Posts Tagged 'museums'

Dinosaur Provincial Park 2014

The Musings has been quiet again in part because I have changed jobs / cities yet again, but also with a general wind-up towards the start of teaching. This is now my third year at Queen Mary, but more importantly for me, I’m finally teaching on a course I have specifically created with a colleague and so can really get to grips with an area that interest me in particular. And so a new course on taxonomy and systematics has come into being and a core part of this is actually a fun hands-on practical, namely hunting down, and then identifying, remains in Dinosaur Provincial Park in Alberta. Yep, for some reason the university trusted me to take a team of undergraduates out into the wilds of Canada and the Tyrrell even sent along a couple of people to help collect what we found (we had an explore, but not collection, permit).

Naturally much of the discovered material was very fragmentary and unsuitable for collection (not least by the Tyrrell’s exacting standards since they are buried in teeth and partial skeletons and don’t care too much about isolated verts or longbones), but this didn’t mean it could not be identified. Picking up key skills in identifying characters that can be used to unite things into groups, or split them off as different is a fundamental basis of taxonomy and key to identifying possible characters for systematic analysis, so it’s an excellent introduction into some practical skills on that side as well as the more obvious aspects fundamental to palaeontology and indeed good science (data collection, archiving data and specimens, access to material etc.).

Even so, there were some great finds. We were supposed to have four days in the field but bad weather restricted this to little more than two (though knowing the weather was coming, we pushed hard with long days to maximise the good ones, so we didn’t loose too much time over all), but we still put a dozen specimens into the Tyrrell collections (both research and teaching) including teeth of dromaeosaurs and troodontids, some ornithomimosaur elements, and best of all a hadrosaur skull. The latter was found eroding out of a cliff and while the lower jaws were going and most of the teeth were out, the rest seems to be in the hillside (with probably a decent bit of postcranium)  and this has been flagged for collection next fieldseason.

As this is the first time we have run this, there were inevitably some teething issues, but I’m delighted to say the feedback from the students has been incredibly positive and they really enjoyed both the fieldwork, the Tyrrell itself and interacting with the academics present on the trip (Musings collaborator Mike Habib also made the trip up and joined us). This is hopefully the first of many future trips as this should be an annual component of the course, so hopefully for me, I’ll have a nice source of material for future posts every year. Meantime, here’s some views, the hadro skull, some tyrannosaur teeth and turtle plastron.

P103 (640x480)

P49 (640x480)

P37 (640x388)

P19 (480x640)

P13 (640x480)

P9 (640x493)

P1 (640x480)

P0 (640x480)

My thanks to all on both sides of the student / staff divide for all their efforts in making this such a great trip for all concerned and I’m really looking forwards to the future of this course.

The Berlin bone room

IMG_1043

I’m badly behind on the blogging here and especially covering my January trip to Berlin owing to a combination of illness, work and the Daspletosaurus project (only 3 weeks left!). Still, while there’s much more to come, I’ll grab a few minutes and post a little about the big bone store in the basement in Berlin featuring these wonderful containers (if you don’t know what they are, feel free to guess, answer at the bottom below the fold).

Continue reading ‘The Berlin bone room’

Variation of tail length in dinosaurs

So I have a new paper out and inevitably I’m going to talk a bit about it on the Musings. While I’ve had a few abstracts and the odd short paper out as sole author, this is pretty much my first proper effort in a major journal where I’m the only author. Not that I didn’t have help of course (which is what the acknowledgements are for) and I do especially want to take the opportunity up front to thank various people for their contributions and help, but most especially Susie Maidment for her help in data collection.

