Non-tyrannosaurs biting like tyrannosaurs

The internet has obviously revolutionised communications between people but it throws up new connections and opportunities that I think few would have seen coming. A couple of years ago, Dan Chure put up a photo on Facebook of a small sauropod femur with some very obvious theropod bites on it. This was from the Dinosaur National Monument site where Dan worked (he’s now retired)  which made it unusual since non-tyrannosaur faunas tend to have far fewer bites in them than do those where the tyrants are present. At first glance though, this looked like a tyrannosaur-type bite with a long set of bite-and-drag marks where the cortex had been really ripped through so this was really unusual. With my extensive background of research on theropod bites, this was something I was very interested in and I didn’t recognise it. I’d assumed something this unusual and interesting would have been described before but not only had it not been (as far as I know it’s not in the literature at all) but no one was even planning to work on it.

So Dan and I got to work on this and inevitably ran into some issues. Identifying what is effectively an isolated and damaged femur from a young animal is tricky. There are a lot of sauropods knocking around in the Morisson and femora are not one of the more diagnostic elements, but we were able to show that it was from a diplodocoid. The femur s under 60 cm long and while that’s obviously a sizeable animal, it is really small for a sauropod and means this was likely a pretty young individual.

The marks on the bone are concentrated on the dorsolateral side of the bone and consist of a series of grooves across the face of the bone that are especially deep at the upper end. At their deepest, these go through the cortex and indeed a fair bit of bone seems to have basically been snapped off, perhaps coming apart as a result of the amount of damage to the element.

This could also have happened at least in part through transport too. Taphonomically the bone has an odd history, apparently isolated, it is actually very close to a second and near identical femur which suggests that both were from a single animal, but there are not other obvious comparable bones nearby and this suggests a very disarticualted carcass. Not only does the other femur lack any bite traces but these are essentially absent in the quarry as a whole. Of the huge number of bones present, only this small saurpod has any bites on it. That’s obviously really rather odd – if loads of carcasses were around, you might expect either tons of bites from theropods getting stuck into the wealth of food or almost none because feeding carnivores avoided biting bones when there was lost of muscle, or they simply couldn’t get to the bodies (if they were say underwater). But one bone badly bitten when even it’s companion wasn’t and then nothing else, is clearly an oddity. It suggests some odd circumstance where this one bone was, perhaps temporarily, accessible to a feeding theropod though the exact details of what may have happened are irrelevant, it does add a level of intrigue to this case.

The bites themselves are reminiscent of those made by tyrannosaurs – long and deep scores made by a bird-like pull back of the head. That action was common among larger theropods but the specialised premaxillary teeth of tyrannosaurs made them well suited to doing this when the teeth were in contact with the bone. Non-tyrannosaurs did not have the inclination to do this when feeding as with their thinner teeth, these would be at risk of breaking. Other fossils show they had the power to bite deep into bones but generally didn’t, rather than couldn’t, making this case a rare example of this behaviour. While it may have been an exception, it does at least show the capacity of non-tyrannosaurs to feed in this way.

Exactly which theropod this may have been though is a still harder question to answer. One of the nice things about bites left by large tyrannosaurs is that they are the only credible candidates for the trace maker in a given environment and you are generally only picking between a couple of pretty closely related species. You may struggle to say if a bite was from Albertosaurus or Daspletosaurus say, but it was still a large tyrannosaur with fundamentally simialr anatomical specialisations and behaviours and therefore general interpretations are going to be pretty solid either way. In the Morrison though you have large allosaurs and ceratosaurs and some unstable / uncertain taxonomy too (like Saurophaganax) meaning the options are much more open.

Various researchers (inlcuding me) have commented on the possibilities of using the spaces between teeth as an indicator of which animal might have left a given mark. However, as Dan and I cover here while in theory that could be useful, in practice we can’t account for the variables of things like ontogeny and missing or offset teeth and the angle at which an animal might drag the head could all dramatically affect the spacing between traces left by the teeth. In short, where there are mutliple credible trace makers it it going to be very hard to pick between them without soemthing diagnostic like shed teeth.

