Posts Tagged ‘dem bones’

The early, hippo-like mammal Coryphodon. I didn’t know it had a patella but it does. From Yale Peabody Museum.

I’m not shy about my fondness for the patella (kneecap) of tetrapod vertebrates, and neither are the other members of RVC’s “Team Patella”. We’ve had a fun 3+ years studying these neglected bones, and today we’ve published a new study of them. Our attention has turned from our prior studies of bird and lepidosaur kneecaps to mammalian ones. Again, we’ve laid the groundwork for a lot of future work by focusing on (1) basic anatomy and (2) evolutionary history of these sesamoid bones, with a lot of synthesis of existing knowledge from the literature; including development and genetics. This particular paper is a sizeable monograph of the state of play in the perusal of patellae in placental and other synapsids. Here’s what we did and found, focusing mostly on bony (ossified) patellae because that allowed us to bring the fossil record better to bear on the problem.

Reference: Samuels, M., Regnault, S., Hutchinson, J.R. 2016. Evolution of the patellar sesamoid bone in mammals. PeerJ 5:e3103 https://doi.org/10.7717/peerj.3103

Stomach-Churning Rating: 1/10; bones and more bones.

The short version of the story is that mammals evolved bony kneecaps about five times, with marsupials gaining and losing them (maybe multiple times) whereas monotremes (platypus and echidna) and placentals (us and other mammals) didn’t do much once they gained them, and a couple of other fossil groups evolved patellae in apparent isolation.

Evolution of the patella in mammals: broad overview from our paper. Click to zoom in.

The marsupial case is the most fascinating one because they may have started with a fibrocartilaginous “patelloid” and then ossified that, then reduced it to a “patelloid” again and again or maybe even regained it. There needs to be a lot more study of this group to see if the standard tale that “just bandicoots and a few other oddballs have a bony patella” is true for the Metatheria (marsupials + extinct kin). And more study of the development of patellae in this group could help establish whether they truly do “regress” into fibrocartilage when they are “lost” in evolution, or if other, more flexible patterns exist, or even if some of the cases of apparent “loss” of a bony patella are actually instances of delayed ossification that only becomes evident in older adults. Our paper largely punts on these issues because of an absence of sufficient data, but we hope that it is inspiration for others to help carry the flag forward for this mystery.

The higgledy-piggledy evolution of a patella in Metatheria, including marsupials. Click to zoom in.

Some bats, too, do funky things with their kneecaps, analogous to the marsupial “patelloid” pattern, and that chiropteran pattern also is not well understood. Why do some bats such as Pteropus fruit bats “lose” their kneecaps whereas others don’t, and why do some bats and other species (e.g. various primates) seem to have an extra thing near their kneecaps often called a “suprapatella”? Kneecap geeks need to know.

The short-nosed bandicoot (marsupial) Isoodon, showing a nice bony patella as typifies this group. From Yale Peabody Museum.

Otherwise, once mammals evolved kneecaps they tended to keep them unless they lost their hindlimbs entirely (or nearly so). Witness the chunky patellae of early whales such as Pakicetus and join us in wondering why those chunks persisted. The evolutionary persistence of blocky bits of bone in the knees of various aquatic animals, especially foot-propelled diving birds, may help answer why, as the hindlimbs surely still played roles in swimming early in cetacean evolution. Ditto for sea cows (Sirenia) and other groups.

Early whale Ambulocetus, showing hefty kneecaps.

But I’m still left wondering why so many groups of land vertebrates (and aquatic ones, too) never turned parts of their knee extensor tendons into bone. We know a bit about the benefits of doing that, to add leverage to those joints that enables the knee muscles to act with dynamic gearing (becoming more forceful “low gear” or more speedy “high gear” in function). Non-avian (and most early avian/avialan) dinosaurs, crocodiles, turtles, amphibians, early mammal relatives, and almost all other known extinct lineages except for those noted above got by just fine without kneecaps, it seems, even in cases where a naïve biomechanist would expect them to be very handy, such as in giant dinosaurs.

A quoll, Dasyurus, with what is probably a fibrocartilaginous “patelloid”. From Yale Peabody Museum.

However, tendons don’t turn to bone unless the right stresses and strains are placed upon them, so maybe kneecaps are a “spandrel” or “exaptation” of sorts, to abuse Gould’s ghost, whose adaptive importance is overemphasized. Maybe that adaptive myopia overshadows a deeper ontogenetic story, of how tissues respond to their history of mechanical loading environment. It has been speculated that maybe (non-marsupial) mammals have broadly “genetically assimilated” their kneecaps, fixing them into semi-permanence in their genetic-developmental programmes, whereas in contrast the few studies of birds indicate more responsiveness and thus less assimilation/fixation. That “evo-devo-mechanics” story is what now fascinates me most and we’ve poked at this question a bit now, with some updates to come- watch this space! Regardless, whether an animal has a bony vs. more squishy soft tissue patella must have consequences for how the knee joint and muscles are loaded, so this kind of question is important.

Giant marsupial Diprotodon (at NHM London); to my knowledge, not known to have had kneecaps- why?

In the meantime, enjoy our latest contribution if it interests you. This paper came about when first author Dr. Mark Samuels emailed me in 2012, saying he’d read some of my old papers on the avian musculoskeletal system and was curious about the evolution of patellae in various lineages. Unlike many doctors and vets I’ve run into, he was deeply fascinated by the evolutionary and fossil components of patellae and how those relate to development, genetics and disorders of patellae. We got talking, found that we were kindred kneecap-spirits, and a collaboration serendipitously spun off from that, soon adding in Sophie. It was a blast!


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A quick heads-up that we just posted on our sister blog Anatomy To You, about a new open-access paper we’ve published on the skeletal anatomy of the tuatara Sphenodon. Lots of cool images you can’t see anywhere else are there!

In focus: The big picture of little bones in tuatara

I give it a Stomach-Churning Rating of 3/10- some picked specimens of tuatara but they’re still cute, not nasty, I’d say.

