Theropods bit sauropods too!

Courtesy of Davide Bonadonna (www.davidebonadonna.it)

For anyone with the misfortune to be a long time reader of these pages, you’ll know I’ve done a fair bit of work on bite traces on various bones. These are very often those bites inflicted by tyrannosaurs, in part because those were often accessible to me, but mostly because being the only large theropods around at the time, it meant it was relatively easy to assign bites to tyrannosaurs. Coupled with their apparent propensity to bite into or through bones compared to other theropods, this also made for fairly abundant specimens to work on.

But what about other faunas, the Late Cretaceous of Asia and North America are weird with their numbers of bone biting tyrannosaurs, but what about sauropod dominated faunas and where the theropods are smaller in general and less able to bite into bone? Having worked on one really intriguingly bitten Diplodocus from the Morrison a while back, this was an issue that had been on my mind with only a handful of bitten sauropod bones described, despite the fact that there were surely plenty more out there.

And so to my new paper. I’d wanted to do some kind of survey of sauropod bites for ages and started on one based on reports in the literature but they were few and far between. Speaking to Emanuel Tschopp and Matt Wedel garnered a few more and specimens that they’d seen in person but it was still rather lacking details, till Emanuel mentioned he had a student, Roberto Lei working on something similar. The two of them then took up the project and did a major survey of the AMNH collections with it’s many, many Morrison sauropod bits (and so dragged Mark Norell into the project too). When we got into analysing the data, we realised that we needed more knowledge of the jaws and teeth of the Morrison theropods that Mark or I could provide and so Christophe Hendrickx was roped in as well to work on that side of things and so here we are.

The paper itself is sizable and there’s loads to go through in terms of background and methodology but as it’s in PeerJ and fully open access I won’t go into all the details here, but it’s well worth checking out and all the supplementary data that is there (including some nice 3D scans of bitten bones). What follows really is more or less a few bullet points of some of the key findings or discussion areas from the paper, but there should be something of interest here for those interested in taphonomy, theropods, sauropods, ecology and more.

Ok so first off there’s a good number of sauropod bites out there – we had more than 80 bitten bones, and now we’ve found them, despite the work on our catalogue, plenty would benefit from detailed descriptions and some taphonomic and anatomical context. But while these are not quite as common as tyrannosaur bites, they are more common than previously realised.

This does come with the huge caveat that there’s clearly huge variation in the Morrison as seen from the very high bite rates in the Mygatt Moore quarry and their almost entire absence in the Carnegie quarry, so it is highly variable and might be hard to find an average value given that.

At least some of the bites we can confidently refer to as scavenging ones given their location (e.g., on the faces of centra) which would be hard to reach except on a long dead carcass when literally tons of meat would have been available before that came to be an accessible part to bite, and no bites we found showed traces of healing or were in a position to have likely been delivered as part of a predation attempt. While hard to prove, it’s likely that most if not all of these bites were either scavenging traces or at least very late stage carcass consumption.

As to who bit them, well we do run into the old problem of there being a bunch of similarly sized theropods with similar teeth and apparently biting capacity that makes it hard to identify which might be responsible for any given bite. We do discuss bite shape patterns and tooth spacing more than has been done before, but ultimately sheer size means we could refer a few to the largest theropods around and exclude a few smaller ones.

Notably, the Morrison theropods show quite a high level of tooth wear, which somewhat clashes with the lack of adaptations to biting into bone (compared to tyrannosaurs) and the lower overall rates of bite traces. So what is wearing their teeth if they are not biting bones? The answer lies in that they are not biting the bones we have as fossils, which are almost exclusively adult animals. Big sauropod bones are hard to bite into and harder still to destroy and eliminate from the fossil record. We know the juveniles are out there as they show up in mass mortality sites, and sauropods likely laid dozens or hundreds of eggs a year, so animals under a ton in mass should abound. They were what were wearing down theropod teeth, being preferentially hunted and consumed with smaller and less ossified bones being rather easier to destroy and not built like the large adult ones that would be picked around.

In short, despite a rather different composition of herbivores and carnivores, some overall similar patterns with theropods as predators and scavengers and taking predominantly juvenile prey seems to have been similar for tyrannosaur and non-tyrannosaur centric faunas. Sauropods were much bigger than the average ceratopsian or hadrosaur but the ecological patterns are similar when it comes to carnivore behaviour.

My thanks as ever to my coauthors and colleagues on the paper and I hope this proved an interesting set of issues. The upcoming episode of Terrible Lizards will have more on this too and Matt has a post of his own over at SV-POW so keep your eyes peeled for more updates

Lei, R., Tschopp, E., Hendrickx, C., Wedel, M., Norell, M.A., & Hone, D.W.E. 2023. Bite and tooth marks on sauropod dinosaurs from the Morrison Formation. PeerJ 11:e16327.

A new and large ctenochasmatid pterosaur from the Solnhofen region

Ok, so new pterosaurs come out all the time and yes, the Solnhofen region of Southern Germany is home to many, many pterosaurs in general and many ctenochasmatids specifically. This probably isn’t really a surprise since they keep turning up and given the quality of the preservation and the amount of time and space that has yet to be explored in the quarries, there’s almost certainly more out there. But, it’s still nice to see another new one, and in this case it’s both near complete and really well preserved and it’s also the largest yet known pterosaur beds from this region.

So, please welcome Petrodactyle wellnhoferi. Fully laid out in wingspan it’s just over 2 m so comparable (but a bit larger than) the largest known Rhamphorhynchus and larger than any of the other pterodactyloids in the Solnhofen beds. It’s also probably a subadult animal based on the lack of fusion in the skull (which has broken up a bit) and bits of the pelvis, although the rest of the skeleton is well fused. So it does look like it would probably have some more growing to do before it died so an adult animal would probably have been even larger. By pterosaur standards of course a 2 m or so wingspan is positively modest, but aside from Dearc and some other unnamed giant bits out there, it’s one the largest pterosaurs prior to the Cretaceous and the largest pterodactyloid too. There’s really not much to say about the size beyond this, but it does suggest that there are still larger things out there to find. I’d also note that there’s a bunch of isolated large wings and other bits in the Solnhofen that are clearly from large ctenochasmatids but Petrodactyle is bigger than any of them and doesn’t appear to be the same thing based on the available measurements of the wings etc.