Right, onto the actual paper. Way back in 2010 I was looking at pterosaur tails in connection to an anuroganthid that turned up with (for one of them) an unusually long tail. This got me thinking about dinosaur tails and it struck me that while we obviously had some taxa with short tails (like Caudipteryx) and some looked pretty long (like Diplodocus) that no one seemed to have looked at just what kind of variation there was. Moreover, the more I thought about it, and the more I looked through papers and collections (and then later on asked various colleagues) the more often I came across ‘complete’ specimens that were nothing but when it came to the distal caudals. And so began my investigation into the tail lengths of the non-avian dinosaurs (though admittedly Archeopteryx sneaks into the paper as do the scansoriopterigids). Obviously the paper is there to be read, but hopefully this will serve as a quick summary and discussion of the basic points for those who can’t get it or don’t want to read it.

The first thing to note is that actually we really do have very few dinosaur fossils with complete tails. Despite a good hunt through the literature, a couple of collections, and exchanges with a number of colleagues I was able to track down very few specimens where every caudal was known. Even in things from localities like the Jehol and Solnhofen where skeletons are preserved in beautiful condition and soft tissues are common, there are actually very few specimens with every caudal vertebra preserved. Sure the sauropods might expect to do badly given how incomplete they always seem to be, and we’ve got more than a few dinosaurs known from only fragmentary remains. However, on the other hand we now have thousands of dinosaur fossils, and some species are known from dozens or even hundreds of good specimens and many of these are from sites of excellent preservation. But for all my searching and asking, I found less than 20 dinosaur specimens in total that have every caudal preserved. That’s really very low. Even things like ankylosaurs and dromaeosaurs with those lovely reinforced tails don’t seem to do any better either, complete tails are really, really rare.

Now there are a good number that are probably close to being complete with only a few distal ones missing, but obviously quite how true this may be is hard to determine. Sure there tends to be a general tapering of the size of the caudals which can give you a reasonable guess as to where it likely ends, especially if they are very small when they stop, but things like Diplodocus with it’s near endless rod-like caudals or the sudden stop in Nomingia means you could easily be wrong. In short, while a specimen like Sue we can probably have a pretty good guess how long the tail was and quite how much was missing, for plenty of other species it’s not going to be so easy. And things get worse from here.

Not only are there few dinosaurs with complete tails, but in one wonderfully illustrative case we have some major intraspecific variation. Two specimens of Leptoceratops are preserved side by side and so we can be confident that these aren’t just the same species, but are even from the same population. The problem is, one has 10 more caudals than the other, and their tails are proportionally rather different in length too. There’s quite a bit of intraspecific variation there, and indeed a look across other amniotes suggests that this is quite common – caudal counts and caudal lengths can vary a lot in tetrapod species. Tail length is sexually dimorphic in some snakes for example, and can vary a lot even in mammals.

Interspecific variation can be high too, which means it may not be safe to reconstruct missing tails from even close relatives. The wonderful little Epidexipteryx has the joint shortest tail known for any dinosaur that I found, but it’s sister taxon, Epidendrosaurus, has one of the longest tail known (and that one is incomplete and would have been longer still). While this might be an unusual case, there’s a decent bit of variation seen in a couple of other clades too.

All of this means that we need to be a fair bit more careful when talking about dinosaur tails and especially when it comes to recounting their size in terms of length. The length of a dinosaur is absolutely ubiquitous in the media as a measure of size and it turns up in a few papers too. However while some taxa are of course known absolutely in terms of their length, and many are probably about right despite being not entirely complete, others would seem to be little more than a best guess – and a best guess based on not very much to be honest. The data for sauropods in particular seems to be incredibly sparse and accounting for the inter- and intraspecific variation seen, I don’t think I’d be confident in reconstructing the tail of something like Argentinosaurs to within even a 50% error – it could be really long or very short and there’s no way of picking one over the other. Even ignoring some of the outliers, there’s a fair bit of variation there and can have quite an effect on the appearance of an animal.

Scott Hartman has been good enough to make this for me – a Spinosaurus with a short, ‘normal’ and long tail. All of these kinds of lengths can be seen in various theropods and to my mind are all plausible – indeed, we’ve been quite conservative here and could easily have copped off another hatful of caudals or plugged on a good few more and the results would still be quite plausible and within the bounds seen by other theropods. Of course note that while the length of that tail in each varies enormously, and as such, so too does the total length of the animal, the mass would not change that much. A 16 m long Spinosaurus sounds massive compared to a 12 m one, but if the only difference is in tail length, then in terms of mass there might not be much in it, just a few tens of kilos in a multi-ton animal.