Still, wit no large tyrannosaurs around in the Morrison, whatever did this was not one so we can at least say confidently that at least one large theropod was engaging in tyrannosaur-style feeding, even if it was rare. Perhaps of course the style of feeding was common but merely tooth-bone contact was limited and this fits with waht we do know about that pull feeding action. Even so, this is something of a frustrating project between the quirky history of the bone and its bites and the uncertain identities of the bone and the trace maker. Hopefully more traces like this will turn up or be described from Jurassic beds and we may begin to piece together the feeding styles of large theropods. This one might be a partial mystery for now, but it hopefully provides some useful data fitting into what we know about the behaviour of some of the big theropods other than tyrannosaurs, even if this leads to the idea that they may have been more simialr to each other in this regards than we previously realised.

 

Hone, D.W.E., & Chure, D.J. 2018. Difficulties in assigning trace makers from theropodan bite marks: an example from a young diplodocoid sauropod. Lethaia.

Citations of lists – a small moan

I used to do this sort of thing a lot on this blog but with the posts generally slowing it has become rather more rare (for better or worse, most readers would likely go for better I imagine) but it’s time for a moan. This is something I have seen before but recently I’ve had a whole spate of papers to review that do this and it seemed something annoying and common enough to put out publicly so that a) hopefully people will agree with me and b) then some will stop doing it.

This is about points in papers were a big long list appears in the text but then all the citations come at the end. So you get something like ‘…as seen in Tyrannosaurus, Tarbosaurus, Daspletosaurus, Gorgosaurus, Albertasaurus and Zhuchengtyrannus (Smith et al., 1994; Jones, 2001; Smith and Jones, 2005, 2007; Smith and Smith, 2016, 2017).

At best this is annoying and at worst actively cryptic about information. In my example there are six taxa and six papers so you can assume that they realte to these taxa in order, but even if they do, it’s a slight pain to work out exactly which paper refers to which one. I’ve seen examples like this with a dozen papers and then you really do have to move your finger along and count to try and work out which is which. Even so, this assumption may not be true – are those papers certainly in the right order? The only way you can find out or to check is to go and read each to follow it through. The point of citations is a paper trail of what you did and where you got the information from and to credit it correctly. So this list in this format is actually making you redo the work of the author and is hardly something that actually helps communicate information.

Worse, I regularly see such lists have different numbers of points to the number of references given. That means that at least some points are covered by a single reference (if they are more numerous) or multiple points are covered in one reference (if there are more points), but again, it’s impossible to know which is which. You are back to having to reread each paper to check.

In short, for the apparent sake of making a list look slightly nicer on the page, the information the reader often wants, even needs (which paper does or does not directly refer to which of those things in the list, be they taxa, anatomical features, localities or whatever) is obscured. Now, I do get that this easier on the eye to read than say ‘Tyrannosaurus,(Smith et al., 1994),  Tarbosaurs (Jones, 2001),but personally I don’t find that an issue, I’ve read enough papers to skim over references while reading without a problem. More importantly, it is perfectly clear exactly which paper refers to which point and so is far superior to a big lump of papers are the end.

If it’s not immediately clear, it can’t immedaitely be verified and you may have to wade through a large number of references to check. This is hardly the end of times, but for me this really helps neither the author show that they have done what they set out to or the reader follow that up. And so really, please, please, cut out the lists followed by a list of references. Authors don’t do it and referees and editors, pick up on it and ask people to make specific points supported by specific references.

Flugsaurier 2018 deadline extended

The LA Flugsaurier meeting is creeping closer and we are working hard to get everything in place. However, as sure as night follows day, people are behind on their abstracts so we have decided to extend the abstract submission deadline by a week! The new deadline is April 9 (not 2nd!).

Keep up with new information and deadlines on the Facebook group or the conference website.

Ceratopsian horns and frills – what drove their evolution?