That statement goes to the obvious question as to this being a new taxon, and well, yes. It’s very obviously distinct from the smaller taxa that have long and low skulls with lots (often lots and lots) more teeth. It’s also not got the long neck of something like Ardeadactylus, and has different teeth and a massively different crest to Cycnorhamphus, and indeed different head to possible ctenochasmatids like Germanodactylus. Overall it’s likely something close to Cycnorhamphus given the size, the tooth arrangement and the expanded frontoparietal crest tat the back of the skull which should have given it a strong bite. That said, the thing it’s arguably most similar to is Normannognathus from the Upper Jurassic of France. Annoyingly however, this is known only from the anterior tip of a snout and jaw making it rather hard to compare but it’s generally similar in size and shape and with a mammoth crest on the nose. However, close inspection shows quite a few differences in the details of the size, shape and position of the teeth and the nasoantobital fenestra and suggests that the two are distinct (though clearly similar) and enough that it’s worthy of a name.

On that note, the name here harks back to the very first formal publication of a pterosaur where famously the ‘Pterodactyle’ was mistakenly spelled or typeset wrong as ‘Petrodactyle’ on the cover. Our name here is intended to honour that work and the progress made in pterosaur research since. (And yes, before anyone asks we did read the ICZN rules carefully and consult with several people on this and we are sure the name is fine, we’re not messing with priority with a known incorrect name, that was never a formal genus anyway, that was put forwards 200 years ago). The species name, rather obviously honours Peter Wellnhofer for his extraordinary work on the Solnhofen pterosaurs (and let’s not forget plenty of other pterosaurs too and Archaeopteryx) and he’s long overdue having a Solnhofen pterosaur named in his honour.

The taphonomy of the specimen is rather unusual and worthy of comment. Most pterosaurs from the area are either brilliant preserved and articulated, or have fallen to bits and so either missing obvious things like wings and legs, or are only preserved wings and legs. Here, the animal has fallen to bits completely, almost every bone that could come apart has, including lots of bits like the first three metacarpals that almost never separate, but it’s also still pretty much all there and with the pieces next to each other (the wing finger bones are close to the hand and upper arm which is close to the scapulocoracoid, the cranium is next to the mandible etc.). This implies that the animal sank intact (or the bits would have dropped off and been lost if it decayed in the floating phase), but that it underwent decay in situ on the bottom and presumably took a good while to be buried or the decay would not have been extensive, and it must have been a low energy system or small bits like the teeth and ribs and toe bones would have drifted off. That’s all unusual for the Solnhofen in general, but it turns up as a pattern in other vertebrate fossils (including some pterosaurs) from the Mörnsheim Formation where this thing is from.

This Formation is on top of the beds in the area and is one that’s not well studied and the local quarry that produced this pterosaur has also been responsible for a bunch of other new taxa recently and suggests that there’s a whole raft of new finds out there still to come which is exciting. Yes, there continue to be new pterosaurs from Germany, but if there’s a whole new fauna from beds that have been little explored and would add a nice temporal aspect to being able so study their evolution that’s really nice.

Of course I’d like to finish by mentioning my collaborators, and in particular René and Bruce Lauer. I imagine few readers are aware of them, but they have created the Lauer Foundation for palaeontology and education and made their collection available for research. I’m sure some readers will already be moving to type that this makes the new specimen part of a private collection and therefore shouldn’t be published on, let alone, named but this isn’t the case. The Foundation has been set up with research in mind and material from it has already been described and named in a number of venues (just not the pterosaurs before now) and they have partnered with several institutes including the Natural History Museum. In short, these specimens are very much in the public realm. I do though want to thank them for allowing me to work on the material and supporting this work (and others which are still to come) as well as the contributions to the paper (René is responsible for the all the photographs including the UV work, and Bruce the stuff on the collection history and geology). I look forwards to doing more in the future with them. 

The paper is fully open access and available online here:

Hone, D.W.E., Lauer, R., Lauer, B., and Spindler, F. 2023. Petrodactyle wellnhoferi (gen. et sp. nov.): A new and large ctenochasmatid pterosaur from the Late Jurassic of Germany. Palaeontologica Electronica.

Everything you didn’t think to ask about the pterosaur sternum (and were afraid to ask)

Pterosaurs flew! No big shock there, but obviously flight places major constraints and selective pressures on the skeleton and we see that with the incredibly conservative nature of the pterosaur skeleton as a whole. So one would think that the associate flight apparatus in particular would be especially conservative and say more constrained than the feet or the neck, but it turns out an absolutely critical part of pterosaur anatomy is both basically all but unstudied and wildly variable, yes, it’s the sternum.

To try and correct that, I’ve just published a huge paper cataloguing and describing basically every sternum for every pterosaur out there. I’ve deliberately not covered every known one for a couple of very well-represented taxa like Rhamphorhynchus (where there’s a dozen or so known) but every taxon with a sternum (more than 60 it turns out!), however incomplete, is included and there are technical drawings of all of the well preserved ones. In this regard I need to give a massive, massive, massive shout-out to Skye McDavid who did all the technical illustrations for this paper and is a major reason why it looks so nice and I think helps communicate the anatomy of these bones. See her work and commission her to draw for you here.  Also a quick thank you to Rene and Bruce Lauer of the Lauer Foundation for providing access to, and photos of, a couple of really useful specimens that filled in a gap for me.

There’s been only a handful of descriptions of pterosaur sterna ever described properly. Hunting though the literature I repeatedly came across one line notes about it, even when one was well-preserved and featured in a photograph and only a couple of papers have looked at them in detail (and then not said much to be honest). Phylogenetic analyses of pterosaurs regularly included no sternum traits or only one or two, less than many simple traits like the unguals or pteroid. This is not a well-studied piece of the skeleton, despite it anchoring all the major flight muscles of (checks notes) a clade of flying animals! And ones that also were quadrupedal, so the sternum (and how it fits to the coracoids) and the associated musculature is also critical for terrestrial locomotion as well. This is the sort of thing that pterosaur works should probably not be overlooking!

