so it’s really a pair rather than a single sheet, with each side sitting in the crux of the leg, down to a now reduced fifth toe and probably terminating at the base of the tail in the midline. Like the brachipatagium (but possibly unlike the propatagium), the uropatagium does have some stiffening fibers present in it, but they only turn up in a few specimens so might not always be present or be generally thinner and less likely to preserve.

This really is the big overall conclusion of the work, and it may not seem like a lot, especially when a lot of this is hardly news. It’s also though still rather sparse overall, we really don’t have that many of these membranes preserved and most of them are for non-pterodactyloids. Even the pterodactyloids we do have are all ctenochasmatoids meaning the data only covers one branch of the pterodactyloid tree and only for specimens from the Jurassic. So, we don’t really know what is going on in any other pterodactyloid lineage or in the Cretaceous as a whole. Based on the shape and structure of the fifth toe and tail in these animals, it’s reasonable to infer that the pattern it is probably very common if not universal for pterodactlyoids, but we don’t actually know.

Although they are obviously quite different animals in a lot of ways, it is notable that the bats show a much greater variety of uropatagial shapes and attachment patterns than do the pterosaurs with varying degrees of attachment to the tail and their calcar (an ankle bone analogous to the pterosaurian fifth toe). That’s despite the fact that pterosaurs clearly have a lot more variation going in terms of size at least compared to bats, and arguably in some other features like terrestrial ability and adoption of marine habitats. In other words, if the relatively ecologically conservative bats have a whole bunch of uropatagial shapes that have evolved in the last 50 million years, how likely is it that the pterosaurs only really had two (plus a probable intermediate shape in something like Skiphosoura) across their much great ranges of size, habits and time? The obvious answer is that of course we don’t know, but it does at least suggest that we might be missing a few odd versions, with the anurognathids being a clear case that seem to combine a long toe and short tail, but their uropatagia are very poorly preserved. The flipside of this argument is that the other wings seem to be incredibly conservative, so maybe this variation we are seeing in the uropatagium is actually quite a bit in context. It’s the sort of thing we can’t easily solve without more specimens.

As I say, there’s a lot more in this long paper. But I’ll also close with saying that it’s taken a while to get here, this project was started at least 15 years ago and was supposed to be a partner to the paper I did with Ross Elgin and Dino Frey on the brachiopatagium that came out in 2011, so it’s been in gestation for quite a while. But good data doesn’t date, and this has been an ongoing source of contention so while it’s taken us quite some time, it’s been great to dust it off and finally get it out. This may also give a little hope to anyone who has had a project stuck for a while that it can still come out one day.

The full paper is available here: HONE DWE & PRONDVAI E. 2025. The shape, structure, function, and evolution of the pterosaurian uropatagium. An Acad Bras Cienc 97: e20250129. DOI 10.1590/0001-3765202520250129.

The Jurassic Park Franchise is Repetitive, Boring and Repetitive

Published 08/07/2025 Uncategorized 6 Comments
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Jurassic World Rebirth is now out. I’ve not seen it yet, but all the indications are that it will be another summer blockbuster than will rake in a ton of cash and then presumably in another two years we’ll have the next instalment of this incredibly lucrative franchise. And yet, it’s increasingly hard for me to feel anything other than fatigue about this series.

You may reasonably assume that this is because I am a palaeontologist, and moreover one who does a lot of work on outreach and scientific communication, and so when by far the most prominent piece of pop culture on prehistoric life hits, I’m inevitably going to be swamped with questions about how these animals looked and acted. To be clear, this is an issue, though not my primary one. The original Jurassic Park movie in 1993 really helped to bring depictions of dinosaurs up to date, no longer were they tail-dragging, slow-moving (and slower of thought) monsters, but quick, agile, and even smart animals, perfectly capable of running around in the rain and dark and not forced to sit out in a desert for warmth or chest deep in water to support their bulk.

In that regard at least, this was a massive milestone, and so it’s frustrating that not only have the films not really stayed up to date with modern science about these animals, but in places they have actively gone backwards. Witness, for example, the near tail-dragging Stegosaurus or the bizarre addition of teeth to the toothless jaws of Gallimimus of Jurassic World (animals that had previously been depicted with more accuracy in earlier movies in the franchise) among others. That comes even when there was a clear attempted excuse for any errors though incomplete genomes for some vs 100% original animals in Jurassic World Dominion, that then presented supposedly ‘genuine’ animals and a prologue of the Cretaceous with animals that were no more accurate than the supposedly incomplete ones.

 So yes, as someone who tries to get the public excited and interested in science, it’s difficult when their frame of reference is Jurassic Park and they think T. rex can’t see you if you don’t move, Pteranodon could pick people up with their feet, of Velociraptor stood over six feet tall. I don’t think anyone would use the Jame Bond franchise to inform their opinion of international espionage but many seem surprisingly willing to treat the Jurassic series as a documentary. This is annoying, but I think says more about the viewers than the filmmakers. It is, after all, fiction. And while these depictions cause issues to science communicators like me, even the best documentaries take some liberties and smear over the details, and many are no more inaccurate than the movies.

And so to my central problem with the JP series – it’s simply boring. At a visceral level, yes there are exciting moments and thrills, but it is all far, far too repetitive. A few years ago I threw up a spreadsheet of all the repeating plot points, events, shots, characters and actions in the films (who says scientists don’t know how to have fun?). It turned out there were an actual ton of them and putting it online led to people spotting still more. Everything from kids somehow ending up in every single film, to there always being some kind of great white hunter character, one dinosaur threatening the cast only to be taken out by another one coming from off screen, getting the dinosaur DNA is a key plot point, someone has to be tricked to go back to the island, Velociraptors jumping through glass, evil corporations trying to exploit the dinosaurs, needing to get the power back on for something to work, there’s another lab we didn’t know about before, people dangling off a cliff in some way, dinosaurs escaping on the mainland, people hiding from dinosaurs under cars, as well as the inevitable chase where the heroes are in an open-topped vehicle.

Now of course every movie franchise and even individual films will have their share of tropes, call-backs and repeats. An action film without a car chase or shootout wouldn’t be much fun, a Bond film would tank at the box office if he was just filing paperwork and not going to an exotic location to find exotic women to save them from ever more exotic henchmen. But in the case of the Jurassic franchise, I think the problem is almost overwhelming and that’s because it’s based around the dinosaurs.

And there is the rub because, fundamentally, the dinosaurs can’t do very much. Yes, they have big teeth and can run around and the smarter ones can open doors, and now they have pterosaurs in the sky and mosasaurs in the water, but really, they are still pretty limited. There are lots of places they cannot easy reach, they can’t use tools, they are not that smart, and they are fundamentally pretty vulnerable to gunfire and other weapons. In other words, they are not actually that much of a threat to people, unless they don’t have weapons or anywhere to hide or are exposed in some way and have to get past the dinosaurs, and they are mostly stuck on an island that people are banned from visiting. This is what we see in other animal movies like Jaws, Lake Placid, Beast and others (even 65): even large and dangerous animals are not actually that dangerous unless you are stuck outside of normal civilisation. Which means the only way you can make dinosaurs into a threat is to contrive the situation where people are ill equipped to deal with them and that becomes ever more difficult with each sequal.

It’s all a bit forgivable in the first film with an experimental park that’s hit by a hurricane and most of the characters have only just got there and don’t know their way around. But after that, it becomes a bit more questionable. There have now been multiple films where some extremely wealthy corporation has gone to the island with the expectation of exploiting the dinosaurs to generate billions of dollars in revenue and knowing there are dinosaurs there. And they go in a few open topped cars and vans with a couple of dozen people and not, say, a few hundred mercenaries with tanks or armoured cars, helicopter support, drones or satellite coverage, night vision equipment and anything more powerful than a normal military rifle. You know, the sort of things that would help you see dinosaurs coming, were capable of killing them, and would protect you if they got to you. Similarly, the park reopens in Jurassic World only apparently with the designers still having no understanding of how to build an enclosure that might keep large animals contained (double doors would seem a good start, as would a very deep moat).