AND, like the Cool-Whip or vanilla ice cream atop your leftover pumpkin pie, there’s an added delicious bonus: a huge dataset of microCT scans from 19 tuatara specimens, free to access here:


We are VERY pumped up about getting this paper and dataset released, so we are spreading the word as wide as we can!


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(Marcela with some furry friends; photo by Oliver Siddon)

(Marcela with some felid friends; photo by Oliver Siddon)

A guest post by Marcela Randau (m.randau@ucl.ac.uk)

Stomach-Churning Rating: 1/10; just bones and data plots!

It is often said that all cats are very similar in terms of their skeletal morphology (“a cat is a cat is a cat”). But is this really the case? It may be if only gross, qualitative anatomy is taken into consideration, i.e., if you just eyeball the skeletons of tigers and lions you might find yourself not knowing which one is which. But with huge advances in technology that allows for extracting detailed shape information off a structure (e.g., a skull) and for analysing this information (‘Geometric Morphometrics’), it has become more and more possible to distinguish between relatively similar forms – which may be from distinct species, separate sexes, or even just different populations of the same taxon.

And it is reasonable to think that cat skeletons might be a lot more different than what meets the eye, as for a lineage of apparently similarly built animals, with not that much variation in diet  (all cats are hypercarnivores) there is substantial variation in body mass (over 300-fold just in living species!) and in ecology across cat species. From the cursorial cheetah to the arboreal clouded leopard, felids present a wide range of locomotory adaptations. Yes, all cats can climb, but some do it better than others: think lion versus margay (yes, they do descend trees head-first). As hypercarnivores, all cats are meat specialists, but they also change with regards to how big their prey is, with a general and sometimes-not-so-black-and-white three-tier classification into small, mixed and large prey specialists. The rule of thumb is ‘if you are lighter than ~20-25 kg, hunt small stuff. If you are heavier than that, hunt BIG BIG things; bigger than yourself. And if you are in the middle ground, hunt some small-ish things, some big-ish things, and things about your size. Well, -ish’ – their prey size preference has a lot to do with energetic constraints (have a look at Carbone et al. 1999; and Carbone et al. 2007, if you’re interested in this). But the fun bit here is that form sometimes correlates quite strongly with function, so we should be able to find differences in some of their bones that carry this ecological signal.

Indeed, for a while now, we have known that the shape of the skull and limbs of felids can tell us a lot about how they move and how big their prey is (Meachen-Samuels and Van Valkenburgh 2009, 2009), but a large proportion of their skeleton has been largely ignored: we don’t know half as much about ecomorphology and evolution of the vertebral column. Well, it was time we changed this a bit! As the PhD student in the Leverhulme-funded ‘Walking the cat back’ (or more informally, “Team Cat”) project, I’ve spend a big chunk of my first two years travelling around the world (well, ok, mainly to several locations in the USA) carrying a heavy pellet case containing my working tool, a Microscribe, to collect 3-D landmarks (Fig. 1) across the presacral vertebral column of several cat species. And some of first results are just out! Check them out by reading our latest paper, “Regional differentiation of felid vertebral column evolution: a study of 3D shape trajectories” in the Organisms Diversity and Evolution journal (Randau, Cuff, et al. 2016).


Fig. 1: Different vertebral morphologies and their respective three-dimensional landmarks. Vertebral images are from CT scans of Acinonyx jubatus (Cheetah, USNM 520539)

Building from results based on our linear vertebral data from the beginning of the year (Randau, Goswami, et al. 2016), the 3-D vertebral coordinates carry a lot more information and we were able to describe how this complex shape-function relationship takes place throughout the axial skeleton (in cats at least) in much better detail than our prior study did. One of the difficulties in studying serial structures such as the vertebral column is that some clades present variation in vertebral count which makes it less straightforward to compare individual vertebrae or regions across species. However, mammals are relatively strongly constrained in vertebral count, and Felidae (cats; living and known fossils) show no variation at all, having 27 presacral vertebrae. So adaptation of the axial skeleton in mammals has been suggested to happen by modification of shape rather than changes in vertebral number.

Using a variety of geometric morphometric analyses, under a phylogenetically informative methodology, we have shown that there is clear shape and functional regionalisation across the vertebral column, with vertebrae forming clusters that share similar signal. Most interestingly, the big picture of these results is a neck region which is either very conservative in shape, or is under much stronger constraints preventing it from responding to direct evolutionary pressures, contrasting with the ‘posteriormost’ post-diaphragmatic tenth thoracic (T10) to last lumbar (L7) vertebral region, which show the strongest ecological correlations.

We were able to analyse shape change through functional vertebral regions, rather than individual vertebrae alone, by making a novel application of a technique called the ‘Phenotypic Trajectory Analysis’, and demonstrated that the direction of vertebral shape trajectories in the morphospace changes considerably between both prey size and locomotory ecomorphs in cats, but that the amount of change in each group was the same. It was again in this T10-L7 region that ecological groups differed the most in vertebral shape trajectories (Fig. 2).


Figure 2: Phenotypic trajectory analysis (PTA) of vertebrae in the T10 – L7 region grouped by prey size (A) and locomotory (B) categories.

So in the postcranial morphology of cats can be distinguished, changing its anatomy in order to accommodate the different lifestyles we see across species. But the distinct parts of this structure respond to selection differently. The next step is figuring out how that might happen and we are working on it.

While Team Cat continues to investigate other biomechanical and evolutionary aspects of postcranial morphology in this interesting family, we’ve been able to discuss some of these and other results in a recent outreach event organised by the University College of London Grant Museum of Zoology and The Royal Veterinary College. We called it “Wild Cats Uncovered: movement evolves”. Check how it went here: (https://blogs.ucl.ac.uk/museums/2016/11/17/cheetah-post-mortem/) and here (http://www.rvc.ac.uk/research/research-centres-and-facilities/structure-and-motion/news/wild-cats-uncovered), with even more pics here (https://www.flickr.com/photos/144824896@N07/sets/72157676695634065/).

References used here:

Carbone, C., Mace, G. M., Roberts, S. C., and Macdonald, D. W. 1999. Energetic constaints on the diet of terrestrial carnivores. Nature 402:286-288.

Carbone, C., Teacher, A., and Rowcliffe, J. M. 2007. The costs of carnivory. PLoS biology 5 (2):e22.