So, estimating the length of a dinosaur without a mostly complete tail could give you a rather inaccurate number. There does seem to have been a fair bit of inaccurate information out there in the literature in the past with people giving ranges of caudal counts for groups when individuals were known with much higher values, and clades being described as having ‘long’ tails when they didn’t (or there was no real way to tell). However, there is a little more to this, I also did an analysis where (as far as possible, which admittedly wasn’t that far) the variation in tail length was compared to snout-vent length.

When examining living species, most biologists use snout-vent length as a proxy for how large animals are. After all, the tail length can vary a lot as we’ve seen, and even weight isn’t a great measure for a lot of living animals as it can fluctuate a lot on an annual basis, and of course isn’t available for specimens in museums. So a measure from the tip of the snout to the vent / anus is a common measure of size but we don’t seem to use it much in palaeontology (and certainly not for dinosaurs). In short therefore, we’re using a measure which not only includes a lot of variation in the tail that might screw up the results (and that most of the time we don’t know for sure anyway), but it’s not compatible with other datasets on extant taxa. The question is though, would the equivalent be any better for dinosaurs?

My simple analysis suggests so – that from the available data, tails are rather more variable in dinosaurs than the body. As for the vent, well, that we obviously don’t know exactly as a decidedly soft tissue structure so I plumped for the last sacral being a point that would be close to the vent and an unambiguous point on the skeleton that would be easily identified and would likely be preserved. This measure (snout-sacrum) is one I suggest we should start using when we want to talk about dinosaurs sizes in terms of length.

So there you have it. We don’t seem to have too many dinosaur tails, those we have suggest much inter- and intraspecific variation and so estimates of total length or using total length may not be very reliable. Snout-sacrum length is probably more reliable and in any case would bring the data in line with that used by most biologists. My final note though is an appeal – despite the work I did trying to uncover dinosaurs with complete tails, I’m sure I’ve missed some. Perhaps they’ve simply not been described, or are squirreled away in obscure journals, or are only listed as paratypes etc. I have seen a couple of things published since this work was finalised that look like the tail is complete but where the paper doesn’t actually say and it’s not entirely clear from the figures. I can’t believe that some of those massed ranks of undescribed Psittacosaurus, Protoceratops and various massed ranks of hadrosaurs and iguanodontians don’t have a few more complete ones lying around that can be measured. So if you do know of any specimens out there with complete tails (and better yet, totally complete specimens in terms of the skull and vertebral column) do please let me know. I’ve exhausted all the easily available avenues to date, but I’d love to do the analysis again with much more data. One day.

Hone, D.W.E. 2012.Variation in the tail length of non-avian dinosaurs.Journal of Vertebrate Paleontology, 32: 1082-1089.

Horniman pterosaurs

Yesterday I put up some photos of the gloriously anachronistic dinosaurs at the Horniman museum. As you’ll have already deduced from the title that they also had a couple of pterosaur models. While presumably hailing from the same era (and perhaps even that same artist) they are not quite as inaccurate, though this is, I suspect, more to do with the fact that our ideas of pterosaurs have changed less over time (or in some cases returned to an earlier idea), rather than any greater level of detail being paid to the pterosaurs.

While there are (inevitably) some mistakes, the only really standout one is the neck of the Pteranodon. It’s absolutely tiny and makes it look like the head has just been welded onto the body. Given that one of the defining characteristics of the pterodactyloids is the long neck, and that in Pteranodon it should be about half to two-thirds of the length of the skull, this is far from a good representation of a pretty basic bit of anatomy.