While I admit that the movies would struggle to keep an audience with ‘every dinosaur is safely locked up and people just look at them’, it’s the fact that we’re now on a seventh movie where the dinosaurs have got out and yet everyone involved is clearly unprepared for this, even when they know exactly what they are going to be facing. Why else are they always in jeeps with no roof, or carrying one decent gun between them, or there is some other accident or plot device to get people stuck on the island in the first place? Because without that, there is no jeopardy and no film. But as the dinosaurs are animals with no agency, limited ability to be a threat and stuck on an island, everything needs to be arranged to force anything to happen, and that’s now increasingly repetitive and increasingly contrived.

These are not the only issues. There is so much focus on the dinosaurs that the characters seem to be a bit flat, and there’s been little moral core to any of them beyond ‘corporations exploiting things are bad’ for at least the last three movies, and arguably they nearly all suffer from this. And however much computer graphics have come on, too many dinosaurs look too polished and shiny and the lack of puppets and animatronics really does make for a lack of realism in far too many shots.

A final problem comes from the continual perception that dinosaurs are fundamentally for kids and that toy sales are clearly a huge part of the marketing and money making. It’s not that Hollywood has ever had a problem with pushing stuff on kids, I remember toys for Robocop, Aliens and Terminator as a kid despite them clearly not being kiddie-friendly franchises. But it does mean that the series insists on being generally light with the violence and swearing and tonally all very similar. It doesn’t make for the greatest experience when you know what it’ll look like and what will happen before the movie is even out.

Just looking at the trailer for Jurassic World Rebirth and we see lots of people (including a kid) on an open-topped boat, followed by them being trapped on a raft, someone dangling off a cliff, a great white hunter with a rifle when most of the others are unarmed, and people going to an island yet again they are not supposed to go to, to try and get dinosaur DNA yet again. I’m sure there will be some great bits to this, and I’m sure it’ll make a lot of money. But I’m also sure that there are plenty of other stories and genres and styles that could be applied to the general world of Jurassic Park that would be fresh and invigorating, and still be profitable.

I would prefer the series had better and more realistic dinosaurs, but I mostly wish it were more fun. Perhaps the eighth one will be better.

New data on pterosaurian soft tissues

Published 10/06/2025 Uncategorized Closed
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Pterosaur fossils are rather paradoxical in that they are generally very rare and fragmentary outside of the few places of exceptional preservation, where they become not only common, but contain the kinds of data most palaeontologists dream of seeing. Not only do we have a lot of very complete and well-preserved specimens, but a great many with various bits of soft tissues too. In addition to the obvious wings, we have beaks, claw sheathes, soft tissue head crests of various forms, throat pouches, tail vanes, scales on the feet, webbing between the toes and, of course, the pycnofibers – we even have some traces of muscle tissues in some. I suspect if we added it all up, we’ve actually got generally more and better soft tissue data for pterosaurs than even the feathered dinosaurs, and from a fraction of the number of specimens too.

Still, there are some bits that are less well known, and various specimens out there that have never been described well or have only recently come to light and so have not been looked at in any detail. As you can imagine, I have a new paper published today looking at some of these exact details, though as so often happens, it’s sort of an offshoot of something else.

As part of my ongoing work tracking down various undescribed Pterodactylus and Rhamphorhynchus specimens, I’ve come across various large bits from Solnhofen beds sitting in museum collections. The really huge wings that I’ve seen, I actually wrote up with my then PhD student Ross Elgin a few years back, but we knew there were more out there, including isolated legs and feet. When I started working with René and Bruce Lauer on the collection from their Foundation, I soon spotted a really nice large leg and foot and thought this would be a good starting point for a paper on these isolated limbs. What I did know until they showed me, was that completely invisible under natural light, the specimen had some exceptional soft tissue preservation under UV, and it was not the only isolated bit like this in their collection. So began a slightly odd pairing of subjects in a paper – large isolated pterodactyloid feet and the soft tissues associated with them. There’s obviously lots more in the paper on these two specimens as well as some others from other collections, but I really want to focus here on the soft tissue material.

The first thing to look at is the webbing between the toes. This has been seen before, including deep in the crux of the metatarsals, but it is arguably clearer and deeper here than seen before and with very clear striations that presumably mark some kind of thickening or stiffening fibers to support it. This is important as it shows that the metatarsals were not bound together at the base of the foot but could themselves spread out if the webbing goes that deep between them.

Of greater interest are the scales on the soles of the feet. These have also been seen plenty of times before, but again are incredibly well-preserved here and certainly the best I’ve seen in person and arguably the best out there. These are incredibly similar to those seen in other pterosaurs which on the one hand is hardly a surprise, but when that includes things like Rhamphorhynchus and then animals as far apart in time and phylogeny as azhdarchids, then it becomes clear just how consistent these apparently were. It looks like pterosaurs sorted out their foot scales out early and then stuck to that pretty much forever.

What’s more surprising is that one of the specimens that represents a wing and a leg, also preserves scales on the hand, and these are, to our knowledge, the first recorded for pterosaurs. Now that should immediately strike you as odd – pterosaurs were quadrupeds and given their build, took a lot of weight on their hands. So, wouldn’t these have scales that were at least as large and tough as those of the feet? Well, apparently not given that we do have a bunch of fossils with scales on the feet but not the hands. Clearly some were present or we wouldn’t see them here, but their clear rarity compared to the feet is a real oddity and difficult to immediately explain, not least when the scales seen here are almost identical to those seen on the feet. We might have just been unlucky and missed them before or they were accidentally lost in preparation, but it does appear to be a pattern.  

All in all, there’s some nice information here and some really neat nuggets of pterosaur anatomy and taxonomy have come out of this, so it’s certainly a paper worth taking a look at if pterosaurs are your thing. There’s more to come too as I have another pterosaur soft tissue paper due out soon so stay tuned.

The paper is Open Access and available here: Hone, D.W.E., Lauer, R., & Lauer, B. 2025. Soft tissue anatomy of pterosaur hands and feet – new information from Solnhofen region pterodactyloid specimens. Lethaia.

Check out the Lauer Foundation website too.

Twenty years as a published scientist – a retrospective

Published 16/05/2025 Dinosaurs , Practical Palaeontology , Science Communication 8 Comments
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Time does fly. I still have very clear memories of various science and biology classes at school, many of my lectures at university, my Masters and my PhD work, and plenty of other formative experiences that led me into my career. But arguably I really became a ‘proper’ scientist when I published my first peer-reviewed paper, back in 2005. As such, this year marks the 20th anniversary of my first foray into being a published academic. As an aside, I’d always has in my head that my first paper came out in May of that year, which is why this post is coming now, but a recent check shows it has a January date on it, so I’m clearly misremembering.

Over the years, this blog has become less and less about palaeontology and dinosaurs in general and moved more and more into covering bits of my research and new papers. This really is a consequence of having ever less time to keep going on here, with more and more commitments in my academic job and home life, as well as my shift into writing books and doing the podcast among other things. With less time for blogging, but not wanting this space to fade away, it’s rather inevitable that I can only really rouse myself occasionally and for the things that most interest me and of course that tends to be when I have a paper out. This post of course rather further exaggerates this pattern, but I hope that after well over 15 years of providing information on this platform, my slow slide into self-indulgence will be tolerated.