So I have another new paper out on sexual selection and what this means for dinosaurs. This one has been led by my PhD student Andy Knapp (follow him on Twitter here) and he agreed to write about it here:

Ceratopsians are among the most instantly recognisable dinosaurs thanks to their enormous, elaborately-adorned skulls. The frills and horns of ceratopsians have been the subject or ongoing debate in palaeontological circles since the discovery of Triceratops in the late 19th century. Triceratops is known to everyone, specialists and non-specialists alike, and remains the classic example of ceratopsian skull morphology, with three large forward-pointing horns and a thick, shield-like frill extending back from the rear of the skull. It seemed obvious to early palaeontologists that these features had evolved for protection. The trouble is that Triceratops is almost alone in possessing this precise combination of features. Many of the larger ceratopsians that we know of didn’t have such large horns, and most had large, weight-saving fenestrae in their frills which would offer little protective value in life. In recent years the large number of known ceratopsian species has increased with a steady stream of new discoveries, each with its own characteristic horn and frill morphologies. These discoveries have posed a whole load of new questions as to what their purpose was.

Large, elaborate features with no obvious use – such as the frills and horns seen in ceratopsians – are expensive to grow and maintain, and obvious parallels in living creatures involve sexually selected features. The most extravagant examples of sexually selected features, as realised by Darwin in his book The Descent of Man, involve extreme sexually dimorphism in traits and/or overall size; peacock tails, elephant seals, etc. In contrast, there is no convincing evidence of sexual dimorphism in any ceratopsian taxa. This has led some researchers to reject the hypothesis of sexual selection as an explanation for exaggerated features in ceratopsians and other dinosaurs, and suggest that instead these features have evolved for species recognition.

Species recognition is the idea that being able to differentiate members of your own species is vital in herding, protection and mating. Basic examples of ‘species recognition’ are everywhere in nature; zebras don’t have trouble telling lions apart from other zebras! The more specific idea that physical traits evolve as a mechanism to allow differentiation is controversial. There are a few known examples of divergence of traits in closely-related taxa where hybridisation could be detrimental to fitness, a process known as reproductive character displacement. This is distinct from ecological character displacement, where sympatric taxa that fill similar ecological niches diverge in traits associated with resource acquisition. The rock nuthatches Sitta neumayer and S. tephronota exist across central Asia in partially overlapping ranges. Where they are sympatric, the distinctive dark eye stripe, ubiquitous across the rest of the two species’ ranges, fades in intensity in the population of S. neumayer. This has been interpreted as an adaptation to prevent hybridisation between the two species. Crucially, other known examples of reproductive character displacement involve minor modifications to pre-existing, often sexually selected features.

Reproductive character displacement is not expected to operate where a taxon exists in isolation, because there is no evolutionary pressure for traits to diverge. This prediction allows us to test the hypothesis of species recognition as an explanation for the presence of distinctive traits in extinct taxa for which we have good geographical information. Ceratopsians fit these criteria well. They were widespread across North America and Asia, speciose, and many species are known from relatively complete remains. We compiled and assessed a list of 350 cladistic character traits for a 46 well-known ceratopsian species and compared how the traits generally considered ornamental, and thus contenders to be species recognition traits, varied between sympatric and non-sympatric species. We also examined at other traits; those that were internal and therefore not visible during the animal’s life, and those that were external but not considered to function as a display trait. We then conducted a pairwise comparison of each possible species pair for three distinct character classes; internal, display, and external non-display.

We then compared the results for species pairs known to be sympatric and, therefore, likely to encounter one another in life, with non-sympatric species pairs. For each category we found increasing character divergence with increasing phylogenetic distance as expected, but, crucially, found no difference between the disparity of the display characters of sympatric species and those of non-sympatric species. This suggests that interaction between species has no effect on the evolution of ornaments in ceratopsians, and that species recognition is not a contributing factor to ornament evolution. Of course, it is entirely plausible that ceratopsians were able to identify conspecifics by their ornamentation, but this would have been a byproduct of ornamentation, not a cause.

The ruling out of species recognition as a driver of ornament evolution, at least in ceratopsians, shortens the list of possible explanations. Avoiding hybridisation would benefit both parties and so the evolution of distinguishing features should tend towards a zero-cost exercise. In contrast, ceratopsian skulls are the largest of any terrestrial vertebrate and impose certain limitations on their bearers. Computer models of ceratopsians have shown their massive skulls shifted their centre of mass further forwards than other quadrupedal dinosaurs. Compared with the hadrosaurs that they shared the ancient river deltas of what is now Canada’s Dinosaur Provincial Park, this made them poor swimmers and liable to drown when crossing bodies of water. This obvious handicap, along with the sheer cost of growing and maintaining such a large component of overall body mass that has no obvious mechanical or ecological function, points to an explanation that favours investment in high-cost structures.