Butterflies & moths

Another little display from the Carnegie I’ve had sat in my files for too long. OK so there’s nothing here that’s linked to archosaurs, or even evolution in general. But what it does do is address just the kind of question that often bugs people. I think a very big proportion of the public would recognise that moths and butterflies are close relatives and that they are different, but aside from the diurnal / nocturnal split and the fact that butterflies tend to be more colourful, they would probably struggle to say how you could tell them apart, or for that matter what linked them together.

My experiences with Ask A Biologist suggest this kind of thing is really common. People have bits of knowledge and part of the full picture, but don’t realise they have only part of the story and even if they did, don’t know how to go about filling in the gaps or putting their knowledge into context. In the case of AAB, someone has realised that don’t know the full picture, or has had their interest piqued by some incident.

In the case it’s actively prompting people – it’s easy to imagine someone looking at this and thinking “Oh yeah, what *is* the difference?”. The headline is a nice attention grabber and it’ll get people to read the short captions below and, hopefully, get them thinking a little more about taxonomy and diversity (if not in those terms) and the world around them. In short, neat idea, well done. I can easily see this being a nice series too – a line of panels of ‘What’s the difference between a shark and a fish?’ or frogs vs toads, newts vs salamanders, goats vs sheep and the like.

What is also nice about this is how much that is conveyed in such a small amount of space and few words. Maximum communication but without filling the place or making people struggle through dense text to get the message across, and all the time filling in other gaps in their knowledge with little extras like the addition of skippers or the relative numbers of species. Great stuff.

Variation and selection

Well hey, another little leftover from the Carnegie I should have mentioned before.

There are of course a multitude of ways of presenting ideas in museum exhibits. This one is not only well done (showing the natural variation present in a selection of specimens of one species alongside male and female differences and by extension a little of the diversity and variation seen between species) but has a little resonance for me as it combines two other displays I have seen and commented on before. Tokyo has a nice cabinet showing the diversity seen in a single species (mentioned here, but not shown I’m afraid) and Oxford commented on the diversity of beetles with this lovely effort.

In all three cases the message is simple, but a profoundly important part of biology as a whole and the mechanics of evolution specifically. Communicating that quickly, effectively, simply but with maximum impact and interest is a real challenge and whoever came up with these various cabinets deserves much credit for having done so.

AMNH pterosaurs 3 – Azhdarchoids

OK so the last two for now. Above is a cast of the famous Quetzalcoatlus wing. This is something I’ve never seen before so is rather cool. There are casts of the humerus floating around in various places, but this is the first time I’ve seen the rest, including that lovely long metacarpal block and pretty thin phalanx 1 of the wing. As with yesterday’s Pteranodon, fingers 1-3 do seem to be backwards though.

Below is a cast of Tupuxuara and again, I’ve seen copies of the head but not the rest. This is an animal that has a proper grounding in the concepts of massive head crests, and indeed a big skull in general and a mount like this really does show off the extreme proportions of this group – the heads are huge, the legs pretty long, but the body? Well the pelvis and sternum almost completely cover it and if you were feeling jaunty, you might be able to cram the torso *thought* the nasoanorbital fenestra. Cool.

Pterosaurs of the AMNH pt 2 – Pteranodon

Following on from yesterday’s coverage of the Solnhofen material, today we move into the Cretaceous and to Pteranodon. There’s a rather incomplete post-cranial specimen, a rather incomplete skull and then a nicely mounted cast / model. Pteranodon is known from a lot of material (over 1 200 specimens have been identified to date) but a huge amount of this stuff in very incomplete and badly broken. So while it is well represented in general, both of the specimens shown here are actually really pretty nice.


Developing Deinosuchus for display

Yesterday I blogged about the newly mounted Deinosuchus displays in Mexico by my friend Héctor Rivera-Sylva. Today rather than the mounts themselves I’m putting up some of Héctor’s photos of the creation of these mounts. The bones are a combination of casts from multiple different individuals (as can be seen by the two different colours of material used in putting the skull together for example). While I provide no detailed commentary (as well, I wasn’t there) all the more obvious issues when making something like that are illustrated – sculpting, test mounting, painting and the like and I think it’s fairly clear to see the major processes at work. My thanks again to Héctor for letting me use these.