Twenty years is a not insignificant milestone, so I thought I’d sit down and, with no real planning, put down a few thoughts about my career in terms of research. I fill focus on that side of things and so despite the books and videos and talks, and my various jobs and research trips, that have taken me around a good part of the world, my friends and collaborators, I did want to focus on my papers. Having now published over 100 peer-reviewed papers and chapters in books and compilations (as well as various comments, replies, corrections, extended abstracts and the like), I do have a decent set to look back on.

Naturally things have changed over the years, and I’ve shifted my focus and interest at various times, or picked up the thread of projects that have come my way and opportunities grasped. I’ve put out papers on subjects as diverse as soft-tissue preservation, trackways, science communication, and even managed to get some work done on extant lineages (not to mention one paper on volcanoes), but there have been a few mainstays in my work that I’d like to focus on.

My very first papers were on Cope’s Rule and the evolution of large size, especially in dinosaurs. Although this is something I’ve not looked at anything like as much in recent years, this was the starting point of my academic publishing (based on my Masters dissertation) and the sheer size of dinosaurs has always been an interest. More recently though, I’ve been less concerned with what was actually going on evolutionarily, and what this means for the animals themselves and how we use that information. That’s led into works on things like the problem of dinosaur tails and what that means for saying how big they were, and the maximum possible sizes of dinosaurs, as well as work on their growth. After all, there’s not much point comparing one of the largest members of species A with a very small member of species B and claiming that A is bigger. So, while this is very much not my primary interest these days, and most of my work in this area was in a flurry at the start of my career, as recently as last year I had a paper out exploring some of these issues, so it remains on my mind. It’s obviously a longstanding area of research in general and while my contributions might be relatively minor, it’s been an important part of my career.

Fairly close behind was the work that led to my first naming of a species, the rhynchosaur Fodonyx. Somewhat ironically, my Masters was in taxonomy but I ended up doing a project on dinosaur size, and then didn’t end up naming a species until my PhD (on macroevolutionary patterns) was finishing up. Still, alpha taxonomy (naming new things and sorting out the identity of specimens) is a field I trained in and has been a part of my work ever since. In total, I’ve now named nearly two dozen dinosaurs, pterosaurs and rhynchosaurs with various authors over the years. While it’s hardly the main thing that I do, I’ve continued to work in this area and won’t stop anytime soon. I regard this work as foundational to the biological sciences – how much confidence can we have in our work if we don’t know what things are? Analysing the evolution of clade but unknowingly including things that are not part of it, or are juveniles or that splits males and females apart etc., will always impact the results and so work starts with the correct identification of specimens. While something like 20 species (and a few other revisions) is a bit of a drop in the ocean in Mesozoic archosauromorph terms, and things like naming taxa will always be contentious or cause disagreements, I’d like to think that I’ve done more good than harm sorting out various bits and adding some names to the pantheon of taxonomy.

More significantly, the main focus of my work for many years now has been on dinosaur ecology and behaviour (while keeping my hand in on the pterosaurs where I can). That obviously covers quite a range of subjects (as I think my recent book shows) and I’ve obviously poked around the edges of a fair few issues (what, if anything, was Spinosaurus doing in water?) but one of the main one has been the diet of dinosaurs, specifically the carnivores. I’ve published quite a series of papers over the years on various key specimens showing things like bite traces, consumed bones and the like, as well as much bigger synthesis papers and reviews, trying to use a lot of datapoints to build up a picture of what theropods were doing. I’ve tried to work around some of the problematic language (‘predator-prey’) and inconsistencies in interpreting predation vs scavenging in these, but my biggest contribution I think, has been to push the idea that theropods primarily targeted non-adult prey. It’s almost a cliché that predators target the old, sick and especially young, but the assumption always seemed to be that the largest theropods tackled the largest prey species. In general, this is probably true, but members of big species don’t start big and that’s where they’re vulnerable. Bringing in studies from all kinds of areas on living groups really helped build a picture of what was common or even normal behaviour for carnivores, and I think I’ve had a decent role in reforming some of our ideas about this subject.

The one area where I think I can claim to have had a truly leading role is in the study of socio-sexual selection and communication. Across a dozen or so papers, I have really pushed and explored the implications of sexual selection, crest and ornament development and what it means for issues like sexual dimorphism, signalling, reproductive strategies, and how we work with this in the fossil record. While the ideas are hardly new to biology, I think I’ve been largely responsible for bringing mutual sexual selection and the issues of monomorphism into dinosaur research and pushing aside problematic explanations like species recognition. We’ve even been able to test some of these ideas (no mean feat with the available data) with, for example, my papers on gharial snouts, dinosaur growth trajectories, and ceratopsian distribution. I think it’s my most important contribution to our understanding of ancient animals and it’s been influential gaining some real traction in the literature. I just wish we had some better datasets to apply these ideas to than just Protoceratops!

I think that’s a decent summary of my publications over the last 20 years. Rereading this, the pterosaurs don’t get much of a look in, despite the fact that I started out on them, and they make up perhaps 30 or even 40% of my papers. That said, they have filtered into every one of these areas, as I’ve named multiple species, looked at their growth and giant individuals, and their head crests, and stomach contents (as well as finding them on the menu of dinosaurs and sharks). In fact, I’m on a bit of a run on pterosaurs at the moment, so there’s plenty more to come on them in the next year or so.

Anyway, I do hope this wasn’t all too self-indulgent and was still an interesting read for anyone who has made it this far. On such an anniversary, a bit of self-reflective noodling seems appropriate, and a bit of self-congratulations warranted. Naturally, this is not the end of my work (I’ve got a bunch of papers in various stages of completion right now, including one that’s been accepted and due out very soon), so I can hopefully continue to develop these themes further.

Obviously, I’ve not done this alone. In addition to all manner of colleagues, mentors, curators and coauthors, even the handful of papers on which I am the sole author relied on access to specimens and would be the result of discussions with colleagues and the help of referees and editors. So, to them I extend my thanks for all of the time and efforts they have committed over the years. I only hope they will continue to provide their friendship and support for many more. Here’s looking forwards to another 20 years of publications.

Welcome Infernodrakon – a new azhdarchid

Published 04/03/2025 Uncategorized 1 Comment

The azhdarchid pterosaurs are well known for including the largest flying animals of all times in their ranks. Giants like Quetzalcoatlus could reach 10 m in wingspan, and in addition to being huge overall, they had large heads on often very long necks. But research on them was often rather limited with their fragmentary remains and problematic taxonomy.

The famously long time it took to see a full description and proper definition of Quetzalcoatlus really did hold up quite a lot of research. Lots of azhdarchid pterosaur bits and some important specimens from across North America and elsewhere were in something of a limbo. They might well belong to this animal (and many we referred to it) but it was hard to be sure until we knew exactly what it actually was.

So it should be no surprise that between this, and some other work giving us a good idea of how azhdarchids varied as they grew and variation along the important neck vertebrae might now ‘release’ a bunch of other specimens from limbo. And so enter Infernodrakon hastacollis – the ‘hell dragon’ with the ‘spear neck’ from the Hell Creek Formation of Montana.

A new paper led by Henry Thomas came out late last week (catching us out a bit, which is why I’m late with this post), is now out naming and redescribing quite a well known azhdarchid specimen. This is a single neck vertebra that couldn’t be much more ‘end Cretaceous’ if it tried – it was actually found alongside the juvenile T. rex skeleton known as Jane. This specimen had been described in 2006 as Quetzalcoatlus sp., but now we have the context to look again, we think it’s a new species.

Henry started this project some time ago and one of the major things that was done as part of this work was to 3D scan and carry out retrodeformation of the really rather crushed cervical. Working with Timothy Gomes and Joseph Peterson (who are also authors on the paper), they were able to restore this element effectively, though the two ends, which contain most of the useful taxonomic information, were in much better shape already.