Meachen-Samuels, J. and Van Valkenburgh, B. 2009. Craniodental indicators of prey size preference in the Felidae. Biol J Linn Soc 96 (4):784-799.

———. 2009. Forelimb indicators of prey-size preference in the Felidae. Journal of morphology 270 (6):729-744.

Randau, M., Cuff, A. R., Hutchinson, J. R., Pierce, S. E., and Goswami, A. 2016. Regional differentiation of felid vertebral column evolution: a study of 3D shape trajectories. Organisms Diversity and Evolution Online First.

Randau, M., Goswami, A., Hutchinson, J. R., Cuff, A. R., and Pierce, S. E. 2016. Cryptic complexity in felid vertebral evolution: shape differentiation and allometry of the axial skeleton. Zoological Journal of the Linnean Society 178 (1):183-202.

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It has been almost three months since my last post here, and things have fallen quiet on our sister blog Anatomy to You, too. I thought it was time for an update, which is mostly a summary of stuff we’ve been doing on my team, but also featuring some interesting images if you stick around. The relative silence here has partly been due to me giving myself some nice holiday time w/family in L.A., then having surgery to fix my right shoulder, then recovering from that and some complications (still underway, but the fact that I am doing this post is itself evidence of recovery).

Stomach-Churning Rating: 4/10; semi-gruesome x-rays of me and hippo bits at the end, but just bones really.

X-ray of my right shoulder from frontal view, unlabelled

X-ray of my right shoulder from frontal view, unlabelled

Labelled x-ray

Labelled x-ray

So my priorities shifted to those things and to what work priorities most badly needed my limited energy and time. I’ve also felt that, especially since my health has had its two-year rough patch, this blog has been quieter and less interactive than it used to be, but that is the nature of things and maybe part of a broader trend in blogs, too. My creative juices in terms of social media just haven’t been at their ~2011-2014 levels but much is out of my control, and I am hopeful that time will reverse that trend. Enough about all this. I want to talk about science for the rest of this post.

My team, and collaborators as well, have published six recent studies that are very relevant to this blog’s theme- how about we run through them quickly? OK then.

  1. Panagiotopoulou, O., Pataky, T.C., Day, M., Hensman, M.C., Hensman, S., Hutchinson, J.R., Clemente, C.J. 2016. Foot pressure distributions during walking in African elephants (Loxodonta africana). Royal Society Open Science 3: 160203.

Our Australian collaborators got five African elephants together in Limpopo, South Africa and walked them over pressure-measuring mats, mimicking our 2012 study of Asian elephants. While sample sizes were too limited to say much statistically, in qualitatively descriptive terms we didn’t find striking differences between the two species’ foot pressure patterns. I particularly like how the centre of pressure of each foot (i.e. abstracting all regional pressures down to one mean point over time) followed essentially the same pattern in our African and Asian elephants, with a variable heelstrike concentration that then moved forward throughout the step, and finally moved toward the outer (3rd-5th; especially 3rd) toes as the foot pushed off the ground, as below.

African elephant foot COP traces vs. time in red; Asian elephant in orange. Left and right forefeet above; hindfeet below.

African elephant foot COP traces vs. time in red; Asian elephant in orange-yellow. Left and right forefeet above; hindfeet below.

Gradually, this work is moving the field toward better ability to use similar techniques to compare elephant foot mechanics among species, individuals, or over time– especially with the potential of using this method (popular in human clinical gait labs) to monitor foot (and broader musculoskeletal) health in elephants. I am hopeful that a difference can be made, and the basic science we’ve done to date will be a foundation for that.

  1. Panagiotopoulou, O., Rankin, J.W., Gatesy, S.M., Hutchinson, J.R. 2016. A preliminary case study of the effect of shoe-wearing on the biomechanics of a horse’s foot. PeerJ 4: e2164.

Finally, about six years after we collected some very challenging experimental data in our lab, we’ve published our first study on them. It’s a methodological study of one horse, not something one can hang any hats on statistically, but we threw the “kitchen sink” of biomechanics at that horse (harmlessly!) by combining standard in vivo forceplate analysis with “XROMM” (scientific rotoscopy with biplanar fluoroscopy or “x-ray video”) to conduct dynamic analysis of forefoot joint motions and forces (with and without horseshoes on the horse), and then to use these data as input values for finite element analysis (FEA) of estimated skeletal stresses and strains. This method sets the stage for some even more ambitious comparative studies that we’re finishing up now. And it is not in short supply of cool biomechanical, anatomical images so here ya go:


Above: The toe bones (phalanges) of our horse’s forefoot in dorsal (cranial/front) view, from our FEA results, with hot colours showing higher relative stresses- in this case, hinting (but not demonstrating statistically) that wearing horseshoes might increase stresses in some regions on the feet. But more convincingly, showing that we have a scientific workflow set up to do these kinds of biomechanical calculations from experiments to computer models and simulations, which was not trivial.

And a cool XROMM video of our horse’s foot motions:

  1. Bates, K.T., Mannion, P.D., Falkingham, P.L., Brusatte, S.L., Hutchinson, J.R., Otero, A., Sellers, W.I., Sullivan, C., Stevens, K.A., Allen, V. 2016. Temporal and phylogenetic evolution of the sauropod dinosaur body plan. Royal Society Open Science 3: 150636.

I had the good fortune of joining a big international team of sauropod experts to look at how the shapes and sizes of body segments in sauropods evolved and how those influenced the position of the body’s centre of mass, similar to what we did earlier with theropod dinosaurs. My role was minor but I enjoyed the study (despite a rough ride with some early reviews) and the final product is one cool paper in my opinion. Here’s an example:


The (embiggenable-by-clicking) plot shows that early dinosaurs shifted their centre of mass (COM) backwards (maybe related to becoming bipedal?) and then sauropods shifted the COM forwards again (i.e. toward their forelimbs and heads) throughout much of their evolution. This was related to quadrupedalism and giant size as well as to evolving a longer neck; which makes sense (and I’m glad the data broadly supported it). But it is also a reminder that not all sauropods moved in the same ways- the change of COM would have required changes in how they moved. There was also plenty of methodological nuance here to cover all the uncertainties but for that, see the 17 page paper and 86 pages of supplementary material…

  1. Randau, M., Goswami, A., Hutchinson, J.R., Cuff, A.R., Pierce, S.E. 2016. Cryptic complexity in felid vertebral evolution: shape differentiation and allometry of the axial skeleton. Zoological Journal of the Linnean Society 178:183-202.