The proliferation of Chinese dinosaur museums

 This link has been doing the rounds for the last few days. It shows a pair of sauropod models that straddle the Chinese-Mongolian border. I think the author is being a bit disingenuous by castigating this as a failed tourist spot. It’s a decorative border post, if a bit naff, though it likely was done to help advertise the nearby dinosaur localities.

However, the central point it makes (“build it and they might not come”) is very pertinent. China is undergoing a massive economic expansion and they are pushing a vast amount of money into science. Coupled with a general pattern of producing large public works and the obvious rich fossil beds it’s perhaps no surprise that new dinosaur and palaeontological museums and parks are springing up around China. What might be a surprise is just how many there are.

I’m not in a position to even guess at the real number, but I have either visited or know about at least a dozen that have started or opened in the last half dozen years and I’ve been to a fair few myself. Huge buildings and collections are appearing in Tinayu, Zhucheng, Shenyang, Zhengzhou, Macau, Lufeng, Xixia and right across Liaoning. I think there are now about a dozen or more in Liaoning alone (and it’s not a big province). While China is a huge country in terms of population and area, I do find it hard to believe that all of these are going to be viable in the long term. Having visited many of these places they are often are in less than perfect condition despite being new and they rarely have many visitors, this at a height of both novelty and public interest in dinosaurs. If nothing else in places there’s one in each town and it’s hard to conceive of each of them drawing in huge crowds with competition in every town within 50 or 100 km. Even with public funding, I’m sceptical that many of these will still be viable in the next dozen years.

All of this is a worry. At the moment there’s a huge ‘gold rush’ to exploit the available fossils and get things into museums. From at least a couple of places I’ve been to I’d suggest that these may not all be being collected in the best manner they could be and that not everything on display should really be there. Nor for that matter is all of it being kept properly and I fear for some specimens. In short the collections are being assembled and curated by people lacking expertise.

Moreover, what might happen to collections that go bust? I’m not used to the concept of museums housing hundreds of specimens going bankrupt. I’m sure it happens on occasion and material has to be moved on or stored for a bit, but what would happen if a major collection suddenly went under? Or will the local authorities step in and fund expensive but failing institutes, draining budgets for science elsewhere to support them?

Perhaps I’m being overly worried, but while I don’t know that much about the economics of museums and catchment areas, and governmental financing, I have seen how many of these places there are and what they are like and how (some) are being run. Some seem to be running out of investment before they have even been built, so it’s not a major leap of imagination to think some will bite the dust and then, well, I don’t know. But I am a bit worried.

Taking photos of fossils in museums

As part of my huge and ongoing (but nearly finished) series of posts on material from the Carnegie museum, it was suggested in the comments that I write about the methods I use to take photos. I doubt there’s anything I can say that an experienced photographer can’t tell you already, but there are a couple of special issues that can come up and it’s something not everyone is likely used to dealing with. As such, I’ll run though it all and hope it helps a few people.

First off, the camera. I’ve always said you can take great shots with a cheap point-and-shoot and you can take terrible ones with a massively expensive SLR. That said it’s much easier to take great photos and harder to take bad ones with a good camera, so if you can afford to invest, it will make a big difference. Aside from that I don’t want to say much about cameras and lenses and settings as, well that’s part of good photography in general rather than taking photos of dinosaurs, but clearly if you want a good photo of the head of a sauropod or the details of a pterosaur strung from the ceiling, you need a good zoom and / or a macro lens. I take most of my stuff in dinosaur halls with about a 25 mm and then I have a 70-300mm zoom for details.

Next up, framing. Obviously how you frame your photo depends on what you want out at the other end, but there are some things to consider. First of all, line up the shot and check all around the edge of the frame that you have everything you want in place. Are all the feet in the bottom of the frame, the tip of the tail in there, the top of the head? Maybe the tail curves away and is hidden behind the body, so if you want it in there, you might have to move. If you want the photo to be of a specific element, consider taking the photo at an angle. For example if the head is angled down, then you’d naturally take a photo that showed that, but you can rotate the camera so the head runs straight left-to-right across the frame. The background may now look odd (beams or windows all crooked) but the bone is better illustrated. Try and make sure there are no people in the frame, or minimise where they are.