The single neck bone is some 350 mm long but is only a few centimetres wide. That makes it incredibly long, even by azhdarchid standards, and it may be proportionally longest vertebra recorded. Obviously one vertebra isn’t the best starting point for working out the size of the animal, but we estimate that it had a wingspan of around 4 m wingspan, though it is not clear if the individual was an adult at the time it died or was still growing. It’s at least possible that Infernodrakon could have reached giant sizes in a large animal.

Despite the inevitable early comparisons to Quetzalcoatlus, we found that it actually had more in common with another giant, Arambourgiana from Jordan. The paper contains a new and detailed phylogeny of the azhdarchids, including a whole bunch of isolated bits which we take a look at, and suggest that there might be some more taxa out there hiding among these parts. Not a real surprise really, but still nice to have some support for this idea and a framework for some more detailed assessments in the future.

I want to finish off by thanking Henry for inviting me onto the project, and the other coauthors for their contributions. Finally, we need to thank Jun-Hyeok Jang for their superlative artwork that they did as a restoration of the animal that was used in the paper.

The paper is online here if you want to see it: Thomas, H.N., Hone, D.W.E., Gomes, T., Peterson, J.E., 2025. Infernodrakon hastacollis gen. et sp. nov., a new azhdarchid pterosaur from the Hell Creek Formation of Montana, and the pterosaur diversity of Maastrichtian North America. Journal of Vertenrate Paleontology, e2442476.

A giant Rhamphorhynchus in London

Published 02/01/2025 Uncategorized 5 Comments
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Typical, you wait ages for a paper on Rhamphorhynchus ontogeny and then they all come at once. Ok, maybe not that quickly, but this is now the second paper on this general subject in the last few months and the third in the last few years. I’ve long gone on about how important taxa like this and Protoceratops (another favourite subject of mine) are because we have lots of specimens and we can start to say something meaningful about population structure, growth, dimorphism and so on. If you’ve not seen these then they were worth looking up as they are directly relevant to this new one, though in the best traditions of scientific publications, this project was started years before the others.

Going back, in 2020 I had a paper out looking at the growth of Rhamphorhynchus. We were able to show that these animals were highly isometric, retaining their proportions as they grew so that apart from a couple of features like the eyes, young animals were basically carbon copies of even large adults. A spin-out from that work was the one published in mid 2024 by Mike Habib and me, looking at the variation in Rhamphorhynchus. It’s one thing to know they grew largely in a straight line, but how much variation around that is there? The answer is, very little. They are incredibly consistent and that’s really good news when so much of pterosaur taxonomy and systematics are based on things like the proportions of bones, so a lot of variation would mean that might not be very reliable. Even after these two works though, there remain questions over some exceptional and unusual specimens.

One such is the truly giant specimen of Rhamphorhynchus held at the Natural History Museum in London. At nearly 2 m in wingspan, until Dearc appeared, it was by far the largest known non-pterodactyloid out there (and is probably still the largest known non-monofenestratan), and it’s about a third bigger than the next largest specimen, which itself is also much larger than the third largest. So the NHM one is an absolute monster, double the size or more of the vast majority of known specimens. Given how archosaurs generally grew, and the effects of sampling biases etc., then the occasional real giant shouldn’t be a surprise (see also my recent paper with Jordan Mallon on T. rex) but at the dame time, very big (and in this case too, allegedly weird) animals then we do need to be careful. Rhamphorhynchus has a mess of a taxonomic history and it should be no surprise that this giant has been assigned to a different species to the others at various times and so is worth a look at.

It’s also interesting as it’s largely in 3D, unlike the majority of the other specimens, but then it’s also not that well preserved and it was rather hacked up and repaired with plaster and horrible old glues a century ago. Happily, the NHM were convinced it was interesting enough to put some work into it and so their lead preparator Mark Graham did some work to reprepare it, revealing a bunch of hidden bones and clearing out some of worse bits of prep and repair. Before he did that, I took enough photos to make a photogrammetric model, so we do have a good record of what it was like before.

This was a project that I originally started with Mark Witton but as it went on, he ran out of time, and so we drafted in Skye McDavid to help us, before Mark eventually dropped out. So Skye and I are the only authors on the paper, but Mark had a big helping hand in the early development of the project so I wanted to thank him here for his contribution.

The short version of all of this is that looking over the giant animal in detail, it is, perhaps unsurprisingly, another Rhamphorhynchus muensteri – it’s the same species as all of the other Solnhofen material, and there’s no reason to think it is distinct. It does have some apparently odd features but when you dig into the details, suddenly they are not as odd as they first appear.

Notably, the openings in the skull look quite large when compared to the orbit, but really this is the orbit getting proportionally smaller. Young vertebrates have large eyes that get absolutely larger, but are proportionally smaller, as they age. So it shouldn’t be a big surprise that an animal far larger than other members of the species has the proportionally smallest eyes, and that makes the other openings appear to be abnormally big.

Similarly, the fusion of the mandibles in the middle appears to be rather short. But again, measuring a few specimens suggests that this is something that progressively reduces as Rhamphorhynchus grows with younger specimens showing more fusion and adults less. Again though, this is proportional so the absolute size of the fusion is greatest in the bigger animals, but the proportion is lower, the jaws are still well-fused. But it does seem to be part of a larger pattern here rather than a unique feature.

Perhaps the most noticeable feature of the NHM giant is their teeth. Rhamphorhynchys teeth are described as being spikes or cones, with a circular cross-section, but the ones here are notably very flat and look more like fat and unserrated theropod teeth than that of other specimens. But again, when you look closely and take some more measurements, it’s clear that these are often more oval than round in smaller Rhamphorhynchys, and that while they never are as flat as seen in the big adults, this might again be part of a progression. Despite the number of good skulls we have for Rhamphorhynchys, so many of the teeth art partly buried in matrix or are tiny and in the jaws, this was supremely hard to measure so I’d certainly want more data here, but what we could extract did suggest that the teeth are changing in shape as the animals mature and that again, this is part of a continuum and the NHM one is not some weird outlier, just at the end of a line.

Collectively, we then suggest this might link to some differing ecology in these really big animals. That again should not be a surprise, bigger animals, especially when they fly, will have different resource needs, move in different ways, and be capable (or incapable) of things that smaller ones are not. Add to that different shaped teeth, and different jaw fusion and it does at least suggest that these big ones were foraging for, and feeding on, different prey, or at least their preferences were shifting.

Anyway, there’s lots more in the paper and as it’s fully open access at PeerJ, you should check it out there. My thanks, of course, to my coauthor Skye, and again thanks to Mark and Mark for their help with the project, and to Sandra Chapman at the NHM who started me off on the project, and Mike Day who helped us with access to the specimen in order to complete it.

The paper is full OA and available here: Hone DWE, McDavid SN. 2025. A giant specimen of Rhamphorhynchus muensteri and comments on the ontogeny of rhamphorhynchines. PeerJ 13:e18587. https://doi.org/10.7717/peerj.18587

Skiphosoura – ‘solving’ the transition to pterodactyloids

Published 18/11/2024 Uncategorized 12 Comments
Life reconstruction of Skiphosoura bavarica. Art by Gabriel Ugueto.

I’m delighted that today I have a new paper out with a really exciting new pterosaur, that I think adds an awful lot to our understanding of pterosaur evolution, as well as the animal itself being rather interesting. It’s often fairly easy to say that a new find ‘fills a gap in the fossil record’ but some gaps are much bigger than others, or a situation is rather complex that can be clearly resolved with the right fine (or at least, provide an interesting new hypothesis). To follow through this new find and its implications, we need to start with a short bit of pterosaur history and evolution.

