Tetrapod Zoology

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Welcome to the third and final part of my write-up of the CEE functional anatomy meeting: for part I go here, and for part II here. Here’s where we wrap things up, but let’s get through the last of the talks: those on tuataras, and yet more on primates…

Marc Jones discussed his work on skull shape and feeding behaviour in rhynchocephalians (the extant tuataras and their Mesozoic relatives: adjacent image, from Marc’s UCL page, shows Marc with a live tuatara). It is generally agreed among herpetologists that Sphenodon is not, as used to be thought, an archaic relict; a sort of poor relation compared to the kinetic-skulled squamates. The complete lower temporal bar of Sphenodon is clearly secondary, as basal rhynchocephalians lacked ossification in this region (Müller (2003) showed that the lower temporal bar has been lost and regained multiple times in diapsid reptiles). Marc has now shown that Sphenodon occupies a distinct region of morphospace when compared to other rhynchocephalians, and most certainly does not represent its group as a whole. Extensive overlaps between some of the cranial bones dampen stresses during biting (I previously mentioned this aspect of Marc’s research in one of the SVPCA 2007 write-ups: go here). Together with Neil Curtis, Marc has been working on an accurate computational model of the Sphenodon head and neck. It looked excellent, with an accurate propalinal jaw action (propaliny = anteroposterior sliding of the lower jaw).

Bringing us back to primates again, Will Parr has been applying laser scanning to hominoid tarsal bones in order to understand how the bones function in walking and running, and he’s also been comparing the tarsals (particularly the calcaneum, astragalus, navicular and cuboid) of different taxa. As if to verify the contention noted earlier that too little work has been done on the anatomy of extant animals, Will complained that we don’t even know how the ankle bones properly function in modern humans. One of the great problems of working with tarsal bones is that their complex shapes and often globular, curved surfaces are difficult to represent accurately with diagrams, and early schematic attempts to depict tarsals as 3D blocks were just too schematic to do anything more than show the relative positions of the bones. New laser scanning technology is providing the solution to these problems. The astragalar facet of Lucy the australopithecine is closer in shape to that of chimps than that of modern humans, which at first sight seems to contradict current thinking on australopithecine gait and walking abilities.

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Evie Vereecke spoke about ‘Bringing primate morphology into the 21st century’ and began by providing a summarised historical review of work on primate anatomy. As early as the 1st century, the physician Galen of Pergamum (AD 129-c. 200) was recommending that people study non-human primates in order to better understand human anatomy. Influential studies by Victorian workers like Richard Owen kept the study of primate anatomy close to the forefront in the world of anatomical research, and today a fascination with primates continues. Several case studies highlighted how new approaches link form with function. Evie discussed the incredible hindlimb musculature that has been shown to function as a power amplifier in galagos (cf. Babcock 1992, Aerts 1998). Comparison across hominoids shows that humans have weak wrist flexors compared to siamangs and chimps. Elbow extensors are proportionally similar in size across all hominoids (including humans), but while elbow flexors are usually as large as extensors in hominoids, flexors are much smaller than extensors in humans. Also interesting is that the Achilles tendon is particularly large in gibbons (as big as that of humans), whereas in other non-hominin hominoids is it smaller [adjacent images show bipedal gaits in Lar gibbon Hylobates lar: image from Aaron Filler's site, but originally from Vereecke et al. 2006a]. Exactly why these differences occur is of course the big question, though there are possible answers: humans don’t climb as much as gibbons or chimps, for example. For more on these areas, see Vereecke et al. (2005, 2006a, b) and Payne et al. (2006a, b).

As you’d expect in a workshop on functional anatomy, it wasn’t all tetrapods of course. Mark Purnell discussed work on tooth microwear in sticklebacks and cichlids, with a brief look at new work on microwear in hadrosaurs at the end. And two talks on insects – one by Walter Federle on the adhesive mechanisms of weaver ant feet and the other by Robin Wootton on how insect wings function, deform and fold – had me spellbound and were among the most memorable of the entire meeting. There were also several posters at the meeting, including those on bite strength in theropods and functional anatomy in cheetahs, but like an idiot I failed to take notes on them.

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All (or nearly all) of the speakers and organisers. Let’s see if I can identify them all: from l to r, Adrian Lister, Evie Vereecke, Marc Jones, Will Parr, Jenny Clack, Renate Weller, Robin Crompton, Victoria Herridge (kneeling), Charlotte Miller (kneeling), John Hutchinson, Mark Purnell, Robin Wooton, Walter Federle, R. McNeill Alexander and Paul O’Higgins.