What astounded me though, as hinted above, is just how incredibly variable they are between and *within* species. For an animal normally so limited in variation this is a key feature which is tremendously varied in overall shape and appearance and with loads of different details in the size, shape, arrangement and thickness of all kinds of bits to it that will affect where and how the coracoids fit, the muscles attach and the shape of the chest as a whole.

However, a major part of this seems to come down to the fact that the sternum is generally really poorly ossified and in fact I suggest it is often primarily cartilaginous in most animals (certainly juveniles) and only becomes bone, and thin bone at that, in near adult animals. That would explain a lot of the variation seen and the often complete absence of the sternum as a whole (or at least the sternal plate) in even some extremely well-preserved pterosaurs that aren’t missing any other features at all. That answers some questions (why the variation) but opens up others. Given how well ossified the flight apparatus is for even embryonic pterosaurs, how the hell have they ended up with a sternal plate of cartilage even in near mature large animals? The forces for flight muscles should be massive and the sort of thing to trigger early ossification not leave it till the last minute. And why is it so varied even in the adults where it’s well-preserved, id there a lot more going on in their muscles and so flight and ability on the ground that we have overlooked? And can we get some useful information out of this on their ecology and evolution, despite the poor preservation? These are questions I’ve left unanswered, but I am looking into them and I’d encourage others to do so as well.

I did, briefly, look at the ontogeny of the sternum and based on a nice (and so far not properly described) sternum seen under UV light it looks like the development is quite close to that hypothesised by Rupert Wild back in the 1970s based on a young Eudimoprhodon specimen. This would nicely align pterosaurs with other derived archosaurs and fits the general idea that they are indeed close to the Dinosauromorpha, but again there much more to do here.

The paper clocks in at 20 000 words and 21 figures (two thirds of which are multi-panel figures) so the MS is already very long and complex and I simply didn’t have the space or energy to get into phylogeny, origins, musculature, mechanics or pterosaur evolution in general even if I’d wanted to. Pointing out some very leading issues and hopefully priming things for future research and discussion is the best I could do after the mammoth description section but I would like to think it leaves the pterosaur sternum in a much better place than we found it and ready to spark renewed interest and research into this critical feature.

This is, to be sure, a pretty niche paper since the discussion in that context is a bit flimsy and I don’t think anyone is going to sit and read through all the descriptions for fun. But any new sternum coming up or any phylogeny or look at flight can now I think use this as a very comprehensive starting point to check what information is out there. Such ‘basic’ papers of anatomical description and illustration are so important (I use Wellnhofer’s 1970s classics and Bennett’s Pteranodon monograph almost every time I write a pterosaur paper) and so I hope this paper will add something useful in that regard. For now though, I’m mostly glad it’s off of my ‘to do’ list.

The paper is fully open access and available online here: Hone, D.W.E. 2023. The anatomy and diversity of the pterosaur sternum. Palaeontologica Electronica, 26.1.A12.

Why I don’t like using modern animal patterns in palaeoart

I remember from some years ago a pub chat with John Conway about what makes ‘good’ palaeoart. We came to the conclusion that it was down to three main things, 1) is it good artistically – is there a nice composition, correct use of perspective, shading and general technique, 2) is it accurate in the sense that the anatomy, environment etc. is right (no Velociraptors vs Diplodocus) and 3) personal taste. In other words, people can produce technically brilliant and scientifically accurate material and you don’t have to like it if it’s not to your taste (though hopefully people would still appreciate it). The others of course remain somewhat subjective too depending on what the artist is actually going for (if you want it to be surrealist or a tribute to 19th Century art then accuracy may not be what you are aiming for – just like John’s own recent History of Painting book.).

This last point about ‘what you like’ is most relevant here because I want to talk about a common theme in palaeoart that I really don’t like and while I’ll try to rationalise and explain it, I do want to be clear that it is a personal preference and so doing this doesn’t really make you wrong and I don’t want to give that impression. So what is this thing I’m now going to moan about for several hundred words? It’s using really clear and obvious patterns and colours from modern animals and applying them to dinosaurs. (And yes, other things too but usually dinosaurs).

I don’t mean really common patterns or general ones like countershading, marine animals being blue or forest ones being dappled or stripes that go through the eyes or anything like that, I mean doing an oviraptorid with the colours of a parrot, or a sauropod with a giraffe pattern or a lammergier pattern on a dromaeosaur or puffin-beaks on pterosaurs or plenty of others. This approach has been around for a long, long time but it appears to be ever more common and increasingly present in high-profile art and projects. I have thought about this a fair bit and what I don’t like boils down to a few key points.

First off, it seems really unoriginal. If you are making palaeoart that is supposed to be as rigorous and scientifically accurate as possible then there’s a lot of creativity potentially taken out of what you can do, but there’s plenty of options and freedom in colours and patterns (while still being realistic) with the unknown. Taking that away that option from yourself and your audience seems a real waste and one I can’t understand. OK, I can’t draw for toffee, but isn’t making up the colours and designs of the animals one of the most fun and creative bits? Just copying another species seems such an incredible waste of an opportunity.

Next up, it’s very distracting. I’m sure there are all manner of weird and unusual animals out there with odd patterns that can be copied without it being obvious (though I still think it’s better avoided) but it certainly pulls me out of looking at the art in front of me and simply going ‘but that just looks like a weird golden pheasant / king vulture / gemsbok’ rather than considering the art itself. It actively does a disservice to the work by distracting you from it.

Perhaps more importantly, I think duplicating well-known colours and patterns is something that, accidentally or deliberately, conveys things about animal depicted because of our understanding and associations with those patterns. If you put a peacock’s colours on a maniraptoran theropod you are imbuing it with cultural or behavioural traits about how they display and their mating system, their habitats and so on that we generally don’t know at all (or are most unlikely to be similar). It’s making inferences that shouldn’t be there and that’s not a good way to communicate about long lost animals and surely that’s a major aim of most palaeoart? I think it often shows a lack of understanding about signals too – after all, something like an agamid might have a bight head and neck to best show off it’s colours, but transferring that to a ceratopsian doesn’t make a lot of sense when the back of the frill and the neck would not be the most obvious place for bright signal colours to appear when the front of the frill has evolved to be the main signal. It’s ignoring or misunderstanding how the signals likely work in both the living model and the extinct animals and again that’s not conveying good information.