For the first couple of centuries of pterosaur research we could split them into two groups: the rhamphorhynchoids and pterodactyloids and the two simply didn’t connect. The earlier rhamphorhyncoids (now properly called ‘non-pterodactyloid pterosaurs’) had proportionally small heads and necks, a separate naris and antorbital fenestra, a short wing metacarpal, wing fingers where phalanx 1 was quite short and 4 quite long, a long fifth toe and, most obviously, a long tail that was usually bound together with long zygapophyses. The pterodactyloids were then the opposite, long heads and necks, a single merged nasoantorbital fenestra (NAOF), a long wing metacarpal, a long 1st and short 4th wing phalanx, a reduced 5th toe and a short and unbound tail.

This all changed with Darwinopterus and the discovery of a pterosaur with a big head and neck, an NAOF but otherwise a very much non-pterodactyloid body plan. This gave us a new grade, the monofenestratans, and when a bunch more species and specimens were found or recognised, they formed a nice cluster that were all close to one another but clearly different from their forerunners and the later pterodactyloids. It certainly answers some questions – the head and neck evolved first and then the rest of the body changed, but it’s not really showing a clear transition or pattern of all of these various characters that are being altered. All of the characters past the neck might have changed second, but in which order did they alter, and which ones came first in the head? For that, we’d really need some more intermediates, one that plugs the gap from the non-pterodactyloids to the first monofenestratans, and then again from these to the pterodactyloids? To try and simplify the problem, we have A, C and E, but can we get B and D? Well, guess what?

So in the new paper out today, I and my colleaguesdescribe and name a new monofenestratan, Skiphosoura. There’s a *lot* I could say here, but there’s a lot in the paper and a massive supplementary info section, so I’ll try and keep this short and sweet and concentrate on the big stuff.

First off, it’s huge, the biggest known from anything like a complete specimen and one of the largest things in the Solnhofen (important aside, it’s from the Solnhofen), alongside the biggest Rhamphorhynhcus and Petrodactyle coming in close to 2 m in wingspan. Although disarticulated, it’s nearly complete with almost every bone present and they are in somewhat 3D, so we get access to tons of data we’ve not had before in the monofenestratans. It has a bony head crest, it’s got big teeth, it’s pretty robust and it’s got long legs. Looking at the specimen that first time I saw it, it was clear it had some odd features and it certainly looked more derived than Darwinopterus and the others, but was it really? When we ran a phylogenetic analysis is where things really got interesting.

Skiphosoura really does come out as ‘D’ in the analogy above, it’s got a bunch of features that we associate with the early monofenestratans, but it’s also got some very pterodactyloid like features that show a transition from one state to the other and plug this gap very effectively. Even more intriguingly, Dearc, the recently described Scottish giant is pulled up from being a derived rhamphorhynchine close to Rhamphorhynchus, and to being ‘B’, the link from these to the monofenestratans. Lining these up we then get a really clear transition for pretty much all of the characters I listed up top.

The head in Dearc is notably long and its neck is longer than earlier forms, plus the naris is huge so these are all more derived that we see in the traditional ‘rhamphorhynchoids’ but are not yet at the  monofenestratan condition (and as an aside, have a more derived prepubis too, so it’s not quite all head and neck first). In Skiphosoura, we have the big head and long neck and confluent NAOF of the monofenestratans, but we also now have a longer wing metacarpal than before, the wing finger proportions are nearly all the same, so 1 is longer and 4 shorter than the earlier forms but not at the pterodactyloid ratios, the fifth toe is greatly reduced, but still has two bones and not the one of the pterodactyloids and most notably the tail is short, but still bound by zygapophyses. So, we’ve got a bunch of features that more derived than in Darwinopterus and kin, but not quite at the pterodactyloid condition.

The evolution of pterodactyloid pterosaurs. Line drawings by Skye McDavid.

This is really, really cool. This is giving us a real insight into the pattern and timing of changes across the whole skeleton and what that means for how and when all these different and important shifts happened. Remember that the pterodactyloids get much bigger than the earlier forms, and have a fundamental change in their wing shape (the massive reduction in the uropatagium that comes with a short tail and reduced 5th toe) and a fundamental difference to how they walk, so these are not just anatomical traits changing, they represent a fundamental shift in their biology and with massive implications for how pterosaurs changed over time and the opening up of new niches and the creation of a new body plan. Skiphosoura and Dearc really plug those gaps and help show the transition and this should be a major source of research going forwards looking at those changes to the body plan and the implications to flight and terrestrial locomotion to explain how the pterodactyloids became the animals that they were and that dominated the Cretaceous. Hopefully this is a first, but major, step in that progression.

There are obviously various other things in this paper too, that are at least worth mentioning here briefly. While this is not the first monofenestratan from the Solnhofen, these are currently very rare and so this is quite an addition. The 3D nature of the skeleton adds a ton of new information on these intermediates and is basically the only one that is preserved like this right now, so it’s really important in that regard. We have a new phylogeny in play, that it addition to the resolution in the middle of the tree, adds some novel relationships down the bottom (or firms up some previously very uncertain areas), and on a personal level, it’s nice to see Petrodactyle included and it pop out basically where I thought it would, and with some more characters supporting it’s identification as a valid taxon. I should mention at this point, that there’s a ton of new characters in this tree (which is really comprehensive) and, if we’re right about the relationships, there is a serious bit of taxonomic revision needed on the various Darwinopterus-like taxa with animals previously considered different species of a single genus being spread around the tree. Finally, we have some commentary on ecology and behaivour of these animals, so there is a lot crammed in and stuff that is relevant to pterosaur evolution, taxonomy, relationships, anatomy, flight, ecology and more. It is, therefore, I think fair to shout about it quite a bit!

Obviously to round off, I want to thank my collaborators and coauthors, Adam Fitch, Stefan Selzer, and René Lauer and Bruce Lauer (and the Lauer Foundation). It’s taken a ton of work to get to this point and I’m delighted we made it. Now go read the rest of the paper because there’s a lot to unpack here and this isn’t doing much more than scratching the surface. You can access it here:

Hone, D.W.E., Fitch, A., Selzer, S., Lauer, R., & Lauer, B. 2024. A new and large darwinopteran reveals the evolutionary transition to the pterodactyloid pterosaurs. Current Biology.

While I’m posting links, it seems like a good opportunity to mention that like so many others, I have made the leap to Bluesky, and I do also have a (not that much used) LinkedIn account too. So if you want to follow me there, please do. For now my Twitter is still running, but I think it’s only a matter of time till that fades, but my Facebook page is still doing fine. There will be a new episode of Terrible Lizards next week that will be all about this paper, so more info coming there soon too.

Uncovering Dinosaur Behaviour

Published 05/11/2024 Uncategorized 4 Comments
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By now I imagine that almost everyone reading this is aware that I have a new book out, but if you somehow did not, then here’s a chance to catch up and learn a bit more about it (and hopefully I can entice you to buy a copy). The title, as is rather given away above, is Uncovering Dinosaur Behaviour and it’s out with Princeton University Press today, though copies have been circulating for a while at a few events and I know it’s been sold at the Smithsonian too.

The subject matter is pretty obvious from the title, but if you have read my other books then the style is a little different. This isn’t a classic popular science work, but somewhere between that and a formal text book (what is sometimes called the grey literature). So the tone of writing is rather more formal, the level is a bit higher (you might well need to look up some words and even concepts if you are not a biology student), and it’s fully referenced throughout (though, ugh, with numbered references – not my choice!). So don’t grab it and think it’ll be a breezy read, it’s there to really be read and through about in way that I don’t think my others have been, and I was aiming for this to be accessible, but also getting much deeper into the subject and with ideas and summaries that will be actively useful for students of science and practicing researchers. I really hope it’ll be a go-to source on this subject for a lot of academics in the next few years. Steve Brusatte read an early version of it and said it read like a series of review papers and that’s what I was aiming for and captures the level of detail I was going for, so that was nice.