I know that I have a horrible habit of coming back from meetings waxing lyrical about how wonderful they were, but this meeting truly was awesome: it seems that much of biology is devoted to getting as far away as possible from the organisms themselves, yet how animals work is easily up there as among the most awe-inspiring, wonderful and fascinating part of it all. And as John Hutchinson said at the opening of the meeting, anatomy also fascinates us because it is beautiful and, indeed, beauty is anatomy. Functional anatomy also has an impact on our daily lives given that we often need to know how our own bodies (and those of our domestic animals) function. What was thought to be a dead and done field is vividly alive, bustling with new work that incorporates new and exciting technology, and more and more people are jumping on the bandwagon. Indeed the meeting was a soar-away success with a huge turnout: about 100 people attended!

I’m not ashamed to say that I want to be in on the functional anatomy movement too, and – while I intend to continue working on the interpretation of incomplete fossils, on historical taxonomy and all that stuff – it does look like I might be heading that way. In fact I have three papers coming out later this year (or next year) on functional anatomy (all of which are going to be discussed here at Tet Zoo: the first appears next month).

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During the socialising afterwards I developed the hypothesis that one can mimic all sorts of different animals during the course of a conversation at a functional anatomy meeting, and not receive any strange looks. I adopted a BHBK gait and also practised some knuckle-walking, and indeed no-one so much as looked at me (as I’ve said before, knuckle-walking is painful for us, as is obvious from the adjacent photo). Mind you, I do normally walk around this way anyway. It was cool to meet and catch up with so many friends old and new. Some of you might know that Colin McHenry and I collaborated on the ecology of secondarily marine tetrapods during the 1990s: we never really finished that work, and even today it’s possible that we might get back to it at some stage. And I owe massive thanks to John Conway for all the help he provided: thanks again John.

That’s all for now – as you read this I am frantically preparing for Dinosaurs – A Historical Perspective. And that’s probably what I’ll be talking about next… (although I did go reptile-spotting over the weekend).

Refs – -

Aerts, P. 1998. Vertical jumping in Galago senegalensis: the quest for an obligate mechanical power amplifier. Philosophical Transactions of the Royal Society of London B 353, 1607-1620

Babcock, S. K. 1992. Muscle architecture in mammalian limbs: design concepts based on hindlimb muscle morphology in galagos. American Zoologist 32, 138A.

Müller, J. 2003. Early loss and multiple return of the lower temporal arcade in diapsid reptiles. Naturwissenschaften 90, 473-476.

Payne, R. C., Crompton, R. H., Isler, K., Savage, R., Vereecke, E. E., Günther, M. M., Thorpe, S. K. S. & D’Août, K. 2006a. Morphological analysis of the hindlimb in apes and humans. I. Muscle architecture. Journal of Anatomy 208, 709-724.

- ., Crompton, R. H., Isler, K., Savage, R., Vereecke, E. E., Günther, M. M., Thorpe, S. K. S. & D’Août, K. 2006b. Morphological analysis of the hindlimb in apes and humans. Part II: Moment arms. Journal of Anatomy 208, 725-742.

Vereecke, E. E., D’Août, K., Payne, R. & Aerts, P. 2005. Functional analysis of the foot and ankle myology of gibbons and bonobos. Journal of Anatomy 206, 453-476.

- ., D’Août, K. & Aerts, P. 2006a. Locomotor versatility in the white-handed gibbon (Hylobates lar): a spatiotemporal analysis of the bipedal, tripedal, and quadrupedal gaits. Journal of Human Evolution 50, 552-567.

- ., D’Août, K. & Aerts, P. 2006b. The dynamics of hylobatid bipedalism: evidence for an energy-saving mechanism? Journal of Experimental Biology 209, 2829-2838.

Comments

  1. #1 John H
    April 30, 2008

    Thanks for the fabulous (and very kind) writeups, Darren! You got all the names in the pic correct.

    The poster presenters were Manabu Sakamoto on theropod jaws and Penelope Hudson on cheetah anatomy (now convincing cheetahs to chase lures in the name of science).

    There were ~10 other posters on subjects like bird hip morphometrics and function, Dunkleosteus fish jaw mechanics, thalattosuchian skull shape, comparative gibbon muscle anatomy, macaque mandible mechanics, and more I am forgetting!

    I must say, the insect talks were some of the top highlights (blasphemy!). Wootton’s use of origami-style insect wings to show how they fold up and fly was a lovely contrast to the complex modelling approaches that dominated a lot of the talks.

  2. #2 Sven DiMilo
    April 30, 2008

    it seems that much of biology is devoted to getting as far away as possible from the organisms themselves, yet how animals work is easily up there as among the most awe-inspiring, wonderful and fascinating part of it all.

    You said it, man. Gel-jockies seem to look at functional organismal biology as a quaint relic of the 19th Century but they just don’t get it!!! (I do ecological physiology; I made a career of biology because I think animals are extremely cool and I make no apologies for that. I also have a tough time getting research funding.)

