Archive for March, 2022

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.

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