Back in 2011, Stephanie Pierce, Jenny Clack and I tried some simple linear morphometrics (shape analysis) to see how pinniped (seal, walrus, etc) mammals changed their vertebral morphology with size and regionally across their backbones. Now in this new study, with “Team Cat” assembled, PhD student Marcela Randau collected her own big dataset for felid (cat) backbones and applied some even fancier techniques to see how cat spines change their shape and size. We found that overall the vertebrae tended to get relatively more robust in larger cats, helping to resist gravity and other forces, and that cats with different ecologies across the arboreal-to-terrestrial spectrum also changed their (lumbar) vertebral shape differently. Now Marcela’s work is diving even deeper into these issues; stay tuned…


Example measurements taken on felid vertebrae, from the neck (A-F) to the lumbar region (G-J), using a cheetah skeleton.

  1. Charles, J.P., Cappellari, O., Spence, A.J., Hutchinson, J.R., Wells, D.J. 2016. Musculoskeletal geometry, muscle architecture and functional specialisations of the mouse hindlimb. PLOS One 11(4): e0147669.

RVC PhD student James Charles measured the heck out of some normal mice, dissecting their hindlimb muscle anatomy, and using microCT scans produced some gorgeous images of that anatomy too. In the process, he also quantified how each muscle is differently specialized for the ability to produce large forces, rapid contractions or fine control. Those data were essential for the next study, where we got more computational!


  1. Charles, J.P., Cappellari, O., Spence, A.J., Wells, D.J., Hutchinson, J.R. 2016. Muscle moment arms and sensitivity analysis of a mouse hindlimb musculoskeletal model. Journal of Anatomy 229:514–535.

James wrangled together a lovely musculoskeletal model of our representative mouse subject’s hindlimb in the SIMM software that my team uses for these kinds of biomechanical analyses. As we normally do as a first step, we used the model to estimate things that are hard to measure directly, such as the leverages (moment arms) of each individual muscle and how those change with limb posture (which can produce variable gearing of muscles around joints). James has his PhD viva (defense) next week so good luck James!


The horse and mouse papers are exemplars of what my team now does routinely. For about 15 years now, I’ve been building my team toward doing these kinds of fusion of data from anatomy, experimental biomechanics, musculoskeletal and other models, and simulation (i.e. estimating unmeasurable parameters by telling a model to execute a behaviour with a given set of criteria to try to perform well). Big thanks go to collaborator Jeff Rankin for helping us move that along lately. Our ostrich study from earlier this year shows the best example we’ve done yet with this, but there’s plenty more to come.

I am incredibly excited that, now that my team has the tools and expertise built up to do what I’ve long wanted to do, we can finally deliver the goods on the aspirations I had back when I was a postdoc, and which we have put enormous effort into pushing forward since then. In addition to new analyses of horses and mice and other animals, we’ll be trying to push the envelope more with how well we can apply similar methods to extinct animals, which brings new challenges– and evolutionary questions that get me very, very fired up.

Here we are, then; time has brought some changes to my life and work and it will continue to as we pass this juncture. I suspect I’ll look back on 2016 and see it as transformative, but it hasn’t been an easy year either, to say the least. “Draining” is the word that leaps to mind right now—but also “Focused” applies, because I had to try to be that, and sometimes succeeded. I’ve certainly benefited a lot at work from having some talented staff, students and other collaborators cranking out cool papers with me.

I still have time to do other things, too. Once in a while, a cool critter manifests in The Freezers. Check out a hippo foot from a CT scan! It’s not my best scan ever (noisy data) but it shows the anatomy fairly well, and some odd pathologies such as tiny floating lumps of mineralized soft tissue here and there. Lots to puzzle over.

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Sorry about the title. It’s the best I could do. In case you missed it on our Anatomy to You blog, we unleashed a hefty database of CT (and some MRI) scans of our frozen crocodile cadavers last week, for free public usage. In total, it’s about 34 individuals from 5 species, in 53 databases constituting around 26,000 individual DICOM file format slices of data. This page has a table of what the data/specimens are. I am writing this post to share some more images and ensure that word gets out. We’re thrilled to be able to finally release this first dataset. We have plans to let loose a LOT more such data in the future, for various organisms that we study.

Stomach-Churning Rating: 2/10- be glad that these data don’t come with an olfactory component, especially the five rotten, maggot-ridden Morelet’s croc specimens, which are among the stinkiest things I’ve dealt with.

Crocodiles are no strangers to this blog, of course, as these past links testify. Indeed, most of the crocodile images I’ve blogged with come from specimens that are in this scan dataset. We even released a “celebrity crocodile, “WCROC” or FNC7 in our dataset, which is the 3.7m long Nile croc from “Inside Nature’s Giants”. It broke our CT scanner back in ~2009 but we got the data, except for the torso, and we also got some MRI scans from it, so we’re chuffed.

Above: The only spectacled caiman (Caiman crocodilus); and indeed the only alligatorid; in our dataset. To watch for: stomach contents/gastroliths, and all the damn osteoderms that I did/didn’t segment in this quickly processed file. This specimen had its limbs dissected for one of our studies, so only the right limbs are visible.

There are some more specimens to come- e.g. five baby Nile crocs‘ datasets (“GNC1-5”) are hiding somewhere in our drives and we just need to dig them up. You might also know that we published some scan data for crocodile vertebral columns (including fossils) in our recent paper with Julia Molnar et al. (and related biomechanical data discussed here), and we published all of our anatomical measurements for a huge set of crocodylian species in our papers by Vivian Allen et al. And then I had an enjoyable collaboration with Colleen Farmer and Emma Schachner on the lung anatomy of various crocodylian species, using these same specimens and related scan datasets.