There are for sure common patterns like the general white and grey of seabirds, or eye stripes and bright breasts in birds, or occasional striping on antelope that can be easily transferred to dinosaurs and pterosaurs and the like *because* they are either generic, or ecologically driven, or are non-descript (you can’t point to a bird with an eye stripe as being unique it’s so common in a way that you can a puffin bill or a macaw’s pattern) and so again, this isn’t any kind of ‘never’ instruction to copy living taxa. But I think it’s far, far more often a problem than it is a good thing and I can’t be the only one who thinks this, can I?

Actually I know I’m not, since I’ve had this conversation with a few colleagues (palaeoartists and academics and those who span the two) and I know I’m not alone, though I also don’t know how far this feeling runs. Again, I’m not saying this can’t or shouldn’t be done and there’s always a time and place to break the ‘rules’ for various reasons, but what appears to be an often default opinion of just taking one set of colours and patterns and transferring them to another is way too common. It is, to me, not only dull and unoriginal but actively misleading in a way and imbues ancient animals with symbolism and traits that they shouldn’t have while taking the audience out of the moment. So please do it less and think about why you do it when you do.

Display features in the fossil record

It’s been more than a while coming but here’s an actual normal blogpost for the blog that’s not just PR for one of my own papers or projects (don’t worry, more of that coming sooner or later). This one has been prompted by some repeated comments I’ve seen in recent months about the hypothesis of various features being used for display by academics discussing dinosaurs in particular, but other extinct animals too.

The argument basically runs ‘you say it’s for display only because you don’t know what it is’ and usually followed with ‘like when archaeologists say it’s for ceremonial purposes when they don’t know what it’s for’. I can’t speak for my fellow professionals studying human culture, but I can very much speak for the assessment of display features having written perhaps more on this than anyone else when it comes to dinosaurs and pterosaurs at least.

First off, yeah, some researchers are very much guilty of this. One recent paper did argue something was for ‘display’ and that was the last word on the subject. That is, there was no actual evidence or discussion of the implications and how it might function or have evolved or what it was a good signal etc. and that’s clearly suboptimal at best. And it’s hardly new, it’s a classic old argument for lots of things on dinosaurs that’s been about for a century at this point and so people arguing for display without data isn’t some recent phenomenon. However, for plenty of cases we either do have decent scientific evidence or it’s fairly trivial to make a reasonable argument and that comes from our understanding of sexual selection in particular and signaling structures in general. So here’s a breakdown of the kind of lines of evidence and reasoning that can support display as a function.

1. It has no clear mechanical function. Not every bit of anatomy is functional in presenting a positive advantage to an animal, and some can be optimised for multiple things, or are used only very occasionally, or, yes, can be cryptic and we don’t know what they are for. But in general, selection is very good at getting rid of things that are costly and not useful (see how quickly flightless birds reduce their wings for example) and things argued to be for display are often large and heavy and are unlikely to survive many round of selection.

2. Diversity of form between species. There’s a reason the claws, fingers, ulna, humeri, spine and even ribs of moles, golden moles, marsupial moles, pangolins, aardvarks, armadillos and anteaters look very similar and that’s convergent evolution based on strong selection for a clear mechanical function. Animals, especially closely related ones, doing the same things in the same ways will almost inevitably end up with very similar anatomy. There’s a reason the wings of birds all look similar (flight), but the variety seen in their tails or head wattles etc. (display) are so varied. There’s probably only one or two optimum mechanical shapes and repeatedly deviating from that, especially in close relatives is a display hallmark. There’s also a general suggestion (though I think untested) that these tend to evolve rapidly as well compared to more classic functional traits.

3. Diversity of form within species. Moose all look alike but their antlers can be very different to one another and there’s usually far more variability of display features between individuals than other anatomical features, and that’s before the possibility of things like dimorphism (though an absence of dimorphism is not an argument against a signalling function for various reasons).

4. Rapid growth late in ontogeny. Sexually selected and display structures grow when the animal is at, or close to, sexual maturity and are very small or non-existent before then. So if there’s any indications of the growth rate from having multiple animals at different ages or sizes this can really help.

5. Structures are costly. A related point to 1, but the idea of ‘honest’ signals means that these features should be expensive to grow or maintain and have some kind of disadvantage for bearing them. And that also means they tend to be big and obvious (though with various trade-offs often at play limiting size – things can’t grow forever).

6. Analogy. While few features are clearly analogous to those seen in living clades (though of course some like fossil deer have lots of living and well-studied relatives) it is possible to draw analogies for some. The elongate tail streamers of microraptorines and various Cretaceous birds are obviously similar to those of numerous extant birds which have been shown to be signaling structures, so it’s reasonable to infer that similarly shaped ones in related animals with similar ecologies and behaviours and doing similar things.

Not everything fits these moulds perfectly. Features can be multi-functional like elephant tusks where they are under sexual selection but also are used to fight off predators, strip bark from trees and other things and probably are under selection to optimise multiple activities. And of course functions can change over evolutionary history with, for example, horns potentially shifting from an initial display feature to an anti-predator function or combining the two. Thus what the original function of a feature may have been and what selection pressures drove it to its current condition are not necessarily the same thing (though I suspect often are).

Take something like pterosaur head crests which have repeatedly been suggested to have some kind of steering function. We’d expect there to be only one or two optimised versions of this given the complexities of flight and the extreme similarity of pterosaur wings to each other, but instead we see enormous varieties of crests, they vary between and within species and both grow in size and change shape during ontogeny and are apparently small or absent in young juveniles. Despite the suggestion that this has a mechanical advantage, it’s not clear how it would work and one might expect if head crests were so useful they would have appeared in birds and bats too at some point, and it’s not like pterosaurs are short of flight control surfaces. Plus of course, for such light and flying animals, these would have been heavy features and therefore presumably costly.