Don’t be afraid to adopt odd posture or lean out and round things to get the shot you want. Obviously be careful of your possessions and the material on display, but you can stretch an arm out over a balcony, or put the camera through a gap. A bit of practice and experience and you can get good shots even when you can’t see the viewfinder.

Be mindful of shadows and light. Your eyes adjust brilliantly to things that a camera won’t. Watch out for bright spots from reflections on glass or off metal supports, shafts of light from windows, or things being hidden in deep shadow. A lot of modern museums really like lots of small spotlights and these are great for eleminating odd shadows, but terrible for making bright spots on your photos. My technique is to alter the angle of the shot such that as many of these as possible are behind the bones, or *just* out of shot. Try enough positions and you should get the kind of shot you want with few, or even, none of these.

Try and avoid using the flash. Dinosaur mounts are a pain to clean and are often dusty, and the bones and mounts can be really quite shiny. A flash shot might get better illumination but it might be full of reflections and all the bones show up grey. So if possible, avoid it, and instead stick the ISO up on the camera and put the exposure time up. You can compensate with a tripod, or even just practice and a steady hand. Leaning on railings also helps keep things steady, or you can balance the camera on a bad or rolled-up jersey to get the shot you want.

In the case of cabinets, you might need to stick the flash on, so shoot at 45 degrees to the plane of the glass, or put the lens flush against the glass, both should stop flare. You can also use yourself to help block out reflections and make a nice dark area on the glass. Hold the camera with one hand (if you can) and use the other to block out spotlights behind you, drape a jersey off your arm, or even tie it around your thighs to hand between your calves. Little things like this can make a small difference and a few of them can add up.

Take lots of photos. With modern digital cameras you can take dozens and throw out loads of bad stuff. Even if it looks fine, take a couple again. If you’re not sure about things, take photos with different settings (flash on or off etc.) and at different ranges or angles. Taking things at subtly different angles can make nice pairs to show off details. If you have time, check some of them on your screen or even download them and check them on a laptop.

Take photos of signs. It’s nice and quick and can give a good reference for all manner of specimens and details. Try and shoot one specimen at a time so nothing is mixed up. Do sort your photos as soon as you can so you know exactly what close-up fits to which specimen.

Finally remember you can tweak things afterwards. You can always adjust tone, colour and exposure on the computer. You can rotate things a bit and crop out errors etc.

Right, that’s it from me, I hope this helps a few of you the next time you’re surrounded with dinosaurs on display.

Sign of the times – dinosaur anatomy

While we’re on the subject of signs and notices, this one especially caught my eye. While it’s obviously in Japanese, it’s clear than it labels all the major bones of the skeletons. This is great for several reasons. First off it shows people are interested in anatomy and that using technical terms is not going to put people off. Moreover it shows and helps people to grasp that for all the differences between these species they are at a fundamental level built to the same plan, obviously with four legs and a neck and ribs and tail etc. but with things like lacrimals and frontals too – there is a lot of things in common and the pattern of bones is effectively identical. You can really appreciate the similarities and differences and follow that while they must have much in common (a common ancestor in fact) they have also diverged from that. Finally, it does provide a frame of reference for people as a whole – I’m sure many of the people reading this sign had been told by a doctor they’d broken a humerus, or their child fractured a tibia, had a malformed metatarsal or needed to see a maxillary surgeon or whatever. These were uncommon terms to them in a hospital, but I bet they remember those words and will see the link to the signs on the wall and thus the beasts in front of them. It’s an excellent little reminder and display of how all vertebrates are linked together.


@Dave_Hone on Twitter

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 354 other followers


Follow

Get every new post delivered to your Inbox.

Join 354 other followers