Above: rotating Crocodylus moreletii (specimen FMC5 from our database) in a happy colour.

Sharing these kind of huge datasets isn’t so easy. Not only do few websites host them cheaply, and with reasonable file size limits, and limited headaches for what info you have to provide, and with some confidence that the websites/databases will still exist in 5-20 years, but also we were hesitant to release the dataset until we felt that it was nicely curated. Researchers can now visit my lab and study the skeletons (or in some cases, the still-frozen specimens) matched up with the scan data, and known body masses or other metadata. We’re not a museum with dedicated curatorial staff, so that was not trivial to reliably organize, and I still worry that somewhere in the dataset we mis-identified a specimen or something. But we’ve done our best, and I’m happy with that for now.

Above: rotating Osteolaemus tetraspis (specimen FDC2 from our database), which was obviously dissected a bit postmortem before we could scan it, but still shows some cool features like the extensive bony armour and the cute little doglike (to me, anyway) skull. I worked with these animals (live) a bit >10 years ago and came to love them. Compared to some other crocodiles we worked with, they had a pleasant demeanour. Like this guy:

Osteolaemus (resting) set up with motion capture markers for a yet-to-be-published study that we did in 2005 (ugh!). It wasn't harmed by this.

Osteolaemus (resting) set up with motion capture markers for a yet-to-be-published gait study that we did in 2005 (ugh!). It wasn’t harmed by this.

Anyway, as a person who likes to maintain quality in the science we do, I also was hesitant to “just” release the DICOM file data rather than beautiful segmented 3D skeletal (or other tissue) geometry that is ready for 3D printing or animation or other uses, or interactive online tools like Sketchfab. Other labs (e.g. Witmerlab) do these kind of things better than we do and they inspire us to raise our game in the future, but I am sure that we will be forgiven for releasing big datasets without gorgeous visuals and more practical, processed files — this time. 🙂  We agree with many other scientists that sharing data is part of modern, responsible science– and it can be fun, too! Oddly enough, in this case we hadn’t used the CT/MRI data much for our own studies; most of the scans were never fully digitized. We just scan everything we get and figured it was time to share these scans.

Enjoy. If you do something cool with the data that we’ve made accessible, please let us know so we can spread the joy!

And if you’re a researcher headed to ICVM next week, I hope to see you there!

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Who needs “Ice Road Truckers” when you have the “John’s Freezer” team on the road with fossils, amphibians, felids and 3D phenotype fun? No one, that’s who. We’re rocking the Cheltenham Science Festival for our first time (as a group), and pulling out all the stops by presenting two events! Here’s the skinny on them, with updates as the week proceeds.

Stomach-Churning Rating: 2/10 for now (just bones), but it could change once the cheetah dissection is under way… 8/10 bloody cheetah bits but only at the end (updated)

Right now, Lauren Sumner-Rooney (of “Anatomy To You” and other fame) is on-site with a rotating team of others from our lab, in the “Free Activity Tents” area of the Imperial Gardens/Square, inside a marquee where we’ll be showing off our NERC-funded tetrapod research all week. This “First Steps” event features not only our past and present work with Jenny Clack, Stephanie Pierce, Julia Molnar and others on Ichthyostega & its “fishapod” mates, but also our “scampering salamanders” research in Spain, Germany and England. I’ve blogged a lot about all that, and won’t repeat it here, but you can see a 3D-printed Ichthyostega skeleton, view the skeleton in a virtual reality 3D environment, see related specimens and engage in kid-friendly activities, and talk to our team about this and other related research.

Ichthyostega 3D printed backbone is born!

Ichthyostega 3D printed backbone is born!

The central themes of that event are how bone structure relates to function and how we can use such information, along with experimental measurements and computer models of real salamanders, to reconstruct how extinct animals might have behaved as well as how swimming animals became walking ones. How did fins transform into limbs and what did that mean for how vertebrates made the evolutionary transition onto land? If you know my team’s work, that encapsulates our general approach to many other problems in evolutionary biomechanics (e.g. how did avian bipedalism evolve?). Added benefits are that you too can explore this theme in a hands-on way, and you can talk with us about it in person. That continues all week (i.e. until Saturday evening); I’ll be around from Thursday afternoon onwards, too. Kids of all ages are welcome!

Ichthyostega 3D print taking shape!

Ichthyostega 3D print taking shape!

Then, on Saturday for our second free event we join forces with Ben Garrod (master of primate evolution, the secrets of bones, and “Attenborough and the Giant Dinosaur”) and RVC’s forensic pathologist Alexander Stoll as well as Sophie Regnault (“sesamoid street” PhD student w/me). As the “Large Animal Dissection” title hints, it’s not the right kind of gig to bring small kids to. There will be blood and stuff— we’ll be dissecting a cheetah together from 10am-4pm. This will involve walking through all the major organ systems, giving evolutionary anecdotes, and plenty more, with an aim to understand how the magnificent adaptations of cheetahs evolved—but also to investigate what problem(s) this animal faced that led to its sad demise. By the day’s end, there will just be a skeleton left. Get a front row seat early for this event, which serendipitously ties into “Team Cat”’s Leverhulme Trust-funded research project (we wanted a big animal and it just happened to be a cheetah; I had hoped for a giant croc or a shark or something but can’t complain!).

Ichthyostega 3D print is ready!

Ichthyostega 3D print is ready!

If you miss these events, please do cry bitter tears of regret. But don’t despair, there will be another “big cat dissection” in the London area in ~November (watch here for details), and plenty more fossil tetrapod stuff to come, plus a LOT more dinosaurs on the horizon!

Guess the bones! (photo by Zoe Self)

Guess the bones! (photo by Zoe Self)

And please come back to this blog post for more pics and stories as the week carries on… For hashtag afficionados, you can follow the fun on Twitter etc. at #firststepsCSF16. What a world we live in!

Update 1: While you’re here, check out our Youtube playlists of tetrapod-related videos:

Lobe-finned fishes

Ichthyostega‘s awesome anatomy

Tetrapod evolution: Tiktaalik to salamanders!

Update 2: Photos of our main stand (about tetrapod evolution)


Our poster/banner display looks nice.