An additional result of our analysis was that at the lowest phylogenetic distances, ornamental traits were around ten times more diverse than internal traits and three times more diverse than non-ornamental external characters. This suggests a general trend for rapid evolution of ornamental traits. Rapid evolution and high-cost are both hallmarks of sexually selected features. If the frills and horns of ceratopsians are sexually selected, as has been previously suggested, they are distinct from extant taxa in being both highly exaggerated and sexually monomorphic. This combination suggests strong sexual selection that applies more-or-less equally to both sexes. Some evidence for ceratopsian ornamentation being sexually selected has been demonstrated previously, and this study both adds to this evidence and rejects a competing hypothesis. Ultimately, our findings open up further avenues for exploring the life history and ecology of these fascinating and enigmatic creatures.

 

Knapp A, Knell RJ, Farke AA, Loewen MA and Hone DWE (2018). Patterns of divergence in the morphology of ceratopsian dinosaurs: sympatry is not a driver of ornament evolution. Proc. R. Soc. B. 20180312. http://dx.doi.org/10.1098/rspb.2018.0312

 

References

Brown WL and Wilson EO (1956) Character displacement. Systematic Zoology. 5: 49-64

Darwin, C. (1871). The Descent of Man and Selection in Relation to Sex. London, John Murray

Henderson DM (2014). Duck Soup: The floating fates of hadrosaurs and ceratopsians at Dinosaur Provincial Park, in Eberth D and Evans D (eds). Hadrosaurs. Bloomington: Indiana University Press. pp. 459-466

Hone, D.W.E., Wood, D., and Knell, R.J. (2016). Positive allometry for exaggerated structures in the ceratopsian dinosaur Protoceratops andrewsi supports socio-sexual signalling. Palaeontologica Electronica. 19.1.5A: 1-13

Knell RJ, Naish D, Tompkins JL, and Hone DWE (2012). Sexual selection in prehistoric animals: detection and implications. Trends in Ecology and Evolution. 28; 38 – 47

Maidment SCR, Henderson DM, and Barret PM (2014). What drove reversions to quadrupedality in ornithischian dinosaurs? Testing hypotheses using centre of mass modelling. Naturwissenschaften. 101: 989 – 1001

Padian, K. and Horner, J.R. (2010). The evolution of ‘bizarre structures’ in dinosaurs: biomechanics, sexual selection, social selection or species recognition? Journal of Zoology. 283; 3 – 17

Flugsaurier 2018 Circular

This has been in the works for too long but we do now have a formal first cicular for Flugsaurier 2018. The abstract submission date is but 6 weeks away, but then you should have known about this conference from 3 years out… 🙂

 

Flugsaurier 2018: Los Angeles
The 6th International Symposium on Pterosaurs: First Circular

Welcome to Los Angeles

We invite all individuals working on, or interested in, pterosaur biology or associated geosciences to submit abstracts for the 2018 Flugsaurier meeting in Los Angeles, CA, USA. The meeting will be held August 10-14 at the University of Southern California and the Natural History Museum of Los Angeles County. Please mark your calendars for what we are sure will be an exciting meetinng!

Current  Calendar:

all events at USC, except Welcome Reception/Specimen Viewing and Field Trip

August 10th: Ice Breaker at USC (AM) and aRernoon technical sessions
August 11th: Technical Session; Welcome Recepion and Specimen Viewing at NHMLA
August 12th: Technical Session (AM); Workshops (PM); Paleoart Exhibition
August 13th: Technical Session (AM); Workshops (PM); Conference Dinner (PM)
August 14th: Field Trip (TBD)

Notes: The NHMLA is located adjacent to the main campus of USC. The Conference Dinner loca4on is TBD, but we expect to use a venue either on the USC campus or in nearby Downtown Los Angeles. The Field Trip costs will be included in the registraion. We hope to arrange a trip to the Moreno Formation of California.