So it’s fairly easy to make a case for these as display features even if we can’t do a detailed analysis of their flight mechanics or look at the detailed ontogeny and variation of many (any?) species to the degree we would like. In short, yes, palaeontologists need to be much better at explaining how and why they are arguing for display as a feature and simply saying ‘it’s big and odd’ while kinda hinting at a couple of these points, really isn’t good enough. But on the other hand, a lot of the things argued to be display features (ankylosaur armour, ceratopsian frills, hadrosaur crests, tyrannosaur hornlets, spinosaur sails etc.) fit most or all of these categories and even if in-depth analyses aren’t possible, it’s certainly a reasonable starting hypothesis that they are there for display.

So the often knee-jerk response of ‘ugh, you just say it’s display without evidence’ belies a real lack of understanding of the ways we can make reasonable inferences about these features and the simple fact that big and weird structures almost by default will match these lines of evidence (when say a big tooth or long leg or extra toe will not) should not argue against these as a starting point for discussion. Display features are rampant in large tetrapods at least and it should be no surprise that highly vision-oriented animals like dinosaurs and pterosaurs would have gone down various display routes. Yes, we need better arguments and testing, but I’m more than confident that many of these features will ultimately be shown to have had display as a major part of their functionality.

Anurognathid pterosaurs ate insects at night

Yes, it’s very early in the year but before 2023 had even hit, this paper managed to squeeze out actually appearing online on New Year’s Eve when I, and indeed most of the world, were not keeping tabs on journals so it rather passed everyone by and I’m now rushing to catch up! The good news is that it’s more anurognathid pterosaurs (arguably the best pterosaurs and certainly the cutest). These odd little animals have had a lot of attention in recent years with a bunch of new finds (some of which include new taxa like Cascocauda) and are just generally an increasingly well-studied clade given how many seem to preserve soft tissues which is rather nice.

For as long as I think anyone remembers, the anurognathids have been considered to be aerial insectivores, flying around at night and trying to catch insects on the wing. I don’t think there are any papers that have seriously challenged this hypothesis, and it’s been the default for decades given that their basic body plan and head shape means they have a massive gape, huge eyes, small teeth and wings well suited to this kind of flight. But it’s also an idea that hasn’t really been tested in any real way, relying on some basic (but perfectly reasonably) comparisons to things like whip-poor-wills and other similar birds.

So the central point of this paper was to try and do some more formal comparisons and see just how the anurognathids fare in comparison. I must confess I didn’t contribute massively to this paper, the lead author Alex Clark, who is based in Cincinnati, contacted me last year with the idea for the paper and really needed help with the pterosaur bit. He’s wrapping up his Masters on bird ecology and thought that it would be a good idea to do some formal comparisons on head shape in various insect-catching birds and those that operate in low light to the anurognathids to see how they overlapped. We also put in some comparisons to some insectivorous bats in terms of their canine shape and the similarly shaped teeth in the pterosaurs.

The details are of course in the paper but the really short version is this. Anurognathid heads shapes in terms of their gape is really similar to that of other birds that catch insects on the wing (like swallows and nightjars) and not like that of other pterosaurs. Their eyes are huge and again are like those of nocturnal, or low-light operating birds (in fact they are generally proportionally even larger). In short, this really strongly supports the conventional interpretations of anurognathid ecology. The tooth comparisons to bats were rather less helpful and the data is very scattered, and it’s at least not contradictory to the general idea.

No, on the one hand, no real surprises here. Our fundamental ideas were solid and the previous comparisons were reasonable, meaningful and turned out to be well-supported. Still, it’s really nice that this does back things up and that our basic inferences about anurognathids were correct and it means that those almost infinite drawings of the spiraling around after insects in the dark are not out of date. On that note, the paper does include some lovely new art of that very action with a new piece by Rudolf Himawan shown here.

I’d like to add a final quick thanks to Chris Bennett for generously letting us reuse some of his drawings to make our own figures clearer and to Manabu Sakamoto who gave us some useful pointers on some of the analyses. Mostly though, I need to thank Alex for inviting me to work with him on this project in the first place and seeing this paper through to the end.

Clark, A.D., and Hone, D.W.E. 2023. Evolutionary pressures of aerial insectivory reflected in anurognathid pterosaurs. Journal of Anatomy.

Microraptor ate mammals!

Ok, if we are being totally reductionist, one Microraptor ate part of one mammal once. But that’s certainly indicative of a pattern and that’s quite exciting. As you might guess, I have a new paper out today describing a Chinese specimen that shows this, though those with excellent memories and niche dinosaur knowledge might already know about this because it’s been announced before and way back in 2010!

Yes, this paper has been on the cards for a very long while. Back in 2010 Hans Larsson was over in the IVPP with his then PhD student Alex Dececchi and looking at various theropods. I was based there at the time working alongside my fellow Postdoc Corwin Sullivan under Professor Xu Xing. While looking over some flattened Yixian specimens, Hans spotted something that really people should have seen before (including me!). Clear as day in the holotype of Microraptor zhaoianus was the foot of a small mammal. Under the ribs.  Yeah, one of the most important and studied early feathered theropod finds had an obvious and very interesting set of stomach contents that had been completely missed.

Hans rather generously asked us all to collaborate on this find and we put in an abstract to SVP that year and so if you have the right knowledge you may have spotted this (or even seen his talk in Pittsburgh). In that regard this isn’t exactly news, and so it might come as a surprise that we ever got this out and so much later. Well, I’ll blame the others for that, (OK, mostly Hans!) but the fact remains it is now out and properly described, documented and put into some context and it’s the first, to my knowledge, example of a dinosaur eating a mammal, so that alone is nice and novel.

We don’t, annoyingly, know what the mammal actually is, despite having a much of things to compare it to, but we do know it’s small (mouse sizes) and doesn’t appear to have much in the way of climbing adaptations so would have been pretty terrestrial. That contrasts with interpretations of Microraptor as some kind of arboreal adapted flier that’s spending a lot of time in the trees. Still, we can’t say if this was predation or scavenging – though either way, it was likely this was picked up on the ground so it’s an interesting nugget of info on Microraptor diet.