Our tent brings in some punters.


Our bones excite people young and old, sighted and blind.


Fun with stickers and lab t-shirts.


Update 3: Cheetah meat & greet
Ben, Alex, Sophie and I tackled the cheetah dissection today and it went GREAT! Much better than I’d optimistically expected. Rain didn’t scare the crowds off and neither did the gore, which there was some of (gelatinous spinal cords, lumpy tumors and at least one flying tiny bit of cheetah flesh that landed on a good-natured audience member!). Photos will tell the tale:




Sophie and Alex help us get set up in our tent.


Our initial rough schedule- although we ended up improvising more after lunch.


Dissectors assemble!


The beast revealed. It was skinned by the museum that loaned it to us.


Alex showing his talent: removing the viscera in one piece from end to end, starting with the tongue.


Impressive finding of a surgical fixture (plate and wires) on the tibia, which had been used to hold the shattered bone back together long enough for it to heal. Added to the kidney disease and liver-spleen-lung cancer, this cheetah was in the sorriest shape of any cadaver I’ve seen yet.


Cheetah coming to pieces: (from bottom) lumbar/pelvic region, hindlimb, thorax, forelimb and other bits.


Dr Adam Rutherford, an eye expert, did a nice dissection of the cheetah’s eye, here showing the tapetum lucidum (reflective membrane), which shows up as light blue colour. Its small size befits the not-very-nocturnal habits of cheetahs.


The lens of the cheetah’s eye. Now cloudy because of dehydration and crystalization, but still fascinating to see.

Want to see more images and the enthusiastic responses from the audience (we got some great feedback)? Check out Twitter’s #cheltscifest feed, or more simply my Storify condensation of the cheetah-related tweets here.

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I have an impression that there is a large disparity between how the public views museums and how scientists who use museums view them. Presumably there are survey data on public attitudes, but surely the common impression is that museums mainly exist to exhibit cool stuff and educate/entertain the public. Yet, furthermore, I bet that many members of the public don’t really understand the nature of museum collections (how and why they are curated and studied) or what those collections even look like. As a researcher who tends to do heavily specimen-oriented and often museum-based research, I thought I’d take the opportunity to describe my experience at one museum collection recently. This visit was fairly representative of what it’s like, as a scientist, to visit a museum with the purpose of using its collection for research, rather than mingling with the public to oggle the exhibits — although I did a little of that at the end of the day…

Stomach-Churning Rating: 4/10; mostly bones except a jar of preserved critters, but also some funky bone pathologies! Darwin hurls once, totally blowing chunks, but only in text.

Early camel is sitting down on the job at the NHMLA.

Early camel is sitting down on the job at the NHMLA.

About two weeks ago, I had the pleasure to spend a fast-paced day in the Ornithology collection of the Natural History Museum of Los Angeles County (NHMLA or LACM). I arranged the visit (you have to be a credible researcher to get access; luckily I seemed to be that!) via email, took an Uber car to the museum, and was quickly cut loose in the collection. I was hosted by the Collections Manager Kimball Garrett, who is an avid birder (adept at citizen science, too!) and a longtime LA native.

Amongst museum curators and collections managers (there can be a distinction between the two but here I’ll refer to them all as “curators”), there is a wide array of attitudes toward and practices with museum collections, regarding how the curators balance their varied duties of not only making the museum collection accessible to researchers (via behind-scenes studies) and the public (via exhibits and behind-scenes tours etc.), but also curation (maintaining a record of what they have in their collection, adding to it, and keeping the specimen in good condition), research, admin, teaching and other duties.

Most curators I’ve known, like Kimball, are passionate about all of these things, and very generous with their time to help scientists make the most of the collection during their visit, offering hospitality and cutting through the bureaucracy as much as possible to ensure that the science gets done. There are those few curators that aren’t great hosts because they’ve had a bad day or a bad attitude (e.g. obsession with paperwork and finding obstacles to accessing specimens for research; or just not responding to communication), but they are few and far between in my experience.

Regardless, the curator is the critical human being that keeps the wheels of specimen-based museum research rolling, and I am appreciative of how deeply dedicated and efficient most curators are. Indeed, I enjoy meeting and chatting with them because they tend not only to be fun people but also incredibly knowledgeable about their collection, museum, and area of expertise. Sadly, this trip was so time-constrained that I didn’t get much time at all for socializing. I had about five hours to get work done so I plunged on in!

Images, as always, can be clicked to emu-biggen them. Thanks to the NHMLA for access!

My initial look down the halls of the osteology storage. Rolling cabinets (on the right) are a typical sight.

My initial look down the halls of the osteology storage. Rolling cabinets (on the right) are a typical sight.

Freezers ahoy!

Freezers ahoy! With Batman watching over them.

A jar of bats? Why not? Batman approves.

A jar of bats? Why not? Batman approves.

The curator cleared a space on a table for me to set bones on. Then the anatomizing and photographing began!

The curator cleared a space on a table for me to set bones on. Then the anatomizing and photographing began!

On entering a museum collection, one quickly gets a sense of its “personality” and the culture of the museum itself, which emerges from the curator, the collection’s history, and the museum’s priorities. There are fun human touches like the ones in the photos below, interspersed between the stinking carcasses awaiting skeletonization, the crumbling bone specimens on tables that need repair or new ID tags, or the rows upon rows of coffee cups ready to fuel the staff’s labours.

Yet another reason why Darwin kicks ass.

Yet another reason why Darwin kicks ass. And fine curator-humour!

Ironic bird pic posted on the wall.

Ironic bird pic posted on the wall.

Below a typical wall-hanging of a bovid skull, an atypical display of a clutch of marshmallow peeps. Contest to see whether the mammalian or pseudo-avian specimens last longest?

Below a typical wall-hanging of a bovid skull, an atypical display of a clutch of marshmallow peeps. Contest to see whether the mammalian or pseudo-avian specimens last longest?