On that note, I do need to thank Andy Farke, Cary Woodruff and Dave Shuker who were all kind enough to read the whole book for me and give me their feedback as my own personal referees, in addition to the two formal ones appointed by Princeton (of which Steve was one). They all gave me their time and help and made for a much stronger, and hopefully more accurate, work. While I’m thanking people, special thanks needs to go to Gabriel Ugueto who is the illustrator. In addition to doing the amazing cover and all of the full colour inserts, he did a couple of dozen line drawings for the text as well. So the book is really well illustrated, with far more pictures than my previous books and there’s a load of photos in there as well, so it really is a beautiful book.

It starts off with quite a long set of introductory chapters to get into the basics of dinosaurs (for non-dinosaur experts), behaviour (for non-ethologists) and then fundamentals of palaeontology and what data is and isn’t available (for non-palaeontologists). After that, it’s a deep dive with, as noted above, a series of review-like chapters with each tackling a major area of dinosaur behaviour: feeding, signalling, combat, reproduction etc. In each I try to lay out the state of the art of our current understanding of the subject, go into where the problems and gaps lie with it, and then finish with some suggestions for future studies and where I think we can go with it. So it’s not just a ‘here’s what we know’ set-up of the traditional text book or review, but also getting into the problems and solutions and trying to be positive about steering the discussion into some more productive areas of research for dinosaur behaviour.

Obviously this is all very dinosaur-centric as you may expect, but I do think I highlight a bunch of issues that are more general concerns with how we reconstruct a lot of palaeo behaviour. I can’t really speak for things like mammoths and trilobites, but certainly some of the things I flag up absolutely appear in papers on fossil crocs, pterosaurs and other Mesozoic animals that I’ve come across and so this book will hopefully have a broader appeal and interest than those just trying to look at allosaurs or alamosaurs.

If you want to know more, I rather inevitably covered this at length in the new episode of my Terrible Lizards podcast, so you can check that out if you want some more info and I got into a lot more detail than I do here. There’s also a link to a healthy discount code which at the time of writing I think is still good to use. I’ve already had one glowing review from Marc Vincent of Love in the Time of Chasmosaurus so check that out if you need more.

The book is available in all kinds of places online and in shops, but here’s the link the Princeton’s webpage as the official source.

Hone, D.W.E. 2024. Uncovering Dinosaur Behaviour. Princeton University Press.

Spinosaur feeding

Published 09/09/2024 Uncategorized 2 Comments

It’s been too long since I got involved in spinosaur research, but I have recently re-entering the fray with a new paper. It was out last week, but I’m in the field and only just got the time and internet access to be able to put this post out.

A couple of years back I was mulling over some issues of the tooth row of spinosaurs and especially the pattern of there being very large teeth at the front of the jaw and in the middle but small in between and at the back. This presumably had some functional significance since this pattern is present in crocodiles, but greatly exaggerated in spinosaurines, but doesn’t show up in a lot of specialist fish eaters like dolphins or gharials. I was chatting to Eric Snively about this, and he suggested that we ask Domenic D’Amore who has done a lot on croc jaws. He was intrigued and suggested we rope in Evan Johnson-Ransome who is in Chicago and is working on spinosaur jaws for his PhD. And so a project was born, to look at the teeth (well alveoli, we have a lot of holes in jaws and not many teeth), and the patterns in the jaws of crocs and spinosaurs and see what we could see.

Dom already had a great dataset on crocs and in a previous paper had categorised their feeding habits based on head and tooth shapes, so we had a great baseline for comparisons. What we’ve found here adding in essentially every spinosaur cranium and jaw that we could, is that spinosaurines and baryonychines do have the same basic pattern going on described above. They have big teeth at the front of the snout, then some really small ones, then bigger ones again and then they reduce in size progressively to the rear. But while the teeth are all generally quite close in size to one another in the baryonychines, this pattern is massively exaggerated in the spinosaurines with much greater differences between the biggest and smallest teeth.

This is already quite well known, but I don’t think we, or anyone else, has realised just how different they are in this regard and the graphs in the work really show this. This pattern really puts the baryonychines closer to more fish-specialist predators with long jaws and thin, similarly-sized teeth, and spinosaurines closer to the big modern crocs, that eat plenty of fish, but also happily go for larger prey and including relatively large tetrapods. Spinosaurines don’t just have absolutely larger teeth (they are generally much bigger animals than baryonychines) but they are proportionally larger too. We also think this explains the undulating jaws of spinopsaurs with the largest teeth having larger roots and so necessitating a deeper jaw to accommodate them. All of this points to a pretty fundamental split in their feeding ecology with spinosaurines pretty clearly built to have a more powerful bite or bigger and / or tougher prey than baryonychines, again both proportionally and absolutely.

As a side note, even big fish-specialist crocs like gharials and Tomistoma are reported to predate on large vertebrates, so given the size of the baryonychines, this really doesn’t rule out them taking things like small dinosaurs or crocs as prey, but does suggest that fish (and other generally smaller aquatic prey) would be a more important part of their diet than in their bigger cousins. We need to be really clear here with sizes – spinosaurines were generally rather bigger than baryonychines so when we say that the former took larger prey than the latter, we mean proportionally. If we had one of each group that were the same size, the baryonychine would generally be taking smaller food than the spinosaurine. So that difference would be still more exaggerated given that spinosaurines are also bigger (at adult).

Another area we comment on is the rosette, the little subcircular expansion at the tip of the jaw and what this means. This turns up in crocs and other fish eaters too, but none of us had actually come across a functional explanation for this and so we are able to propose one here. Moving though water quickly is of course tough, and so reducing drag is really important and having thin jaws will really help here. But, you also want to snag what you are aiming at, and it’s going to be trying to escape, then a wider jaw will help. So we think the rosette is a compromise, allowing the jaw to be generally narrow but wider at the point most likely to contact prey and so give it a better chance of grabbing something without overly slowing it down.

Once you have grabbed the food, what then? Spinosaurs are odd for theropods in that they don’t have curved teeth and they have reduced or no serrations, and the alignment of the upper and lower jaws are good for holding but not much else. In short, they are not well suited to cutting off chunks of flesh or taking apart something large in the way that other theropods could with their slicing dentition. That points to a couple of possibilities then, either spinosaurs generally took fairly small stuff that they then swallowed whole or with the minimum of processing, or they had another mechanism to break up what they grabbed. They can hardly do a croc-like death roll, and their proportions are odd enough that a foot-pin and pull with the teeth that other theropods could do might not work here either. A bit of a leftfield suggestion we have is that the arms might have played a roll, some terrapins will use their claws to shred fish in the water and then grab the bits, and while they are built very differently, spinosaurs are nothing if not well equipped in the strong-arms-and-big-claws department, so it’s something they might well have been able to do.

So, there should be some useful data and ideas in there. As I said before, it’s no secret that spinosaurines and baryonychines are built a bit differently, especially in the tooth department, but we have gone well beyond that basic fact and built up some decent ideas about the kinds of things they might be trying to catch, and then how they would process them. Small steps perhaps, but certainly chipping away at the issues of their ecology and giving us some ideas to work on.

Finally, I do of course need to thank my colleagues for all their work on this paper, it’s been a really enjoyable process putting this together. You can read the full paper here:

D’Amore, D.C., Johnson‐Ransom, E., Snively, E. and Hone, D.W., Prey size and ecological separation in spinosaurid theropods based on heterodonty and rostrum shape. The Anatomical Record.