Abstract Information
Abstracts have a limit of 500 words with up to 3 references (Harvard format) and 1 figure.
For details, or to determine if abstracts meet criteria, please contact Michael Habib:
habibm@usc.edu. Abstracts can be submi]ed here. We will accept mul?ple submissions from authors but only one talk per lead author. Abstracts will be reviewed. We cannot guarantee speaker or poster slots. Abstracts submissions are due by midnight, Pacific Time, on March 26th. EDIT: Deadline extended – the new deadline is April 9th.

Host Committee:
Host committee will also be the review committee for all abstract submissions Michael Habib (Chair), Brent Breithaupt, Nathan Carroll, David Hone, Lu Junchang, Elizabeth Martin-Silverstone, Taissa Rodrigues.
Special Thanks goes to Luis Chiappe for hosting the NHMLA components of the program.

Travel Information

Accommodations:
The closest hotel is the Radisson Hotel Los Angeles Midtown at USC. Rooms at this hotel
average 178 USD per night: https://www.radisson.com/los-angeles-hotel-ca-90007
Less expensive options can be found in some parts of Downtown Los Angeles. The American Hotel often has rooms for 85 USD per night: http://www.americanhotella.com/. The hotel is walking distance from a light rail sta?on, from which rail travel to USC and the NHMLA is approximately 10-12 minutes.

We are currently working with USC to secure some low-cost housing on campus. We expect this to be limited and available mostly to students. More informa?on about on-campus housing will follow as soon as it is confirmed.

Travel to Los Angeles:
The closest airport to the conference venue is Los Angeles International (LAX). However,
travelers can also fly into Hollywood Burbank Airport (BUR) or Long Beach Airport (LGB). LAX runs regular buses to Union Sta?on, from which light rail can be taken to Downtown Los Angeles and USC.
Note that travel to the United States for a conference typically requires a B Class Visitor Visa, unless the port of origin is part of the Visa Waiver Program. For details on Visitor Visa applications, and to determine if your country of origin is associated with a VWP, please check here: https://travel.state.gov/content/travel/en/us-visas/business.html

Natural Histroy Museums of LA County:
The Natural History Museum of Los Angeles County is the largest natural and historical museum in the western United States. Its collections include nearly 35 million specimens and artifacts and cover 4.5 billion years of history. The NHMLA houses an extensive collection of specimens from the Niobrara Chalk and Pierre Shale, including a sizeable collection of Pteranodon specimens and one of the few partial skeletons of Nyctosaurus. In 2016, the NMHLA hosted Pterosaurs: Flight in the Age of Dinosaurs, from the AMNH.

Other Area Museums:
Alf Museum, Claremont CA: The Raymond M. Alf Museum of Paleontology, located on the
campus of The Webb Schools, houses extensive vertebrate fossil collections, including multiple excellent pterosaur specimens. It is the only nationally accredited museum in the USA on a high school campus. The Alf Museum provides a unique research program for Webb students where they study fossils they find on collec?ng trips and publish the results of their research in collaboration with museum staff, a unique program for secondary school students.
Tar Pits Museum, Los Angeles CA: Part of the LACM system of museums (along with the
NHMLA), the Tar Pits Museum in Los Angeles has one of the largest Pleistocene collections in the world. Active excavation continues throughout the year on the grounds of the museum, which is located in the Miracle Mile district.

 

The official website to keep an eye on is this one: https://flugsaurier2018.wordpress.com/

 

New Perspectives in Pterosaur Palaeobiology

So a new volume of papers in now online that I have edited and now there’s lots of pterosaur goodness to access. This is above titled volume produced by the Geological Society and is volume 455 in the Lyell Collection. The full list of papers and links is here but while most have been available online for some time, there is not this pretty published hardbacked version (cover art and photo by Mark Witton).