The NHMLA’s collection is a world-class one, which I why I chose it as the example for this post. When I entered the collection, I got that staggering sense of awe that I love feeling, to look down the halls of cabinets full of skeletonized specimens of birds and be overwhelmed by the vast scientific resource it represents, and the effort it has taken to create and maintain it. Imagine entering a library in which every book had the librarian’s hand in writing and printing it, and that those books’ contents were largely mysteries to humanity, only some of which you could investigate during your visit. Museum collections exist to fuel generations of scientific inquiry in this way. Their possibilities are endless. And that is why I love visiting them, because every trip is an adventure into the unknown– you do not know what you will find. Like these random encounters I had in the collection’s shelves:

Sectioned moa thigh bones, showing thick walls and spars of trabecular bone criss-crossing the marrow cavities.

Sectioned moa thigh bones, showing thick walls and spars of trabecular bone criss-crossing the marrow cavities.

My gut reaction was that this is a moa wishbone (furcula)- not often seen! It is definitely not a shoulder girdle (scapulocoracoid), which would be larger and more robust, and have a proper shoulder joint. It could, though, be a small odd rib, I suppose.

My gut reaction was that this is a moa wishbone (furcula)- not often seen! It is definitely not a shoulder girdle (scapulocoracoid), which would be larger and more robust, and have a proper shoulder joint. It could, though, be a small odd rib, I suppose. EDIT: Think again, John! See 1st comment below, and follow-ups. I seem to be totally wrong and the ID of scapulocoracoid is right.

A cigar box makes an excellent improvised container for moa toe bones- why not?

A cigar box makes an excellent improvised container for moa toe bones- why not?

Moa feet: all the moa to love!

Moa feet: all the moa to love!

May the skull of the magpie goose (Anseranas semipalmata) haunt your nightmares.

May the skull of the magpie goose (Anseranas semipalmata) haunt your nightmares.

Double-owie: headed shank (tibiotarsus) bone of a magpie goose (Anseranas semipalmata). No mystery why this guy died: vet staff at the zoo tried to fix a major bone fracture, and it had time to heal (frothy bone formation) but presumably succumbed to these injuries/infection.

Healed shank (tibiotarsus) bone of the same magpie goose as above. It had its own nightmares! No mystery why this guy died: vet staff at the zoo tried to fix a major bone fracture (bracing it with tubes and metal spars), and it had time to heal (see the frothy bone formation) but presumably succumbed to these injuries/infection.

Kiwi (Apteryx australis mantelli) hand, showing feather attachments and remnant of finger(s).

Kiwi (Apteryx australis mantelli) hand, showing feather attachments and remnant of finger(s).

Now that I’m in the collection shelves area, it brings me to this trip and my purpose for it! I wanted to look at some “basal birds” for our ongoing patella (kneecap) evolution project, to check which species (or individuals, such as juveniles/adults) have patellae. Every museum visit as a scientist is fundamentally about testing whether what you think you know about nature is correct or not. We’d published on how the patella evolved in birds, but mysteries remain about which species definitely had a patella or how it develops. Museum collections often have the depth and breath of individual variation and taxonomic coverage to be able to address such mysteries, and every museum collection has different strengths that can test those ideas in different, often surprising, ways. So I ventured off to see what the NHMLA would teach me.

Shelves full of boxes, begging to be opened- but unlike Pandora's box, they release joyous science!

Shelves full of boxes, begging to be opened- but unlike Pandora’s box, they release joyous science!

Boxes of kiwis, oh frabjous day! A nice sample size like this for a "rare" (to Northern hemispherites) bird is a pleasure to see.

Boxes of kiwis, oh frabjous day! A nice sample size like this for a “rare” (to Northern hemispherites) bird is a pleasure to see.

Well, in my blitz through this museum collection I didn’t see a single damn patella!

As that kneecap bone is infamously seldom preserved in nice clean museum specimens, this did not surprise me. So I took serendipity by the horns to check some of my ideas about how the limb joints in birds in general develop and evolve. One thing I’ve been educating myself about with my freezer specimens and with museum visits (plus the scientific literature) is how the ends (epiphyses) of the limb bones form in different species of land vertebrates (tetrapods). There are complex patterns linked with evolution, biomechanics and development that still need to be understood.

Left side view of the pelvis of a very mature, HUGE Casuarius casuarius (cassowary). The space between the ilium (upper flat bone) and ischium (elongate bone on middle right side) has begun to be closed by a mineralization of the membrane that spanned those bones in life. A side effect of maturity, most likely. But cool- I've never seen this in a ratite bird before, that I can recall.

Left side view of the pelvis of a very mature, HUGE Casuarius casuarius (cassowary). The space between the ilium (upper flat bone) and ischium (elongate bone on middle right side) has begun to be closed by a mineralization of the membrane that spanned those bones in life. A side effect of maturity, most likely. But cool- I’ve never seen this in a ratite bird before, that I can recall.

Hatchling ostrich thigh bones (femora), showing the un-ossified ends that in life would be occupied by thick cartilage.

Hatchling ostrich thigh bones (femora), showing the pitted, un-ossified ends that in life would be occupied by thick cartilage.

A more adult ostrich's femora, with more ossified ends and thinner cartilages.

A more adult ostrich’s femora, with more ossified ends and thinner cartilages.

Rhea pennata (Darwin's rhea) femora (thigh bones), left (top) one with major pathology on the knee end; overgrown bone. Owie!

Rhea pennata (Darwin’s rhea) femora; right (top) one with a major pathology on the knee end; overgrown bone (osteoarthritis?). Owie!

Also very-unfused knee joints of a Darwin's rhea. Cool Y-shape!

Also very-unfused knee joints of a Darwin’s rhea hatchling. Cool Y-shape!