On that note, this is now the fourth reported set of stomach contents for this genus with fish, lizards and birds also on the menu. Rather oddly, both fish and birds have been suggested to be something that Microraptor was specialised for, despite showing a) a diverse diet and b) no particularly obvious anatomical specialisations for either of these. Indeed, there’s a greater diversity of things eaten known for this animal now than any other dinosaur and that rather points to a generalist diet of any small thing going down the hatch. This of course comes with a few caveats here, there’s multiple specimens of Microraptor at play from more than one putative species and it’s at least possible that 1 species preferred things like lizards and mammals say, while another took birds etc. or these varied over time and space. Still, if there was any kind of specialistion we would expect to see multiple examples of single clades being taken, and I think that a generalist diet is likely.

That also fits with what we see in other small theropods as there are several with stomach contents or pellets featuring multiple taxa (e.g., Scipionyx) and suggesting they tended to eat a variety of things and specifically those that were rather smaller than them. This is in fact a bit of a pattern in general and while mammals aren’t always the best analogies, there is lots of data for them, and this is a trend seen there so it might well be that small theropod (be they small taxa or juveniles of big ones) tended to be more generalist. We do need to be careful here of course as we also then have preservation biases – Microraptor might, for example, have predated primarily on things like invertebrates and we know there were loads of beetles, spiders and the like around in the Jehol. But those don’t tend to fossilise well (especially not if crunched up and partially digested) compared to small bones, so perhaps these are just missing.

So one other thing we worked in here was to look at the jaw shape of dromaeosaurs in general and how this might fit with biting mechanics and so diet. While generally having incomplete skulls, Microraptor has a rather short head and lies in contrast to animals like Velociraptor with a longer and more slender skull, pointing to a proportionally harder but lest quick bite in the former (for its size) b. That also points to them not being especially adapted for things like insects where a hard bite wouldn’t be too necessary to kill or process them, but a quick bite would be an advantage. So while Micrioraptor might well have taken invertebrates as part of its diet, it doesn’t appear to be especially well suited to the task and biting small vertebrates looks like it was something more normal.

So there we have it, dinosaurs – perhaps unsurprisingly – ate mammals (and at least got their own back for Rapenomammus) at least on occasion. And more than that, Microraptor was (probably) a generalist predator of small vertebrate prey, though we can’t rule out scavenging or indeed other things like insects or even fruit as occasional parts of the diet. This might well be something common to many small theropods, though the general lack of data inhibits us from saying too much, the overall pattern of what information we have would tend to confirm this. It has taken us far too long to get this information out into the world but it’s finally made it and adds a nice note on theropod ecology and behaviour.

Finally, a quick thanks to my coauthors for sticking through all of this but also especially Ralph Attanasia III who kindly provided the illustration that went out with the press release and is shown above.

Hone, D.W.E., Dececchi, T.A., Sullivan, C., Xu, X., and Larsson, H.C.E. 2023. Generalist diet of Microraptor zhaoianus included mammals. Journal of Vertebrate Paleontology.

Larsson, H.C.E., Hone, D.W.E., Dececchi, T.A., Sullivan, C. & Xu, X. 2010. The winged non-avian dinosaur Microraptor fed on mammals: implications for the Jehol Biota ecosystems. Society of Vertebrate Paleontology (SVP), Pittsburgh, U.S.A.

Fifteen years of Musings

The Musings has been very quiet the last few years. I’ve obviously been busy at work and a lot of my outreach has shifted with the podcast (now more than 50 episodes done), various books (2 out, another nearly ready to got to the publisher), having the Guardian column for a few years, and being based in the UK again, I’m able to go and do more things in person, and then there’s Twitter of course which is so much better for dropping in a photo and comment than WordPress ever was.

Inevitably therefore, my output here has dropped and while it has typically been only a few posts a year and usually based around new papers. It still works very well for this, I can go into far more detail than on Twitter or similar platforms, cover all the ground I want to, link back to things, show photos or figures, and have control over it all (unlike media coverage). In short, I still like the format of blogs and I think they still have a place and I’m loathe to give up this one even if it has moved to being much more infrequent and most of the time is now only really about my research. So, it is likely to trundle on for now and fans and readers (assuming they still exist) can expect a few more posts to come and I’ve no immediate plans to wind this up.

That said, while it might be on a long and slow decline, I can take some solace in that it’s still going for now and by my count it’s now some 15 years of blogging (the vast majority on here and then a brief forerunner in a previous and now I think lost website). Compared to the palaeo-centric blogs out there (for example my hopelessly out of date and not at all curated list in the sidebar) I think this means that I’m one of the very longest out there and certainly one of fairly few survivors of the great burst of new palaeo blogs from the 2005-2010 era. I’d like to think that’s in part because this has remained a useful resource and while the posts and comments are less frequent than they used to be, plenty of old posts are still getting plenty of hits daily with some occasional big spikes when new stories break (the Fighting Dinosaurs post is going to be racking up hits forever).

So, Happy Anniversary to the Musings (even if that’s coming from its author) and I do hope there will be at least a few more years of posts to come.

The Future of Dinosaurs

After numerous substantial delays, my next popular science book is out now with Hodder. Called by the slightly cryptic title of ‘The Future of Dinosaurs’ the subtitle rather better explains what it’s really about ‘What we don’t know, what we can, and what we’ll never know’. Yes, this is all about the gaps in our knowledge and trying to spot some things that we probably can solve in the future with further application of our new techniques and new finds, but also look for areas which might essentially be unsolvable.

So this is a bit of futurism and crystal ball gazing, but hopefully something that’s interesting and based on a real understanding of current palaeontology. It’s not all just guesswork and gaps though, clearly to set the scene of what we *don’t* know, I have to start with what we do. What’s the state of play for various different aspects of dinosaur biology (there’s chapters on origins, physiology, appearance, behaviour, extinction and more) and what is certain or uncertain.

From there, it’s other what we don’t know. To give an example, we have recently started to piece together the colours and patterns of some dinosaurs which is something that I think many researchers thought would be effectively impossible. Its potential is enormous for understanding dinosaur biology, but it’s also something that we’ve clearly not yet exploited. Working out the (rough) colour of one black, white and orange Anchiornis is great, but we don’t know if that individual was an exceptional animal – maybe it was leucistic or melanistic and others were less black or less white in places, maybe it was a male in breeding plumage and the females were a different colour, maybe they went white in winter, maybe they were different colours in different regions or this changed over time? All of these are possible, perhaps even likely, and with the huge numbers of well-preserved specimens that have been discovered already and the likelihood of even more being found in the future, then this is something that I think we will inevitably begin to tackle in the coming years (OK, maybe decades). It really should be possible and while it would take a ton of time and research effort, there’s no obvious barrier to eventually being able to work this out and is something we will build on and understand better soon.