This volume is ultimately the product of the  2015 Flugsaurier meeting held in Portsmouth and features a number of papers that were presented there as well as others that have come in. There is a new taxon named (an anuroganthid!) and papers on taxonomy, systematics, anatomy, ecology, ontogeny and biomechanics. There are 17 papers and an introduction and as such I think it’s fair to say that this is a major collection and anyone with a serious interest in pterosaurs is going to need to read this.

Sadly the collection is not OA and these volumes can be expensive, but they are generally available at a reduced rate after a year or so. Unlike earlier editions the individual papers have been produced as high quality PDFs and distributed to authors, so if there’s a particular paper you are desperate for, I’m sure you can enquire. Personally I like dead tree versions of things, and this volume is printed on nice paper and has nice colour figures too which is clearly a bonus.

I should take a moment to thank Mark Witton and Dave Martill my coeditors in this venture and all the referees who took time to work on these papers. Also I’d like to thank the staff of the Geological Society who accepted our pitch and helped guide us through the work necessary to get this volume completed. I’m very pleased with the finla result and it’s nice to see citations already accruing for the papers within. The books are bing printed and shipped so for anyone who has ordered or was an author on a paper, expect these to arrive in the next few weeks.

Enjoy!

 

 

Sexual selection: patterns in the history of life

Longtime reads will know I have a huge interest in sexual selection and what that might mean for the evolution of all kinds of features (horns, crests, colours, feathers) in various archosaurs. In an effort to explore this further and help make new research connections, I have got together with Rob Knell and Doug Emlen to arrange a small meeting on this through the Royal Society. This will take place on the 9th and 10th of May next year jsut outside London.

The speaker list is fantastic and includes palaeontologists, modellers, theorists and people who link between those disciplines and with interests in dinosaurs, birds, insects, mammals and other clades. In short, this should least to a wide ranging discussion and opportunities for people to put some ideas out get and get collaborations and research going in major new directions.

Attendance is free (though there are costs for accommodation and food) but you will need to register and places may be limited. All of the details of the meeting are here including the speaker list. We hope to also run a poster session for non-speakers too.

 

 

Hawkins’ St George and the, errr, ‘dragon’

I was recently introduced to the image below and thought it was something I should share. Given my interest in pterosaurs and palaeoart I was rather surpised by it as I was completely unaware of its existence. That is is by a British artist with a major influence on early depicitons of fossil animals only added to my surpise that it had passed me by. Perhaps it is well known and I’ve simply managed to miss it, but I rather supect it may not be common knowledge at all since it was apparently not created for a palaeontological audience.

The picture in question was made in 1783 by Benjamin Waterhouse Hawkins, he of the Crystal Palace dinosaurs fame. Hawkins designed these, and many other sculptures, and produced all manner of artworks that were used to show off dinosaurs and other ancient beasts. In this case this wasn’t ever a palaeoart pic as such but really an illustration of the legend of St George and the dragon only with the latter having a very prehistoric bent. Those who know the Crystal Palace animals will reconise the pictured ‘pterodactyl’ as being a very close representative of the pterosaurs that sit on a rock above the dinosaurs. This animal is rather larger than these and would be big for a pterosaur known at the time, (and huge for a Pterodactylus) but despite some oddities (the back of the head in particular, and the very long tails) is very clearly pterosaurian.

Given the number of prominent scientists of the age who are at some level creationists (including Richard Owen, Hawkins’ employer on the Crystal Palace sculptures) it is tempting to assume that this was an influence in illustrating such a religious figure with something that’s perhaps less a fictional dragon and more real, if extinct, creature. Is there an attempt here to give credence to the legend by suggesting the dragon was real, if a little out of time? I can’t help suspect so, though I don’t know Hawkins’ intent, perhaps it was simply a case of a nice bit of inspiration for him to be able to use one set of ideas on a second project. Either way, for me it’s a rather interesting piece of early pterosaur illustration and one that deserves to be better known.

 

Write me a review!

Calling all my fellow academics, I am the new Reviews Editor for the Journal of Zoology and as a result I’m on the lookout for review papers that cover any aspect of whole organism biology (behaviour, ecology, taxonomy, evolution, anatomy and many other aspects). The journal has a good track record of covering palaeo topics (including dinosaur combat, display, trilobite diversity) so it’s not all about fluffy mammals.