In birds, most of the bones don’t have anything that truly could be called an epiphysis– the bone ends are capped with thick cartilage that only gradually becomes bone as the birds get older, and even old-ish birds can still have a lot of cartilage (see photos above)– no “secondary centre” (true epiphysis) of bone mineralization ever forms inside that cartilage. However, there are two curious apparent exceptions to this absence of true epiphyses in avian limbs:

(1) in the knee joint, something like an epiphysis forms on the upper end of the tibia (shank bone) and fuses during growth (shown below). Sometimes that unfused epiphysis is confused with a patella, as our recent paper discussed; in any case, where that “epiphysis” came from in avian evolution is unclear. But also:

(2) in the ankle joint, several bones on both sides (shank and foot) of the joint fuse to the long-bones of the limbs, acting like epiphyses. It is well documented by the fossil record of non-avian and avian dinosaurs that these were the tarsals: at least five different bones (astragalus, calcaneum and distal tarsals) were individual bones for millions of years in various dinosaurs, then these all fused to form the “epiphyses” of the shank and foot, eventually completing this gradual fusion within the bird lineage. Modern birds obliterate the boundaries between these five or more bones as they grow.

These are worthwhile questions to pursue because they show us (1) how odd, little-explored features of the avian skeleton came to be; and (2) potentially more generally why limb bones develop the many ways they do in vertebrates, and how they might develop incorrectly — or heal if damaged.

Images below from the NHMLA collections show how this is the case. Fortunately(?) for me, they supported how I thought the “epiphyses” of avian limbs develop/evolved; there were no big surprises. But I still learned neat details about how this happens in individual species or lineages, especially for the knee joint.

Juvenile kiwi's shank (tibiotarsus) bones viewed from the top (proximal) ends, showing the bubbly nubbins of bone (very bottom of each bone image) that are the "cranial tibial epiphyses" often mistaken for patellae.

Juvenile kiwi’s shank (tibiotarsus) bones viewed from the top (proximal) ends, showing the bubbly nubbins of bone (very bottom of each bone image; lighter region) that are the “cranial tibial epiphyses” often mistaken for patellae.

Subadult kiwi's tibiotarsi in same view as above, showing the epiphyses fusing onto the tibiae.

Subadult kiwi’s tibiotarsi in same view as above, showing the smooth triangular epiphyses fusing onto the tibiae.

Adult kiwi's tibiotarsi (sorry, blurry photo) in which all fusion is complete.

Adult kiwi’s tibiotarsi (sorry, blurry photo) in which all fusion is complete.

Looking down at the top/ankle end of the tarsometatarsal (sole) bones in a hatchling ostrich: the three bones are separate and hollow, where "cartilage cones" would have filled them in.

Looking down at the top/ankle end of the tarsometatarsal (sole) bones in a hatchling ostrich: the three bones are separate and hollow, where “cartilage cones” would have filled them in. The left and right bones have different amounts of ossification; not unusual in such a young bird.

Ossified tendons (little spurs of long, thin bone) on the soles of the feet (tarsometatarsal bones) of a brush-turkey (Alectura lathami)- seldom described in this unusual galliform bird or its close relatives, and thus nice to see. These would be parts of the toe-flexor tendons.

Ossified tendons (little spurs of long, thin bone) on the soles of the feet (tarsometatarsal bones) of a brush-turkey (Alectura lathami)- seldom described in this unusual galliform bird or its close relatives, and thus nice to see. These would be parts of the toe-flexor tendons. Another nice thing about these two tarsometatarsus specimens is that their fusion is basically complete- each is one single bone unit, as in normal adult birds, rather than five or more.

My visit to the NHMLA bird bone collection was a lot of fun, because I got to do what I love: opening box after box of bone specimens, with bated breath wondering what would be inside. In this case, familiarity was inside, but my knowledge of avian bone development and evolution still improved. I got to look at a lot of ostriches, rheas, cassowaries and kiwis, more than I’d seen in one museum before, and that broadened my sample of young, juvenile and adult animals that I’d seen for these species. Their knees and ankles all grew in grossly similar ways, supporting this assumption in my prior work and building my confidence in published ideas. It’s always good to check such things. Each box opened takes some careful observation and cross-checking against all the facts and ideas swirling around in your head. You take notes, scale photos, measurements, do comparisons between specimens, and just explore; letting your curiosity run unleashed as you assemble knowledge, Tetris-like, in your mind.

And I had a lot of fun because a museum collection visit is like swimming in anatomy. You’re surrounded by more specimens than you could ever fully comprehend. Sometimes you run across an odd specimen whose anatomy tells you something about its life, like pathologies such as the terrible fractured magpie goose leg shown above. Or you see some curatorial touch that makes you chuckle at an apparent inside joke or mutter respect for their careful organization in tending their charges. That feeling of pulling open a museum drawer or box lid and peering inside is like few others in science — there might be disappointment inside (e.g. “Crap, that specimen sucks!”), boredom (“Oh. Another one of these!?”) or the joy of discovery (“Holy *@$£, I’ve never seen that before!”). My first scientific publication (in 1998) came from rummaging through the UCMP museum collections as a grad student and spotting an obscure pelvic bone that turned out to be highly diagnostic for the equally obscure clade of bird-like dinosaurs called alvarezsaurids. I happened to open that drawer with the alvarezsaurid specimen at the right time, shortly after the first ever specimen of that dinosaur had been described in the literature (~1994). Before then, no one could have identified what that bone was!

There is time for hours of quiet introspection during museum collection studies, immersed in this wealth of anatomical resources and isolated in a silent, climate-controlled tomb-like hall. It is relaxing and overwhelming at the same time. Especially in my case with just five hours to survey numerous species, you have to budget your time and think efficiently. It’s a unique challenge to explore a museum collection as a researcher. If you don’t learn something — especially in a good museum collection — you’re doing it wrong. In this time of tight finances and trends to close museums or stow away precious collections, it is important to vocally celebrate what a vast treasure museum collections are, and how the people that maintain them are vital stewards of those treasures.

I set the cat amongst the pigeons by also visiting the Page Museum at the La Brea Tar Pits in LA, to study fossil cats-- like this American lion (Panthera atrox) code-named "Fluffy", that we CT scanned during my LA visit-- more about that later!

I set the cat amongst the pigeons by also visiting the Page Museum at the La Brea Tar Pits in LA, to study fossil cats– like this American lion (Panthera atrox), code-named “Fluffy”, that we CT scanned during my LA visit– more about that later!

EDIT: I hurried this post off during my free time today, and still feel I didn’t fully capture the deep, complex feelings I have regarding museum collections and the delight I get from studying them. Other freezerinos, please add your thoughts in the Comments below!

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