On the other hand, there are things we’ll perhaps never know about their feathers and colours. We can only work out some aspects of colour and patterns and things that rely on e.g. the orientation of the melanosomes that we use to work out colour are almost always going to be disrupted and other pigments for whatever reason don’t leave any kind of trace in the fossil record and can never be detected. It is also going to be nearly impossible to work out what displays they might have done, how they might have paired up or had different mating systems and so on, and so the colours will only get us so far.

While lots of people have talked at various times about where various branches of science are going next and what discoveries remain to be made, I don’t think there’s ever been a book like this trying to tackle lots of different aspects of our understanding (or lack thereof) and what shape our knowledge of dinosaurs might look like in the future. How successful I am, either in predicting what’s going to happen, or in suggesting why it might be the case, or for that matter in interesting my audience of course remains to be seen, but the book is out there now so let’s see.

If you do want to buy it, it’s available now as a physical book and ebook in the UK at least, and there is an audiobook version coming soon. This is also going to be released in North America soon through Princeton University Press under a different title (and different cover) as ‘How Fast did T. rex Run?’ but the content is identical.

Cascocauda – a new anurognathid pterosaur

Back when I was working on my big review of all anurognathid pterosaur specimens and their taxonomy, I realised that at least a couple of then unnamed specimens were probably distinctive and warranted naming.

One of them was a rather small, and not especially well preserved skeleton, that despite being nearly complete and with rather poor conditions to the bones, had extensive soft tissues. The preservation of these (both wings and filaments) had been the basis of some work on the specimen and not knowing what else might be going on, I dropped some of the authors a line to ask if they had any interest in the taxonomy of the thing and what they might be planning to do about it.

Cascocauda. Taken from Yang et al., 2022

As it happened, Zixiao Yang was indeed looking further into this as part of his PhD and was putting together a dataset on anurognathids to look at their growth. Having also been looking at this area in pterosaurs too they were kind enough to invite me to join them, and this work is now out.

The first thing to note is that we find that the specimen in question is indeed a new taxon and is named Cascocauda rong roughly translating as the fluffy ancient tail. For an anurognathid at least it has a rather long tail and hence that was chosen to be a key part of its new name. In terms of its relationships, we find it to be with the recently named Sinomacrops and Batrachognathus with all the other anurognathids forming a clade as the sister taxon to this group. We actually got this result using two different versions of the phylogenetic codings of which more in a second.

In addition to this more ‘basic’ work, the main part of the paper looks at the ontogeny of anuroganthids as a whole. While work that I’ve done (and plenty of others) have noted that a lot of pterosaur traits seems to be isometric and basically unchanging with growth, a) we don’t know how true that is of all taxa and b) if it’s not that’s potentially a big problem given how many taxonomic and phylogenetic traits we use for pterosaurs based on things like the ratios of the wing and leg bones.

So this is something we looked at here with the anurognathids, though with the rather odd caveat that we basically took the group as a whole rather than looking at the ontogeny of a single species (since that’s basically impossible). But if the anurognathids are as conservative morphologically as we think that they are then this is a reasonable approach to take and is certainly worth a look.

We do find that various bits of anuroganthids vary with size in some interesting ways though perhaps the most interesting is the length, and especially width, of the skull. They are called frog-mouths for a reason and that big gape is a key feature yet larger anuroganthids have a proportionally smaller skull. That points to both adults and juveniles having surprisingly similar head sizes and suggests that they are feeding on relatively similar sized prey even as they themselves get rather bigger.

Some other traits also appear to change during growth and could well be throwing off analyses that have used these characters when trying to piece together their phylogeny so these were removed or recoded in the analysis. As it happens this didn’t actually make a real difference to our results, but it’s nice to know that this isn’t apparel screwing up the relationships of the anurognathids at least, though it’s going to be something to keep an eye on in future when looking at pterosaur phylogenies given the number of taxa represented by only juvenile animals.

I’ll leave things there and won’t go into more detail since the paper is easily accessible and that will be the place to go for more details.

Yang, Z., Benton, M.J., Hone, D.W.E., Xu, X., McNamara, M.E., and Jiang, B. 2022. Allometric analysis sheds light on the systematics and ontogeny of the anurognathid pterosaurs. Journal of Vertebrate Paleontology.

Welcome Dearc, a giant rhamphorhynchine

Today sees the publication of a new and very cool British pterosaur – Dearc sgiathanach and as I got to see the paper a while back as a referee I thought I’d used that privileged advanced knowledge to write a post about it as it’s a really neat animal and British (and specifically Scottish) pterosaurs do not come around every day.

Photo of the skull and part of the body of Dearc, taken from Natalia Jagielska’s Twitter feed

First off, the basics on the name. It’s full name basically means ‘wing reptile from Skye’ and following s recent trend of using local languages for scientific names rather than Latin or ancient Greek, this is actually based on Gaelic. That’s really rather neat and I can’t think of any other Mesozoic animal so named in the UK and I hope it is not the last. Oh, and the authors (Natalia Jagielska and company) were also good enough to include a phonetic pronunciation in the paper (link below) as ‘jark ski-an-ach’ so hopefully people will be using that properly.

For a Middle Jurassic pterosaur, it has got a lot of good material and not only is it preserved in 3D (and there’s some great CT scan data of it) with most of the skull and wings, and a good amount of the vertebrae column etc. as well. You’d always want more of course, but it’s really a lot and in good condition too. The paper covers a lot of the anatomy in depth but I’m also sure there will be more to come on this in the future.

It’s clearly a non-monofenestratan pterosaur and actually one that is very close to Rhamphorhynchus, enough in fact to be found to be a member of the Rhamphorhynchinae in the phylogenetic analysis that they did. It actually comes out with the odd Chinese pterosaur Angustinaripterus which is known from a single large skull with exceptionally long teeth. In short, you’d expect this animal to be one of the larger and later version of these non-monofenestratans and a shoreline or even oceangoing predator of fish.