I think reviews are important to science and provide a great platform for state-of-the-art updates, for people entering new fields (including students) and for steering debates or having new ideas put out there. They are also, I think, often a great paper to write as part of a PhD – they might not be REF-able, but give you a chance to get to grips with a subject and are often highly cited. In short, if you have an idea for a review you are likely to find me a sympathtic ear with a possible opening for you.

In particular I’m keen to reach out beyond the regular readers here, so do please pass on the gist of this message to people far and wide, especially in the biological / invertebrate divisions where I know far fewer people that the dinosaur / vertebrate community.

Tenth Anniversary Post

This blogpost is in fact a bit late since this date passed on the 7th of September, but I have now been blogging for a full decade. The archives here do not quite reach back that far, but very long time readers will know that I first started on the now defunct DinoBase pages (though these are available on some internet archive sites) hence the apparent gap.

I don’t want this post to turn into a long ramble about all of my posts and things I have got done, how I got blogging and so on, (this is after all covered in various places), but this seemed too big a milestone to ignore. I’m really not sure when I started all of this, how long I thought I might keep going for, but I doubt it would have included a guess of anything like ten years.

Back then I was still on my first postdoc with no guarantee of employment in another year or so, let alone an academic career and I was already running Ask A Biologist which was a massive outreach project in its own right. If I’d thought about it, I think I would have considered five years to be a big but achievable target and while I’m hardly going at the rate I once was, to still be going is something I’m rather proud of.

That really is it, just a post to mark the passing of the event. The blog will continue, slowly, as things progress and topics come up that I still want to talk about or are relevant. I doubt that I will still be going in 2027, but that in some ways doesn’t seem too far away or too unlikely. Time will clearly tell but I’m not stopping any time soon.

Flugsaurier 2018 Los Angeles

Well it’s been a while coming but the dates are finally fixed for next year’s pterosaur conference. Keep your diaries free for the 10th-14th of August next year.

As ususal there will be talks, posters, specimens and a fieldtrip (or possibly two) and we hope to be havikng a fairly major palaeoart presence as well. Details will be finalised ASAP but the basics are now all in hand.

Mike Habib is leading this one though his parent institutues of the University of Southern California and the Los Angeles County Museum. Luis Chiappe of the latter has been extremely helpful and the rest of the committee will comprise of Brent Breihaupt, Taissa Rodrigues, Lu Junchang, Liz Martin-Silverstone and myself. Volunteers for additional ssistance are also welcome.

Obviously this is still early days but a number of people have already committed and we are expecting a good turnout. Now that we are out of phase with ICVM, I am hoping that we will capture a bunch of people who are interested in pterosaurs but not been able to come in the past and not simply be solely those with a pterosaur research focus. If you have toyed with these animals or wanted to do more on them, or are a curator with a couple of bits in your collection this might be the conference for you.

Anyway, stay tuned, more will be coming soon and I’ll keep things posted here and e-mails will be going out to the ususal suspects as well as on the DML and Vert Pal lists and I’m sure we will get a Facebook group or simialr up and running soon. Hope to see you there.

In the meantime, almost all the papers from the Portsmouth meeting are now online and the formal book should be printe by the end of the year (or very early 2018), so now is the time to read up on your favourite flying mesozoic archosaurs.

Soft tissues and pterosaur taphonomy, but not as you might expect

In what now seems like a distant and past life, I briefly had a job in University College Dublin teaching in the biology department. Happily, this was on the floor above the earth sciences dept which had a healthy population of palaeontologists including some friends from my previous jobs in both Bristol and Germany. It meant that I had a good time chatting to colleagues on both sides of the ‘divide’ about various research aspects.