Mea Culpa – Luchibang the Chimera

Published 17/08/2024 Uncategorized 15 Comments

It has been a long time since I wrote such an important post, but this is a big subject and science is about self-correction and it would be wrong not to note when I made the error (and though hopefully also in this case, have worked to fix it). At least some readers will remember the cool istiodactylid pterosaur I named a couple of years ago – Luchibang a decent sized, but young animal, that was really well preserved.

Even during review, and after publication, a couple of colleagues said they thought it was a chimera – two specimens stuck together to make a more complete one. Such a practice is not uncommon with Chinese fossils (and plenty of others) and indeed one of my coauthors Xu Xing was instrumental in revealing the famous ‘archaeoraptor’ as a chimera. Many of these forgeries or composites are hilariously easy to spot and are not well done, indeed one of the original referees on the first paper who was happy with the specimen, the much-missed Lu Junchang, once took me on a tour of local dodgy specimens in Beijing fossil shops.

Given that we knew the specimen had come from a fossil dealer and the prevalence of such specimens, we did take the suggestion most seriously. The suggestion was that the head had been added to the body and so for our phylogenetic analysis we ran the head and body separately and together to see if they clustered together or apart on the tree and they came largely together. I re-prepared parts of the specimen myself and even had this process witnessed by a fellow and independent palaeontologist who verified we could find no joins or glues in the suspect areas. The specimen, with these issues, was presented at a pterosaur conference to talk though the possible fakery with an expert audience and go over the specimen as a whole, the characters in the head and body, the phylogeny and the preparation work.

In short, I think we did just about everything we could have realistically done to ensure that the specimen was genuine. (Note, it was way, way too big to do anything like CT or X-ray it and those cost a ton of money, and the specimen was very fragile so transporting it was a bad idea, and something like UV photography we had experimented with on Chinese material and found known fakes that looked genuine and known genuine specimens that could look like fakes, so it’s not that reliable on these rocks). Indeed, one paper that has cited the original Luchibang paper did so discussing how to spot forgeries from China and used our work as a reference for what they did to check that their own specimen was genuine.

But, as I’ve already given away, I was wrong. I was fooled. Someone did indeed combine two different specimens and did such a superlative job that I and others missed it, even when specifically looking for it. In fact even those who had raised suspicions of it, had identified breaks in the specimen as joins that are different to those we have now found (i.e., it wasn’t assembled in the way they thought it was and hadn’t identified the correct joins because they were well hidden).

This revelation came about because the slab was actually damaged in a flood in a museum that was housing the specimen and this clearly destroyed some glues or something that held them together and the top layers of rock that had been used to disguise the joins. A Chinese PhD student working on pterosaurs, Shunxing Jiang, got in touch with me about this and so we set out to correct the record, and so we have a new paper out (along with Xu Xing and Adam Fitch from the original paper, and with Yizhi Xu too) trying to fix the record.

The head of the specimen is still that of an istiodactylid and we have actually retained this as a holotype and name-bearing specimen. The recent Ozeki et al. (2023) paper had coded this as a head only in their analysis because of their concern about the postcranium and this was still borne out as a unique taxon, and our original diagnosis was actually based primarily around features of the head so we do still think there is a new taxon here. As such this remains a valid Chinese istiodactylid.

We have however, naturally, revised and changed other major interpretations. We don’t know the ontogenetic stage of the animal and its unusual proportions are clearly incorrect (or at least, unknown) and so our ecological interpretations are also off the table. To do as thorough as job as possible in correcting things, we have listed every paper that has cited the original Luchibang paper and went through to see if their results or interpretations might have been affected. Happily most are not at all, and others it is a very simple correction, but we hope this will have mitigated the effects of our mistake as far as possible and of course this new paper stands as a formal correction of the issue.

I am sure there will be some wailing and gnashing of teeth, but this really should not produce any kind of crisis in palaeontology. There are fakes out there and they do occasionally get into the literature. It’s been a problem in the past and will be one in the future too, but it’s not like museums are full of fakes and all the amazing Chinese specimens are chimeras etc. But it is a humbling, even humiliating, lesson that even as someone who has written about these issues on this very blog and took time and effort to check, could still be caught out. I did my best and came up short.

But I can take some consolation in that we have acted swiftly to correct the record and put out this paper and this post to try and clear up the mess and inform colleagues of the issues and how we think the chimera was assembled. I don’t think there should be any panic about existing collections, but it does mean we need to learn more about how these forgeries are perpetuated and be on our guard against them. That I and other colleagues were fooled (even if others were still suspicious) shows the quality of the work and that even being careful is not always enough.

The full paper is online and open access and also published in the same journal so hopefully linking up the original erroneous paper and this correction a little more effectively and to help point people to the correction.

Hone, David W. E., Jiang, Shunxing, Fitch, Adam J., Xu, Yizhi, and Xu, Xing. 2024. A reassessment on Luchibang xingzhe: A still valid istiodactylid pterosaur within a chimera. Palaeontologia Electronica, 27(2):a41.

On the trail of giant Tyrannosaurus rex

Published 24/07/2024 Uncategorized 4 Comments
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So today a paper breaks that has managed to cause controversy and misunderstanding for the last couple of years without having even been published. But today it is formally out and I’m sure that all the same issues (and more besides) will arise, so I’ll (at least attempt) to set the record straight here right now and cut off at least some of the (misguided or even malicious) representation that I’ve seen already. And that has come about really because my colleague Jordan Mallon and I suggest that T. rex could get to some 15 m in length and 15 tons in mass! Much, much bigger than any contemporary estimates, so what gives?

I should note already that to at least some readers, this isn’t news. We had an abstract on this project at a couple of conferences and journalists got hold of that, and while we did answer a couple of questions that came our way, we didn’t give any interviews or promote the work and so it’s rather inevitable that it got misreported and then that got misinterpreted. The most obvious problems were claims that:

a) our work only applied to T. rex (it doesn’t, it’s just the model)

b) we were upscaling the estimates for known animals (we weren’t, these are our projections of how big they could get) and

c) we did this to make sure T. rex stayed at the biggest theropod because we are T. rex stans ( I have *literally seen this* and it’s obvious stupid).

So what do we say and what do we mean? The best start point to get to that is to look at how we started on this. From the start of my career, I’ve been working on sizes of dinosaurs and the issues of estimating their size and what that means for their biology. Dinosaurs really were very odd in terms of how big they got and that opens up lots of interesting questions about how they got that big, how they grew, and how they functioned ecologically at large sizes. That interests the public too, and as a result there has inevitably been something of a parade of both ‘the largest X of all time’ for various dinosaur species and clades as well as ‘which was biggest?’ arguments over both species and specimens. And these are not inherently boring, but a) there’s a lot of them and b) a lot of it is kinda meaningless when scaling up fragments of specimens to try and work out which might have been 1% longer or heavier. But in particular this is meaningless when we look at specimens.

There are no good specimens of Spinosaurus. There are a handful of poor ones for Giganotosaurus. So we don’t know what we have for these animals in terms of normality – both are huge, but have we by chance found one of the largest members of these species (think a 2 m tall human) but we’ve randomly only ever found small individuals of something that never normally gets a mention in these debates like Acrocanthosaurus or Zhuchengtyrannus for that matter? Maybe they regularly got to 18 m long but as we’ve only even seen a couple of ‘small’ ones, we assume that’s their normal size. This is the kind of thing we were thinking about – do we really have a good idea of just how big the big species of relatively well-known species like Tyrannosaurus rex could be based on what we have? Are Scotty and Sue already giants, or are they more modestly sized and animals could get way, way bigger? After all, you wouldn’t pick 1000 random humans and think you likely got close to the largest human ever, so why do we think that might be the case for Tyrannosaurus, let alone Spinosaurus? This is after all, really common in biology. Look up the record sizes for individuals almost any species and they are massively bigger than the average or even typically ‘large’ animals and there’s no reason to think that even large dinosaurs wouldn’t fit this pattern.