What’s really interesting about this animal is its size. The largest good specimen of any non-pterodactyloid pterosaur that we have is a really large Rhamphorhynchus that is held in the Natural History Museum in London and is right around 1.8 m in wingspan or perhaps is a touch more. That is already much larger than any other specimen (the next biggest is about 1.4 m) and while there are some odd large bones out there (like the Angustinaripterus skull) that has long been thought to be about as big as they get. On top of that, Rhamphorhynchus is from near the end of the Late Jurassic and so (anurognathids aside) is among the very last of the non-pterodactyloid pterosaurs. 

Although incomplete and impossible to measure or estimate perfectly accurately, Dearc is complete and robust enough to give it an estimate of over 2.5 m in wingspan. So that’s massively bigger than we have for even the largest Rhamphorhynchus (out of 150 specimens!) and being Middle Jurassic, it’s much older too. Add to that, it probably had more growing to do too.

So that pretty much blows out of the water two classic ideas about the size of non-pterodactyloids. They could get above 2 m in wingspan and indeed much bigger, and it didn’t take them till the very end of the Jurassic to even get up to 2 m in wingspan. That’s really quite an interesting shift in our perceptions of their evolution and in particular means they were getting into some biomechanical realms that we didn’t think they could achieve without a pterodactyloid bauplan. In short, this is a really cool find and it promises much more in the future for our understanding of the evolution and flight of these pterosaurs.

Jagielska, N., et al., 2022. An exquisite skeleton from the Middle Jurassic of Scotland illuminates an earlier origin of large pterosaurs. Current Biology.

Ceratosuchops and Riparovenator: two new British Baryonychines

Today sees the publication of my most recent paper and it’s inevitably exciting as it describes two (yes two, count them) new, large theropods from the UK. Both join the burgeoning ranks of the spinosaurs, which have been increasing in lumber a lot of late and more specifically these are baryonychines.

While Spinosaurus tends to get all the attention, it and its kin, the especially large and sail-backed spinosaurines are known from extremely fragmentary remains and the smaller and less spiny baryonychines include Suchomimus and Baryonyx that are known from much more material.

In the case of the latter, this has been absolutely central to work on the spinosaurs as a whole as being the most complete and by far the best described specimen out there. The foundational monograph by Alan Charig and Angela Milner (who sadly passed away recently) being a cornerstone of spinosaur research. It’s also inevitably rather central to our work here since with two new baryonychines then we going to have to compare them to Baryonyx.

As usual, I don’t want to get into the minutia here since if you really want to look through the details of the diagnoses and traits and stratigraphy that’s all covered in the paper and this post is better placed to give some context to what we have done and why. The first thing of course is the names and their meanings. First off we have Ceratosuchops inferodios or the horned crocodile face hell-heron, the generic name referring to its appearance and species referring to the putative ecology of spinosaurs as a whole. After that is Riparovenator milnerae or Milner’s riverside hunter, in tribute to Angela’s work on these animals and again the ecology of these animals.

The second obvious thing to look at is what actually is there for the remains. Sadly, (if rather predictably) not that much though we do have nice snouts and parts of the skull roof and braincase for both, and in the case of Riparovenator, there’s also a nice section of tail. While pretty incomplete therefore, we do have more than some other spinosaurids and crucially we have the same parts of the skulls of both of these as we do for Baryonyx and Suchomimus. That’s obviously a huge bonus when it comes to the taxonomy work of sorting these animals out and we can make direct comparisons to these parts of the skulls that hold a lot of important traits.

Still, an obvious question about these British animals would be the vexed issue of ontogeny and if one (or both) were juveniles of each other. Happily, all three of the British ones are all extremely similar in size (within about 105 of each other) so it would be pretty hard to argue that they were very different ages and so the differences in anatomy are going to be ‘real’ and not part of their growth patterns. (And if they were very different ages but still the same size that would also suggest they have very different growth patterns and are therefore likely different taxa anyway). While we’re on the subject of the quality of the data here, it’s also worth noting that the specimens are generally really well preserved and not distorted so again, it’s a pretty safe bet to take the available features at face value as being genuine.

A major part of this paper is a new phylogenetic analysis done at the specimen level, with loads of odd bits and scraps of spinosaur material included for the first time in a comprehensive study (though some more things have appeared since we finished so it’s not 100% coverage). There’s not too many real surprises in there, but it should be a great start for resolving some other taxonomic issues for spinosaurs going forwards. One key thing though is the very clear signal that all of the earliest spinosaur material is European in origin and it looks to be a very strong case that this is a European group that then migrated out from here on multiple occasions.

Finally, there is the issue of the ecology of these animals. We don’t actually know if the two were contemporaneous with each either and either or both could be with Baryonyx and so while I’m sure some people will read this as ‘there were three together?!!’ we don’t actually say that. It’s perfectly possible from the data we have that all were somewhat separate in time and in space and of course niche partitioning is absolutely a thing too. I wrote this post on these issues a while back with this paper in mind to make the point about these kinds of situations and how it is easy to misinterpret them or assume that multiple species of large carnivores being together is somehow unusual or wrong. In the case of spinosaurs in particular, I’ve suggested that they are rather off in that they are except when they are common when they are suddenly very common (https://archosaurmusings.wordpress.com/2010/01/25/a-late-cretaceous-asian-baryonychine-probably/

) and this perhaps another example of that and hence the plethora of finds in the South of the UK.

I’ll finish up here, but obviously I want to thank Chris Barker and Neil Gostling for inviting me into this project and all my co-authors for their contributions to this publication. The paper is fully open access and available here: Barker, C.T., Hone, D.W.E., Naish, D., Cau, A., Lockwood, J.A.F., Foster, B., Clarkin, C.E., Schneider, P., and Gostling, N.J. 2021. New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European Origins of Spinosauridae. Scientific reports.

There’s lots more about these finds online with a Terrible Lizards podcast here with Chris Barker and Darren Naish, and both Darren and Andrea Cau have blogposts out on this too.