  3. #3 Darren Naish
    April 30, 2008

    I also have a tough time getting research funding

    I gave up long ago on the prospect of ever getting research funding after a long and soul-crushing series of rejections. Everything I’ve ever done (in terms of published research) has been unfunded. My feeling today is that grant applications are not worth the incredible amount of time they take, so I both laugh and cry when (mostly American) colleagues say to me “why don’t you just get a grant?”. And for those who care, Tet Zoo does not exactly generate enough income to fund anything other than bus-fare…

    I think it was the singer Kate Nash (no relation) who wrote “You said I must eat so many lemons…”

  4. #4 David Marjanovi?
    April 30, 2008

    Mind you, I do normally walk around this way anyway.

    O RLY?

    If you don’t like applying for grants, come to France. At the CNRS you don’t even really need to know French because you don’t need to teach, and getting tenure is easy.

  5. #5 Jerzy
    April 30, 2008

    Thanks for fascinating stuff. So, why humans wave their arms walking?

  6. #6 Zach Miller
    April 30, 2008

    I often knuckle-walk. It’s a shame our legs are so damn long, or else it might be more comfortabe. Also, our knuckles are bare, so hard surfaces hurt.

    I usually adopt a unique kaiju-esque posture while knuckle-walking: I drop onto my knees and bend my elbows slightly, which seems to cushion my poor fingers a bit.

  7. #7 David Marjanovi?
    April 30, 2008

    So, why [do] humans wave their arms [when] walking?

    Mostly for balance.

  8. #8 Tengu
    April 30, 2008

    I read (cant remember where, Im sad to say)Functional anatomy is out of fashion because it involves messy dead things.

  9. #9 John Scanlon, FCD
    April 30, 2008

    Not just messy dead things, but connected at least in the public mind with messy dead people. And phyical anthropology is especially suspect because it’s equated with nasty racism (unless you use the magic word ‘forensic’).
    David, is CNRS for Europeans only? :)

  10. #10 Darren Naish
    May 1, 2008

    Quadrupedality in humans: I was planning to devote a whole article to this some time (incorporating stuff on the quadrupedal people now known from Turkey and elsewhere) but don’t know when I’ll get round to it. I’m particularly interested in this subject because I’m a habitual quadruped: I knuckle-walk when going up the stairs (although not in public). It seems that this behaviour is more common than generally realised. I also suffer from knee problems, meaning that it’s not always easy to maintain a locked knee during the support phase of walking, so I sometimes have to walk with a compliant, Patty-type gait.

    While play-fighting with Will yesterday I accidentally punched the edge of a radiator, so today things in my left hand are painful. And is any of this linked to the chronic wrist and finger pains I’ve been suffering from lately? (I have 100% stopped playing Wii games for this reason). Huh, and to think that some people think we’re different from other primates.

  11. #11 David Marjanovi?
    May 1, 2008

    David, is CNRS for Europeans only? :)

    Not at all. My thesis supervisor is Canadian.

    I’m told Anne Warren is the last palaeontologist in Australia, all other jobs have been cut…?

  12. #12 Zach Miller
    May 1, 2008

    Darren, I knuckle-walk up stairs too, whether in public or not. Sometimes I get wierd looks, but I’ve told people to try it–it’s more comfortable than going up on two feet! Good to find another knuckle-walker among all you bipedal freaks! ;-)

  13. #13 Brian
    May 2, 2008

    I must admit I’ve always had a penchant for going quadrupedal when going up steep stairs as well.

  14. #14 johannes
    May 2, 2008

    > I’m told Anne Warren is the last palaeontologist in Australia, all
    > other jobs have been cut…?

    What happened to Tim Flannery and Steve Wroe?

  15. #15 David Marjanovi?
    May 2, 2008

    What happened to Tim Flannery and Steve Wroe?

    I don’t know, but M. S. Y. Lee does neontology now.

  16. #16 Graham King
    May 3, 2008

    Well here I am online when I should ‘really’ be packing for The Best Dinosaur Conference Ever. Wanted to catch up here tho. Darren your info from functional anatomy is great, appreciate your posting all that detail. would like to see origami insect wing-making taught in primary schools, to enhance appreciation of ‘bugs’. great stuff. i hope at the conference to pick up tips on how best to pose as a stegosaur (parade costume I have in mind…)

    I am pleased to hear marsupial predators beat placentals in the bite stakes, is that weird of me?

    It seems now there is a throng of facultative knuckle-walkers at large (Should we start a club? campaign for more knuckle-friendly design in public buildings?). I too go tetrapod going up stairs, usually using my palms though. Partly for stability at speed but partly cos I like how it feels and sounds (drumming on the stairs). I’d be interested to see how this trait is distributed across populations. And any social correlates.

    really must pack now. see you folks!