So to look at this we (OK, Jordan) took a big dataset of alligators as a model for tyrannosaur growth, applied some filters and options to this (sexual dimorphism, biases in the fossil record), and applied it to the datasets we have of Tyrannosaurus that factor in things like the hypothesised growth rates and their distribution of sizes and try and model where the upper end of tyrannosaur sizes might be.

We find that Scotty and Sue are probably in the top 1% of body sizes (c. 8 t and 12 m long), so they genuinely are very big animals and it’ll probably be a long time before we find a decent skeleton that is bigger. So they are probably safe for now as your top picks for big theropods. But much as we expected, they are not even close to being as large as our model predicts. Our upper bound for this is some 15 m long and 15 t (note you don’t have to be much longer to be a lot heavier since you are increasing in three dimensions).

To be 100000% clear – we do not have any remains of any theropods this size. This is an estimate, based on a bunch of other estimates, extrapolations and uncertainties and we are in no way shape or form claiming this is *the* magic number of how big they got. But, based on the available data, we think it’s a pretty good ballpark figure and would be a good starting point when assessing say, the biomechanics or physiology of a giant tyrannosaur. We think it’s a pretty robust starting point for further discussions.

Obviously this issue does apply to huge numbers of dinosaurs and other fossil animals too. Things like various fossil mammals were we do have datasets of dozens and dozens of animals that likely represent a real population and might have a more constrained growth are going to be less affected (say mammoths), but any discussions about things like the largest sauropods, crocodilians, pterosaurs, temnospondyls etc. really should bounce into these same problems. If you have even a dozen specimens, but especially if you have only one or two, are they in the middle of the distribution of sizes, or at the bottom, or at the top? If they are already at the top, most others would be much smaller and vice versa, and that’s going to be a far bigger problem for working out ‘which species was bigger?’ than the fact that a different scaling approach to an incomplete tail might make your favoured animal 20 cm longer and now the biggest.

There is something of an irony here of course about us writing a paper that treads a fine line between “15 tons T. rex how awesome” and “2 “we need to stop arguing about how big dinosaurs were” but we have hopefully stayed on the right side. After all, big size is inherently interesting ecologically and biomechanically and this is worth talking about – working out what populations were like and how they were structured is important, and things like size are massively important for functional biology and looking at things like prey sizes in predators or feeding heights in herbivores (and then competition) are fundamentally linked to size. But it hopefully also then does highlight the futility of the constant ‘which was biggest?’ arguments and claims when we really don’t have any idea what the distribution of sizes are like on top of the traditional problems of scaling individuals from fragments.

We’re not stupid enough to think we will even begin to curb this endlessly running argument, but hopefully it will give pause for thought and we can at least try and steer the discussion towards things like what this means for these animals. Spinosaurus and Giaganotosaurus were massive carnivores, whichever way you look at it, and they lived at different times, in different places, with different faunas and environments to Tyrannosaurus and so each would be unique. That one of these might once in two million years have produced an animal marginally longer or heavier than the other two really doesn’t tell us anything about any of them and their size is what is interesting.

Anyway, there’s lots more to unpack so go ahead and click through the link to the paper. It is fully OA and should be accessible at the link below. I need to sign off by saying thanks to Jordan Mallon for all his hard work on this, he is very much the senior author of two here, and to Mark Witton who kindly provided some early art form his upcoming book which we were allowed to use in the paper and in the PR materials we have put out. And a final reminder, T. rex is cool, but we really didn’t do this work to make it the biggest and bestest dinosaur eva, after all, it already was.

Mallon, J.C .& Hone, D.W.E. 2024. Estimation of maximum body size in fossil species: a case study using Tyrannosaurus rex. Ecology and Evolution. DOI: https://doi.org/10.1002/ece3.11658

Intraspecific variation in Rhamphorhynchus

Published 18/07/2024 Uncategorized Closed
Tags: ,

Over the years I’ve muttered about intraspecific variation on here a fair bit. In general, it’s a problem for vertebrate palaeontology as our sample sizes are really low, so working out if having two more teeth is normal variation or likely a feature of taxonomic and ecological significance, or if this much larger individual is just part of a spectrum or a male is very hard to do. It leaves a lot of gaps and uncertainty in our interpretations and there’s not much we can do about it. However, what is odd is that there are cases where we very much can act on this and haven’t (cough, Coelophysis, cough) but today in a paper led by Mike Habib, we’ve tackled that issue for Rhamphorhynchus at least.

There are simply loads and loads of these out there, getting on for a couple of hundred in public collections and many of them are complete, or at least complete enough, that you can measure most of the major elements and see what the variation is like. We went into this expect this to actually be quite low as flight is supposed to be pretty constraining on how animals move and so their exact proportions and shapes might be more limited than terrestrial animals and those that swim. Also, it’s an opportunity to look at the idea that tail vanes were sexually selected display features, since if that was the major reason for the tail to be long, we’d expect this to either show more variation, or to be bigger in bigger specimens.

We do indeed find high levels of constraint (i.e., low levels of variation) in the head, neck, torso, forelimbs and hindlimbs, but also somewhat unexpectedly, in the tail too. That does very much point to them being very consistent at all sizes and that’s really useful to know for a few reasons.

First of all it’s very useful for various taxonomic and systematic characters, since for pterosaurs we often use differences in things like the ratios of the wing phalanges or the humerus vs femur to see how similar or how different they were. So this consistency within a species is good evidence that deviations from this represent genuine differences (or that things that are very similar are probably related). This really then should prove to be pretty foundational for future studies (and means that the old ones reliant on this assumption are pretty safe).

Second, it does well support the idea that all of Rhamphorhyncus muensteri are one species and that the revision by Chris Bennett that lumped several supposedly different taxa into this one was appropriate and that these do all belong together. Chris’ paper was already very solid but this is an independently line of evidence to support his revision, and again, so many papers are based on this species that having this firmed up (and future lumping or splitting of other species looking at their consistency) is really nice.

Although as noted above, the tail was low in variation, this did increase in larger individuals. Anyone who has kept up with the sexual selection literature and some of the stuff I’ve done on this with dinosaurs and pterosaurs will know that this is largely the pattern you would expect here. If the tail was important in providing at least some control in flight, that would explain the low variation, but when the animals get bigger and become sexually mature and signaling could / would dominate then we’d expect increasing variation as tails get larger and a longer tail might be an important signal. Early pterosaurs had tail vanes at the end of the tail, which absolutely could function to help control flight, but they are also quite varied in shape (despite the limited number known) and that they change in late in ontogeny which are both pretty major indicators of a signaling function.

This is a pretty short and simple paper, building on a major dataset that I’ve been building for years on top of Wellnhofer’s original big set of Rhamphorhynchus measurements. These kinds of dataset are invaluable for studies like this that can help frame our understandings of basic information about a species (just think how many arguments on things like species identification, ontogeny, anagenesis and the like could be resolved for tyrannosaurs if we had a dataset of 150 animals of one species) and we do need to do more like this for the datasets we do have or could get (I’d love to get full skeletal measurements of all the good Protoceratops out there). So while it’s not the biggest and most in depth publication, it really does provide some useful support for major ideas and hopefully sets up a lot more for the future.

The paper is in PeerJ so it’s fully OA and available here:

Habib, M.B., & Hone, D.W.E. 2024. Intraspecific variation in the pterosaur Rhamphorhynchus muensteri – implications for flight and socio-sexual signaling. PeerJ: 17524.

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