One day I was talking to Sue Beardmore (then doing her PhD) and her supervisor Paddy Orr about taphonomy. Through discussion with Paddy, Sue had developed a method of assessing the taphonomy of a vertebrate skeleton in aquatic settings, which could be used to compare environmental conditions among several localities, and infer differences and even changes through time. In theory, if we have the same or very similar species (that will essentially decay in the same way because of their similarities) preserved at two localities, it is possible that their final preserved state will still be different because they were subjected to different external processes. For example, they might have disarticulated to different degrees, suggesting differences in the relative time over which they had decayed before burial by sediments. If their completeness was different, it would suggest a greater number of, or more intense, (biostratinomic) processes. Perhaps one was exposed to stronger currents and less settled waters, which would move away any bits of the body that had separated during decay. In quiet water with few such processes, decay still occurs, resulting in the disarticulation of the skeleton without separated bits moving far from the main part of the carcass. Sue and Paddy have gone on to publish a series of papers exploring this idea, but I realized that it could also be turned around and used from an alternate perspective.

Differences in taphonomy between two related animals in the same environment should reflect differences in anatomy and in particular how well various body parts are secured to each other. In other words, the way in which various bits of the animals have decayed, disarticulated and / or lost allow us to infer something about the soft tissues, even though they are not preserved. This idea inevitably led me to pterosaurs and the huge numbers of Rhamphorhynchus and Pterodactylus specimens that have been recovered from the Solnhofen. They are pretty close relatives and certainly overlap strongly in time and space in these ancient lagoons but we also know that a profound shift in bony anatomy was going on between the two – is this also reflected in their soft tissue? Roping in Emma Lawlor who was then looking for a research project for her undergraduate dissertation, we then had a project to put together.

First off of course we needed to survey pretty much every specimen that we could (and as far as possible in person) leading to examining a whole lot of fossils and supported by photos where necessary. Essentially the animal is divided up into a bunch of segments (head, limbs, tail, body etc.) and are scored for articulation (attached to the right other bit of the body e.g. the wing to the shoulder, fingers to the wrist) and also completeness (so whether or not they are present on the specimen). A fossil could potentially be 100% complete but with 0% articulation, though the two factors are at least partly correlated since anything lost is also by definition disarticulated.

Going through the data there are some simple but fairly stark patterns that emerge. First off, a lot of the specimens are more or less complete and more or less articulated. That’s perhaps no big surprise – the Solnhofen waters are famously fairly anoxic and still, which is why we so often get lots of very well preserved specimens, even including fragile things like pterosaurs as well as soft tissues being retained. Still, it does highlight the general situation at play and that’s also importantly because pterosaurs were generally pretty pneumatic and less dense than many other vertebrates. That would imply that they could potentially float for a long time before sinking which would allow for lots of bits to come off and go missing. That this is generally fairly rare suggests that these effects were pretty limited. When we do see loss of articulation we also see loss of the elements, so decay when it did occur was likely mostly in the floating phase, and that things did not tend to fall apart much once the specimen had settled or we would see lower articulation with higher completeness. In short, there wasn’t much going on at the bottom, likely due to both low currents and limited bioturbation.

Generally, Pterodactylus specimens are less complete than Rhamphorhynchus which may point to them floating for longer (since they are more pneumatic) allowing things to be lost, but could also point to greater transport to sites before sinking and burial. There are also far fewer specimens of Pterodactylus available so this may be a result of the limited data exaggerating the differences a little.

Despite the long and presumably heavy tail of Rhamphorhynchus, this was preserved far more often than the much smaller one of Pterodactylus. This implies that in the former the tail was very strongly attached to the body and was held on with a strong set of muscles and / or ligaments and points to its greater use than in later shorter tailed pterosaurs. Where we see limb loss in Rhamphorhynchus this seems to coincide with the loss of the other limb from the same side – in short if you lose a left arm you also tend to lose a left leg. That points to the idea that the two are attached to each other quite firmly and tallies with the ankle attachment for the main wing membrane.

There’s some other issues at play in these patterns of course (and various other similarities and differences) which I won’t dwell on as that is what the paper is for, but this should give an idea of what we have done and what we can potentially infer with these methods. Sure, the information available is rather limited but it gives a framework for looking at certain anatomical areas in more detail, and it’s likely possible to combine this with other information to delve more deeply into our understanding of pterosaur soft tissues.

Beardmore, S.R., Lawlor, E., & Hone, D.W.E. 2017. The taphonomy of Solnhofen pterosaurs reveals soft-tissue anatomical differences between basal and derived forms. Naturwissenschaften.

 


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